import torch
from transformers import AutoModelForCausalLM, AutoTokenizer
from typing import Dict, List, Any
import  json
class EndpointHandler:
    def __init__(self, path=""):
        # Load the model and tokenizer
        self.device = torch.device("cuda" if torch.cuda.is_available() else "cpu")
        self.model = AutoModelForCausalLM.from_pretrained(path, torch_dtype=torch.bfloat16).to(self.device).eval()
        self.tokenizer = AutoTokenizer.from_pretrained(path)

    def __call__(self, data: Dict[str, Any]) -> List[Dict[str, Any]]:
        # Handle the incoming request
        if isinstance(data, str):
            try:
                data = json.loads(data)
            except json.JSONDecodeError:
                raise ValueError("Input data is not valid JSON.")

        # Ensure the input data is properly structured
        if isinstance(data, dict) and "inputs" in data:
            input_text = data["inputs"].get("text")
            template = data["inputs"].get("template")
        else:
            raise ValueError("Invalid input format. Expected a dictionary with 'inputs' key.")

        # Validate that input_text and template are strings
        if not isinstance(input_text, str) or not isinstance(template, str):
            raise ValueError("Both 'text' and 'template' should be strings.")
        
        # Run the prediction
        output = self.predict_NuExtract([input_text], template)
        
        return [{"extracted_information": output}]
    

    def predict_NuExtract(self, texts, template, batch_size=1, max_length=10_000, max_new_tokens=4_000):
        # Generate prompts based on the template
        template = json.dumps(json.loads(template), indent=4)
        prompts = [f"""<|input|>\n### Template:\n{template}\n### Text:\n{text}\n\n<|output|>""" for text in texts]
        outputs = []
        
        with torch.no_grad():
            for i in range(0, len(prompts), batch_size):
                batch_prompts = prompts[i:i+batch_size]
                batch_encodings = self.tokenizer(batch_prompts, return_tensors="pt", truncation=True, padding=True, max_length=max_length).to(self.device)
                pred_ids = self.model.generate(**batch_encodings, max_new_tokens=max_new_tokens)
                outputs += self.tokenizer.batch_decode(pred_ids, skip_special_tokens=True)

        return [output.split("<|output|>")[1] for output in outputs]