import os
import threading

from transformers import (
    AutoTokenizer, 
    AutoModel, 
    AutoModelForSeq2SeqLM, 
    AutoModelForCausalLM,
    AutoConfig
)
import torch
import logging

# Set up logging
logging.basicConfig(level=logging.INFO)
logger = logging.getLogger(__name__)

class CodeDebuggerWrapper:
    def __init__(self, model_name="Girinath11/aiml_code_debug_model"):
        self.model_name = model_name
        self.model = None
        self.tokenizer = None
        self.model_type = None
        self._ensure_model()
    
    def _ensure_model(self):
        """Load model and tokenizer with fallback strategies."""
        logger.info(f"Loading model {self.model_name} ...")
        
        try:
            # Load tokenizer first
            self.tokenizer = AutoTokenizer.from_pretrained(self.model_name)
            logger.info("✅ Tokenizer loaded successfully")
            
            # Add pad token if it doesn't exist
            if self.tokenizer.pad_token is None:
                self.tokenizer.pad_token = self.tokenizer.eos_token
            
            # Check model configuration
            config = AutoConfig.from_pretrained(self.model_name)
            logger.info(f"Model config type: {type(config).__name__}")
            
            # Try different model loading strategies
            loading_strategies = [
                ("AutoModel with trust_remote_code", lambda: AutoModel.from_pretrained(
                    self.model_name, trust_remote_code=True
                )),
                ("AutoModelForCausalLM with trust_remote_code", lambda: AutoModelForCausalLM.from_pretrained(
                    self.model_name, trust_remote_code=True
                )),
                ("AutoModelForSeq2SeqLM with trust_remote_code", lambda: AutoModelForSeq2SeqLM.from_pretrained(
                    self.model_name, trust_remote_code=True
                )),
                ("AutoModel without trust_remote_code", lambda: AutoModel.from_pretrained(
                    self.model_name
                )),
                ("AutoModelForCausalLM without trust_remote_code", lambda: AutoModelForCausalLM.from_pretrained(
                    self.model_name
                )),
            ]
            
            for strategy_name, strategy_func in loading_strategies:
                try:
                    logger.info(f"Trying: {strategy_name}")
                    self.model = strategy_func()
                    self.model_type = type(self.model).__name__
                    logger.info(f"✅ Successfully loaded model with {strategy_name}")
                    logger.info(f"Model type: {self.model_type}")
                    break
                except Exception as e:
                    logger.warning(f"❌ {strategy_name} failed: {str(e)[:100]}...")
                    continue
            
            if self.model is None:
                raise RuntimeError("❌ Failed to load model with any strategy")
            
            # Set to evaluation mode
            self.model.eval()
            logger.info("✅ Model set to evaluation mode")
            
        except Exception as e:
            logger.error(f"❌ Critical error in model loading: {e}")
            raise
    
    def debug(self, code: str) -> str:
        """Debug the provided code."""
        if not code or not code.strip():
            return "❌ Please provide some code to debug."
        
        try:
            # Prepare input with a clear prompt
            prompt = f"### Task: Debug and fix the following Python code\n\n### Input Code:\n{code}\n\n### Fixed Code:"
            
            # Tokenize input
            inputs = self.tokenizer(
                prompt, 
                return_tensors="pt", 
                max_length=512, 
                truncation=True,
                padding=True
            )
            
            logger.info(f"Input tokenized. Input IDs shape: {inputs['input_ids'].shape}")
            
            # Generate response based on model type
            with torch.no_grad():
                if hasattr(self.model, 'generate'):
                    logger.info("Using generate method")
                    
                    # Generation parameters
                    generation_kwargs = {
                        **inputs,
                        'max_new_tokens': 256,
                        'num_beams': 3,
                        'early_stopping': True,
                        'do_sample': True,
                        'temperature': 0.7,
                        'pad_token_id': self.tokenizer.pad_token_id,
                    }
                    
                    # Add eos_token_id if available
                    if hasattr(self.tokenizer, 'eos_token_id') and self.tokenizer.eos_token_id is not None:
                        generation_kwargs['eos_token_id'] = self.tokenizer.eos_token_id
                    
                    try:
                        outputs = self.model.generate(**generation_kwargs)
                        response = self.tokenizer.decode(outputs[0], skip_special_tokens=True)
                        
                        # Clean up the response
                        if prompt in response:
                            response = response.replace(prompt, "").strip()
                        
                        # If response is empty or too short, provide a fallback
                        if not response or len(response.strip()) < 10:
                            response = f"The model processed your code but didn't generate a clear fix. Original code:\n\n{code}\n\n💡 Tip: Check for common issues like indentation, syntax errors, or missing imports."
                        
                    except Exception as gen_error:
                        logger.error(f"Generation error: {gen_error}")
                        response = f"❌ Error during code generation: {str(gen_error)}\n\nOriginal code:\n{code}"
                
                else:
                    # For encoder-only models
                    logger.info("Model doesn't support generation. Using encoder-only approach.")
                    outputs = self.model(**inputs)
                    
                    # This is a simplified approach - you might need to add a classification head
                    # or use a different strategy based on your specific model
                    response = f"⚠️  This model type ({self.model_type}) doesn't support text generation directly.\n\nOriginal code:\n{code}\n\n💡 Consider using a generative model (T5, GPT, BART) for code debugging tasks."
            
            return response
            
        except Exception as e:
            logger.error(f"Error in debug method: {e}")
            return f"❌ Error during debugging: {str(e)}\n\nOriginal code:\n{code}"