"""
Inference script for docstring generation from Python code.
Uses Hugging Face Transformers (T5 or CodeT5).
"""

import argparse
from transformers import AutoModelForSeq2SeqLM, AutoTokenizer
import torch


def generate_docstring(
    code: str,
    model_name: str = "t5-small",
    max_length: int = 128,
    num_beams: int = 4,
    device: str = None,
) -> str:
    if device is None:
        device = "cuda" if torch.cuda.is_available() else "cpu"

    tokenizer = AutoTokenizer.from_pretrained(model_name)
    model = AutoModelForSeq2SeqLM.from_pretrained(model_name).to(device)

    # T5 expects a prefix for the task; we use "summarize:" for generic text/code summary
    input_text = "summarize: " + code
    inputs = tokenizer(input_text, return_tensors="pt", truncation=True, max_length=512).to(device)

    with torch.no_grad():
        out = model.generate(
            **inputs,
            max_length=max_length,
            num_beams=num_beams,
            early_stopping=True,
        )

    return tokenizer.decode(out[0], skip_special_tokens=True)


def main():
    parser = argparse.ArgumentParser()
    parser.add_argument("--input", type=str, required=True, help="Python code snippet (or path to file)")
    parser.add_argument("--model_name", type=str, default="t5-small")
    parser.add_argument("--max_length", type=int, default=128)
    parser.add_argument("--num_beams", type=int, default=4)
    args = parser.parse_args()

    code = args.input
    if len(code) < 260 and code.endswith(".py"):
        try:
            with open(code, "r") as f:
                code = f.read()
        except Exception:
            pass

    docstring = generate_docstring(
        code,
        model_name=args.model_name,
        max_length=args.max_length,
        num_beams=args.num_beams,
    )
    print(docstring)


if __name__ == "__main__":
    main()