import torch
import base64
import io
import re
from typing import Dict, List, Any
from PIL import Image
from transformers import AutoProcessor, AutoModelForImageTextToText


class EndpointHandler:
    def __init__(self, path=""):
        self.processor = AutoProcessor.from_pretrained(path, trust_remote_code=True)
        self.model = AutoModelForImageTextToText.from_pretrained(
            path,
            torch_dtype=torch.float16,
            device_map="auto",
            trust_remote_code=True,
        ).eval()
        self.device = next(self.model.parameters()).device

    def __call__(self, data: Dict[str, Any]) -> List[Dict[str, Any]]:
        inputs_data = data.get("inputs", data)

        # Accept base64 image
        if isinstance(inputs_data, dict):
            image_b64 = inputs_data.get("image", "")
            prompt = inputs_data.get("prompt", "Text Recognition:")
        elif isinstance(inputs_data, str):
            image_b64 = inputs_data
            prompt = "Text Recognition:"
        else:
            return [{"error": "Invalid input format"}]

        # Decode image
        try:
            image_bytes = base64.b64decode(image_b64)
            image = Image.open(io.BytesIO(image_bytes)).convert("RGB")
        except Exception as e:
            return [{"error": f"Failed to decode image: {str(e)}"}]

        # Build messages
        messages = [
            {
                "role": "user",
                "content": [
                    {"type": "image", "image": image},
                    {"type": "text", "text": prompt},
                ],
            }
        ]

        # Process
        text = self.processor.apply_chat_template(
            messages, tokenize=False, add_generation_prompt=True
        )
        proc_inputs = self.processor(
            text=[text], images=[image], padding=True, return_tensors="pt"
        )
        proc_inputs = {k: v.to(self.device) for k, v in proc_inputs.items()}

        # Generate
        with torch.no_grad():
            output = self.model.generate(
                **proc_inputs,
                temperature=0.1,
                max_new_tokens=8192,
                do_sample=True,
            )

        prompt_len = proc_inputs["input_ids"].shape[1]
        new_tokens = output[:, prompt_len:]
        text_output = self.processor.tokenizer.batch_decode(
            new_tokens, skip_special_tokens=True
        )[0]

        return [{"generated_text": text_output}]