import os
import logging
import uuid
import json
import pandas as pd
from datetime import datetime
from typing import List, Dict, Any, Optional
from datasets import Dataset, load_dataset
from huggingface_hub import HfApi, HfFolder, CommitOperationAdd

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

class ChatHistoryManager:
    """
    Manages chat history persistence using Hugging Face Datasets.
    Supports both local storage and syncing to Hugging Face Hub.
    """
    
    def __init__(self, dataset_name=None, local_dir="./data/chat_history"):
        """
        Initialize the chat history manager.
        
        Args:
            dataset_name: Hugging Face dataset name (username/repo)
            local_dir: Local directory to store chat history
        """
        self.dataset_name = dataset_name or os.getenv("HF_DATASET_NAME")
        self.local_dir = local_dir
        self.hf_api = HfApi()
        self.token = os.getenv("HF_API_KEY")
        
        # Create local directory if it doesn't exist
        os.makedirs(self.local_dir, exist_ok=True)
        
        # Local path for the jsonl file
        self.local_file = os.path.join(self.local_dir, "chat_history.jsonl")
        
        # Ensure the file exists
        if not os.path.exists(self.local_file):
            with open(self.local_file, "w") as f:
                f.write("")
                
        logger.info(f"Chat history manager initialized with local file: {self.local_file}")
        if self.dataset_name:
            logger.info(f"Will sync to HF dataset: {self.dataset_name}")
    
    def load_history(self) -> List[Dict[str, Any]]:
        """Load chat history from local file or Hugging Face dataset."""
        try:
            # First try to load from local file
            if os.path.exists(self.local_file) and os.path.getsize(self.local_file) > 0:
                with open(self.local_file, "r") as f:
                    lines = f.readlines()
                    history = [json.loads(line) for line in lines if line.strip()]
                    logger.info(f"Loaded {len(history)} conversations from local file")
                    return history
            
            # If local file is empty or doesn't exist, try to load from HF
            if self.dataset_name and self.token:
                try:
                    dataset = load_dataset(self.dataset_name, token=self.token)
                    history = dataset["train"].to_pandas().to_dict("records")
                    logger.info(f"Loaded {len(history)} conversations from Hugging Face")
                    
                    # Write back to local file
                    self._write_history_to_local(history)
                    return history
                except Exception as e:
                    logger.warning(f"Error loading from Hugging Face: {e}")
            
            # If we get here, return empty history
            return []
        except Exception as e:
            logger.error(f"Error loading chat history: {e}")
            return []
    
    def save_conversation(self, conversation: Dict[str, Any]) -> bool:
        """
        Save a conversation to history.
        
        Args:
            conversation: Dict with keys: user_query, assistant_response, 
                          timestamp, sources (optional)
        
        Returns:
            bool: True if successful
        """
        try:
            # Add ID and timestamp if not present
            if "id" not in conversation:
                conversation["id"] = str(uuid.uuid4())
            if "timestamp" not in conversation:
                conversation["timestamp"] = datetime.now().isoformat()
            
            # Append to local file
            with open(self.local_file, "a") as f:
                f.write(json.dumps(conversation) + "\n")
            
            logger.info(f"Saved conversation to local file: {conversation['id']}")
            return True
        except Exception as e:
            logger.error(f"Error saving conversation: {e}")
            return False
    
    def sync_to_hub(self) -> bool:
        """Sync local chat history to Hugging Face Hub."""
        if not self.dataset_name or not self.token:
            logger.warning("Cannot sync to Hub: missing dataset name or token")
            return False
            
        try:
            # Read the local file
            history = self.load_history()
            if not history:
                logger.warning("No history to sync")
                return False
                
            # Create a Dataset object
            ds = Dataset.from_pandas(
                pd.DataFrame(history)
            )
            
            # Push to Hub
            ds.push_to_hub(
                self.dataset_name,
                token=self.token,
                private=True
            )
            
            logger.info(f"Successfully synced {len(history)} conversations to Hugging Face Hub")
            return True
        except Exception as e:
            logger.error(f"Error syncing to Hub: {e}")
            return False
    
    def _write_history_to_local(self, history: List[Dict[str, Any]]) -> bool:
        """Write history list to local file."""
        try:
            with open(self.local_file, "w") as f:
                for conversation in history:
                    f.write(json.dumps(conversation) + "\n")
            return True
        except Exception as e:
            logger.error(f"Error writing history to local file: {e}")
            return False
    
    def get_conversations_by_date(self, start_date=None, end_date=None) -> List[Dict[str, Any]]:
        """Get conversations filtered by date range."""
        history = self.load_history()
        
        if not start_date and not end_date:
            return history
            
        filtered = []
        for conv in history:
            timestamp = conv.get("timestamp", "")
            if not timestamp:
                continue
                
            try:
                conv_date = datetime.fromisoformat(timestamp)
                
                if start_date and end_date:
                    if start_date <= conv_date <= end_date:
                        filtered.append(conv)
                elif start_date:
                    if start_date <= conv_date:
                        filtered.append(conv)
                elif end_date:
                    if conv_date <= end_date:
                        filtered.append(conv)
            except ValueError:
                continue
                
        return filtered
    
    def search_conversations(self, query: str) -> List[Dict[str, Any]]:
        """Search conversations by keyword (simple text match)."""
        history = self.load_history()
        query = query.lower()
        
        results = []
        for conv in history:
            user_query = conv.get("user_query", "").lower()
            assistant_response = conv.get("assistant_response", "").lower()
            
            if query in user_query or query in assistant_response:
                results.append(conv)
                
        return results