#include "rocksdb_shim.h"
#include <rocksdb/db.h>
#include <rocksdb/options.h>
#include <rocksdb/slice.h>
#include <cstring>
#include <string>

// Internal structure wrapping rocksdb::DB
struct jormun_db {
    rocksdb::DB* db;
};

// Placeholder for WAL iterator (not implemented yet)
struct jormun_wal_iter {
    // TODO: Implement with TransactionLogIterator when needed
    void* placeholder;
};

// Open database
jormun_db* jormun_db_open(const char* path, int create_if_missing, char** err) {
    rocksdb::Options options;
    options.create_if_missing = create_if_missing != 0;
    
    rocksdb::DB* db_ptr = nullptr;
    rocksdb::Status status = rocksdb::DB::Open(options, path, &db_ptr);
    
    if (!status.ok()) {
        if (err) {
            std::string error_msg = status.ToString();
            *err = strdup(error_msg.c_str());
        }
        return nullptr;
    }
    
    jormun_db* jdb = new jormun_db;
    jdb->db = db_ptr;
    return jdb;
}

// Close database
void jormun_db_close(jormun_db* db) {
    if (db) {
        delete db->db;
        delete db;
    }
}

// Put key-value pair
void jormun_db_put(jormun_db* db,
                   const void* key, size_t keylen,
                   const void* val, size_t vallen,
                   char** err) {
    if (!db || !db->db) {
        if (err) *err = strdup("Database is null");
        return;
    }
    
    rocksdb::WriteOptions write_options;
    rocksdb::Slice key_slice(static_cast<const char*>(key), keylen);
    rocksdb::Slice val_slice(static_cast<const char*>(val), vallen);
    
    rocksdb::Status status = db->db->Put(write_options, key_slice, val_slice);
    
    if (!status.ok() && err) {
        std::string error_msg = status.ToString();
        *err = strdup(error_msg.c_str());
    }
}

// Get value for key
unsigned char* jormun_db_get(jormun_db* db,
                             const void* key, size_t keylen,
                             size_t* vallen,
                             char** err) {
    if (!db || !db->db) {
        if (err) *err = strdup("Database is null");
        return nullptr;
    }
    
    rocksdb::ReadOptions read_options;
    rocksdb::Slice key_slice(static_cast<const char*>(key), keylen);
    std::string value;
    
    rocksdb::Status status = db->db->Get(read_options, key_slice, &value);
    
    if (status.IsNotFound()) {
        *vallen = 0;
        return nullptr;
    }
    
    if (!status.ok()) {
        if (err) {
            std::string error_msg = status.ToString();
            *err = strdup(error_msg.c_str());
        }
        return nullptr;
    }
    
    // Allocate and copy value
    *vallen = value.size();
    unsigned char* result = static_cast<unsigned char*>(malloc(value.size()));
    if (result) {
        memcpy(result, value.data(), value.size());
    }
    
    return result;
}

// Free memory allocated by the shim
void jormun_free(void* p) {
    free(p);
}

// ============================================================================
// WAL Replication Functions (Stubs for now - to be implemented)
// ============================================================================

// Get latest sequence number
uint64_t jormun_latest_sequence(jormun_db* db) {
    if (!db || !db->db) return 0;
    return db->db->GetLatestSequenceNumber();
}

// Create WAL iterator (stub)
jormun_wal_iter* jormun_wal_iter_create(jormun_db* db, uint64_t seq, char** err) {
    (void)db;
    (void)seq;
    if (err) {
        *err = strdup("WAL iteration not yet implemented");
    }
    return nullptr;
}

// Destroy WAL iterator (stub)
void jormun_wal_iter_destroy(jormun_wal_iter* it) {
    if (it) {
        delete it;
    }
}

// Get next batch from WAL (stub)
int jormun_wal_iter_next(jormun_wal_iter* it,
                         uint64_t* batch_start_seq,
                         unsigned char** out_data,
                         size_t* out_len,
                         char** err) {
    (void)it;
    (void)batch_start_seq;
    (void)out_data;
    (void)out_len;
    if (err) {
        *err = strdup("WAL iteration not yet implemented");
    }
    return 0;
}

// Apply write batch (stub)
void jormun_apply_writebatch(jormun_db* db,
                             const unsigned char* data, size_t len,
                             char** err) {
    (void)db;
    (void)data;
    (void)len;
    if (err) {
        *err = strdup("WAL apply not yet implemented");
    }
}