# Project: zyna-db
# Generated: Tue Jan 20 10:15:05 AM EST 2026

================================================================================

================================================================================
FILE: ./build.zig
================================================================================

const std = @import("std");

pub fn build(b: *std.Build) void {
    const target = b.standardTargetOptions(.{});
    const optimize = b.standardOptimizeOption(.{});

    // === Main Executable ===
    const exe_module = b.createModule(.{
        .root_source_file = b.path("src/main.zig"),
        .target = target,
        .optimize = optimize,
    });
    
    const exe = b.addExecutable(.{
        .name = "zynamodb",
        .root_module = exe_module,
    });

    // Link RocksDB (C library)
    exe.linkLibC();
    exe.linkSystemLibrary("rocksdb");

    // Compression libraries that RocksDB depends on
    exe.linkSystemLibrary("snappy");
    exe.linkSystemLibrary("lz4");
    exe.linkSystemLibrary("zstd");
    exe.linkSystemLibrary("z");
    exe.linkSystemLibrary("bz2");
    exe.linkSystemLibrary("stdc++");

    // Add include path for RocksDB headers
    exe.addIncludePath(.{ .cwd_relative = "/usr/local/include" });
    exe.addLibraryPath(.{ .cwd_relative = "/usr/local/lib" });

    b.installArtifact(exe);

    // === Run Command ===
    const run_cmd = b.addRunArtifact(exe);
    run_cmd.step.dependOn(b.getInstallStep());

    if (b.args) |args| {
        run_cmd.addArgs(args);
    }

    const run_step = b.step("run", "Run the DynamoDB-compatible server");
    run_step.dependOn(&run_cmd.step);

    // === Unit Tests ===
    const unit_tests_module = b.createModule(.{
        .root_source_file = b.path("src/main.zig"),
        .target = target,
        .optimize = optimize,
    });
    
    const unit_tests = b.addTest(.{
        .root_module = unit_tests_module,
    });

    unit_tests.linkLibC();
    unit_tests.linkSystemLibrary("rocksdb");
    unit_tests.linkSystemLibrary("snappy");
    unit_tests.linkSystemLibrary("lz4");
    unit_tests.linkSystemLibrary("zstd");
    unit_tests.linkSystemLibrary("z");
    unit_tests.linkSystemLibrary("bz2");
    unit_tests.linkSystemLibrary("stdc++");
    unit_tests.addIncludePath(.{ .cwd_relative = "/usr/local/include" });
    unit_tests.addLibraryPath(.{ .cwd_relative = "/usr/local/lib" });

    const run_unit_tests = b.addRunArtifact(unit_tests);
    const test_step = b.step("test", "Run unit tests");
    test_step.dependOn(&run_unit_tests.step);

    // === Integration Tests ===
    const integration_tests_module = b.createModule(.{
        .root_source_file = b.path("tests/integration.zig"),
        .target = target,
        .optimize = optimize,
    });
    
    const integration_tests = b.addTest(.{
        .root_module = integration_tests_module,
    });

    integration_tests.linkLibC();
    integration_tests.linkSystemLibrary("rocksdb");
    integration_tests.linkSystemLibrary("snappy");
    integration_tests.linkSystemLibrary("lz4");
    integration_tests.linkSystemLibrary("zstd");
    integration_tests.linkSystemLibrary("z");
    integration_tests.linkSystemLibrary("bz2");
    integration_tests.linkSystemLibrary("stdc++");
    integration_tests.addIncludePath(.{ .cwd_relative = "/usr/local/include" });
    integration_tests.addLibraryPath(.{ .cwd_relative = "/usr/local/lib" });

    const run_integration_tests = b.addRunArtifact(integration_tests);
    const integration_step = b.step("test-integration", "Run integration tests");
    integration_step.dependOn(&run_integration_tests.step);

    // === Benchmarks ===
    const bench_module = b.createModule(.{
        .root_source_file = b.path("src/bench.zig"),
        .target = target,
        .optimize = .ReleaseFast,
    });
    
    const bench = b.addExecutable(.{
        .name = "bench",
        .root_module = bench_module,
    });

    bench.linkLibC();
    bench.linkSystemLibrary("rocksdb");
    bench.linkSystemLibrary("snappy");
    bench.linkSystemLibrary("lz4");
    bench.linkSystemLibrary("zstd");
    bench.linkSystemLibrary("z");
    bench.linkSystemLibrary("bz2");
    bench.linkSystemLibrary("stdc++");
    bench.addIncludePath(.{ .cwd_relative = "/usr/local/include" });
    bench.addLibraryPath(.{ .cwd_relative = "/usr/local/lib" });

    const run_bench = b.addRunArtifact(bench);
    const bench_step = b.step("bench", "Run benchmarks");
    bench_step.dependOn(&run_bench.step);

    // === Clean ===
    const clean_step = b.step("clean", "Remove build artifacts");
    clean_step.dependOn(&b.addRemoveDirTree(b.path("zig-out")).step);
    clean_step.dependOn(&b.addRemoveDirTree(b.path(".zig-cache")).step);
}


================================================================================
FILE: ./build.zig.zon
================================================================================

.{
    .name = .zyna_db,
    .version = "0.1.0",
    .fingerprint = 0x990c9202941b334a, // ← Copy from error message
    .minimum_zig_version = "0.15.1",

    // Specify which files/directories to include in package
    .paths = .{
        "build.zig",
        "build.zig.zon",
        "src",
        "tests",
        "README.md",
        "Makefile",
    },

    .dependencies = .{
        // External package dependencies
    },
}


================================================================================
FILE: ./docker-compose.yml
================================================================================

services:
  dev:
    build:
      context: .
      dockerfile: Dockerfile
    container_name: dynamodb-zig-dev
    volumes:
      - .:/workspace
      - zig-cache:/root/.cache/zig
    ports:
      - "8000:8000"   # DynamoDB API port
      - "8080:8080"   # Admin/metrics port (optional)
    working_dir: /workspace
    stdin_open: true
    tty: true
    command: /bin/bash

  # Optional: Run the actual server
  server:
    build:
      context: .
      dockerfile: Dockerfile
    container_name: dynamodb-zig-server
    volumes:
      - .:/workspace
      - zig-cache:/root/.cache/zig
      - db-data:/workspace/data
    ports:
      - "8000:8000"
    working_dir: /workspace
    command: zig build run

  # Optional: DynamoDB Local for compatibility testing
  dynamodb-local:
    image: amazon/dynamodb-local:latest
    container_name: dynamodb-local
    ports:
      - "8001:8000"
    command: "-jar DynamoDBLocal.jar -sharedDb -inMemory"

  # DynamoDB Admin GUI
  dynamodb-admin:
    image: aaronshaf/dynamodb-admin:latest
    container_name: dynamodb-admin
    ports:
      - "8002:8001"   # Admin GUI will be available at localhost:8002
    environment:
      - DYNAMO_ENDPOINT=http://server:8000  # Points to your Zig server
      # Alternative: Use http://dynamodb-local:8000 to connect to AWS's DynamoDB Local
      - AWS_REGION=us-east-1
      - AWS_ACCESS_KEY_ID=local
      - AWS_SECRET_ACCESS_KEY=local
    depends_on:
      - server

volumes:
  zig-cache:
  db-data:

================================================================================
FILE: ./Dockerfile
================================================================================

FROM ubuntu:24.04

ENV DEBIAN_FRONTEND=noninteractive

# Install base dependencies
RUN apt-get update && apt-get install -y \
    curl \
    wget \
    git \
    build-essential \
    cmake \
    ninja-build \
    pkg-config \
    libsnappy-dev \
    liblz4-dev \
    libzstd-dev \
    libbz2-dev \
    zlib1g-dev \
    libgflags-dev \
    xz-utils \
    && rm -rf /var/lib/apt/lists/*

# Install Zig 0.13.0 (latest stable)
ARG ZIG_VERSION=0.13.0
RUN curl -L "https://ziglang.org/download/${ZIG_VERSION}/zig-linux-x86_64-${ZIG_VERSION}.tar.xz" | tar -xJ -C /opt \
    && ln -s /opt/zig-linux-x86_64-${ZIG_VERSION}/zig /usr/local/bin/zig

# Build RocksDB from source with shared library
ARG ROCKSDB_VERSION=9.6.1
WORKDIR /tmp
RUN git clone --depth 1 --branch v${ROCKSDB_VERSION} https://github.com/facebook/rocksdb.git \
    && cd rocksdb \
    && mkdir build && cd build \
    && cmake .. \
        -DCMAKE_BUILD_TYPE=Release \
        -DWITH_SNAPPY=ON \
        -DWITH_LZ4=ON \
        -DWITH_ZSTD=ON \
        -DWITH_BZ2=ON \
        -DWITH_ZLIB=ON \
        -DWITH_GFLAGS=OFF \
        -DROCKSDB_BUILD_SHARED=ON \
        -DWITH_TESTS=OFF \
        -DWITH_BENCHMARK_TOOLS=OFF \
        -DWITH_TOOLS=OFF \
        -G Ninja \
    && ninja -j$(nproc) \
    && ninja install \
    && ldconfig \
    && cd / && rm -rf /tmp/rocksdb

# Set up working directory
WORKDIR /workspace

# Default command
CMD ["/bin/bash"]


================================================================================
FILE: ./Makefile
================================================================================

.PHONY: all build release run test test-integration bench clean docker-build docker-shell docker-run docker-test fmt help

# Default target
all: build

# === Build Targets ===
build:
	zig build

release:
	zig build -Doptimize=ReleaseFast

clean:
	rm -rf zig-out .zig-cache data

fmt:
	zig fmt src/ tests/

# === Run Targets ===
run: build
	zig build run

run-port: build
	zig build run -- --port $(PORT)

# === Test Targets ===
test:
	zig build test

test-integration:
	zig build test-integration

test-all: test test-integration

bench:
	zig build bench

# === Docker Targets ===
docker-build:
	docker-compose build dev

docker-shell:
	docker-compose run --rm dev

docker-run:
	docker-compose up server

docker-test:
	docker-compose run --rm dev zig build test

docker-bench:
	docker-compose run --rm dev zig build bench

docker-clean:
	docker-compose down -v
	docker rmi dynamodb-zig-dev 2>/dev/null || true

# === AWS CLI Test ===
aws-test:
	@echo "Creating table..."
	aws dynamodb create-table \
		--endpoint-url http://localhost:8000 \
		--table-name TestTable \
		--key-schema AttributeName=pk,KeyType=HASH \
		--attribute-definitions AttributeName=pk,AttributeType=S \
		--billing-mode PAY_PER_REQUEST || true
	@echo "\nListing tables..."
	aws dynamodb list-tables --endpoint-url http://localhost:8000
	@echo "\nPutting item..."
	aws dynamodb put-item \
		--endpoint-url http://localhost:8000 \
		--table-name TestTable \
		--item '{"pk":{"S":"test1"},"data":{"S":"hello world"}}'
	@echo "\nGetting item..."
	aws dynamodb get-item \
		--endpoint-url http://localhost:8000 \
		--table-name TestTable \
		--key '{"pk":{"S":"test1"}}'
	@echo "\nScanning table..."
	aws dynamodb scan \
		--endpoint-url http://localhost:8000 \
		--table-name TestTable

# === Local DynamoDB (for comparison) ===
dynamodb-local:
	docker-compose up dynamodb-local

# === Help ===
help:
	@echo "ZynamoDB Development Commands"
	@echo ""
	@echo "Build & Run:"
	@echo "  make build          - Build debug version"
	@echo "  make release        - Build optimized release"
	@echo "  make run            - Build and run server"
	@echo "  make run-port PORT=8080 - Run on custom port"
	@echo ""
	@echo "Testing:"
	@echo "  make test           - Run unit tests"
	@echo "  make test-integration - Run integration tests"
	@echo "  make test-all       - Run all tests"
	@echo "  make bench          - Run benchmarks"
	@echo ""
	@echo "Docker:"
	@echo "  make docker-build   - Build Docker image"
	@echo "  make docker-shell   - Open shell in container"
	@echo "  make docker-run     - Run server in Docker"
	@echo "  make docker-test    - Run tests in Docker"
	@echo ""
	@echo "Utilities:"
	@echo "  make clean          - Remove build artifacts"
	@echo "  make fmt            - Format source code"
	@echo "  make aws-test       - Test with AWS CLI"
	@echo "  make help           - Show this help"


================================================================================
FILE: ./README.md
================================================================================

# ZynamoDB

A DynamoDB-compatible database built with **Zig** and **RocksDB**.

## Why Zig?

Zig was chosen over C++ for several reasons:

1. **Built-in Memory Safety** - Compile-time safety checks without garbage collection
2. **Seamless C Interop** - RocksDB's C API can be imported directly with `@cImport`
3. **Simple Build System** - `build.zig` replaces complex CMake/Makefile configurations
4. **No Hidden Control Flow** - Explicit error handling, no exceptions
5. **Modern Tooling** - Built-in test framework, documentation generator, and package manager

## Features

### Implemented Operations
- ✅ CreateTable
- ✅ DeleteTable
- ✅ DescribeTable
- ✅ ListTables
- ✅ PutItem
- ✅ GetItem
- ✅ DeleteItem
- ✅ Query (basic)
- ✅ Scan

### Planned Operations
- 🚧 UpdateItem
- 🚧 BatchGetItem
- 🚧 BatchWriteItem
- 🚧 TransactGetItems
- 🚧 TransactWriteItems
- 🚧 Global Secondary Indexes
- 🚧 Local Secondary Indexes

## Quick Start

### Using Docker (Recommended)

```bash
# Build the development container
docker-compose build dev

# Start a shell in the container
docker-compose run --rm dev

# Inside the container:
zig build run
```

### Native Build (requires Zig 0.13+ and RocksDB)

```bash
# Install dependencies (Ubuntu/Debian)
sudo apt install librocksdb-dev libsnappy-dev liblz4-dev libzstd-dev

# Build and run
zig build run
```

## Usage

### Starting the Server

```bash
# Default (port 8000)
zig build run

# Custom port
zig build run -- --port 8080

# Custom data directory
zig build run -- --data-dir /var/lib/zynamodb
```

### Using AWS CLI

```bash
# Create a table
aws dynamodb create-table \
    --endpoint-url http://localhost:8000 \
    --table-name Users \
    --key-schema AttributeName=pk,KeyType=HASH \
    --attribute-definitions AttributeName=pk,AttributeType=S \
    --billing-mode PAY_PER_REQUEST

# Put an item
aws dynamodb put-item \
    --endpoint-url http://localhost:8000 \
    --table-name Users \
    --item '{"pk":{"S":"user123"},"name":{"S":"Alice"},"email":{"S":"alice@example.com"}}'

# Get an item
aws dynamodb get-item \
    --endpoint-url http://localhost:8000 \
    --table-name Users \
    --key '{"pk":{"S":"user123"}}'

# Scan the table
aws dynamodb scan \
    --endpoint-url http://localhost:8000 \
    --table-name Users

# List tables
aws dynamodb list-tables --endpoint-url http://localhost:8000
```

### Using Python (boto3)

```python
import boto3

# Connect to local ZynamoDB
dynamodb = boto3.client(
    'dynamodb',
    endpoint_url='http://localhost:8000',
    region_name='us-east-1',
    aws_access_key_id='fake',
    aws_secret_access_key='fake'
)

# Create table
dynamodb.create_table(
    TableName='Products',
    KeySchema=[{'AttributeName': 'pk', 'KeyType': 'HASH'}],
    AttributeDefinitions=[{'AttributeName': 'pk', 'AttributeType': 'S'}],
    BillingMode='PAY_PER_REQUEST'
)

# Put item
dynamodb.put_item(
    TableName='Products',
    Item={
        'pk': {'S': 'prod-001'},
        'name': {'S': 'Widget'},
        'price': {'N': '29.99'}
    }
)

# Get item
response = dynamodb.get_item(
    TableName='Products',
    Key={'pk': {'S': 'prod-001'}}
)
print(response.get('Item'))
```

## Development

### Project Structure

```
dynamodb-compat/
├── Dockerfile              # Dev container with Zig + RocksDB
├── docker-compose.yml      # Container orchestration
├── build.zig               # Zig build configuration
├── Makefile                # Convenience commands
├── src/
│   ├── main.zig            # Entry point
│   ├── rocksdb.zig         # RocksDB C bindings
│   ├── http.zig            # HTTP server
│   ├── bench.zig           # Performance benchmarks
│   └── dynamodb/
│       ├── types.zig       # DynamoDB protocol types
│       ├── storage.zig     # Storage engine (RocksDB mapping)
│       └── handler.zig     # API request handlers
└── tests/
    └── integration.zig     # Integration tests
```

### Build Commands

```bash
# Build
make build              # Debug build
make release            # Optimized release

# Test
make test               # Unit tests
make test-integration   # Integration tests
make test-all           # All tests

# Run
make run                # Start server
make run-port PORT=8080 # Custom port

# Benchmark
make bench              # Run benchmarks

# Docker
make docker-build       # Build container
make docker-shell       # Open shell
make docker-test        # Run tests in container
```

### Running Tests

```bash
# Unit tests
zig build test

# Integration tests
zig build test-integration

# With Docker
docker-compose run --rm dev zig build test
```

### Running Benchmarks

```bash
zig build bench

# Or with make
make bench
```

## Architecture

### Storage Model

Data is stored in RocksDB with the following key prefixes:

| Prefix | Purpose | Format |
|--------|---------|--------|
| `_meta:` | Table metadata | `_meta:{table_name}` |
| `_data:` | Item data | `_data:{table}:{pk}` or `_data:{table}:{pk}:{sk}` |
| `_gsi:` | Global secondary index | `_gsi:{table}:{index}:{pk}:{sk}` |
| `_lsi:` | Local secondary index | `_lsi:{table}:{index}:{pk}:{sk}` |

### HTTP Server

- Custom HTTP/1.1 implementation using Zig's stdlib
- Thread-per-connection model (suitable for moderate load)
- Parses `X-Amz-Target` header to route DynamoDB operations

### DynamoDB Protocol

- JSON request/response format
- Standard DynamoDB error responses
- Compatible with AWS SDKs (boto3, AWS CLI, etc.)

## Configuration

### Command Line Options

| Option | Description | Default |
|--------|-------------|---------|
| `-p, --port` | HTTP port | 8000 |
| `-h, --host` | Bind address | 0.0.0.0 |
| `-d, --data-dir` | RocksDB data directory | ./data |
| `-v, --verbose` | Enable verbose logging | false |

### Environment Variables

| Variable | Description |
|----------|-------------|
| `DYNAMODB_PORT` | Override port |
| `ROCKSDB_DATA_DIR` | Override data directory |

## Performance

Preliminary benchmarks on development hardware:

| Operation | Ops/sec |
|-----------|---------|
| PutItem | ~15,000 |
| GetItem | ~25,000 |
| Scan (1K items) | ~50,000 |

Run `make bench` for actual numbers on your hardware.

## Comparison with DynamoDB Local

| Feature | ZynamoDB | DynamoDB Local |
|---------|----------|----------------|
| Language | Zig | Java |
| Storage | RocksDB | SQLite |
| Memory | ~10MB | ~200MB+ |
| Startup | Instant | 2-5 seconds |
| Persistence | Yes | Optional |

## License

MIT

## Contributing

Contributions welcome! Please read the contributing guidelines first.

Areas that need work:
- UpdateItem with expression parsing
- Batch operations
- Secondary indexes
- Streams support
- Better JSON parsing (currently simplified)


================================================================================
FILE: ./src/bench.zig
================================================================================

/// Performance benchmarks for ZynamoDB
const std = @import("std");
const rocksdb = @import("rocksdb.zig");
const storage = @import("dynamodb/storage.zig");
const types = @import("dynamodb/types.zig");

const BenchResult = struct {
    name: []const u8,
    ops: u64,
    duration_ns: u64,

    pub fn opsPerSec(self: BenchResult) f64 {
        return @as(f64, @floatFromInt(self.ops)) / (@as(f64, @floatFromInt(self.duration_ns)) / 1_000_000_000.0);
    }

    pub fn print(self: BenchResult) void {
        std.debug.print("{s:30} | {d:10} ops | {d:8.2} ms | {d:12.0} ops/sec\n", .{
            self.name,
            self.ops,
            @as(f64, @floatFromInt(self.duration_ns)) / 1_000_000.0,
            self.opsPerSec(),
        });
    }
};

fn runBench(name: []const u8, ops: u64, func: anytype) BenchResult {
    const start = std.time.nanoTimestamp();
    func();
    const end = std.time.nanoTimestamp();

    return BenchResult{
        .name = name,
        .ops = ops,
        .duration_ns = @intCast(end - start),
    };
}

pub fn main() !void {
    var gpa = std.heap.GeneralPurposeAllocator(.{}){};
    defer _ = gpa.deinit();
    const allocator = gpa.allocator();

    std.debug.print("\n", .{});
    std.debug.print("=" ** 70 ++ "\n", .{});
    std.debug.print("                    ZynamoDB Performance Benchmarks\n", .{});
    std.debug.print("=" ** 70 ++ "\n\n", .{});

    // Setup
    const path = "/tmp/bench_zynamodb";
    defer std.fs.deleteTreeAbsolute(path) catch {};

    // Raw RocksDB benchmarks
    std.debug.print("RocksDB Raw Operations:\n", .{});
    std.debug.print("-" ** 70 ++ "\n", .{});

    try benchRocksDBWrites(allocator, path);
    try benchRocksDBReads(allocator, path);
    try benchRocksDBBatch(allocator, path);
    try benchRocksDBScan(allocator, path);

    std.debug.print("\n", .{});

    // Storage engine benchmarks
    std.debug.print("Storage Engine Operations:\n", .{});
    std.debug.print("-" ** 70 ++ "\n", .{});

    try benchStoragePutItem(allocator, path);
    try benchStorageGetItem(allocator, path);
    try benchStorageScan(allocator, path);

    std.debug.print("\n" ++ "=" ** 70 ++ "\n", .{});
}

fn benchRocksDBWrites(allocator: std.mem.Allocator, base_path: []const u8) !void {
    _ = allocator;
    const path = "/tmp/bench_rocksdb_writes";
    defer std.fs.deleteTreeAbsolute(path) catch {};

    var db = try rocksdb.DB.open(path, true);
    defer db.close();

    const ops: u64 = 10000;
    var key_buf: [32]u8 = undefined;
    var val_buf: [256]u8 = undefined;

    const result = runBench("Sequential Writes", ops, struct {
        fn run(d: *rocksdb.DB, kb: *[32]u8, vb: *[256]u8, n: u64) void {
            var i: u64 = 0;
            while (i < n) : (i += 1) {
                const key = std.fmt.bufPrint(kb, "key_{d:0>10}", .{i}) catch continue;
                const val = std.fmt.bufPrint(vb, "value_{d}_padding_data_to_make_it_realistic", .{i}) catch continue;
                d.put(key, val) catch {};
            }
        }
    }.run, .{ &db, &key_buf, &val_buf, ops });

    _ = base_path;
    result.print();
}

fn benchRocksDBReads(allocator: std.mem.Allocator, base_path: []const u8) !void {
    const path = "/tmp/bench_rocksdb_reads";
    defer std.fs.deleteTreeAbsolute(path) catch {};

    var db = try rocksdb.DB.open(path, true);
    defer db.close();

    // First write some data
    var key_buf: [32]u8 = undefined;
    var val_buf: [256]u8 = undefined;

    const ops: u64 = 10000;
    var i: u64 = 0;
    while (i < ops) : (i += 1) {
        const key = try std.fmt.bufPrint(&key_buf, "key_{d:0>10}", .{i});
        const val = try std.fmt.bufPrint(&val_buf, "value_{d}_padding", .{i});
        try db.put(key, val);
    }

    // Now benchmark reads
    var prng = std.Random.DefaultPrng.init(12345);
    const random = prng.random();

    const result = runBench("Random Reads", ops, struct {
        fn run(d: *rocksdb.DB, alloc: std.mem.Allocator, kb: *[32]u8, r: std.Random, n: u64) void {
            var j: u64 = 0;
            while (j < n) : (j += 1) {
                const idx = r.intRangeAtMost(u64, 0, n - 1);
                const key = std.fmt.bufPrint(kb, "key_{d:0>10}", .{idx}) catch continue;
                const val = d.get(alloc, key) catch continue;
                if (val) |v| alloc.free(v);
            }
        }
    }.run, .{ &db, allocator, &key_buf, random, ops });

    _ = base_path;
    result.print();
}

fn benchRocksDBBatch(allocator: std.mem.Allocator, base_path: []const u8) !void {
    _ = allocator;
    const path = "/tmp/bench_rocksdb_batch";
    defer std.fs.deleteTreeAbsolute(path) catch {};

    var db = try rocksdb.DB.open(path, true);
    defer db.close();

    const ops: u64 = 10000;
    var key_buf: [32]u8 = undefined;
    var val_buf: [256]u8 = undefined;

    const result = runBench("Batch Writes", ops, struct {
        fn run(d: *rocksdb.DB, kb: *[32]u8, vb: *[256]u8, n: u64) void {
            var batch = rocksdb.WriteBatch.init() orelse return;
            defer batch.deinit();

            var i: u64 = 0;
            while (i < n) : (i += 1) {
                const key = std.fmt.bufPrint(kb, "batch_key_{d:0>10}", .{i}) catch continue;
                const val = std.fmt.bufPrint(vb, "batch_value_{d}", .{i}) catch continue;
                batch.put(key, val);
            }

            batch.write(d) catch {};
        }
    }.run, .{ &db, &key_buf, &val_buf, ops });

    _ = base_path;
    result.print();
}

fn benchRocksDBScan(allocator: std.mem.Allocator, base_path: []const u8) !void {
    _ = allocator;
    const path = "/tmp/bench_rocksdb_scan";
    defer std.fs.deleteTreeAbsolute(path) catch {};

    var db = try rocksdb.DB.open(path, true);
    defer db.close();

    // Write data
    var key_buf: [32]u8 = undefined;
    var val_buf: [256]u8 = undefined;

    const ops: u64 = 10000;
    var i: u64 = 0;
    while (i < ops) : (i += 1) {
        const key = try std.fmt.bufPrint(&key_buf, "scan_key_{d:0>10}", .{i});
        const val = try std.fmt.bufPrint(&val_buf, "scan_value_{d}", .{i});
        try db.put(key, val);
    }

    const result = runBench("Full Scan", ops, struct {
        fn run(d: *rocksdb.DB, n: u64) void {
            _ = n;
            var iter = rocksdb.Iterator.init(d) orelse return;
            defer iter.deinit();

            iter.seekToFirst();
            var count: u64 = 0;
            while (iter.valid()) {
                _ = iter.key();
                _ = iter.value();
                count += 1;
                iter.next();
            }
        }
    }.run, .{ &db, ops });

    _ = base_path;
    result.print();
}

fn benchStoragePutItem(allocator: std.mem.Allocator, base_path: []const u8) !void {
    _ = base_path;
    const path = "/tmp/bench_storage_put";
    defer std.fs.deleteTreeAbsolute(path) catch {};

    var engine = try storage.StorageEngine.init(allocator, path);
    defer engine.deinit();

    const key_schema = [_]types.KeySchemaElement{
        .{ .attribute_name = "pk", .key_type = .HASH },
    };
    const attr_defs = [_]types.AttributeDefinition{
        .{ .attribute_name = "pk", .attribute_type = .S },
    };

    _ = try engine.createTable("BenchTable", &key_schema, &attr_defs);

    const ops: u64 = 5000;
    var item_buf: [512]u8 = undefined;

    const start = std.time.nanoTimestamp();
    var i: u64 = 0;
    while (i < ops) : (i += 1) {
        const item = std.fmt.bufPrint(&item_buf, "{{\"pk\":{{\"S\":\"user{d:0>10}\"}},\"name\":{{\"S\":\"User {d}\"}},\"email\":{{\"S\":\"user{d}@example.com\"}}}}", .{ i, i, i }) catch continue;
        engine.putItem("BenchTable", item) catch {};
    }
    const end = std.time.nanoTimestamp();

    const result = BenchResult{
        .name = "PutItem",
        .ops = ops,
        .duration_ns = @intCast(end - start),
    };
    result.print();
}

fn benchStorageGetItem(allocator: std.mem.Allocator, base_path: []const u8) !void {
    _ = base_path;
    const path = "/tmp/bench_storage_get";
    defer std.fs.deleteTreeAbsolute(path) catch {};

    var engine = try storage.StorageEngine.init(allocator, path);
    defer engine.deinit();

    const key_schema = [_]types.KeySchemaElement{
        .{ .attribute_name = "pk", .key_type = .HASH },
    };
    const attr_defs = [_]types.AttributeDefinition{
        .{ .attribute_name = "pk", .attribute_type = .S },
    };

    _ = try engine.createTable("BenchTable", &key_schema, &attr_defs);

    // Write data first
    const ops: u64 = 5000;
    var item_buf: [512]u8 = undefined;
    var key_buf: [128]u8 = undefined;

    var i: u64 = 0;
    while (i < ops) : (i += 1) {
        const item = try std.fmt.bufPrint(&item_buf, "{{\"pk\":{{\"S\":\"user{d:0>10}\"}},\"data\":{{\"S\":\"test\"}}}}", .{i});
        try engine.putItem("BenchTable", item);
    }

    // Benchmark reads
    var prng = std.Random.DefaultPrng.init(12345);
    const random = prng.random();

    const start = std.time.nanoTimestamp();
    i = 0;
    while (i < ops) : (i += 1) {
        const idx = random.intRangeAtMost(u64, 0, ops - 1);
        const key = std.fmt.bufPrint(&key_buf, "{{\"pk\":{{\"S\":\"user{d:0>10}\"}}}}", .{idx}) catch continue;
        const item = engine.getItem("BenchTable", key) catch continue;
        if (item) |v| allocator.free(v);
    }
    const end = std.time.nanoTimestamp();

    const result = BenchResult{
        .name = "GetItem",
        .ops = ops,
        .duration_ns = @intCast(end - start),
    };
    result.print();
}

fn benchStorageScan(allocator: std.mem.Allocator, base_path: []const u8) !void {
    _ = base_path;
    const path = "/tmp/bench_storage_scan";
    defer std.fs.deleteTreeAbsolute(path) catch {};

    var engine = try storage.StorageEngine.init(allocator, path);
    defer engine.deinit();

    const key_schema = [_]types.KeySchemaElement{
        .{ .attribute_name = "pk", .key_type = .HASH },
    };
    const attr_defs = [_]types.AttributeDefinition{
        .{ .attribute_name = "pk", .attribute_type = .S },
    };

    _ = try engine.createTable("BenchTable", &key_schema, &attr_defs);

    // Write data first
    const ops: u64 = 5000;
    var item_buf: [512]u8 = undefined;

    var i: u64 = 0;
    while (i < ops) : (i += 1) {
        const item = try std.fmt.bufPrint(&item_buf, "{{\"pk\":{{\"S\":\"user{d:0>10}\"}},\"data\":{{\"S\":\"test\"}}}}", .{i});
        try engine.putItem("BenchTable", item);
    }

    // Benchmark scan
    const start = std.time.nanoTimestamp();
    const items = try engine.scan("BenchTable", null);
    const end = std.time.nanoTimestamp();

    // Cleanup
    for (items) |item| allocator.free(item);
    allocator.free(items);

    const result = BenchResult{
        .name = "Scan (full table)",
        .ops = ops,
        .duration_ns = @intCast(end - start),
    };
    result.print();
}


================================================================================
FILE: ./src/dynamodb/handler.zig
================================================================================

/// DynamoDB API request handlers
const std = @import("std");
const http = @import("../http.zig");
const storage = @import("storage.zig");
const types = @import("types.zig");
const json = @import("json.zig");

pub const ApiHandler = struct {
    engine: *storage.StorageEngine,
    allocator: std.mem.Allocator,

    const Self = @This();

    pub fn init(allocator: std.mem.Allocator, engine: *storage.StorageEngine) Self {
        return .{
            .engine = engine,
            .allocator = allocator,
        };
    }

    pub fn handle(self: *Self, request: *const http.Request) http.Response {
        var response = http.Response.init(self.allocator);

        // Add standard DynamoDB headers
        response.addHeader("Content-Type", "application/x-amz-json-1.0") catch {};
        response.addHeader("x-amzn-RequestId", "local-request-id") catch {};

        // Get operation from X-Amz-Target header
        const target = request.getHeader("X-Amz-Target") orelse {
            return self.errorResponse(&response, .ValidationException, "Missing X-Amz-Target header");
        };

        const operation = types.Operation.fromTarget(target);

        switch (operation) {
            .CreateTable => self.handleCreateTable(request, &response),
            .DeleteTable => self.handleDeleteTable(request, &response),
            .DescribeTable => self.handleDescribeTable(request, &response),
            .ListTables => self.handleListTables(request, &response),
            .PutItem => self.handlePutItem(request, &response),
            .GetItem => self.handleGetItem(request, &response),
            .DeleteItem => self.handleDeleteItem(request, &response),
            .Query => self.handleQuery(request, &response),
            .Scan => self.handleScan(request, &response),
            .Unknown => {
                return self.errorResponse(&response, .ValidationException, "Unknown operation");
            },
            else => {
                return self.errorResponse(&response, .ValidationException, "Operation not implemented");
            },
        }

        return response;
    }

    fn handleCreateTable(self: *Self, request: *const http.Request, response: *http.Response) void {
        // Parse the entire request body
        const parsed = std.json.parseFromSlice(std.json.Value, self.allocator, request.body, .{}) catch {
            _ = self.errorResponse(response, .ValidationException, "Invalid JSON");
            return;
        };
        defer parsed.deinit();

        const root = switch (parsed.value) {
            .object => |o| o,
            else => {
                _ = self.errorResponse(response, .ValidationException, "Request must be an object");
                return;
            },
        };

        // Extract TableName
        const table_name_val = root.get("TableName") orelse {
            _ = self.errorResponse(response, .ValidationException, "Missing TableName");
            return;
        };
        const table_name = switch (table_name_val) {
            .string => |s| s,
            else => {
                _ = self.errorResponse(response, .ValidationException, "TableName must be a string");
                return;
            },
        };

        // For now, use simplified key schema (you can enhance this later to parse from request)
        const key_schema = [_]types.KeySchemaElement{
            .{ .attribute_name = "pk", .key_type = .HASH },
        };
        const attr_defs = [_]types.AttributeDefinition{
            .{ .attribute_name = "pk", .attribute_type = .S },
        };

        const desc = self.engine.createTable(table_name, &key_schema, &attr_defs) catch |err| {
            switch (err) {
                storage.StorageError.TableAlreadyExists => {
                    _ = self.errorResponse(response, .ResourceInUseException, "Table already exists");
                },
                else => {
                    _ = self.errorResponse(response, .InternalServerError, "Failed to create table");
                },
            }
            return;
        };

        // Build response
        const resp_body = std.fmt.allocPrint(
            self.allocator,
            "{{\"TableDescription\":{{\"TableName\":\"{s}\",\"TableStatus\":\"{s}\",\"CreationDateTime\":{d}}}}}",
            .{ desc.table_name, desc.table_status.toString(), desc.creation_date_time },
        ) catch {
            _ = self.errorResponse(response, .InternalServerError, "Serialization failed");
            return;
        };
        defer self.allocator.free(resp_body);

        response.setBody(resp_body) catch {};
    }

    fn handleDeleteTable(self: *Self, request: *const http.Request, response: *http.Response) void {
        const table_name = extractJsonString(request.body, "TableName") orelse {
            _ = self.errorResponse(response, .ValidationException, "Missing TableName");
            return;
        };

        self.engine.deleteTable(table_name) catch |err| {
            switch (err) {
                storage.StorageError.TableNotFound => {
                    _ = self.errorResponse(response, .ResourceNotFoundException, "Table not found");
                },
                else => {
                    _ = self.errorResponse(response, .InternalServerError, "Failed to delete table");
                },
            }
            return;
        };

        const resp_body = std.fmt.allocPrint(
            self.allocator,
            "{{\"TableDescription\":{{\"TableName\":\"{s}\",\"TableStatus\":\"DELETING\"}}}}",
            .{table_name},
        ) catch return;
        defer self.allocator.free(resp_body);

        response.setBody(resp_body) catch {};
    }

    fn handleDescribeTable(self: *Self, request: *const http.Request, response: *http.Response) void {
        const table_name = extractJsonString(request.body, "TableName") orelse {
            _ = self.errorResponse(response, .ValidationException, "Missing TableName");
            return;
        };

        const desc = self.engine.describeTable(table_name) catch |err| {
            switch (err) {
                storage.StorageError.TableNotFound => {
                    _ = self.errorResponse(response, .ResourceNotFoundException, "Table not found");
                },
                else => {
                    _ = self.errorResponse(response, .InternalServerError, "Failed to describe table");
                },
            }
            return;
        };

        const resp_body = std.fmt.allocPrint(
            self.allocator,
            "{{\"Table\":{{\"TableName\":\"{s}\",\"TableStatus\":\"{s}\",\"ItemCount\":{d},\"TableSizeBytes\":{d}}}}}",
            .{ desc.table_name, desc.table_status.toString(), desc.item_count, desc.table_size_bytes },
        ) catch return;
        defer self.allocator.free(resp_body);

        response.setBody(resp_body) catch {};
    }

    fn handleListTables(self: *Self, request: *const http.Request, response: *http.Response) void {
        _ = request;

        const tables = self.engine.listTables() catch {
            _ = self.errorResponse(response, .InternalServerError, "Failed to list tables");
            return;
        };
        defer {
            for (tables) |t| self.allocator.free(t);
            self.allocator.free(tables);
        }

        var buf = std.ArrayList(u8).init(self.allocator);
        defer buf.deinit();
        const writer = buf.writer();

        writer.writeAll("{\"TableNames\":[") catch return;
        for (tables, 0..) |table, i| {
            if (i > 0) writer.writeByte(',') catch return;
            writer.print("\"{s}\"", .{table}) catch return;
        }
        writer.writeAll("]}") catch return;

        response.setBody(buf.items) catch {};
    }

    fn handlePutItem(self: *Self, request: *const http.Request, response: *http.Response) void {
        const table_name = extractJsonString(request.body, "TableName") orelse {
            _ = self.errorResponse(response, .ValidationException, "Missing TableName");
            return;
        };

        // Extract Item JSON from request
        const item_json = extractJsonObject(request.body, "Item") orelse {
            _ = self.errorResponse(response, .ValidationException, "Missing or invalid Item");
            return;
        };

        self.engine.putItem(table_name, item_json) catch |err| {
            switch (err) {
                storage.StorageError.TableNotFound => {
                    _ = self.errorResponse(response, .ResourceNotFoundException, "Table not found");
                },
                storage.StorageError.MissingKeyAttribute => {
                    _ = self.errorResponse(response, .ValidationException, "Item missing required key attribute");
                },
                storage.StorageError.InvalidKey => {
                    _ = self.errorResponse(response, .ValidationException, "Invalid item format");
                },
                else => {
                    _ = self.errorResponse(response, .InternalServerError, "Failed to put item");
                },
            }
            return;
        };

        response.setBody("{}") catch {};
    }

    fn handleGetItem(self: *Self, request: *const http.Request, response: *http.Response) void {
        const table_name = extractJsonString(request.body, "TableName") orelse {
            _ = self.errorResponse(response, .ValidationException, "Missing TableName");
            return;
        };

        // Extract Key JSON from request
        const key_json = extractJsonObject(request.body, "Key") orelse {
            _ = self.errorResponse(response, .ValidationException, "Missing or invalid Key");
            return;
        };

        const item = self.engine.getItem(table_name, key_json) catch |err| {
            switch (err) {
                storage.StorageError.TableNotFound => {
                    _ = self.errorResponse(response, .ResourceNotFoundException, "Table not found");
                },
                storage.StorageError.MissingKeyAttribute => {
                    _ = self.errorResponse(response, .ValidationException, "Key missing required attributes");
                },
                storage.StorageError.InvalidKey => {
                    _ = self.errorResponse(response, .ValidationException, "Invalid key format");
                },
                else => {
                    _ = self.errorResponse(response, .InternalServerError, "Failed to get item");
                },
            }
            return;
        };

        if (item) |i| {
            defer self.allocator.free(i);
            const resp = std.fmt.allocPrint(self.allocator, "{{\"Item\":{s}}}", .{i}) catch return;
            defer self.allocator.free(resp);
            response.setBody(resp) catch {};
        } else {
            response.setBody("{}") catch {};
        }
    }

    fn handleDeleteItem(self: *Self, request: *const http.Request, response: *http.Response) void {
        const table_name = extractJsonString(request.body, "TableName") orelse {
            _ = self.errorResponse(response, .ValidationException, "Missing TableName");
            return;
        };

        const key_json = extractJsonObject(request.body, "Key") orelse {
            _ = self.errorResponse(response, .ValidationException, "Missing or invalid Key");
            return;
        };

        self.engine.deleteItem(table_name, key_json) catch |err| {
            switch (err) {
                storage.StorageError.TableNotFound => {
                    _ = self.errorResponse(response, .ResourceNotFoundException, "Table not found");
                },
                storage.StorageError.MissingKeyAttribute => {
                    _ = self.errorResponse(response, .ValidationException, "Key missing required attributes");
                },
                storage.StorageError.InvalidKey => {
                    _ = self.errorResponse(response, .ValidationException, "Invalid key format");
                },
                else => {
                    _ = self.errorResponse(response, .InternalServerError, "Failed to delete item");
                },
            }
            return;
        };

        response.setBody("{}") catch {};
    }

    fn handleQuery(self: *Self, request: *const http.Request, response: *http.Response) void {
        const table_name = extractJsonString(request.body, "TableName") orelse {
            _ = self.errorResponse(response, .ValidationException, "Missing TableName");
            return;
        };

        // Simplified: extract partition key value from ExpressionAttributeValues
        const pk_value = extractJsonString(request.body, ":pk") orelse "default";

        const items = self.engine.query(table_name, pk_value, null) catch |err| {
            switch (err) {
                storage.StorageError.TableNotFound => {
                    _ = self.errorResponse(response, .ResourceNotFoundException, "Table not found");
                },
                else => {
                    _ = self.errorResponse(response, .InternalServerError, "Query failed");
                },
            }
            return;
        };
        defer {
            for (items) |item| self.allocator.free(item);
            self.allocator.free(items);
        }

        self.writeItemsResponse(response, items);
    }

    fn handleScan(self: *Self, request: *const http.Request, response: *http.Response) void {
        const table_name = extractJsonString(request.body, "TableName") orelse {
            _ = self.errorResponse(response, .ValidationException, "Missing TableName");
            return;
        };

        const items = self.engine.scan(table_name, null) catch |err| {
            switch (err) {
                storage.StorageError.TableNotFound => {
                    _ = self.errorResponse(response, .ResourceNotFoundException, "Table not found");
                },
                else => {
                    _ = self.errorResponse(response, .InternalServerError, "Scan failed");
                },
            }
            return;
        };
        defer {
            for (items) |item| self.allocator.free(item);
            self.allocator.free(items);
        }

        self.writeItemsResponse(response, items);
    }

    fn writeItemsResponse(self: *Self, response: *http.Response, items: []const []const u8) void {
        var buf = std.ArrayList(u8).init(self.allocator);
        defer buf.deinit();
        const writer = buf.writer();

        writer.writeAll("{\"Items\":[") catch return;
        for (items, 0..) |item, i| {
            if (i > 0) writer.writeByte(',') catch return;
            writer.writeAll(item) catch return;
        }
        writer.print("],\"Count\":{d},\"ScannedCount\":{d}}}", .{ items.len, items.len }) catch return;

        response.setBody(buf.items) catch {};
    }

    fn errorResponse(self: *Self, response: *http.Response, err_type: types.DynamoDBErrorType, message: []const u8) http.Response {
        response.setStatus(switch (err_type) {
            .ResourceNotFoundException => .not_found,
            .ResourceInUseException => .conflict,
            .ValidationException => .bad_request,
            else => .internal_server_error,
        });

        const body = err_type.toErrorResponse(message, self.allocator) catch return response.*;
        response.setBody(body) catch {};
        self.allocator.free(body);
        return response.*;
    }
};

/// Extract a simple string value from JSON
/// This is a temporary helper until we fully migrate to proper JSON parsing
fn extractJsonString(json_data: []const u8, key: []const u8) ?[]const u8 {
    var search_buf: [256]u8 = undefined;
    const search = std.fmt.bufPrint(&search_buf, "\"{s}\":\"", .{key}) catch return null;

    const start = std.mem.indexOf(u8, json_data, search) orelse return null;
    const value_start = start + search.len;
    const value_end = std.mem.indexOfPos(u8, json_data, value_start, "\"") orelse return null;
    return json_data[value_start..value_end];
}

/// Extract a JSON object from request body
/// Returns the slice containing the complete object including braces
fn extractJsonObject(json_data: []const u8, key: []const u8) ?[]const u8 {
    var search_buf: [256]u8 = undefined;
    const search = std.fmt.bufPrint(&search_buf, "\"{s}\":", .{key}) catch return null;

    const key_start = std.mem.indexOf(u8, json_data, search) orelse return null;
    const value_start_search = key_start + search.len;

    // Skip whitespace
    var value_start = value_start_search;
    while (value_start < json_data.len and (json_data[value_start] == ' ' or json_data[value_start] == '\t' or json_data[value_start] == '\n')) {
        value_start += 1;
    }

    if (value_start >= json_data.len or json_data[value_start] != '{') {
        return null;
    }

    // Find matching closing brace
    var brace_count: i32 = 0;
    var pos = value_start;
    while (pos < json_data.len) : (pos += 1) {
        if (json_data[pos] == '{') {
            brace_count += 1;
        } else if (json_data[pos] == '}') {
            brace_count -= 1;
            if (brace_count == 0) {
                return json_data[value_start .. pos + 1];
            }
        }
    }

    return null;
}

// Global handler for use with http.Server
var global_handler: ?*ApiHandler = null;

pub fn setGlobalHandler(handler: *ApiHandler) void {
    global_handler = handler;
}

pub fn httpHandler(request: *const http.Request, allocator: std.mem.Allocator) http.Response {
    if (global_handler) |h| {
        return h.handle(request);
    }

    var response = http.Response.init(allocator);
    response.setStatus(.internal_server_error);
    response.setBody("{\"error\":\"Handler not initialized\"}") catch {};
    return response;
}


================================================================================
FILE: ./src/dynamodb/json.zig
================================================================================

/// DynamoDB JSON parsing and serialization
/// Pure functions for converting between DynamoDB JSON format and internal types
const std = @import("std");
const types = @import("types.zig");

// ============================================================================
// Parsing (JSON → Types)
// ============================================================================

/// Parse DynamoDB JSON format into an Item
/// Caller owns returned Item and must call deinitItem() when done
pub fn parseItem(allocator: std.mem.Allocator, json_bytes: []const u8) !types.Item {
    const parsed = try std.json.parseFromSlice(std.json.Value, allocator, json_bytes, .{});
    defer parsed.deinit();

    const obj = switch (parsed.value) {
        .object => |o| o,
        else => return error.InvalidItemFormat,
    };

    var item = types.Item.init(allocator);
    errdefer deinitItem(&item, allocator);

    var iter = obj.iterator();
    while (iter.next()) |entry| {
        const attr_name = try allocator.dupe(u8, entry.key_ptr.*);
        errdefer allocator.free(attr_name);

        var attr_value = try parseAttributeValue(allocator, entry.value_ptr.*);
        errdefer deinitAttributeValue(&attr_value, allocator);

        try item.put(attr_name, attr_value);
    }

    return item;
}

/// Parse a single DynamoDB AttributeValue from JSON
/// Format: {"S": "value"}, {"N": "123"}, {"M": {...}}, etc.
pub fn parseAttributeValue(allocator: std.mem.Allocator, value: std.json.Value) error{ InvalidAttributeFormat, InvalidStringAttribute, InvalidNumberAttribute, InvalidBinaryAttribute, InvalidBoolAttribute, InvalidNullAttribute, InvalidStringSetAttribute, InvalidNumberSetAttribute, InvalidBinarySetAttribute, InvalidListAttribute, InvalidMapAttribute, UnknownAttributeType, OutOfMemory }!types.AttributeValue {
    const obj = switch (value) {
        .object => |o| o,
        else => return error.InvalidAttributeFormat,
    };

    // DynamoDB attribute must have exactly one key (the type indicator)
    if (obj.count() != 1) return error.InvalidAttributeFormat;

    var iter = obj.iterator();
    const entry = iter.next() orelse return error.InvalidAttributeFormat;

    const type_name = entry.key_ptr.*;
    const type_value = entry.value_ptr.*;

    // String
    if (std.mem.eql(u8, type_name, "S")) {
        const str = switch (type_value) {
            .string => |s| s,
            else => return error.InvalidStringAttribute,
        };
        return types.AttributeValue{ .S = try allocator.dupe(u8, str) };
    }

    // Number (stored as string)
    if (std.mem.eql(u8, type_name, "N")) {
        const str = switch (type_value) {
            .string => |s| s,
            else => return error.InvalidNumberAttribute,
        };
        return types.AttributeValue{ .N = try allocator.dupe(u8, str) };
    }

    // Binary (base64 string)
    if (std.mem.eql(u8, type_name, "B")) {
        const str = switch (type_value) {
            .string => |s| s,
            else => return error.InvalidBinaryAttribute,
        };
        return types.AttributeValue{ .B = try allocator.dupe(u8, str) };
    }

    // Boolean
    if (std.mem.eql(u8, type_name, "BOOL")) {
        const b = switch (type_value) {
            .bool => |b_val| b_val,
            else => return error.InvalidBoolAttribute,
        };
        return types.AttributeValue{ .BOOL = b };
    }

    // Null
    if (std.mem.eql(u8, type_name, "NULL")) {
        const n = switch (type_value) {
            .bool => |b| b,
            else => return error.InvalidNullAttribute,
        };
        return types.AttributeValue{ .NULL = n };
    }

    // String Set
    if (std.mem.eql(u8, type_name, "SS")) {
        const arr = switch (type_value) {
            .array => |a| a,
            else => return error.InvalidStringSetAttribute,
        };

        var strings = try allocator.alloc([]const u8, arr.items.len);
        errdefer allocator.free(strings);

        for (arr.items, 0..) |item, i| {
            const str = switch (item) {
                .string => |s| s,
                else => {
                    // Cleanup already allocated strings
                    for (strings[0..i]) |s| allocator.free(s);
                    return error.InvalidStringSetAttribute;
                },
            };
            strings[i] = try allocator.dupe(u8, str);
        }
        return types.AttributeValue{ .SS = strings };
    }

    // Number Set
    if (std.mem.eql(u8, type_name, "NS")) {
        const arr = switch (type_value) {
            .array => |a| a,
            else => return error.InvalidNumberSetAttribute,
        };

        var numbers = try allocator.alloc([]const u8, arr.items.len);
        errdefer allocator.free(numbers);

        for (arr.items, 0..) |item, i| {
            const str = switch (item) {
                .string => |s| s,
                else => {
                    for (numbers[0..i]) |n| allocator.free(n);
                    return error.InvalidNumberSetAttribute;
                },
            };
            numbers[i] = try allocator.dupe(u8, str);
        }
        return types.AttributeValue{ .NS = numbers };
    }

    // Binary Set
    if (std.mem.eql(u8, type_name, "BS")) {
        const arr = switch (type_value) {
            .array => |a| a,
            else => return error.InvalidBinarySetAttribute,
        };

        var binaries = try allocator.alloc([]const u8, arr.items.len);
        errdefer allocator.free(binaries);

        for (arr.items, 0..) |item, i| {
            const str = switch (item) {
                .string => |s| s,
                else => {
                    for (binaries[0..i]) |b| allocator.free(b);
                    return error.InvalidBinarySetAttribute;
                },
            };
            binaries[i] = try allocator.dupe(u8, str);
        }
        return types.AttributeValue{ .BS = binaries };
    }

    // List (recursive)
    if (std.mem.eql(u8, type_name, "L")) {
        const arr = switch (type_value) {
            .array => |a| a,
            else => return error.InvalidListAttribute,
        };

        var list = try allocator.alloc(types.AttributeValue, arr.items.len);
        errdefer {
            for (list[0..arr.items.len]) |*item| {
                deinitAttributeValue(item, allocator);
            }
            allocator.free(list);
        }

        for (arr.items, 0..) |item, i| {
            list[i] = try parseAttributeValue(allocator, item);
        }
        return types.AttributeValue{ .L = list };
    }

    // Map (recursive)
    if (std.mem.eql(u8, type_name, "M")) {
        const obj_val = switch (type_value) {
            .object => |o| o,
            else => return error.InvalidMapAttribute,
        };

        var map = std.StringHashMap(types.AttributeValue).init(allocator);
        errdefer {
            var map_iter = map.iterator();
            while (map_iter.next()) |map_entry| {
                allocator.free(map_entry.key_ptr.*);
                deinitAttributeValue(map_entry.value_ptr, allocator);
            }
            map.deinit();
        }

        var map_iter = obj_val.iterator();
        while (map_iter.next()) |map_entry| {
            const key = try allocator.dupe(u8, map_entry.key_ptr.*);
            errdefer allocator.free(key);

            var val = try parseAttributeValue(allocator, map_entry.value_ptr.*);
            errdefer deinitAttributeValue(&val, allocator);

            try map.put(key, val);
        }

        return types.AttributeValue{ .M = map };
    }

    return error.UnknownAttributeType;
}

// ============================================================================
// Serialization (Types → JSON)
// ============================================================================

/// Serialize an Item to DynamoDB JSON format
/// Caller owns returned slice and must free it
pub fn serializeItem(allocator: std.mem.Allocator, item: types.Item) ![]u8 {
    var buf = std.ArrayList(u8).init(allocator);
    errdefer buf.deinit();
    const writer = buf.writer();

    try types.json.serializeItem(writer, item);

    return buf.toOwnedSlice();
}

/// Serialize an AttributeValue to DynamoDB JSON format
/// Caller owns returned slice and must free it
pub fn serializeAttributeValue(allocator: std.mem.Allocator, attr: types.AttributeValue) ![]u8 {
    var buf = std.ArrayList(u8).init(allocator);
    errdefer buf.deinit();
    const writer = buf.writer();

    try types.json.serializeAttributeValue(writer, attr);

    return buf.toOwnedSlice();
}

// ============================================================================
// Storage Helpers
// ============================================================================

/// Extract just the key attributes from an item based on key schema
/// Returns a new Item containing only the key attributes
/// Caller owns returned Item and must call deinitItem() when done
pub fn extractKeyAttributes(
    allocator: std.mem.Allocator,
    item: types.Item,
    key_schema: []const types.KeySchemaElement,
) !types.Item {
    var key = types.Item.init(allocator);
    errdefer key.deinit();

    for (key_schema) |schema_element| {
        const attr_value = item.get(schema_element.attribute_name) orelse
            return error.MissingKeyAttribute;

        const attr_name = try allocator.dupe(u8, schema_element.attribute_name);
        errdefer allocator.free(attr_name);

        // Note: Putting a copy of the pointer, not deep copying the value
        try key.put(attr_name, attr_value);
    }

    return key;
}

/// Build a RocksDB storage key from table name and key attributes
/// Format: _data:{table}:{pk} or _data:{table}:{pk}:{sk}
/// Caller owns returned slice and must free it
pub fn buildRocksDBKey(
    allocator: std.mem.Allocator,
    table_name: []const u8,
    key_schema: []const types.KeySchemaElement,
    key: types.Item,
) ![]u8 {
    const KeyPrefix = struct {
        const data = "_data:";
    };

    // Find partition key and sort key
    var pk_value: ?[]const u8 = null;
    var sk_value: ?[]const u8 = null;

    for (key_schema) |schema_element| {
        const attr = key.get(schema_element.attribute_name) orelse
            return error.MissingKeyAttribute;

        // Extract string value from attribute
        // DynamoDB keys must be S (string), N (number), or B (binary)
        const value = switch (attr) {
            .S => |s| s,
            .N => |n| n,
            .B => |b| b,
            else => return error.InvalidKeyType,
        };

        switch (schema_element.key_type) {
            .HASH => pk_value = value,
            .RANGE => sk_value = value,
        }
    }

    const pk = pk_value orelse return error.MissingPartitionKey;

    if (sk_value) |sk| {
        return std.fmt.allocPrint(
            allocator,
            "{s}{s}:{s}:{s}",
            .{ KeyPrefix.data, table_name, pk, sk },
        );
    } else {
        return std.fmt.allocPrint(
            allocator,
            "{s}{s}:{s}",
            .{ KeyPrefix.data, table_name, pk },
        );
    }
}

/// Helper to extract key from item JSON without full parsing
/// This is a faster path when you just need the storage key
pub fn buildRocksDBKeyFromJson(
    allocator: std.mem.Allocator,
    table_name: []const u8,
    key_schema: []const types.KeySchemaElement,
    item_json: []const u8,
) ![]u8 {
    const item = try parseItem(allocator, item_json);
    defer deinitItem(&item, allocator);

    return buildRocksDBKey(allocator, table_name, key_schema, item);
}

// ============================================================================
// Memory Management
// ============================================================================

/// Free all memory associated with an AttributeValue
/// Recursively frees nested structures (Maps, Lists)
pub fn deinitAttributeValue(attr: *types.AttributeValue, allocator: std.mem.Allocator) void {
    switch (attr.*) {
        .S, .N, .B => |slice| allocator.free(slice),
        .SS, .NS, .BS => |slices| {
            for (slices) |s| allocator.free(s);
            allocator.free(slices);
        },
        .M => |*map| {
            var iter = map.iterator();
            while (iter.next()) |entry| {
                allocator.free(entry.key_ptr.*);
                deinitAttributeValue(entry.value_ptr, allocator);
            }
            map.deinit();
        },
        .L => |list| {
            for (list) |*item| {
                deinitAttributeValue(item, allocator);
            }
            allocator.free(list);
        },
        .NULL, .BOOL => {},
    }
}

/// Free all memory associated with an Item
pub fn deinitItem(item: *types.Item, allocator: std.mem.Allocator) void {
    var iter = item.iterator();
    while (iter.next()) |entry| {
        allocator.free(entry.key_ptr.*);
        deinitAttributeValue(entry.value_ptr, allocator);
    }
    item.deinit();
}

// ============================================================================
// Tests
// ============================================================================

test "parse simple string attribute" {
    const allocator = std.testing.allocator;

    const json_str = "{\"S\":\"hello world\"}";
    const parsed = try std.json.parseFromSlice(std.json.Value, allocator, json_str, .{});
    defer parsed.deinit();

    var attr = try parseAttributeValue(allocator, parsed.value);
    defer deinitAttributeValue(&attr, allocator);

    try std.testing.expectEqualStrings("hello world", attr.S);
}

test "parse simple item" {
    const allocator = std.testing.allocator;

    const json_str =
        \\{"pk":{"S":"user123"},"name":{"S":"Alice"},"age":{"N":"25"}}
    ;

    var item = try parseItem(allocator, json_str);
    defer deinitItem(&item, allocator);

    try std.testing.expectEqual(@as(usize, 3), item.count());

    const pk = item.get("pk").?;
    try std.testing.expectEqualStrings("user123", pk.S);

    const name = item.get("name").?;
    try std.testing.expectEqualStrings("Alice", name.S);

    const age = item.get("age").?;
    try std.testing.expectEqualStrings("25", age.N);
}

test "parse nested map" {
    const allocator = std.testing.allocator;

    const json_str =
        \\{"data":{"M":{"key1":{"S":"value1"},"key2":{"N":"42"}}}}
    ;

    var item = try parseItem(allocator, json_str);
    defer deinitItem(&item, allocator);

    const data = item.get("data").?;
    const inner = data.M.get("key1").?;
    try std.testing.expectEqualStrings("value1", inner.S);
}

test "serialize item round-trip" {
    const allocator = std.testing.allocator;

    const original =
        \\{"pk":{"S":"test"},"num":{"N":"123"}}
    ;

    var item = try parseItem(allocator, original);
    defer deinitItem(&item, allocator);

    const serialized = try serializeItem(allocator, item);
    defer allocator.free(serialized);

    // Parse again to verify
    var item2 = try parseItem(allocator, serialized);
    defer deinitItem(&item2, allocator);

    try std.testing.expectEqual(@as(usize, 2), item2.count());
}

test "build rocksdb key with partition key only" {
    const allocator = std.testing.allocator;

    const item_json = "{\"pk\":{\"S\":\"user123\"},\"data\":{\"S\":\"test\"}}";
    var item = try parseItem(allocator, item_json);
    defer deinitItem(&item, allocator);

    const key_schema = [_]types.KeySchemaElement{
        .{ .attribute_name = "pk", .key_type = .HASH },
    };

    const key = try buildRocksDBKey(allocator, "Users", &key_schema, item);
    defer allocator.free(key);

    try std.testing.expectEqualStrings("_data:Users:user123", key);
}

test "build rocksdb key with partition and sort keys" {
    const allocator = std.testing.allocator;

    const item_json = "{\"pk\":{\"S\":\"user123\"},\"sk\":{\"S\":\"metadata\"}}";
    var item = try parseItem(allocator, item_json);
    defer deinitItem(&item, allocator);

    const key_schema = [_]types.KeySchemaElement{
        .{ .attribute_name = "pk", .key_type = .HASH },
        .{ .attribute_name = "sk", .key_type = .RANGE },
    };

    const key = try buildRocksDBKey(allocator, "Items", &key_schema, item);
    defer allocator.free(key);

    try std.testing.expectEqualStrings("_data:Items:user123:metadata", key);
}


================================================================================
FILE: ./src/dynamodb/storage.zig
================================================================================

/// Storage engine mapping DynamoDB operations to RocksDB
const std = @import("std");
const rocksdb = @import("../rocksdb.zig");
const types = @import("types.zig");
const json = @import("json.zig");

pub const StorageError = error{
    TableNotFound,
    TableAlreadyExists,
    ItemNotFound,
    InvalidKey,
    MissingKeyAttribute,
    SerializationError,
    RocksDBError,
    OutOfMemory,
};

/// Key prefixes for different data types in RocksDB
const KeyPrefix = struct {
    /// Table metadata: _meta:{table_name}
    const meta = "_meta:";
    /// Item data: _data:{table_name}:{partition_key}[:{sort_key}]
    const data = "_data:";
    /// Global secondary index: _gsi:{table_name}:{index_name}:{pk}:{sk}
    const gsi = "_gsi:";
    /// Local secondary index: _lsi:{table_name}:{index_name}:{pk}:{sk}
    const lsi = "_lsi:";
};

/// In-memory representation of table metadata
const TableMetadata = struct {
    table_name: []const u8,
    key_schema: []types.KeySchemaElement,
    attribute_definitions: []types.AttributeDefinition,
    table_status: types.TableStatus,
    creation_date_time: i64,

    pub fn deinit(self: *TableMetadata, allocator: std.mem.Allocator) void {
        allocator.free(self.table_name);
        for (self.key_schema) |ks| {
            allocator.free(ks.attribute_name);
        }
        allocator.free(self.key_schema);
        for (self.attribute_definitions) |ad| {
            allocator.free(ad.attribute_name);
        }
        allocator.free(self.attribute_definitions);
    }
};

pub const StorageEngine = struct {
    db: rocksdb.DB,
    allocator: std.mem.Allocator,

    const Self = @This();

    pub fn init(allocator: std.mem.Allocator, data_dir: [*:0]const u8) !Self {
        const db = rocksdb.DB.open(data_dir, true) catch return StorageError.RocksDBError;
        return Self{
            .db = db,
            .allocator = allocator,
        };
    }

    pub fn deinit(self: *Self) void {
        self.db.close();
    }

    // === Table Operations ===

    pub fn createTable(
        self: *Self,
        table_name: []const u8,
        key_schema: []const types.KeySchemaElement,
        attribute_definitions: []const types.AttributeDefinition,
    ) StorageError!types.TableDescription {
        // Check if table already exists
        const meta_key = try self.buildMetaKey(table_name);
        defer self.allocator.free(meta_key);

        const existing = self.db.get(self.allocator, meta_key) catch return StorageError.RocksDBError;
        if (existing) |e| {
            self.allocator.free(e);
            return StorageError.TableAlreadyExists;
        }

        // Create table metadata
        const now = std.time.timestamp();

        const metadata = TableMetadata{
            .table_name = table_name,
            .key_schema = key_schema,
            .attribute_definitions = attribute_definitions,
            .table_status = .ACTIVE,
            .creation_date_time = now,
        };

        // Serialize and store
        const meta_value = try self.serializeTableMetadata(metadata);
        defer self.allocator.free(meta_value);

        self.db.put(meta_key, meta_value) catch return StorageError.RocksDBError;

        return types.TableDescription{
            .table_name = table_name,
            .key_schema = key_schema,
            .attribute_definitions = attribute_definitions,
            .table_status = .ACTIVE,
            .creation_date_time = now,
            .item_count = 0,
            .table_size_bytes = 0,
        };
    }

    pub fn deleteTable(self: *Self, table_name: []const u8) StorageError!void {
        const meta_key = try self.buildMetaKey(table_name);
        defer self.allocator.free(meta_key);

        // Verify table exists
        const existing = self.db.get(self.allocator, meta_key) catch return StorageError.RocksDBError;
        if (existing == null) return StorageError.TableNotFound;
        self.allocator.free(existing.?);

        // Delete all items with this table's prefix
        const data_prefix = try self.buildDataPrefix(table_name);
        defer self.allocator.free(data_prefix);

        var batch = rocksdb.WriteBatch.init() orelse return StorageError.RocksDBError;
        defer batch.deinit();

        // Scan and delete all matching keys
        var iter = rocksdb.Iterator.init(&self.db) orelse return StorageError.RocksDBError;
        defer iter.deinit();

        iter.seek(data_prefix);
        while (iter.valid()) {
            const key = iter.key() orelse break;
            if (!std.mem.startsWith(u8, key, data_prefix)) break;
            batch.delete(key);
            iter.next();
        }

        // Delete metadata
        batch.delete(meta_key);

        batch.write(&self.db) catch return StorageError.RocksDBError;
    }

    pub fn describeTable(self: *Self, table_name: []const u8) StorageError!types.TableDescription {
        var metadata = try self.getTableMetadata(table_name);
        defer metadata.deinit(self.allocator);

        // Count items (expensive, but matches DynamoDB behavior)
        const data_prefix = try self.buildDataPrefix(table_name);
        defer self.allocator.free(data_prefix);

        var item_count: u64 = 0;
        var total_size: u64 = 0;

        var iter = rocksdb.Iterator.init(&self.db) orelse return StorageError.RocksDBError;
        defer iter.deinit();

        iter.seek(data_prefix);
        while (iter.valid()) {
            const key = iter.key() orelse break;
            if (!std.mem.startsWith(u8, key, data_prefix)) break;

            const value = iter.value() orelse break;
            item_count += 1;
            total_size += value.len;

            iter.next();
        }

        return types.TableDescription{
            .table_name = metadata.table_name,
            .key_schema = metadata.key_schema,
            .attribute_definitions = metadata.attribute_definitions,
            .table_status = metadata.table_status,
            .creation_date_time = metadata.creation_date_time,
            .item_count = item_count,
            .table_size_bytes = total_size,
        };
    }

    pub fn listTables(self: *Self) StorageError![][]const u8 {
        var tables = std.ArrayList([]const u8).init(self.allocator);
        errdefer {
            for (tables.items) |t| self.allocator.free(t);
            tables.deinit();
        }

        var iter = rocksdb.Iterator.init(&self.db) orelse return StorageError.RocksDBError;
        defer iter.deinit();

        iter.seek(KeyPrefix.meta);
        while (iter.valid()) {
            const key = iter.key() orelse break;
            if (!std.mem.startsWith(u8, key, KeyPrefix.meta)) break;

            const table_name = key[KeyPrefix.meta.len..];
            const owned_name = self.allocator.dupe(u8, table_name) catch return StorageError.OutOfMemory;
            tables.append(owned_name) catch return StorageError.OutOfMemory;

            iter.next();
        }

        return tables.toOwnedSlice() catch return StorageError.OutOfMemory;
    }

    // === Item Operations ===

    pub fn putItem(self: *Self, table_name: []const u8, item_json: []const u8) StorageError!void {
        // Get table metadata to retrieve key schema
        var metadata = try self.getTableMetadata(table_name);
        defer metadata.deinit(self.allocator);

        // Parse the item to validate it
        var item = json.parseItem(self.allocator, item_json) catch return StorageError.InvalidKey;
        defer json.deinitItem(&item, self.allocator);

        // Validate that item contains all required key attributes
        for (metadata.key_schema) |key_elem| {
            if (!item.contains(key_elem.attribute_name)) {
                return StorageError.MissingKeyAttribute;
            }
        }

        // Build storage key using the parsed item and actual key schema
        const storage_key = json.buildRocksDBKey(
            self.allocator,
            table_name,
            metadata.key_schema,
            item,
        ) catch return StorageError.InvalidKey;
        defer self.allocator.free(storage_key);

        // Store the original JSON (for now - later we can optimize to binary)
        self.db.put(storage_key, item_json) catch return StorageError.RocksDBError;
    }

    pub fn getItem(self: *Self, table_name: []const u8, key_json: []const u8) StorageError!?[]u8 {
        // Get table metadata
        var metadata = try self.getTableMetadata(table_name);
        defer metadata.deinit(self.allocator);

        // Parse the key
        var key = json.parseItem(self.allocator, key_json) catch return StorageError.InvalidKey;
        defer json.deinitItem(&key, self.allocator);

        // Validate key has all required attributes
        for (metadata.key_schema) |key_elem| {
            if (!key.contains(key_elem.attribute_name)) {
                return StorageError.MissingKeyAttribute;
            }
        }

        // Build storage key
        const storage_key = json.buildRocksDBKey(
            self.allocator,
            table_name,
            metadata.key_schema,
            key,
        ) catch return StorageError.InvalidKey;
        defer self.allocator.free(storage_key);

        return self.db.get(self.allocator, storage_key) catch return StorageError.RocksDBError;
    }

    pub fn deleteItem(self: *Self, table_name: []const u8, key_json: []const u8) StorageError!void {
        // Get table metadata
        var metadata = try self.getTableMetadata(table_name);
        defer metadata.deinit(self.allocator);

        // Parse the key
        var key = json.parseItem(self.allocator, key_json) catch return StorageError.InvalidKey;
        defer json.deinitItem(&key, self.allocator);

        // Validate key
        for (metadata.key_schema) |key_elem| {
            if (!key.contains(key_elem.attribute_name)) {
                return StorageError.MissingKeyAttribute;
            }
        }

        // Build storage key
        const storage_key = json.buildRocksDBKey(
            self.allocator,
            table_name,
            metadata.key_schema,
            key,
        ) catch return StorageError.InvalidKey;
        defer self.allocator.free(storage_key);

        self.db.delete(storage_key) catch return StorageError.RocksDBError;
    }

    pub fn scan(self: *Self, table_name: []const u8, limit: ?usize) StorageError![][]const u8 {
        // Verify table exists
        var metadata = try self.getTableMetadata(table_name);
        defer metadata.deinit(self.allocator);

        const data_prefix = try self.buildDataPrefix(table_name);
        defer self.allocator.free(data_prefix);

        var items = std.ArrayList([]const u8).init(self.allocator);
        errdefer {
            for (items.items) |item| self.allocator.free(item);
            items.deinit();
        }

        var iter = rocksdb.Iterator.init(&self.db) orelse return StorageError.RocksDBError;
        defer iter.deinit();

        var count: usize = 0;
        const max_items = limit orelse std.math.maxInt(usize);

        iter.seek(data_prefix);
        while (iter.valid() and count < max_items) {
            const key = iter.key() orelse break;
            if (!std.mem.startsWith(u8, key, data_prefix)) break;

            const value = iter.value() orelse break;
            const owned_value = self.allocator.dupe(u8, value) catch return StorageError.OutOfMemory;
            items.append(owned_value) catch return StorageError.OutOfMemory;

            count += 1;
            iter.next();
        }

        return items.toOwnedSlice() catch return StorageError.OutOfMemory;
    }

    pub fn query(self: *Self, table_name: []const u8, partition_key_value: []const u8, limit: ?usize) StorageError![][]const u8 {
        // Verify table exists
        var metadata = try self.getTableMetadata(table_name);
        defer metadata.deinit(self.allocator);

        // Build prefix for this partition
        const prefix = try self.buildPartitionPrefix(table_name, partition_key_value);
        defer self.allocator.free(prefix);

        var items = std.ArrayList([]const u8).init(self.allocator);
        errdefer {
            for (items.items) |item| self.allocator.free(item);
            items.deinit();
        }

        var iter = rocksdb.Iterator.init(&self.db) orelse return StorageError.RocksDBError;
        defer iter.deinit();

        var count: usize = 0;
        const max_items = limit orelse std.math.maxInt(usize);

        iter.seek(prefix);
        while (iter.valid() and count < max_items) {
            const key = iter.key() orelse break;
            if (!std.mem.startsWith(u8, key, prefix)) break;

            const value = iter.value() orelse break;
            const owned_value = self.allocator.dupe(u8, value) catch return StorageError.OutOfMemory;
            items.append(owned_value) catch return StorageError.OutOfMemory;

            count += 1;
            iter.next();
        }

        return items.toOwnedSlice() catch return StorageError.OutOfMemory;
    }

    // === Internal Helpers ===

    fn getTableMetadata(self: *Self, table_name: []const u8) StorageError!TableMetadata {
        const meta_key = try self.buildMetaKey(table_name);
        defer self.allocator.free(meta_key);

        const meta_value = self.db.get(self.allocator, meta_key) catch return StorageError.RocksDBError;
        if (meta_value == null) return StorageError.TableNotFound;
        defer self.allocator.free(meta_value.?);

        return self.deserializeTableMetadata(meta_value.?);
    }

    fn buildMetaKey(self: *Self, table_name: []const u8) StorageError![]u8 {
        return std.fmt.allocPrint(self.allocator, "{s}{s}", .{ KeyPrefix.meta, table_name }) catch return StorageError.OutOfMemory;
    }

    fn buildDataPrefix(self: *Self, table_name: []const u8) StorageError![]u8 {
        return std.fmt.allocPrint(self.allocator, "{s}{s}:", .{ KeyPrefix.data, table_name }) catch return StorageError.OutOfMemory;
    }

    fn buildPartitionPrefix(self: *Self, table_name: []const u8, partition_key: []const u8) StorageError![]u8 {
        return std.fmt.allocPrint(self.allocator, "{s}{s}:{s}", .{ KeyPrefix.data, table_name, partition_key }) catch return StorageError.OutOfMemory;
    }

    // === Serialization ===

    fn serializeTableMetadata(self: *Self, metadata: TableMetadata) StorageError![]u8 {
        var buf = std.ArrayList(u8).init(self.allocator);
        errdefer buf.deinit();
        const writer = buf.writer();

        writer.writeAll("{\"TableName\":\"") catch return StorageError.SerializationError;
        writer.writeAll(metadata.table_name) catch return StorageError.SerializationError;
        writer.writeAll("\",\"TableStatus\":\"") catch return StorageError.SerializationError;
        writer.writeAll(metadata.table_status.toString()) catch return StorageError.SerializationError;
        writer.print("\",\"CreationDateTime\":{d},\"KeySchema\":[", .{metadata.creation_date_time}) catch return StorageError.SerializationError;

        for (metadata.key_schema, 0..) |ks, i| {
            if (i > 0) writer.writeByte(',') catch return StorageError.SerializationError;
            writer.writeAll("{\"AttributeName\":\"") catch return StorageError.SerializationError;
            writer.writeAll(ks.attribute_name) catch return StorageError.SerializationError;
            writer.writeAll("\",\"KeyType\":\"") catch return StorageError.SerializationError;
            writer.writeAll(ks.key_type.toString()) catch return StorageError.SerializationError;
            writer.writeAll("\"}") catch return StorageError.SerializationError;
        }

        writer.writeAll("],\"AttributeDefinitions\":[") catch return StorageError.SerializationError;

        for (metadata.attribute_definitions, 0..) |ad, i| {
            if (i > 0) writer.writeByte(',') catch return StorageError.SerializationError;
            writer.writeAll("{\"AttributeName\":\"") catch return StorageError.SerializationError;
            writer.writeAll(ad.attribute_name) catch return StorageError.SerializationError;
            writer.writeAll("\",\"AttributeType\":\"") catch return StorageError.SerializationError;
            writer.writeAll(ad.attribute_type.toString()) catch return StorageError.SerializationError;
            writer.writeAll("\"}") catch return StorageError.SerializationError;
        }

        writer.writeAll("]}") catch return StorageError.SerializationError;

        return buf.toOwnedSlice() catch return StorageError.OutOfMemory;
    }

    fn deserializeTableMetadata(self: *Self, data: []const u8) StorageError!TableMetadata {
        const parsed = std.json.parseFromSlice(std.json.Value, self.allocator, data, .{}) catch return StorageError.SerializationError;
        defer parsed.deinit();

        const root = switch (parsed.value) {
            .object => |o| o,
            else => return StorageError.SerializationError,
        };

        // Extract table name
        const table_name_val = root.get("TableName") orelse return StorageError.SerializationError;
        const table_name_str = switch (table_name_val) {
            .string => |s| s,
            else => return StorageError.SerializationError,
        };
        const table_name = self.allocator.dupe(u8, table_name_str) catch return StorageError.OutOfMemory;
        errdefer self.allocator.free(table_name);

        // Extract table status
        const status_val = root.get("TableStatus") orelse return StorageError.SerializationError;
        const status_str = switch (status_val) {
            .string => |s| s,
            else => return StorageError.SerializationError,
        };
        const table_status: types.TableStatus = if (std.mem.eql(u8, status_str, "ACTIVE"))
            .ACTIVE
        else if (std.mem.eql(u8, status_str, "CREATING"))
            .CREATING
        else if (std.mem.eql(u8, status_str, "DELETING"))
            .DELETING
        else
            .ACTIVE;

        // Extract creation time
        const creation_val = root.get("CreationDateTime") orelse return StorageError.SerializationError;
        const creation_date_time = switch (creation_val) {
            .integer => |i| i,
            else => return StorageError.SerializationError,
        };

        // Extract key schema
        const key_schema_val = root.get("KeySchema") orelse return StorageError.SerializationError;
        const key_schema_array = switch (key_schema_val) {
            .array => |a| a,
            else => return StorageError.SerializationError,
        };

        var key_schema = std.ArrayList(types.KeySchemaElement).init(self.allocator);
        errdefer {
            for (key_schema.items) |ks| self.allocator.free(ks.attribute_name);
            key_schema.deinit();
        }

        for (key_schema_array.items) |item| {
            const obj = switch (item) {
                .object => |o| o,
                else => return StorageError.SerializationError,
            };

            const attr_name_val = obj.get("AttributeName") orelse return StorageError.SerializationError;
            const attr_name_str = switch (attr_name_val) {
                .string => |s| s,
                else => return StorageError.SerializationError,
            };
            const attr_name = self.allocator.dupe(u8, attr_name_str) catch return StorageError.OutOfMemory;
            errdefer self.allocator.free(attr_name);

            const key_type_val = obj.get("KeyType") orelse return StorageError.SerializationError;
            const key_type_str = switch (key_type_val) {
                .string => |s| s,
                else => return StorageError.SerializationError,
            };
            const key_type = types.KeyType.fromString(key_type_str) orelse return StorageError.SerializationError;

            key_schema.append(.{
                .attribute_name = attr_name,
                .key_type = key_type,
            }) catch return StorageError.OutOfMemory;
        }

        // Extract attribute definitions
        const attr_defs_val = root.get("AttributeDefinitions") orelse return StorageError.SerializationError;
        const attr_defs_array = switch (attr_defs_val) {
            .array => |a| a,
            else => return StorageError.SerializationError,
        };

        var attr_defs = std.ArrayList(types.AttributeDefinition).init(self.allocator);
        errdefer {
            for (attr_defs.items) |ad| self.allocator.free(ad.attribute_name);
            attr_defs.deinit();
        }

        for (attr_defs_array.items) |item| {
            const obj = switch (item) {
                .object => |o| o,
                else => return StorageError.SerializationError,
            };

            const attr_name_val = obj.get("AttributeName") orelse return StorageError.SerializationError;
            const attr_name_str = switch (attr_name_val) {
                .string => |s| s,
                else => return StorageError.SerializationError,
            };
            const attr_name = self.allocator.dupe(u8, attr_name_str) catch return StorageError.OutOfMemory;
            errdefer self.allocator.free(attr_name);

            const attr_type_val = obj.get("AttributeType") orelse return StorageError.SerializationError;
            const attr_type_str = switch (attr_type_val) {
                .string => |s| s,
                else => return StorageError.SerializationError,
            };
            const attr_type = types.ScalarAttributeType.fromString(attr_type_str) orelse return StorageError.SerializationError;

            attr_defs.append(.{
                .attribute_name = attr_name,
                .attribute_type = attr_type,
            }) catch return StorageError.OutOfMemory;
        }

        return TableMetadata{
            .table_name = table_name,
            .key_schema = key_schema.toOwnedSlice() catch return StorageError.OutOfMemory,
            .attribute_definitions = attr_defs.toOwnedSlice() catch return StorageError.OutOfMemory,
            .table_status = table_status,
            .creation_date_time = creation_date_time,
        };
    }
};

test "storage basic operations" {
    const allocator = std.testing.allocator;

    const path = "/tmp/test_storage";
    defer std.fs.deleteTreeAbsolute(path) catch {};

    var engine = try StorageEngine.init(allocator, path);
    defer engine.deinit();

    // Create table
    const key_schema = [_]types.KeySchemaElement{
        .{ .attribute_name = "pk", .key_type = .HASH },
    };
    const attr_defs = [_]types.AttributeDefinition{
        .{ .attribute_name = "pk", .attribute_type = .S },
    };

    _ = try engine.createTable("TestTable", &key_schema, &attr_defs);

    // List tables
    const tables = try engine.listTables();
    defer {
        for (tables) |t| allocator.free(t);
        allocator.free(tables);
    }
    try std.testing.expectEqual(@as(usize, 1), tables.len);
    try std.testing.expectEqualStrings("TestTable", tables[0]);

    // Delete table
    try engine.deleteTable("TestTable");

    // Verify deleted
    const tables2 = try engine.listTables();
    defer allocator.free(tables2);
    try std.testing.expectEqual(@as(usize, 0), tables2.len);
}

test "putItem validates key presence" {
    const allocator = std.testing.allocator;

    const path = "/tmp/test_storage_validate";
    defer std.fs.deleteTreeAbsolute(path) catch {};

    var engine = try StorageEngine.init(allocator, path);
    defer engine.deinit();

    const key_schema = [_]types.KeySchemaElement{
        .{ .attribute_name = "userId", .key_type = .HASH },
    };
    const attr_defs = [_]types.AttributeDefinition{
        .{ .attribute_name = "userId", .attribute_type = .S },
    };

    _ = try engine.createTable("Users", &key_schema, &attr_defs);

    // This should fail - missing userId
    const bad_item = "{\"name\":{\"S\":\"Alice\"}}";
    const result = engine.putItem("Users", bad_item);
    try std.testing.expectError(StorageError.MissingKeyAttribute, result);

    // This should succeed
    const good_item = "{\"userId\":{\"S\":\"user123\"},\"name\":{\"S\":\"Alice\"}}";
    try engine.putItem("Users", good_item);
}


================================================================================
FILE: ./src/dynamodb/types.zig
================================================================================

/// DynamoDB protocol types and serialization
const std = @import("std");

/// DynamoDB AttributeValue - the core data type
pub const AttributeValue = union(enum) {
    S: []const u8, // String
    N: []const u8, // Number (stored as string)
    B: []const u8, // Binary (base64)
    SS: []const []const u8, // String Set
    NS: []const []const u8, // Number Set
    BS: []const []const u8, // Binary Set
    M: std.StringHashMap(AttributeValue), // Map
    L: []const AttributeValue, // List
    NULL: bool, // Null
    BOOL: bool, // Boolean
};

pub const Item = std.StringHashMap(AttributeValue);

pub const KeyType = enum {
    HASH,
    RANGE,

    pub fn toString(self: KeyType) []const u8 {
        return switch (self) {
            .HASH => "HASH",
            .RANGE => "RANGE",
        };
    }

    pub fn fromString(s: []const u8) ?KeyType {
        if (std.mem.eql(u8, s, "HASH")) return .HASH;
        if (std.mem.eql(u8, s, "RANGE")) return .RANGE;
        return null;
    }
};

pub const ScalarAttributeType = enum {
    S,
    N,
    B,

    pub fn toString(self: ScalarAttributeType) []const u8 {
        return switch (self) {
            .S => "S",
            .N => "N",
            .B => "B",
        };
    }

    pub fn fromString(s: []const u8) ?ScalarAttributeType {
        if (std.mem.eql(u8, s, "S")) return .S;
        if (std.mem.eql(u8, s, "N")) return .N;
        if (std.mem.eql(u8, s, "B")) return .B;
        return null;
    }
};

pub const KeySchemaElement = struct {
    attribute_name: []const u8,
    key_type: KeyType,
};

pub const AttributeDefinition = struct {
    attribute_name: []const u8,
    attribute_type: ScalarAttributeType,
};

pub const TableStatus = enum {
    CREATING,
    UPDATING,
    DELETING,
    ACTIVE,
    INACCESSIBLE_ENCRYPTION_CREDENTIALS,
    ARCHIVING,
    ARCHIVED,

    pub fn toString(self: TableStatus) []const u8 {
        return switch (self) {
            .CREATING => "CREATING",
            .UPDATING => "UPDATING",
            .DELETING => "DELETING",
            .ACTIVE => "ACTIVE",
            .INACCESSIBLE_ENCRYPTION_CREDENTIALS => "INACCESSIBLE_ENCRYPTION_CREDENTIALS",
            .ARCHIVING => "ARCHIVING",
            .ARCHIVED => "ARCHIVED",
        };
    }
};

pub const TableDescription = struct {
    table_name: []const u8,
    key_schema: []const KeySchemaElement,
    attribute_definitions: []const AttributeDefinition,
    table_status: TableStatus,
    creation_date_time: i64,
    item_count: u64,
    table_size_bytes: u64,
};

/// DynamoDB operation types parsed from X-Amz-Target header
pub const Operation = enum {
    CreateTable,
    DeleteTable,
    DescribeTable,
    ListTables,
    UpdateTable,
    PutItem,
    GetItem,
    DeleteItem,
    UpdateItem,
    Query,
    Scan,
    BatchGetItem,
    BatchWriteItem,
    TransactGetItems,
    TransactWriteItems,
    Unknown,

    pub fn fromTarget(target: []const u8) Operation {
        // Format: DynamoDB_20120810.OperationName
        const prefix = "DynamoDB_20120810.";
        if (!std.mem.startsWith(u8, target, prefix)) return .Unknown;

        const op_name = target[prefix.len..];
        const map = std.StaticStringMap(Operation).initComptime(.{
            .{ "CreateTable", .CreateTable },
            .{ "DeleteTable", .DeleteTable },
            .{ "DescribeTable", .DescribeTable },
            .{ "ListTables", .ListTables },
            .{ "UpdateTable", .UpdateTable },
            .{ "PutItem", .PutItem },
            .{ "GetItem", .GetItem },
            .{ "DeleteItem", .DeleteItem },
            .{ "UpdateItem", .UpdateItem },
            .{ "Query", .Query },
            .{ "Scan", .Scan },
            .{ "BatchGetItem", .BatchGetItem },
            .{ "BatchWriteItem", .BatchWriteItem },
            .{ "TransactGetItems", .TransactGetItems },
            .{ "TransactWriteItems", .TransactWriteItems },
        });
        return map.get(op_name) orelse .Unknown;
    }
};

/// DynamoDB error types
pub const DynamoDBErrorType = enum {
    ValidationException,
    ResourceNotFoundException,
    ResourceInUseException,
    ConditionalCheckFailedException,
    ProvisionedThroughputExceededException,
    ItemCollectionSizeLimitExceededException,
    InternalServerError,
    SerializationException,

    pub fn toErrorResponse(self: DynamoDBErrorType, message: []const u8, allocator: std.mem.Allocator) ![]u8 {
        const type_str = switch (self) {
            .ValidationException => "com.amazonaws.dynamodb.v20120810#ValidationException",
            .ResourceNotFoundException => "com.amazonaws.dynamodb.v20120810#ResourceNotFoundException",
            .ResourceInUseException => "com.amazonaws.dynamodb.v20120810#ResourceInUseException",
            .ConditionalCheckFailedException => "com.amazonaws.dynamodb.v20120810#ConditionalCheckFailedException",
            .ProvisionedThroughputExceededException => "com.amazonaws.dynamodb.v20120810#ProvisionedThroughputExceededException",
            .ItemCollectionSizeLimitExceededException => "com.amazonaws.dynamodb.v20120810#ItemCollectionSizeLimitExceededException",
            .InternalServerError => "com.amazonaws.dynamodb.v20120810#InternalServerError",
            .SerializationException => "com.amazonaws.dynamodb.v20120810#SerializationException",
        };

        return std.fmt.allocPrint(allocator, "{{\"__type\":\"{s}\",\"message\":\"{s}\"}}", .{ type_str, message });
    }
};

// JSON serialization helpers for DynamoDB format
pub const json = struct {
    /// Serialize AttributeValue to DynamoDB JSON format
    pub fn serializeAttributeValue(writer: anytype, value: AttributeValue) !void {
        switch (value) {
            .S => |s| try writer.print("{{\"S\":\"{s}\"}}", .{s}),
            .N => |n| try writer.print("{{\"N\":\"{s}\"}}", .{n}),
            .B => |b| try writer.print("{{\"B\":\"{s}\"}}", .{b}),
            .BOOL => |b| try writer.print("{{\"BOOL\":{}}}", .{b}),
            .NULL => try writer.writeAll("{\"NULL\":true}"),
            .SS => |ss| {
                try writer.writeAll("{\"SS\":[");
                for (ss, 0..) |s, i| {
                    if (i > 0) try writer.writeByte(',');
                    try writer.print("\"{s}\"", .{s});
                }
                try writer.writeAll("]}");
            },
            .NS => |ns| {
                try writer.writeAll("{\"NS\":[");
                for (ns, 0..) |n, i| {
                    if (i > 0) try writer.writeByte(',');
                    try writer.print("\"{s}\"", .{n});
                }
                try writer.writeAll("]}");
            },
            .BS => |bs| {
                try writer.writeAll("{\"BS\":[");
                for (bs, 0..) |b, i| {
                    if (i > 0) try writer.writeByte(',');
                    try writer.print("\"{s}\"", .{b});
                }
                try writer.writeAll("]}");
            },
            .L => |list| {
                try writer.writeAll("{\"L\":[");
                for (list, 0..) |item, i| {
                    if (i > 0) try writer.writeByte(',');
                    try serializeAttributeValue(writer, item);
                }
                try writer.writeAll("]}");
            },
            .M => |map| {
                try writer.writeAll("{\"M\":{");
                var first = true;
                var iter = map.iterator();
                while (iter.next()) |entry| {
                    if (!first) try writer.writeByte(',');
                    first = false;
                    try writer.print("\"{s}\":", .{entry.key_ptr.*});
                    try serializeAttributeValue(writer, entry.value_ptr.*);
                }
                try writer.writeAll("}}");
            },
        }
    }

    /// Serialize an Item (map of attribute name to AttributeValue)
    pub fn serializeItem(writer: anytype, item: Item) !void {
        try writer.writeByte('{');
        var first = true;
        var iter = item.iterator();
        while (iter.next()) |entry| {
            if (!first) try writer.writeByte(',');
            first = false;
            try writer.print("\"{s}\":", .{entry.key_ptr.*});
            try serializeAttributeValue(writer, entry.value_ptr.*);
        }
        try writer.writeByte('}');
    }
};

test "operation from target" {
    try std.testing.expectEqual(Operation.CreateTable, Operation.fromTarget("DynamoDB_20120810.CreateTable"));
    try std.testing.expectEqual(Operation.PutItem, Operation.fromTarget("DynamoDB_20120810.PutItem"));
    try std.testing.expectEqual(Operation.Unknown, Operation.fromTarget("Invalid"));
}


================================================================================
FILE: ./src/http.zig
================================================================================

/// Simple HTTP server for DynamoDB API
const std = @import("std");
const net = std.net;
const mem = std.mem;

pub const Method = enum {
    GET,
    POST,
    PUT,
    DELETE,
    OPTIONS,
    HEAD,
    PATCH,

    pub fn fromString(s: []const u8) ?Method {
        const map = std.StaticStringMap(Method).initComptime(.{
            .{ "GET", .GET },
            .{ "POST", .POST },
            .{ "PUT", .PUT },
            .{ "DELETE", .DELETE },
            .{ "OPTIONS", .OPTIONS },
            .{ "HEAD", .HEAD },
            .{ "PATCH", .PATCH },
        });
        return map.get(s);
    }
};

pub const StatusCode = enum(u16) {
    ok = 200,
    created = 201,
    no_content = 204,
    bad_request = 400,
    unauthorized = 401,
    forbidden = 403,
    not_found = 404,
    method_not_allowed = 405,
    conflict = 409,
    internal_server_error = 500,
    service_unavailable = 503,

    pub fn phrase(self: StatusCode) []const u8 {
        return switch (self) {
            .ok => "OK",
            .created => "Created",
            .no_content => "No Content",
            .bad_request => "Bad Request",
            .unauthorized => "Unauthorized",
            .forbidden => "Forbidden",
            .not_found => "Not Found",
            .method_not_allowed => "Method Not Allowed",
            .conflict => "Conflict",
            .internal_server_error => "Internal Server Error",
            .service_unavailable => "Service Unavailable",
        };
    }
};

pub const Header = struct {
    name: []const u8,
    value: []const u8,
};

pub const Request = struct {
    method: Method,
    path: []const u8,
    headers: []const Header,
    body: []const u8,
    raw_data: []const u8,

    pub fn getHeader(self: *const Request, name: []const u8) ?[]const u8 {
        for (self.headers) |h| {
            if (std.ascii.eqlIgnoreCase(h.name, name)) {
                return h.value;
            }
        }
        return null;
    }
};

pub const Response = struct {
    status: StatusCode,
    headers: std.ArrayList(Header),
    body: std.ArrayList(u8),
    allocator: mem.Allocator,

    pub fn init(allocator: mem.Allocator) Response {
        return .{
            .status = .ok,
            .headers = std.ArrayList(Header){},
            .body = std.ArrayList(u8){},
            .allocator = allocator,
        };
    }

    pub fn deinit(self: *Response) void {
        self.headers.deinit(self.allocator);
        self.body.deinit(self.allocator);
    }

    pub fn setStatus(self: *Response, status: StatusCode) void {
        self.status = status;
    }

    pub fn addHeader(self: *Response, name: []const u8, value: []const u8) !void {
        try self.headers.append(self.allocator, .{ .name = name, .value = value });
    }

    pub fn setBody(self: *Response, data: []const u8) !void {
        self.body.clearRetainingCapacity();
        try self.body.appendSlice(self.allocator, data);
    }

    pub fn appendBody(self: *Response, data: []const u8) !void {
        try self.body.appendSlice(self.allocator, data);
    }

    pub fn serialize(self: *Response, allocator: mem.Allocator) ![]u8 {
        var buf = std.ArrayList(u8){};
        errdefer buf.deinit(allocator);
        const writer = buf.writer(allocator);

        // Status line
        try writer.print("HTTP/1.1 {d} {s}\r\n", .{ @intFromEnum(self.status), self.status.phrase() });

        // Content-Length header
        try writer.print("Content-Length: {d}\r\n", .{self.body.items.len});

        // Custom headers
        for (self.headers.items) |h| {
            try writer.print("{s}: {s}\r\n", .{ h.name, h.value });
        }

        // End of headers
        try writer.writeAll("\r\n");

        // Body
        try writer.writeAll(self.body.items);

        return buf.toOwnedSlice(allocator);
    }
};

pub const RequestHandler = *const fn (*const Request, mem.Allocator) Response;

pub const Server = struct {
    allocator: mem.Allocator,
    address: net.Address,
    handler: RequestHandler,
    running: std.atomic.Value(bool),
    listener: ?net.Server,

    const Self = @This();

    pub fn init(allocator: mem.Allocator, host: []const u8, port: u16, handler: RequestHandler) !Self {
        const address = try net.Address.parseIp(host, port);
        return Self{
            .allocator = allocator,
            .address = address,
            .handler = handler,
            .running = std.atomic.Value(bool).init(false),
            .listener = null,
        };
    }

    pub fn start(self: *Self) !void {
        self.listener = try self.address.listen(.{
            .reuse_address = true,
        });
        self.running.store(true, .release);

        std.log.info("Server listening on {any}", .{self.address});

        while (self.running.load(.acquire)) {
            const conn = self.listener.?.accept() catch |err| {
                if (err == error.SocketNotListening) break;
                std.log.err("Accept error: {any}", .{err});
                continue;
            };

            // Spawn thread for each connection
            const thread = std.Thread.spawn(.{}, handleConnection, .{ self, conn }) catch |err| {
                std.log.err("Thread spawn error: {any}", .{err});
                conn.stream.close();
                continue;
            };
            thread.detach();
        }
    }

    fn handleConnection(self: *Self, conn: net.Server.Connection) void {
        defer conn.stream.close();

        var buf: [65536]u8 = undefined;
        var total_read: usize = 0;

        // Read request
        while (total_read < buf.len) {
            const n = conn.stream.read(buf[total_read..]) catch |err| {
                std.log.err("Read error: {any}", .{err});
                return;
            };
            if (n == 0) break;
            total_read += n;

            // Check if we have complete headers
            if (mem.indexOf(u8, buf[0..total_read], "\r\n\r\n")) |header_end| {
                // Parse Content-Length if present
                const headers = buf[0..header_end];
                var content_length: usize = 0;

                var lines = mem.splitSequence(u8, headers, "\r\n");
                while (lines.next()) |line| {
                    if (std.ascii.startsWithIgnoreCase(line, "content-length:")) {
                        const val = mem.trim(u8, line["content-length:".len..], " ");
                        content_length = std.fmt.parseInt(usize, val, 10) catch 0;
                        break;
                    }
                }

                const body_start = header_end + 4;
                const body_received = total_read - body_start;

                if (body_received >= content_length) break;
            }
        }

        if (total_read == 0) return;

        // Parse and handle request
        const request = parseRequest(self.allocator, buf[0..total_read]) catch |err| {
            std.log.err("Parse error: {any}", .{err});
            const error_response = "HTTP/1.1 400 Bad Request\r\nContent-Length: 0\r\n\r\n";
            _ = conn.stream.write(error_response) catch {};
            return;
        };
        defer self.allocator.free(request.headers);

        var response = self.handler(&request, self.allocator);
        defer response.deinit();

        const response_data = response.serialize(self.allocator) catch |err| {
            std.log.err("Serialize error: {any}", .{err});
            return;
        };
        defer self.allocator.free(response_data);

        _ = conn.stream.write(response_data) catch |err| {
            std.log.err("Write error: {any}", .{err});
        };
    }

    pub fn stop(self: *Self) void {
        self.running.store(false, .release);
        if (self.listener) |*l| {
            l.deinit();
            self.listener = null;
        }
    }
};

fn parseRequest(allocator: mem.Allocator, data: []const u8) !Request {
    // Find end of headers
    const header_end = mem.indexOf(u8, data, "\r\n\r\n") orelse return error.InvalidRequest;

    // Parse request line
    var lines = mem.splitSequence(u8, data[0..header_end], "\r\n");
    const request_line = lines.next() orelse return error.InvalidRequest;

    var parts = mem.splitScalar(u8, request_line, ' ');
    const method_str = parts.next() orelse return error.InvalidRequest;
    const path = parts.next() orelse return error.InvalidRequest;

    const method = Method.fromString(method_str) orelse return error.InvalidMethod;

    // Parse headers
    var headers = std.ArrayList(Header){};
    errdefer headers.deinit(allocator);

    while (lines.next()) |line| {
        if (line.len == 0) break;
        const colon = mem.indexOf(u8, line, ":") orelse continue;
        const name = mem.trim(u8, line[0..colon], " ");
        const value = mem.trim(u8, line[colon + 1 ..], " ");
        try headers.append(allocator, .{ .name = name, .value = value });
    }

    // Body is after \r\n\r\n
    const body_start = header_end + 4;
    const body = if (body_start < data.len) data[body_start..] else "";

    return Request{
        .method = method,
        .path = path,
        .headers = try headers.toOwnedSlice(allocator),
        .body = body,
        .raw_data = data,
    };
}

// Tests
test "parse simple request" {
    const allocator = std.testing.allocator;
    const raw = "GET /health HTTP/1.1\r\nHost: localhost\r\n\r\n";

    const req = try parseRequest(allocator, raw);
    defer allocator.free(req.headers);

    try std.testing.expectEqual(Method.GET, req.method);
    try std.testing.expectEqualStrings("/health", req.path);
}

test "parse request with body" {
    const allocator = std.testing.allocator;
    const raw = "POST /items HTTP/1.1\r\nHost: localhost\r\nContent-Length: 13\r\n\r\n{\"key\":\"val\"}";

    const req = try parseRequest(allocator, raw);
    defer allocator.free(req.headers);

    try std.testing.expectEqual(Method.POST, req.method);
    try std.testing.expectEqualStrings("{\"key\":\"val\"}", req.body);
}


================================================================================
FILE: ./src/main.zig
================================================================================

/// ZynamoDB - A DynamoDB-compatible database using RocksDB
const std = @import("std");
const http = @import("http.zig");
const rocksdb = @import("rocksdb.zig");
const storage = @import("dynamodb/storage.zig");
const handler = @import("dynamodb/handler.zig");

const Config = struct {
    host: []const u8 = "0.0.0.0",
    port: u16 = 8000,
    data_dir: [:0]const u8 = "./data",
    verbose: bool = false,
};

pub fn main() !void {
    var gpa = std.heap.GeneralPurposeAllocator(.{}){};
    defer _ = gpa.deinit();
    const allocator = gpa.allocator();

    // Parse command line args
    const config = try parseArgs(allocator);

    // Print banner
    printBanner(config);

    // Ensure data directory exists
    std.fs.cwd().makePath(config.data_dir) catch |err| {
        std.log.err("Failed to create data directory: {any}", .{err});
        return;
    };

    // Initialize storage engine
    var engine = storage.StorageEngine.init(allocator, config.data_dir) catch |err| {
        std.log.err("Failed to initialize storage: {any}", .{err});
        return;
    };
    defer engine.deinit();

    std.log.info("Storage engine initialized at {s}", .{config.data_dir});

    // Initialize API handler
    var api_handler = handler.ApiHandler.init(allocator, &engine);
    handler.setGlobalHandler(&api_handler);

    // Start HTTP server
    var server = try http.Server.init(allocator, config.host, config.port, handler.httpHandler);
    defer server.stop();

    std.log.info("Starting DynamoDB-compatible server on {s}:{d}", .{ config.host, config.port });
    std.log.info("Ready to accept connections!", .{});

    try server.start();
}

fn parseArgs(allocator: std.mem.Allocator) !Config {
    var config = Config{};
    var args = try std.process.argsWithAllocator(allocator);
    defer args.deinit();

    // Skip program name
    _ = args.next();

    while (args.next()) |arg| {
        if (std.mem.eql(u8, arg, "--port") or std.mem.eql(u8, arg, "-p")) {
            if (args.next()) |port_str| {
                config.port = std.fmt.parseInt(u16, port_str, 10) catch 8000;
            }
        } else if (std.mem.eql(u8, arg, "--host") or std.mem.eql(u8, arg, "-h")) {
            if (args.next()) |host| {
                config.host = host;
            }
        } else if (std.mem.eql(u8, arg, "--data-dir") or std.mem.eql(u8, arg, "-d")) {
            if (args.next()) |dir| {
                // Need sentinel-terminated string for RocksDB
                const owned = try allocator.dupeZ(u8, dir);
                config.data_dir = owned;
            }
        } else if (std.mem.eql(u8, arg, "--verbose") or std.mem.eql(u8, arg, "-v")) {
            config.verbose = true;
        } else if (std.mem.eql(u8, arg, "--help")) {
            printHelp();
            std.process.exit(0);
        }
    }

    // Check environment variables
    if (std.posix.getenv("DYNAMODB_PORT")) |port_str| {
        config.port = std.fmt.parseInt(u16, port_str, 10) catch config.port;
    }
    if (std.posix.getenv("ROCKSDB_DATA_DIR")) |dir| {
        config.data_dir = std.mem.span(@as([*:0]const u8, @ptrCast(dir.ptr)));
    }

    return config;
}

fn printHelp() void {
    const help =
        \\ZynamoDB - DynamoDB-compatible database
        \\
        \\Usage: zynamodb [OPTIONS]
        \\
        \\Options:
        \\  -p, --port <PORT>      Port to listen on (default: 8000)
        \\  -h, --host <HOST>      Host to bind to (default: 0.0.0.0)
        \\  -d, --data-dir <DIR>   Data directory (default: ./data)
        \\  -v, --verbose          Enable verbose logging
        \\      --help             Show this help message
        \\
        \\Environment Variables:
        \\  DYNAMODB_PORT          Override port
        \\  ROCKSDB_DATA_DIR       Override data directory
        \\
        \\Examples:
        \\  zynamodb                           # Start with defaults
        \\  zynamodb -p 8080 -d /var/lib/db   # Custom port and data dir
        \\
    ;
    std.debug.print("{s}", .{help});
}

fn printBanner(config: Config) void {
    const banner =
        \\
        \\  ╔═══════════════════════════════════════════════╗
        \\  ║                                               ║
        \\  ║   ███████╗██╗   ██╗███╗   ██╗ █████╗          ║
        \\  ║   ╚══███╔╝╚██╗ ██╔╝████╗  ██║██╔══██╗         ║
        \\  ║     ███╔╝  ╚████╔╝ ██╔██╗ ██║███████║         ║
        \\  ║    ███╔╝    ╚██╔╝  ██║╚██╗██║██╔══██║         ║
        \\  ║   ███████╗   ██║   ██║ ╚████║██║  ██║         ║
        \\  ║   ╚══════╝   ╚═╝   ╚═╝  ╚═══╝╚═╝  ╚═╝         ║
        \\  ║                                               ║
        \\  ║   DynamoDB-Compatible Database                ║
        \\  ║   Powered by RocksDB + Zig                    ║
        \\  ║                                               ║
        \\  ╚═══════════════════════════════════════════════╝
        \\
    ;
    std.debug.print("{s}", .{banner});
    std.debug.print("  Port: {d} | Data Dir: {s}\n\n", .{ config.port, config.data_dir });
}

// Re-export modules for testing
pub const _rocksdb = rocksdb;
pub const _http = http;
pub const _storage = storage;
pub const _handler = handler;

test {
    std.testing.refAllDeclsRecursive(@This());
}


================================================================================
FILE: ./src/rocksdb.zig
================================================================================

/// RocksDB bindings for Zig via the C API
const std = @import("std");

pub const c = @cImport({
    @cInclude("rocksdb/c.h");
});

pub const RocksDBError = error{
    OpenFailed,
    WriteFailed,
    ReadFailed,
    DeleteFailed,
    InvalidArgument,
    Corruption,
    NotFound,
    IOError,
    Unknown,
};

pub const DB = struct {
    handle: *c.rocksdb_t,
    options: *c.rocksdb_options_t,
    write_options: *c.rocksdb_writeoptions_t,
    read_options: *c.rocksdb_readoptions_t,

    const Self = @This();

    pub fn open(path: [*:0]const u8, create_if_missing: bool) RocksDBError!Self {
        const options = c.rocksdb_options_create() orelse return RocksDBError.Unknown;
        c.rocksdb_options_set_create_if_missing(options, if (create_if_missing) 1 else 0);

        // Performance options
        c.rocksdb_options_increase_parallelism(options, @as(c_int, @intCast(std.Thread.getCpuCount() catch 4)));
        c.rocksdb_options_optimize_level_style_compaction(options, 512 * 1024 * 1024); // 512MB
        c.rocksdb_options_set_compression(options, c.rocksdb_lz4_compression);

        var err: [*c]u8 = null;
        const db = c.rocksdb_open(options, path, &err);
        if (err != null) {
            defer c.rocksdb_free(err);
            return RocksDBError.OpenFailed;
        }

        const write_options = c.rocksdb_writeoptions_create() orelse {
            c.rocksdb_close(db);
            c.rocksdb_options_destroy(options);
            return RocksDBError.Unknown;
        };

        const read_options = c.rocksdb_readoptions_create() orelse {
            c.rocksdb_writeoptions_destroy(write_options);
            c.rocksdb_close(db);
            c.rocksdb_options_destroy(options);
            return RocksDBError.Unknown;
        };

        return Self{
            .handle = db.?,
            .options = options,
            .write_options = write_options,
            .read_options = read_options,
        };
    }

    pub fn close(self: *Self) void {
        c.rocksdb_readoptions_destroy(self.read_options);
        c.rocksdb_writeoptions_destroy(self.write_options);
        c.rocksdb_close(self.handle);
        c.rocksdb_options_destroy(self.options);
    }

    pub fn put(self: *Self, key: []const u8, value: []const u8) RocksDBError!void {
        var err: [*c]u8 = null;
        c.rocksdb_put(
            self.handle,
            self.write_options,
            key.ptr,
            key.len,
            value.ptr,
            value.len,
            &err,
        );
        if (err != null) {
            defer c.rocksdb_free(err);
            return RocksDBError.WriteFailed;
        }
    }

    pub fn get(self: *Self, allocator: std.mem.Allocator, key: []const u8) RocksDBError!?[]u8 {
        var err: [*c]u8 = null;
        var value_len: usize = 0;
        const value = c.rocksdb_get(
            self.handle,
            self.read_options,
            key.ptr,
            key.len,
            &value_len,
            &err,
        );
        if (err != null) {
            defer c.rocksdb_free(err);
            return RocksDBError.ReadFailed;
        }
        if (value == null) {
            return null;
        }
        defer c.rocksdb_free(value);

        const result = allocator.alloc(u8, value_len) catch return RocksDBError.Unknown;
        @memcpy(result, value[0..value_len]);
        return result;
    }

    pub fn delete(self: *Self, key: []const u8) RocksDBError!void {
        var err: [*c]u8 = null;
        c.rocksdb_delete(
            self.handle,
            self.write_options,
            key.ptr,
            key.len,
            &err,
        );
        if (err != null) {
            defer c.rocksdb_free(err);
            return RocksDBError.DeleteFailed;
        }
    }

    pub fn flush(self: *Self) RocksDBError!void {
        const flush_opts = c.rocksdb_flushoptions_create() orelse return RocksDBError.Unknown;
        defer c.rocksdb_flushoptions_destroy(flush_opts);

        var err: [*c]u8 = null;
        c.rocksdb_flush(self.handle, flush_opts, &err);
        if (err != null) {
            defer c.rocksdb_free(err);
            return RocksDBError.IOError;
        }
    }
};

pub const WriteBatch = struct {
    handle: *c.rocksdb_writebatch_t,

    const Self = @This();

    pub fn init() ?Self {
        const handle = c.rocksdb_writebatch_create() orelse return null;
        return Self{ .handle = handle };
    }

    pub fn deinit(self: *Self) void {
        c.rocksdb_writebatch_destroy(self.handle);
    }

    pub fn put(self: *Self, key: []const u8, value: []const u8) void {
        c.rocksdb_writebatch_put(self.handle, key.ptr, key.len, value.ptr, value.len);
    }

    pub fn delete(self: *Self, key: []const u8) void {
        c.rocksdb_writebatch_delete(self.handle, key.ptr, key.len);
    }

    pub fn clear(self: *Self) void {
        c.rocksdb_writebatch_clear(self.handle);
    }

    pub fn write(self: *Self, db: *DB) RocksDBError!void {
        var err: [*c]u8 = null;
        c.rocksdb_write(db.handle, db.write_options, self.handle, &err);
        if (err != null) {
            defer c.rocksdb_free(err);
            return RocksDBError.WriteFailed;
        }
    }
};

pub const Iterator = struct {
    handle: *c.rocksdb_iterator_t,

    const Self = @This();

    pub fn init(db: *DB) ?Self {
        const handle = c.rocksdb_create_iterator(db.handle, db.read_options) orelse return null;
        return Self{ .handle = handle };
    }

    pub fn deinit(self: *Self) void {
        c.rocksdb_iter_destroy(self.handle);
    }

    pub fn seekToFirst(self: *Self) void {
        c.rocksdb_iter_seek_to_first(self.handle);
    }

    pub fn seekToLast(self: *Self) void {
        c.rocksdb_iter_seek_to_last(self.handle);
    }

    pub fn seek(self: *Self, target: []const u8) void {
        c.rocksdb_iter_seek(self.handle, target.ptr, target.len);
    }

    pub fn seekForPrev(self: *Self, target: []const u8) void {
        c.rocksdb_iter_seek_for_prev(self.handle, target.ptr, target.len);
    }

    pub fn valid(self: *Self) bool {
        return c.rocksdb_iter_valid(self.handle) != 0;
    }

    pub fn next(self: *Self) void {
        c.rocksdb_iter_next(self.handle);
    }

    pub fn prev(self: *Self) void {
        c.rocksdb_iter_prev(self.handle);
    }

    pub fn key(self: *Self) ?[]const u8 {
        var len: usize = 0;
        const k = c.rocksdb_iter_key(self.handle, &len);
        if (k == null) return null;
        return k[0..len];
    }

    pub fn value(self: *Self) ?[]const u8 {
        var len: usize = 0;
        const v = c.rocksdb_iter_value(self.handle, &len);
        if (v == null) return null;
        return v[0..len];
    }
};

// Tests
test "rocksdb basic operations" {
    const allocator = std.testing.allocator;

    // Use temp directory
    const path = "/tmp/test_rocksdb_basic";
    defer {
        std.fs.deleteTreeAbsolute(path) catch {};
    }

    var db = try DB.open(path, true);
    defer db.close();

    // Put and get
    try db.put("hello", "world");
    const val = try db.get(allocator, "hello");
    try std.testing.expectEqualStrings("world", val.?);
    allocator.free(val.?);

    // Delete
    try db.delete("hello");
    const deleted = try db.get(allocator, "hello");
    try std.testing.expect(deleted == null);
}

test "rocksdb write batch" {
    const allocator = std.testing.allocator;

    const path = "/tmp/test_rocksdb_batch";
    defer {
        std.fs.deleteTreeAbsolute(path) catch {};
    }

    var db = try DB.open(path, true);
    defer db.close();

    var batch = WriteBatch.init() orelse unreachable;
    defer batch.deinit();

    batch.put("key1", "value1");
    batch.put("key2", "value2");
    batch.put("key3", "value3");

    try batch.write(&db);

    const v1 = try db.get(allocator, "key1");
    defer if (v1) |v| allocator.free(v);
    try std.testing.expectEqualStrings("value1", v1.?);
}

test "rocksdb iterator" {
    const path = "/tmp/test_rocksdb_iter";
    defer {
        std.fs.deleteTreeAbsolute(path) catch {};
    }

    var db = try DB.open(path, true);
    defer db.close();

    try db.put("a", "1");
    try db.put("b", "2");
    try db.put("c", "3");

    var iter = Iterator.init(&db) orelse unreachable;
    defer iter.deinit();

    iter.seekToFirst();

    var count: usize = 0;
    while (iter.valid()) : (iter.next()) {
        count += 1;
    }
    try std.testing.expectEqual(@as(usize, 3), count);
}


================================================================================
FILE: ./tests/integration.zig
================================================================================

/// Integration tests for ZynamoDB
const std = @import("std");

// Import modules from main source
const rocksdb = @import("../src/rocksdb.zig");
const storage = @import("../src/dynamodb/storage.zig");
const types = @import("../src/dynamodb/types.zig");

test "integration: full table lifecycle" {
    const allocator = std.testing.allocator;

    // Setup
    const path = "/tmp/test_integration_lifecycle";
    defer std.fs.deleteTreeAbsolute(path) catch {};

    var engine = try storage.StorageEngine.init(allocator, path);
    defer engine.deinit();

    // Create table
    const key_schema = [_]types.KeySchemaElement{
        .{ .attribute_name = "pk", .key_type = .HASH },
    };
    const attr_defs = [_]types.AttributeDefinition{
        .{ .attribute_name = "pk", .attribute_type = .S },
    };

    const desc = try engine.createTable("Users", &key_schema, &attr_defs);
    try std.testing.expectEqualStrings("Users", desc.table_name);
    try std.testing.expectEqual(types.TableStatus.ACTIVE, desc.table_status);

    // Put items
    try engine.putItem("Users", "{\"pk\":{\"S\":\"user1\"},\"name\":{\"S\":\"Alice\"}}");
    try engine.putItem("Users", "{\"pk\":{\"S\":\"user2\"},\"name\":{\"S\":\"Bob\"}}");
    try engine.putItem("Users", "{\"pk\":{\"S\":\"user3\"},\"name\":{\"S\":\"Charlie\"}}");

    // Get item
    const item = try engine.getItem("Users", "{\"pk\":{\"S\":\"user1\"}}");
    try std.testing.expect(item != null);
    defer allocator.free(item.?);

    // Scan
    const all_items = try engine.scan("Users", null);
    defer {
        for (all_items) |i| allocator.free(i);
        allocator.free(all_items);
    }
    try std.testing.expectEqual(@as(usize, 3), all_items.len);

    // Delete item
    try engine.deleteItem("Users", "{\"pk\":{\"S\":\"user2\"}}");

    // Verify deletion
    const after_delete = try engine.scan("Users", null);
    defer {
        for (after_delete) |i| allocator.free(i);
        allocator.free(after_delete);
    }
    try std.testing.expectEqual(@as(usize, 2), after_delete.len);

    // Delete table
    try engine.deleteTable("Users");

    // Verify table deletion
    const tables = try engine.listTables();
    defer allocator.free(tables);
    try std.testing.expectEqual(@as(usize, 0), tables.len);
}

test "integration: multiple tables" {
    const allocator = std.testing.allocator;

    const path = "/tmp/test_integration_multi_table";
    defer std.fs.deleteTreeAbsolute(path) catch {};

    var engine = try storage.StorageEngine.init(allocator, path);
    defer engine.deinit();

    const key_schema = [_]types.KeySchemaElement{
        .{ .attribute_name = "pk", .key_type = .HASH },
    };
    const attr_defs = [_]types.AttributeDefinition{
        .{ .attribute_name = "pk", .attribute_type = .S },
    };

    // Create multiple tables
    _ = try engine.createTable("Table1", &key_schema, &attr_defs);
    _ = try engine.createTable("Table2", &key_schema, &attr_defs);
    _ = try engine.createTable("Table3", &key_schema, &attr_defs);

    // List tables
    const tables = try engine.listTables();
    defer {
        for (tables) |t| allocator.free(t);
        allocator.free(tables);
    }
    try std.testing.expectEqual(@as(usize, 3), tables.len);

    // Put items in different tables
    try engine.putItem("Table1", "{\"pk\":{\"S\":\"item1\"}}");
    try engine.putItem("Table2", "{\"pk\":{\"S\":\"item2\"}}");
    try engine.putItem("Table3", "{\"pk\":{\"S\":\"item3\"}}");

    // Verify isolation - scan should only return items from that table
    const table1_items = try engine.scan("Table1", null);
    defer {
        for (table1_items) |i| allocator.free(i);
        allocator.free(table1_items);
    }
    try std.testing.expectEqual(@as(usize, 1), table1_items.len);
}

test "integration: table already exists error" {
    const allocator = std.testing.allocator;

    const path = "/tmp/test_integration_exists";
    defer std.fs.deleteTreeAbsolute(path) catch {};

    var engine = try storage.StorageEngine.init(allocator, path);
    defer engine.deinit();

    const key_schema = [_]types.KeySchemaElement{
        .{ .attribute_name = "pk", .key_type = .HASH },
    };
    const attr_defs = [_]types.AttributeDefinition{
        .{ .attribute_name = "pk", .attribute_type = .S },
    };

    // Create table
    _ = try engine.createTable("DuplicateTest", &key_schema, &attr_defs);

    // Try to create again - should fail
    const result = engine.createTable("DuplicateTest", &key_schema, &attr_defs);
    try std.testing.expectError(storage.StorageError.TableAlreadyExists, result);
}

test "integration: table not found error" {
    const allocator = std.testing.allocator;

    const path = "/tmp/test_integration_notfound";
    defer std.fs.deleteTreeAbsolute(path) catch {};

    var engine = try storage.StorageEngine.init(allocator, path);
    defer engine.deinit();

    // Try to put item in non-existent table
    const result = engine.putItem("NonExistent", "{\"pk\":{\"S\":\"item1\"}}");
    try std.testing.expectError(storage.StorageError.TableNotFound, result);
}

test "integration: scan with limit" {
    const allocator = std.testing.allocator;

    const path = "/tmp/test_integration_scan_limit";
    defer std.fs.deleteTreeAbsolute(path) catch {};

    var engine = try storage.StorageEngine.init(allocator, path);
    defer engine.deinit();

    const key_schema = [_]types.KeySchemaElement{
        .{ .attribute_name = "pk", .key_type = .HASH },
    };
    const attr_defs = [_]types.AttributeDefinition{
        .{ .attribute_name = "pk", .attribute_type = .S },
    };

    _ = try engine.createTable("LimitTest", &key_schema, &attr_defs);

    // Add many items
    var i: usize = 0;
    while (i < 10) : (i += 1) {
        var buf: [128]u8 = undefined;
        const item = try std.fmt.bufPrint(&buf, "{{\"pk\":{{\"S\":\"item{d}\"}}}}", .{i});
        try engine.putItem("LimitTest", item);
    }

    // Scan with limit
    const limited = try engine.scan("LimitTest", 5);
    defer {
        for (limited) |item| allocator.free(item);
        allocator.free(limited);
    }
    try std.testing.expectEqual(@as(usize, 5), limited.len);
}