# /// script
# requires-python = ">=3.10"
# dependencies = [
#     "torch",
#     "transformers>=4.55.0",
#     "datasets",
#     "hf-xet >= 1.1.7",
#     "huggingface-hub[hf_transfer]",
#     "accelerate",
# ]
# ///
"""
Minimal GPT OSS generation script for HF Jobs.

Based on official HuggingFace blog recommendations.
Works on regular GPUs (L4, A10G, A100) without Flash Attention 3.

Usage:
    # Quick local test
    uv run gpt_oss_minimal.py \
        --input-dataset davanstrien/haiku_dpo \
        --output-dataset username/haiku-raw \
        --prompt-column question \
        --max-samples 2

    # HF Jobs execution (A10G for $1.50/hr)
    hf jobs uv run --flavor a10g-small \
        https://huggingface.co/datasets/uv-scripts/openai-oss/raw/main/gpt_oss_minimal.py \
        --input-dataset davanstrien/haiku_dpo \
        --output-dataset username/haiku-raw \
        --prompt-column question
"""

import argparse
import os
import sys

import torch
from datasets import Dataset, load_dataset
from huggingface_hub import get_token, login
from transformers import AutoModelForCausalLM, AutoTokenizer

# Enable fast downloads
os.environ["HF_HUB_ENABLE_HF_TRANSFER"] = "1"


def main():
    parser = argparse.ArgumentParser(
        description="Minimal GPT OSS generation for HF Jobs"
    )
    parser.add_argument(
        "--input-dataset", required=True, help="Input dataset on HF Hub"
    )
    parser.add_argument(
        "--output-dataset", required=True, help="Output dataset on HF Hub"
    )
    parser.add_argument(
        "--prompt-column", default="prompt", help="Column containing prompts"
    )
    parser.add_argument("--model-id", default="openai/gpt-oss-20b", help="Model to use")
    parser.add_argument("--max-samples", type=int, help="Limit number of samples")
    parser.add_argument(
        "--max-new-tokens", type=int, default=1024, help="Max tokens to generate"
    )
    parser.add_argument(
        "--reasoning-effort", 
        choices=["low", "medium", "high"], 
        default="medium",
        help="Reasoning effort level (default: medium)"
    )
    args = parser.parse_args()

    # Check GPU availability
    if not torch.cuda.is_available():
        print(
            "ERROR: GPU required. Use HF Jobs with --flavor a10g-small or run on GPU machine"
        )
        sys.exit(1)

    print(f"GPU: {torch.cuda.get_device_name(0)}")
    print(f"Memory: {torch.cuda.get_device_properties(0).total_memory / 1024**3:.1f}GB")

    # Authenticate
    token = os.environ.get("HF_TOKEN") or get_token()
    if not token:
        print(
            "ERROR: HF_TOKEN required. Set HF_TOKEN env var or run: huggingface-cli login"
        )
        sys.exit(1)
    login(token=token, add_to_git_credential=False)

    # Load tokenizer (following official blog)
    print(f"Loading tokenizer: {args.model_id}")
    tokenizer = AutoTokenizer.from_pretrained(args.model_id)

    # Load model (without Flash Attention 3 for compatibility)
    print(f"Loading model: {args.model_id}")
    print("Note: MXFP4 will auto-dequantize to bf16 on non-Hopper GPUs")

    model = AutoModelForCausalLM.from_pretrained(
        args.model_id,
        device_map="auto",
        torch_dtype="auto",  # Let transformers choose optimal dtype
        # NOT using: attn_implementation="kernels-community/vllm-flash-attn3"
        # as it requires H100/H200 GPUs
    )
    print("Model loaded successfully")

    # Load dataset
    print(f"Loading dataset: {args.input_dataset}")
    dataset = load_dataset(args.input_dataset, split="train")

    if args.prompt_column not in dataset.column_names:
        print(f"ERROR: Column '{args.prompt_column}' not found")
        print(f"Available columns: {dataset.column_names}")
        sys.exit(1)
    # if args.random_sample:
    #     dataset.shuffle()
    #     print(f"Random sampling enabled. Using {args.max_samples} samples.")

    # Limit samples if requested
    if args.max_samples:
        dataset = dataset.select(range(min(args.max_samples, len(dataset))))

    print(f"Processing {len(dataset)} examples")

    # Process each example
    results = []
    for i, example in enumerate(dataset):
        print(f"[{i + 1}/{len(dataset)}] Processing...")

        prompt_text = example[args.prompt_column]

        # Create messages (user message only, as per official examples)
        messages = [{"role": "user", "content": prompt_text}]

        # Apply chat template with reasoning_effort parameter
        inputs = tokenizer.apply_chat_template(
            messages, 
            add_generation_prompt=True, 
            return_tensors="pt", 
            return_dict=True,
            reasoning_effort=args.reasoning_effort  # "low", "medium", or "high"
        ).to(model.device)

        # Generate
        with torch.no_grad():
            generated = model.generate(
                **inputs,
                max_new_tokens=args.max_new_tokens,
                do_sample=True,
                temperature=0.7,
            )

        # Decode only the generated part (excluding input)
        response = tokenizer.decode(
            generated[0][inputs["input_ids"].shape[-1] :],
            skip_special_tokens=False,  # Keep channel markers
        )

        # Store raw output with channel markers
        results.append(
            {
                "prompt": prompt_text,
                "raw_output": response,
                "model": args.model_id,
                "reasoning_effort": args.reasoning_effort,
            }
        )

        # Show preview of output structure
        if i == 0:
            print("Sample output preview (first 200 chars):")
            print(response[:200])
            print("...")

    # Create and push dataset
    print("\nCreating output dataset...")
    output_dataset = Dataset.from_list(results)

    print(f"Pushing to {args.output_dataset}...")
    output_dataset.push_to_hub(args.output_dataset, token=token)

    print(f"\n✅ Complete!")
    print(f"Dataset: https://huggingface.co/datasets/{args.output_dataset}")
    print(f"\nOutput format:")
    print("- prompt: Original prompt")
    print("- raw_output: Full model response with channel markers")
    print("- model: Model ID used")
    print(f"- reasoning_effort: {args.reasoning_effort}")
    print(
        "\nTo extract final response, look for text after '<|channel|>final<|message|>'"
    )


if __name__ == "__main__":
    main()