#!/usr/bin/env python3
"""
Evaluate Qwen3-Omni models on the LVBench benchmark.

LVBench: 1549 multiple-choice questions over 103 long videos.
Metrics: accuracy (overall, per video type).

Usage:
  python eval_lvbench.py \
    --base-model Qwen/Qwen3-Omni-30B-A3B-Instruct \
    --video-dir /opt/dlami/nvme/lvbench \
    --max-samples 30 --label vanilla_qwen3omni

  python eval_lvbench.py \
    --base-model Rakancorle11/qwen3omni_full_sft_revised_thinker_key \
    --adapter /opt/dlami/nvme/LlamaFactory/saves/.../adapter \
    --label dpo_v4_8632
"""

from __future__ import annotations

import argparse
import gc
import json
import os
import re
import tempfile
import shutil
from pathlib import Path
from typing import Any, Dict, List, Optional

import torch
from tqdm import tqdm

DEFAULT_VIDEO_DIR = Path("/opt/dlami/nvme/lvbench")
DEFAULT_OUTPUT_DIR = Path("/home/ubuntu/eval_results/lvbench")

VIDEO_TYPES = ["cartoon", "documentary", "live", "selfmedia", "sport", "tv"]

MCQ_PROMPT = (
    "Select the best answer to the following multiple-choice question "
    "based on the video. Respond with only the letter (A, B, C, or D) "
    "of the correct option.\n"
)


def parse_args() -> argparse.Namespace:
    p = argparse.ArgumentParser(description="Evaluate on LVBench benchmark.")
    p.add_argument("--base-model", type=str,
                    default="Qwen/Qwen3-Omni-30B-A3B-Instruct")
    p.add_argument("--adapter", type=str, default=None)
    p.add_argument("--video-dir", type=Path, default=DEFAULT_VIDEO_DIR)
    p.add_argument("--output-dir", type=Path, default=DEFAULT_OUTPUT_DIR)
    p.add_argument("--max-samples", type=int, default=-1)
    p.add_argument("--max-new-tokens", type=int, default=32)
    p.add_argument("--temperature", type=float, default=0.0)
    p.add_argument("--label", type=str, default=None)
    p.add_argument("--vllm", action="store_true", default=False,
                    help="Use vLLM offline batch inference instead of transformers (much faster).")
    p.add_argument("--tp", type=int, default=None,
                    help="Tensor parallel size for vLLM (default: all visible GPUs).")
    p.add_argument("--batch-size", type=int, default=16,
                    help="Batch size for vLLM generate().")
    p.add_argument("--gpu-memory-utilization", type=float, default=0.90)
    p.add_argument("--max-model-len", type=int, default=65536)
    return p.parse_args()


# ---------------------------------------------------------------------------
# Model loading — identical to eval_videomme.py / eval_dpo_sync.py
# ---------------------------------------------------------------------------
def load_model(base_model: str, adapter: Optional[str]):
    import json as _json
    from transformers import (
        AutoConfig,
        AutoProcessor,
        Qwen3OmniMoeForConditionalGeneration,
        Qwen3OmniMoeThinkerConfig,
        Qwen3OmniMoeThinkerForConditionalGeneration,
    )

    print(f"[load] Base model: {base_model}")
    processor = AutoProcessor.from_pretrained(base_model, trust_remote_code=True)

    model_path = Path(base_model)
    cfg_path = model_path / "config.json" if model_path.exists() else None

    model_type = None
    if cfg_path and cfg_path.exists():
        with open(cfg_path, "r") as f:
            model_type = _json.load(f).get("model_type")
    if not model_type:
        try:
            from huggingface_hub import hf_hub_download
            cached = hf_hub_download(base_model, "config.json")
            with open(cached, "r") as f:
                model_type = _json.load(f).get("model_type")
        except Exception:
            pass

    print(f"[load] Detected model_type: {model_type}")

    if model_type == "qwen3_omni_moe_thinker":
        config = Qwen3OmniMoeThinkerConfig.from_pretrained(base_model)
        model = Qwen3OmniMoeThinkerForConditionalGeneration.from_pretrained(
            base_model, config=config, torch_dtype=torch.bfloat16, device_map="auto",
        )
    else:
        config = AutoConfig.from_pretrained(base_model, trust_remote_code=True)
        model = Qwen3OmniMoeForConditionalGeneration.from_pretrained(
            base_model, config=config, torch_dtype=torch.bfloat16, device_map="auto",
        )

    if adapter:
        from peft import PeftModel
        from safetensors.torch import load_file, save_file

        print(f"[load] Loading LoRA adapter: {adapter}")
        adapter_cfg_path = Path(adapter) / "adapter_config.json"
        with open(adapter_cfg_path) as f:
            adapter_cfg = _json.loads(f.read())
        target_modules = adapter_cfg.get("target_modules", [])
        needs_remap = (
            any(t.startswith("model.layers.") for t in target_modules)
            and model_type != "qwen3_omni_moe_thinker"
        )

        if needs_remap:
            print("[load] Adapter trained on thinker-only; remapping keys...")
            tmp_dir = Path(tempfile.mkdtemp(prefix="adapter_remap_"))
            for fn in Path(adapter).iterdir():
                if fn.is_dir():
                    continue
                if fn.name == "adapter_config.json":
                    new_targets = []
                    for t in target_modules:
                        if t.startswith("model.layers."):
                            new_targets.append("thinker." + t)
                        elif t[0].isdigit():
                            new_targets.append("thinker.model.layers." + t)
                        else:
                            new_targets.append(t)
                    adapter_cfg["target_modules"] = new_targets
                    with open(tmp_dir / "adapter_config.json", "w") as f:
                        json.dump(adapter_cfg, f, indent=2)
                elif fn.suffix == ".safetensors" and "adapter" in fn.name:
                    tensors = load_file(str(fn))
                    remapped = {}
                    for k, v in tensors.items():
                        if ".model.layers." in k and ".thinker." not in k:
                            new_k = k.replace(
                                "base_model.model.model.layers.",
                                "base_model.model.thinker.model.layers.",
                            )
                            remapped[new_k] = v
                        else:
                            remapped[k] = v
                    save_file(remapped, str(tmp_dir / fn.name))
                else:
                    shutil.copy2(str(fn), str(tmp_dir / fn.name))
            adapter = str(tmp_dir)

        model = PeftModel.from_pretrained(model, adapter)
        model = model.merge_and_unload()

    if hasattr(model, "disable_talker"):
        model.disable_talker()
    model.eval()
    print(f"[load] Model ready ({type(model).__name__}). Device: {model.device}")
    return model, processor


# ---------------------------------------------------------------------------
# Inference
# ---------------------------------------------------------------------------
def run_inference(model, processor, video_path: str, prompt: str,
                  max_new_tokens: int, temperature: float) -> str:
    from qwen_omni_utils import process_mm_info

    tmp_dir = tempfile.mkdtemp(prefix="eval_lvb_")
    masked_video = os.path.join(tmp_dir, "clip.mp4")
    os.symlink(os.path.abspath(video_path), masked_video)

    conversation = [
        {
            "role": "user",
            "content": [
                {"type": "video", "video": masked_video},
                {"type": "text", "text": prompt},
            ],
        }
    ]

    text = processor.apply_chat_template(
        conversation, add_generation_prompt=True, tokenize=False,
    )
    audios, images, videos = process_mm_info(conversation, use_audio_in_video=False)
    inputs = processor(
        text=text, audio=audios, images=images, videos=videos,
        return_tensors="pt", padding=True, use_audio_in_video=False,
    )

    model_dtype = next(model.parameters()).dtype
    converted = {}
    for k, v in inputs.items():
        if hasattr(v, "to"):
            v = v.to(model.device)
            if torch.is_floating_point(v):
                v = v.to(model_dtype)
        converted[k] = v
    inputs = converted

    from transformers import Qwen3OmniMoeThinkerForConditionalGeneration
    is_thinker = isinstance(model, Qwen3OmniMoeThinkerForConditionalGeneration)
    if is_thinker:
        gen_kwargs = {"max_new_tokens": max_new_tokens, "do_sample": temperature > 0}
    else:
        gen_kwargs = {
            "thinker_max_new_tokens": max_new_tokens,
            "use_audio_in_video": False,
            "return_audio": False,
            "do_sample": temperature > 0,
        }
    if temperature > 0:
        gen_kwargs["temperature"] = temperature
        gen_kwargs["top_p"] = 0.9

    with torch.inference_mode():
        output_ids = model.generate(**inputs, **gen_kwargs)

    if isinstance(output_ids, tuple):
        output_ids = output_ids[0]

    prompt_len = inputs["input_ids"].shape[1]
    response = processor.batch_decode(
        output_ids[:, prompt_len:], skip_special_tokens=True,
    )[0].strip()

    shutil.rmtree(tmp_dir, ignore_errors=True)
    return response


def preprocess_video_for_vllm(video_path: str):
    """Extract video frames using qwen_omni_utils, return numpy array for vLLM.
    Caps at 128 frames to stay within vLLM encoder cache (62720 tokens).
    """
    from qwen_omni_utils import process_mm_info
    import numpy as np

    messages = [{
        "role": "user",
        "content": [
            {"type": "video", "video": video_path, "nframes": 128},
            {"type": "text", "text": "placeholder"},
        ],
    }]
    audios, images, videos = process_mm_info(messages, use_audio_in_video=False)
    video_tensor = videos[0]
    video_np = (video_tensor * 255).byte().numpy()
    return video_np


SYSTEM_PROMPT = (
    "You are Qwen, a virtual human developed by the Qwen Team, Alibaba "
    "Group, capable of perceiving auditory and visual inputs, as well as "
    "generating text and speech."
)


def build_vllm_prompt(question: str) -> str:
    return (
        f"<|im_start|>system\n{SYSTEM_PROMPT}<|im_end|>\n"
        f"<|im_start|>user\n"
        f"<|vision_start|><|video_pad|><|vision_end|>"
        f"{question}<|im_end|>\n"
        f"<|im_start|>assistant\n"
    )


def extract_answer(text: str) -> str:
    """Extract a single letter A/B/C/D from model output."""
    text = text.strip()
    prefixes = [
        "The best answer is", "The correct answer is",
        "The answer is", "The answer", "Best answer:", "Best option:",
    ]
    for prefix in prefixes:
        text = text.replace(prefix, "")

    if len(text.split()) > 10 and not re.search(r"[ABCD]", text):
        return ""
    m = re.search(r"[ABCD]", text)
    return m[0] if m else ""


# ---------------------------------------------------------------------------
# Dataset loading
# ---------------------------------------------------------------------------
def load_lvbench(video_dir: Path, max_samples: int) -> List[Dict[str, Any]]:
    from datasets import load_dataset
    ds = load_dataset("lmms-lab/LVBench", split="train")
    data = []
    skipped = 0
    for row in ds:
        vid = row["key"]
        video_path = video_dir / f"{vid}.mp4"
        if not video_path.exists():
            skipped += 1
            continue

        prompt = MCQ_PROMPT + row["question"] + "\nThe best answer is:"

        data.append({
            "uid": row["uid"],
            "video_id": vid,
            "video_path": str(video_path),
            "video_type": row["type"],
            "question_type": row["question_type"],
            "question": row["question"],
            "gt_answer": row["answer"],
            "time_reference": row.get("time_reference", ""),
            "prompt": prompt,
        })
    if skipped:
        print(f"[data] Skipped {skipped} questions (video not found)")
    if max_samples > 0:
        data = data[:max_samples]
    return data


# ---------------------------------------------------------------------------
# Metrics
# ---------------------------------------------------------------------------
def compute_metrics(results: List[Dict[str, Any]]) -> Dict[str, Any]:
    total = len(results)
    if total == 0:
        return {}

    correct = sum(1 for r in results if r["pred_answer"].upper() == r["gt_answer"].upper())
    overall_acc = correct / total

    def acc_for(items):
        if not items:
            return None
        c = sum(1 for r in items if r["pred_answer"].upper() == r["gt_answer"].upper())
        return round(c / len(items), 4)

    per_type = {}
    for vt in VIDEO_TYPES:
        subset = [r for r in results if r["video_type"] == vt]
        if subset:
            per_type[vt] = {"accuracy": acc_for(subset), "count": len(subset)}

    q_types = set()
    for r in results:
        if isinstance(r.get("question_type"), list):
            q_types.update(r["question_type"])
        elif r.get("question_type"):
            q_types.add(r["question_type"])

    per_qtype = {}
    for qt in sorted(q_types):
        subset = [r for r in results if qt in (r.get("question_type", [])
                  if isinstance(r.get("question_type"), list) else [r.get("question_type")])]
        if subset:
            per_qtype[qt] = {"accuracy": acc_for(subset), "count": len(subset)}

    return {
        "total_samples": total,
        "overall_accuracy": round(overall_acc, 4),
        "per_video_type": per_type,
        "per_question_type": per_qtype,
    }


def print_summary(metrics: Dict[str, Any], label: str) -> None:
    print()
    print(f"{'=' * 65}")
    print(f"  LVBench Summary: {label}")
    print(f"{'=' * 65}")
    print(f"  Total samples:         {metrics['total_samples']}")
    print(f"  Overall Accuracy:      {metrics['overall_accuracy']:.1%}")

    print(f"  ─── Per Video Type ───")
    for vt in VIDEO_TYPES:
        if vt in metrics.get("per_video_type", {}):
            d = metrics["per_video_type"][vt]
            print(f"    {vt:15s}: {d['accuracy']:.1%}  ({d['count']} questions)")

    print(f"  ─── Per Question Type ───")
    for qt, d in sorted(metrics.get("per_question_type", {}).items()):
        print(f"    {qt:30s}: {d['accuracy']:.1%}  ({d['count']})")

    print(f"{'=' * 65}")


# ---------------------------------------------------------------------------
# Main
# ---------------------------------------------------------------------------
def main() -> None:
    args = parse_args()
    label = args.label or (
        Path(args.adapter).name if args.adapter
        else Path(args.base_model).name
    )

    out_dir = args.output_dir / label
    out_dir.mkdir(parents=True, exist_ok=True)
    results_jsonl = out_dir / "eval_results.jsonl"
    metrics_json = out_dir / "metrics.json"
    summary_txt = out_dir / "summary.txt"

    print("[data] Loading LVBench dataset...")
    test_data = load_lvbench(args.video_dir, args.max_samples)
    print(f"[data] {len(test_data)} questions ready for evaluation")

    processed = set()
    if results_jsonl.exists():
        with open(results_jsonl) as f:
            for line in f:
                obj = json.loads(line)
                processed.add(obj["uid"])
        print(f"[resume] {len(processed)} already processed, skipping")

    use_vllm = args.vllm
    model = processor = llm = None
    vllm_preprocess_stats: Dict[str, int] | None = None

    if use_vllm:
        from vllm import LLM, SamplingParams
        tp = args.tp or torch.cuda.device_count()
        model_path = args.base_model
        print(f"[vllm] Loading {model_path} with tp={tp} ...")
        llm = LLM(
            model=model_path,
            tensor_parallel_size=tp,
            max_model_len=args.max_model_len,
            max_num_seqs=4,
            limit_mm_per_prompt={"video": 1},
            gpu_memory_utilization=args.gpu_memory_utilization,
            dtype="bfloat16",
            trust_remote_code=True,
        )
        sampling_params = SamplingParams(
            temperature=args.temperature if args.temperature > 0 else 0.0,
            top_p=0.9 if args.temperature > 0 else 1.0,
            max_tokens=args.max_new_tokens,
        )

        print("[vllm] Preprocessing videos ...")
        todo = [item for item in test_data if item["uid"] not in processed]
        preprocessed = {}
        preprocess_failed_paths: set[str] = set()

        for i, item in enumerate(todo):
            vp = item["video_path"]
            if vp in preprocessed or vp in preprocess_failed_paths:
                continue
            try:
                preprocessed[vp] = preprocess_video_for_vllm(vp)
            except Exception as e:
                preprocess_failed_paths.add(vp)
                print(f"  [skip] preprocess error: {Path(vp).name}: {e}")
            if (i + 1) % 50 == 0:
                print(f"  Preprocessed {i+1}/{len(todo)} ...")

        n_pp_skip = sum(1 for item in todo if item["video_path"] in preprocess_failed_paths)
        if preprocess_failed_paths:
            print(
                f"[vllm] Preprocess failed for {len(preprocess_failed_paths)} video(s), "
                f"{n_pp_skip} question(s) will not use vLLM (run continues)."
            )
        vllm_preprocess_stats = {
            "preprocess_failed_videos": len(preprocess_failed_paths),
            "preprocess_skipped_questions": n_pp_skip,
        }

        vllm_todo = [item for item in todo if item["video_path"] in preprocessed]
        fallback_items = []
        print(f"[vllm] {len(vllm_todo)} questions ready, running inference ...")

        for i, item in enumerate(vllm_todo):
            if item["uid"] in processed:
                continue
            inp = {
                "prompt": build_vllm_prompt(item["prompt"]),
                "multi_modal_data": {"video": preprocessed[item["video_path"]]},
            }
            try:
                outputs = llm.generate([inp], sampling_params=sampling_params)
                raw_output = outputs[0].outputs[0].text.strip()
                pred = extract_answer(raw_output)
                result = {
                    "uid": item["uid"],
                    "video_id": item["video_id"],
                    "video_type": item["video_type"],
                    "question_type": item["question_type"],
                    "gt_answer": item["gt_answer"],
                    "pred_answer": pred,
                    "correct": pred.upper() == item["gt_answer"].upper(),
                    "raw_output": raw_output,
                }
                with open(results_jsonl, "a", encoding="utf-8") as f:
                    f.write(json.dumps(result, ensure_ascii=False) + "\n")
                processed.add(item["uid"])
            except (ValueError, RuntimeError) as exc:
                if "longer than the maximum model length" in str(exc):
                    print(f"  [too long] {item['uid']} -> fallback")
                    fallback_items.append(item)
                else:
                    raise

            if (i + 1) % 50 == 0:
                print(f"  [vllm] [{i+1}/{len(vllm_todo)}] done, {len(fallback_items)} deferred")

        preprocessed.clear()

        vllm_results = []
        if results_jsonl.exists():
            with open(results_jsonl) as f:
                for line in f:
                    vllm_results.append(json.loads(line))
        if vllm_results:
            vllm_metrics = compute_metrics(vllm_results)
            vllm_metrics_path = out_dir / "metrics_vllm.json"
            with open(vllm_metrics_path, "w", encoding="utf-8") as f:
                json.dump(vllm_metrics, f, indent=2, ensure_ascii=False)
            print(f"[vllm] Intermediate metrics saved to {vllm_metrics_path}")
            print_summary(vllm_metrics, label + " (vllm only)")

        if fallback_items:
            print(f"[fallback] Running {len(fallback_items)} long-video questions with transformers ...")
            del llm
            gc.collect()
            torch.cuda.empty_cache()

            model, processor = load_model(args.base_model, args.adapter)
            for item in tqdm(fallback_items, desc="Fallback", unit="q"):
                if item["uid"] in processed:
                    continue
                try:
                    raw_output = run_inference(
                        model, processor, item["video_path"], item["prompt"],
                        args.max_new_tokens, args.temperature,
                    )
                except Exception as exc:
                    import traceback
                    print(f"  [error] {item['uid']}: {exc}")
                    traceback.print_exc()
                    raw_output = ""

                pred = extract_answer(raw_output)
                result = {
                    "uid": item["uid"],
                    "video_id": item["video_id"],
                    "video_type": item["video_type"],
                    "question_type": item["question_type"],
                    "gt_answer": item["gt_answer"],
                    "pred_answer": pred,
                    "correct": pred.upper() == item["gt_answer"].upper(),
                    "raw_output": raw_output,
                }
                with open(results_jsonl, "a", encoding="utf-8") as f:
                    f.write(json.dumps(result, ensure_ascii=False) + "\n")
                processed.add(item["uid"])
                gc.collect()
                torch.cuda.empty_cache()

    else:
        print("[model] Loading model...")
        model, processor = load_model(args.base_model, args.adapter)

        for item in tqdm(test_data, desc="LVBench", unit="q"):
            if item["uid"] in processed:
                continue

            try:
                raw_output = run_inference(
                    model, processor, item["video_path"], item["prompt"],
                    args.max_new_tokens, args.temperature,
                )
            except Exception as exc:
                import traceback
                print(f"  [error] {item['uid']}: {exc}")
                traceback.print_exc()
                raw_output = ""

            pred = extract_answer(raw_output)

            result = {
                "uid": item["uid"],
                "video_id": item["video_id"],
                "video_type": item["video_type"],
                "question_type": item["question_type"],
                "gt_answer": item["gt_answer"],
                "pred_answer": pred,
                "correct": pred.upper() == item["gt_answer"].upper(),
                "raw_output": raw_output,
            }

            with open(results_jsonl, "a", encoding="utf-8") as f:
                f.write(json.dumps(result, ensure_ascii=False) + "\n")

            processed.add(item["uid"])
            gc.collect()
            torch.cuda.empty_cache()

    all_results = []
    if results_jsonl.exists():
        with open(results_jsonl) as f:
            for line in f:
                all_results.append(json.loads(line))

    if not all_results:
        print("[warn] No results to compute metrics from.")
        return

    metrics = compute_metrics(all_results)
    metrics["eval_config"] = {
        "base_model": args.base_model,
        "adapter": args.adapter,
        "video_dir": str(args.video_dir),
        "max_new_tokens": args.max_new_tokens,
        "temperature": args.temperature,
    }
    if vllm_preprocess_stats is not None:
        metrics["eval_config"]["vllm_preprocess_skips"] = vllm_preprocess_stats

    with open(metrics_json, "w", encoding="utf-8") as f:
        json.dump(metrics, f, indent=2, ensure_ascii=False)

    print_summary(metrics, label)

    with open(summary_txt, "w", encoding="utf-8") as f:
        import io, contextlib
        buf = io.StringIO()
        with contextlib.redirect_stdout(buf):
            print_summary(metrics, label)
        f.write(buf.getvalue())

    print(f"\n[output] Results: {results_jsonl}")
    print(f"[output] Metrics: {metrics_json}")
    print(f"[output] Summary: {summary_txt}")


if __name__ == "__main__":
    main()