#!/usr/bin/env python3
"""Test torch.compile + CuTeDSL NVFP4 runner via custom_op.

Critical test: does torch.compile (fullgraph mode) accept the
nvfp4::moe_gemm custom op and produce a working compiled graph?

Run on the B200:
  docker run --rm --gpus all --entrypoint python3 \
    -v /root/nvfp4-megamoe-kernel:/root/nvfp4-megamoe-kernel \
    -v /root/nvidia-meeting:/root/nvidia-meeting:ro \
    nvfp4-megamoe-kernel-vllm:latest \
    /root/nvfp4-megamoe-kernel/tests/test_compile_custom_op.py
"""
import os
import sys
import json
import glob
import torch
from safetensors import safe_open

REPO_ROOT = os.path.dirname(os.path.dirname(os.path.abspath(__file__)))
sys.path.insert(0, REPO_ROOT)

from cutedsl.runner import CuTeDSLMoERunner
from cutedsl.custom_ops import register_runner, nvfp4_moe_gemm

NVFP4_MODEL_DIR = "/root/nvidia-meeting/DeepSeek-V4-Pro-NVFP4"
DEVICE = "cuda"


def find_shards(model_dir):
    index_path = os.path.join(model_dir, "model.safetensors.index.json")
    key_to_shard = {}
    if os.path.exists(index_path):
        with open(index_path) as f:
            index = json.load(f)
        for key, shard in index["weight_map"].items():
            key_to_shard[key] = os.path.join(model_dir, shard)
    else:
        for sf in glob.glob(os.path.join(model_dir, "*.safetensors")):
            with safe_open(sf, framework="pt") as f:
                for key in f.keys():
                    key_to_shard[key] = sf
    return key_to_shard


def load_layer_tensors(model_dir, layer_idx):
    key_to_shard = find_shards(model_dir)
    layer_prefix = f"layers.{layer_idx}."
    shard_to_keys = {}
    for key, shard in key_to_shard.items():
        norm_key = key.removeprefix("model.")
        if not norm_key.startswith(layer_prefix):
            continue
        shard_to_keys.setdefault(shard, []).append((key, norm_key))
    tensors = {}
    for shard, keys in shard_to_keys.items():
        with safe_open(shard, framework="pt") as f:
            for orig_key, norm_key in keys:
                tensors[norm_key] = f.get_tensor(orig_key)
    return tensors


def prepare_nvfp4_weights_direct(nvfp4_tensors, layer_idx, expert_indices, intermediate_size):
    from cutedsl.bridge import quantize_activation_nvfp4, quantize_weight_to_nvfp4
    l1_fp4, l1_sf, l1_gs = [], [], []
    l2_fp4, l2_sf, l2_gs = [], [], []
    
    for e in expert_indices:
        gate_w = nvfp4_tensors[f"layers.{layer_idx}.mlp.experts.{e}.gate_proj.weight"].to(DEVICE)
        up_w = nvfp4_tensors[f"layers.{layer_idx}.mlp.experts.{e}.up_proj.weight"].to(DEVICE)
        gate_sf = nvfp4_tensors[f"layers.{layer_idx}.mlp.experts.{e}.gate_proj.weight_scale"].to(DEVICE)
        up_sf = nvfp4_tensors[f"layers.{layer_idx}.mlp.experts.{e}.up_proj.weight_scale"].to(DEVICE)
        gate_gs = nvfp4_tensors[f"layers.{layer_idx}.mlp.experts.{e}.gate_proj.weight_scale_2"].item()
        up_gs = nvfp4_tensors[f"layers.{layer_idx}.mlp.experts.{e}.up_proj.weight_scale_2"].item()
        
        fused_w = torch.cat([gate_w, up_w], dim=0)
        fused_w_fp4 = fused_w.view(torch.float4_e2m1fn_x2).permute(1, 0).contiguous()
        fused_sf = torch.cat([gate_sf, up_sf], dim=0).permute(1, 0).contiguous()
        l1_max_gs = max(gate_gs, up_gs)
        if gate_gs != up_gs:
            fused_sf_f32 = fused_sf.float()
            fused_sf_f32[:, :intermediate_size] *= (gate_gs / l1_max_gs)
            fused_sf_f32[:, intermediate_size:] *= (up_gs / l1_max_gs)
            fused_sf = fused_sf_f32.to(torch.float8_e4m3fn)
        l1_fp4.append(fused_w_fp4)
        l1_sf.append(fused_sf)
        l1_gs.append(l1_max_gs)
        
        down_key = f"layers.{layer_idx}.mlp.experts.{e}.down_proj.weight"
        if down_key in nvfp4_tensors:
            down_w = nvfp4_tensors[down_key].to(DEVICE)
            down_sf = nvfp4_tensors[f"layers.{layer_idx}.mlp.experts.{e}.down_proj.weight_scale"].to(DEVICE)
            down_gs = nvfp4_tensors[f"layers.{layer_idx}.mlp.experts.{e}.down_proj.weight_scale_2"].item()
            l2_fp4.append(down_w.view(torch.float4_e2m1fn_x2).permute(1, 0).contiguous())
            l2_sf.append(down_sf.permute(1, 0).contiguous())
            l2_gs.append(down_gs)
    
    return {
        'l1_fp4': l1_fp4, 'l1_sf': l1_sf, 'l1_gs': l1_gs,
        'l2_fp4': l2_fp4, 'l2_sf': l2_sf, 'l2_gs': l2_gs,
    }


def main():
    torch.manual_seed(42)
    expert_indices = [0, 1, 2]
    hidden_size = 7168
    intermediate_size = 3072

    print("=" * 70)
    print("  torch.compile + CuTeDSL Custom Op Test")
    print("=" * 70)

    # Load weights
    nvfp4_tensors = load_layer_tensors(NVFP4_MODEL_DIR, 0)
    weights = prepare_nvfp4_weights_direct(nvfp4_tensors, 0, expert_indices, intermediate_size)

    # Create runner
    runner = CuTeDSLMoERunner(
        num_experts=len(expert_indices),
        hidden_size=hidden_size,
        intermediate_size=intermediate_size,
        max_num_tokens=8,
        top_k=2,
        device="cuda",
    )
    runner.prepare_weights_direct(
        weights['l1_fp4'], weights['l1_sf'], weights['l1_gs'],
        weights['l2_fp4'], weights['l2_sf'], weights['l2_gs'],
    )
    runner_id = register_runner(runner)

    # Test input
    hidden_states = torch.randn(4, hidden_size, dtype=torch.bfloat16, device=DEVICE) * 2.0
    topk_ids = torch.tensor([[0, 1]] * 4, dtype=torch.int32, device=DEVICE)
    topk_weights = torch.tensor([[0.6, 0.4]] * 4, dtype=torch.float32, device=DEVICE)

    # 1. Warmup: compute activation global scales
    print("\n[0] Computing activation global scales (warmup)...")
    runner.compute_activation_global_scales(hidden_states, topk_weights, topk_ids)
    print(f"  L1 gs: {runner._l1_activation_global_scale:.6f}")
    print(f"  L2 gs: {runner._l2_activation_global_scale:.6f}")

    # 1. Eager mode (baseline)
    print("\n[1/2] Running eager mode (baseline)...")
    runner._ensure_stacked()
    eager_out = nvfp4_moe_gemm(hidden_states, topk_weights, topk_ids, runner_id, hidden_size)
    print(f"  Eager output: amax={eager_out.abs().max():.4f} mean={eager_out.float().mean():.6f}")

    # 2. torch.compile fullgraph
    print("\n[2/2] Running torch.compile(fullgraph=True)...")
    try:
        @torch.compile(fullgraph=True)
        def compiled_fn(hs, tw, ti):
            return nvfp4_moe_gemm(hs, tw, ti, runner_id, hidden_size)
        
        compiled_out = compiled_fn(hidden_states, topk_weights, topk_ids)
        print(f"  Compiled output: amax={compiled_out.abs().max():.4f} mean={compiled_out.float().mean():.6f}")
        
        # Compare
        if eager_out.shape == compiled_out.shape:
            cos = torch.nn.functional.cosine_similarity(
                eager_out.flatten().unsqueeze(0).float(),
                compiled_out.flatten().unsqueeze(0).float(),
            ).item()
            print(f"\n  Eager vs Compiled: cosine={cos:.6f}")
            if cos > 0.99:
                print("  ✅ torch.compile produces matching output!")
            else:
                print(f"  ⚠️  Cosine {cos:.4f} < 0.99 — check for numerical issues")
        else:
            print(f"  ❌ Shape mismatch: eager={eager_out.shape} compiled={compiled_out.shape}")
    except Exception as e:
        print(f"  ❌ torch.compile FAILED: {type(e).__name__}: {e}")
        import traceback
        traceback.print_exc()
        sys.exit(1)

    print("\n" + "=" * 70)
    print("  Test complete ✅")
    print("=" * 70)


if __name__ == "__main__":
    main()