"""
UIPress Step 1: Baseline Evaluation
====================================
Test multiple VLMs on Design2Code to establish baselines.
Measures: visual token count, generation quality, latency.

IMPORTANT: This script runs in the uipress-qwen conda environment.
    For Qwen3-VL:   needs transformers>=4.57 (recommended default path)
    For Qwen2.5-VL: works well on transformers==4.49.0 (compat path)

Usage:
    conda activate uipress-qwen

    # Quick test (5 samples)
    python scripts/step1_baseline.py --max_samples 5

    # Full eval (all samples)
    python scripts/step1_baseline.py --max_samples -1

    # With 4-bit quantization (saves VRAM)
    python scripts/step1_baseline.py --model qwen3_vl_8b --max_samples 20 --use_4bit

    # Qwen3-VL (requires latest transformers)
    python scripts/step1_baseline.py --model qwen3_vl_2b --max_samples 5
"""

# ---- HuggingFace 镜像 (必须在其他 import 之前) ----
import os
os.environ["HF_ENDPOINT"] = os.environ.get("HF_ENDPOINT", "https://hf-mirror.com")
os.environ["HF_HOME"] = os.environ.get("HF_HOME", "/root/rivermind-data/huggingface")

import argparse
import json
import sys
import time
from pathlib import Path

import torch
from PIL import Image
from tqdm import tqdm

# Project root
PROJECT_ROOT = Path(__file__).parent.parent
sys.path.insert(0, str(PROJECT_ROOT))


# ============================================================
# Model Loaders
# ============================================================

class Qwen25VLModel:
    """Wrapper for Qwen2.5-VL models."""

    def __init__(self, model_id: str, use_4bit: bool = False):
        from transformers import AutoProcessor, Qwen2_5_VLForConditionalGeneration

        self.model_id = model_id
        print(f"Loading {model_id}...")

        load_kwargs = {
            "trust_remote_code": True,
            "torch_dtype": torch.bfloat16,
            "device_map": "auto",
        }

        if use_4bit:
            from transformers import BitsAndBytesConfig
            load_kwargs["quantization_config"] = BitsAndBytesConfig(
                load_in_4bit=True,
                bnb_4bit_compute_dtype=torch.bfloat16,
                bnb_4bit_use_double_quant=True,
                bnb_4bit_quant_type="nf4",
            )

        self.model = Qwen2_5_VLForConditionalGeneration.from_pretrained(
            model_id, **load_kwargs
        )
        self.processor = AutoProcessor.from_pretrained(
            model_id, trust_remote_code=True
        )
        self.model.eval()

    def generate(self, image: Image.Image, prompt: str, max_new_tokens: int = 4096):
        """Generate HTML code from a UI screenshot."""
        messages = [
            {
                "role": "user",
                "content": [
                    {"type": "image", "image": image},
                    {"type": "text", "text": prompt},
                ],
            }
        ]

        text = self.processor.apply_chat_template(
            messages, tokenize=False, add_generation_prompt=True
        )
        inputs = self.processor(
            text=[text],
            images=[image],
            padding=True,
            return_tensors="pt",
        ).to(self.model.device)

        # Count visual tokens
        n_visual_tokens = 0
        if "image_grid_thw" in inputs:
            grid = inputs["image_grid_thw"]
            n_visual_tokens = int(grid.prod(dim=-1).sum().item())

        # Generate
        t_start = time.time()
        with torch.no_grad():
            output_ids = self.model.generate(
                **inputs,
                max_new_tokens=max_new_tokens,
                temperature=0.0,
                do_sample=False,
                repetition_penalty=1.0,
            )
        t_end = time.time()

        # Decode output (skip input tokens)
        input_len = inputs["input_ids"].shape[1]
        generated_ids = output_ids[0][input_len:]
        output_text = self.processor.tokenizer.decode(
            generated_ids, skip_special_tokens=True
        )

        return {
            "output": output_text,
            "n_visual_tokens": n_visual_tokens,
            "n_input_tokens": int(input_len),
            "n_output_tokens": len(generated_ids),
            "latency_s": t_end - t_start,
        }


class Qwen3VLModel:
    """Wrapper for Qwen3-VL models. Requires transformers>=4.57."""

    def __init__(self, model_id: str, use_4bit: bool = False):
        # Check transformers version
        import transformers
        version = transformers.__version__
        print(f"  transformers version: {version}")

        try:
            from transformers import Qwen3VLForConditionalGeneration, AutoProcessor
        except ImportError:
            print(f"[ERROR] Qwen3VLForConditionalGeneration not found in transformers=={version}")
            print(f"  Qwen3-VL requires transformers>=4.57 or install from source:")
            print(f"    pip install git+https://github.com/huggingface/transformers")
            sys.exit(1)

        self.model_id = model_id
        print(f"Loading {model_id}...")

        load_kwargs = {
            "trust_remote_code": True,
            "torch_dtype": torch.bfloat16,
            "device_map": "auto",
        }

        if use_4bit:
            from transformers import BitsAndBytesConfig
            load_kwargs["quantization_config"] = BitsAndBytesConfig(
                load_in_4bit=True,
                bnb_4bit_compute_dtype=torch.bfloat16,
                bnb_4bit_use_double_quant=True,
                bnb_4bit_quant_type="nf4",
            )

        self.model = Qwen3VLForConditionalGeneration.from_pretrained(
            model_id, **load_kwargs
        )
        self.processor = AutoProcessor.from_pretrained(
            model_id, trust_remote_code=True
        )
        self.model.eval()

    def generate(self, image: Image.Image, prompt: str, max_new_tokens: int = 4096):
        """Generate HTML code from a UI screenshot."""
        messages = [
            {
                "role": "user",
                "content": [
                    {"type": "image", "image": image},
                    {"type": "text", "text": prompt},
                ],
            }
        ]

        # Qwen3-VL uses return_dict=True in apply_chat_template
        inputs = self.processor.apply_chat_template(
            messages,
            tokenize=True,
            add_generation_prompt=True,
            return_dict=True,
            return_tensors="pt",
        ).to(self.model.device)

        # Count visual tokens
        n_visual_tokens = 0
        if "image_grid_thw" in inputs:
            grid = inputs["image_grid_thw"]
            n_visual_tokens = int(grid.prod(dim=-1).sum().item())

        # Generate
        t_start = time.time()
        with torch.no_grad():
            output_ids = self.model.generate(
                **inputs,
                max_new_tokens=max_new_tokens,
                temperature=0.7,
                top_p=0.8,
                top_k=20,
            )
        t_end = time.time()

        # Decode output (skip input tokens)
        generated_ids = [
            out_ids[len(in_ids):]
            for in_ids, out_ids in zip(inputs["input_ids"], output_ids)
        ]
        output_text = self.processor.batch_decode(
            generated_ids, skip_special_tokens=True, clean_up_tokenization_spaces=False
        )[0]

        input_len = inputs["input_ids"].shape[1]

        return {
            "output": output_text,
            "n_visual_tokens": n_visual_tokens,
            "n_input_tokens": int(input_len),
            "n_output_tokens": len(generated_ids[0]),
            "latency_s": t_end - t_start,
        }


# ============================================================
# Prompt Templates
# ============================================================

UI2CODE_PROMPT = """You are an expert web developer. Given a screenshot of a webpage, generate the complete HTML code that would reproduce this webpage as closely as possible.

Requirements:
- Generate a single, self-contained HTML file
- Include inline CSS styles (no external stylesheets)
- Reproduce the layout, colors, text content, and visual structure
- Use semantic HTML elements where appropriate

Generate ONLY the HTML code, nothing else."""

UI2CODE_PROMPT_SHORT = """Convert this webpage screenshot to HTML code. Generate a complete, self-contained HTML file with inline CSS. Output only the code."""


# ============================================================
# Data Loading
# ============================================================

def load_design2code(data_dir: str, max_samples: int = -1):
    """Load Design2Code test set."""
    data_path = Path(data_dir)

    # Try HuggingFace datasets format first
    hf_path = data_path / "design2code"
    if hf_path.exists():
        from datasets import load_from_disk
        ds = load_from_disk(str(hf_path))
        if hasattr(ds, 'keys'):
            split = list(ds.keys())[0]
            print(f"  Using split: '{split}' from DatasetDict")
            ds = ds[split]
        samples = []
        for i, item in enumerate(ds):
            if max_samples > 0 and i >= max_samples:
                break
            img = item.get("image") or item.get("screenshot")
            if img is not None and not isinstance(img, Image.Image):
                img = Image.open(img).convert("RGB")
            samples.append({
                "id": str(i),
                "image": img,
                "html": item.get("text", item.get("code", item.get("html", ""))),
            })
        return samples

    # Try raw file format (testset_final/)
    testset_dir = data_path / "testset_final"
    if testset_dir.exists():
        samples = []
        png_files = sorted(testset_dir.glob("*.png"))
        for i, png_path in enumerate(png_files):
            if max_samples > 0 and i >= max_samples:
                break
            html_path = png_path.with_suffix(".html")
            html_code = html_path.read_text(encoding="utf-8") if html_path.exists() else ""
            samples.append({
                "id": png_path.stem,
                "image": Image.open(png_path).convert("RGB"),
                "html": html_code,
            })
        return samples

    print(f"[WARNING] No Design2Code data found at {data_path}")
    print("Run: python scripts/download_data.py")
    return []


# ============================================================
# Main Evaluation
# ============================================================

def evaluate_model(model, samples, prompt, output_dir, model_name):
    """Run inference on all samples and save results."""
    output_dir = Path(output_dir)
    output_dir.mkdir(parents=True, exist_ok=True)

    results = []
    html_dir = output_dir / "html_predictions"
    html_dir.mkdir(exist_ok=True)

    for sample in tqdm(samples, desc=f"Evaluating {model_name}"):
        try:
            result = model.generate(
                image=sample["image"],
                prompt=prompt,
                max_new_tokens=4096,
            )

            html_output = extract_html(result["output"])

            html_file = html_dir / f"{sample['id']}.html"
            html_file.write_text(html_output, encoding="utf-8")

            results.append({
                "id": sample["id"],
                "n_visual_tokens": result["n_visual_tokens"],
                "n_input_tokens": result["n_input_tokens"],
                "n_output_tokens": result["n_output_tokens"],
                "latency_s": round(result["latency_s"], 2),
                "output_length": len(html_output),
            })

        except Exception as e:
            import traceback
            print(f"[ERROR] Sample {sample['id']}: {e}")
            traceback.print_exc()
            results.append({
                "id": sample["id"],
                "error": str(e),
            })

    # Save summary
    summary = {
        "model": model_name,
        "n_samples": len(results),
        "n_errors": sum(1 for r in results if "error" in r),
        "avg_visual_tokens": avg([r.get("n_visual_tokens", 0) for r in results if "error" not in r]),
        "avg_output_tokens": avg([r.get("n_output_tokens", 0) for r in results if "error" not in r]),
        "avg_latency_s": avg([r.get("latency_s", 0) for r in results if "error" not in r]),
        "results": results,
    }

    summary_file = output_dir / "summary.json"
    with open(summary_file, "w") as f:
        json.dump(summary, f, indent=2, ensure_ascii=False)

    print(f"\n{'='*60}")
    print(f"Model: {model_name}")
    print(f"Samples: {summary['n_samples']} (errors: {summary['n_errors']})")
    print(f"Avg visual tokens: {summary['avg_visual_tokens']:.0f}")
    print(f"Avg output tokens: {summary['avg_output_tokens']:.0f}")
    print(f"Avg latency: {summary['avg_latency_s']:.2f}s")
    print(f"Results saved to: {output_dir}")
    print(f"{'='*60}\n")

    return summary


def extract_html(text: str) -> str:
    """Extract HTML code from model output, handling markdown fences."""
    if "```html" in text:
        start = text.find("```html") + 7
        end = text.find("```", start)
        if end > start:
            return text[start:end].strip()
    if "```" in text:
        start = text.find("```") + 3
        end = text.find("```", start)
        if end > start:
            return text[start:end].strip()

    stripped = text.strip()
    if stripped.startswith(("<!DOCTYPE", "<html", "<HTML", "<!doctype")):
        return stripped

    if "<" in stripped and ">" in stripped:
        return stripped

    return stripped


def avg(lst):
    """Safe average."""
    valid = [x for x in lst if x is not None and x > 0]
    return sum(valid) / len(valid) if valid else 0


# ============================================================
# CLI
# ============================================================

MODEL_REGISTRY = {
    # Qwen2.5-VL (works with transformers>=4.46)
    "qwen2_5_vl_7b": ("qwen25", "Qwen/Qwen2.5-VL-7B-Instruct"),
    # Qwen3-VL (needs transformers>=4.57)
    "qwen3_vl_2b":   ("qwen3",  "Qwen/Qwen3-VL-2B-Instruct"),
    "qwen3_vl_4b":   ("qwen3",  "Qwen/Qwen3-VL-4B-Instruct"),
    "qwen3_vl_8b":   ("qwen3",  "Qwen/Qwen3-VL-8B-Instruct"),
}


def main():
    parser = argparse.ArgumentParser(description="UIPress Step 1: Baseline Evaluation")
    parser.add_argument("--model", type=str, default="qwen3_vl_2b",
                        choices=list(MODEL_REGISTRY.keys()),
                        help="Model to evaluate (default: qwen3_vl_2b)")
    parser.add_argument("--max_samples", type=int, default=5,
                        help="Max samples to evaluate (-1 for all)")
    parser.add_argument("--use_4bit", action="store_true",
                        help="Use 4-bit quantization (saves VRAM)")
    parser.add_argument("--data_dir", type=str,
                        default=str(PROJECT_ROOT / "data"),
                        help="Path to data directory")
    parser.add_argument("--output_dir", type=str,
                        default=str(PROJECT_ROOT / "results"),
                        help="Path to output directory")
    parser.add_argument("--prompt", type=str, default="short",
                        choices=["full", "short"],
                        help="Prompt style")
    args = parser.parse_args()

    prompt = UI2CODE_PROMPT if args.prompt == "full" else UI2CODE_PROMPT_SHORT

    # Load data
    print("Loading Design2Code dataset...")
    samples = load_design2code(args.data_dir, args.max_samples)
    if not samples:
        print("No data loaded. Run: python scripts/download_data.py")
        sys.exit(1)
    print(f"Loaded {len(samples)} samples")

    # Create model
    model_type, model_id = MODEL_REGISTRY[args.model]

    if model_type == "qwen25":
        model = Qwen25VLModel(model_id, use_4bit=args.use_4bit)
    elif model_type == "qwen3":
        model = Qwen3VLModel(model_id, use_4bit=args.use_4bit)

    # Output directory
    model_output_dir = Path(args.output_dir) / args.model

    # Run evaluation
    summary = evaluate_model(
        model=model,
        samples=samples,
        prompt=prompt,
        output_dir=model_output_dir,
        model_name=args.model,
    )

    # Save comparison
    comp_file = Path(args.output_dir) / "step1_comparison.json"
    existing = {}
    if comp_file.exists():
        with open(comp_file) as f:
            existing = json.load(f)
    existing[args.model] = summary
    with open(comp_file, "w") as f:
        json.dump(existing, f, indent=2, default=str)
    print(f"Comparison updated: {comp_file}")


if __name__ == "__main__":
    main()