from datetime import datetime
from typing import Optional, List, Dict, Any
from bson import ObjectId
import logging

from app.core.nosql_client import db

logger = logging.getLogger(__name__)

class WalletModel:
    """Model for managing user wallet operations"""
    
    wallet_collection = db["user_wallets"]
    transaction_collection = db["wallet_transactions"]
    
    @staticmethod
    async def get_wallet_balance(customer_id: str) -> float:
        """Get current wallet balance for a user"""
        try:
            wallet = await WalletModel.wallet_collection.find_one({"customer_id": customer_id})
            if wallet:
                return wallet.get("balance", 0.0)
            else:
                # Create wallet if doesn't exist
                await WalletModel.create_wallet(customer_id)
                return 0.0
        except Exception as e:
            logger.error(f"Error getting wallet balance for user {customer_id}: {str(e)}")
            return 0.0
    
    @staticmethod
    async def create_wallet(customer_id: str, initial_balance: float = 0.0) -> bool:
        """Create a new wallet for a user"""
        try:
            wallet_doc = {
                "customer_id": customer_id,
                "balance": initial_balance,
                "created_at": datetime.utcnow(),
                "updated_at": datetime.utcnow()
            }
            
            result = await WalletModel.wallet_collection.insert_one(wallet_doc)
            logger.info(f"Created wallet for user {customer_id} with balance {initial_balance}")
            return result.inserted_id is not None
        except Exception as e:
            logger.error(f"Error creating wallet for user {customer_id}: {str(e)}")
            return False
    
    @staticmethod
    async def update_balance(customer_id: str, amount: float, transaction_type: str, 
                           description: str = "", reference_id: str = None) -> bool:
        """Update wallet balance and create transaction record"""
        try:
            # Get current balance
            current_balance = await WalletModel.get_wallet_balance(customer_id)
            
            # Calculate new balance
            if transaction_type in ["credit", "refund", "cashback"]:
                new_balance = current_balance + amount
            elif transaction_type in ["debit", "payment", "withdrawal"]:
                if current_balance < amount:
                    logger.warning(f"Insufficient balance for user {customer_id}. Current: {current_balance}, Required: {amount}")
                    return False
                new_balance = current_balance - amount
            else:
                logger.error(f"Invalid transaction type: {transaction_type}")
                return False
            
            # Update wallet balance
            update_result = await WalletModel.wallet_collection.update_one(
                {"customer_id": customer_id},
                {
                    "$set": {
                        "balance": new_balance,
                        "updated_at": datetime.utcnow()
                    }
                },
                upsert=True
            )
            
            # Create transaction record
            transaction_doc = {
                "customer_id": customer_id,
                "amount": amount,
                "transaction_type": transaction_type,
                "description": description,
                "reference_id": reference_id,
                "balance_before": current_balance,
                "balance_after": new_balance,
                "timestamp": datetime.utcnow(),
                "status": "completed"
            }
            
            await WalletModel.transaction_collection.insert_one(transaction_doc)
            
            logger.info(f"Updated wallet for user {customer_id}: {transaction_type} of {amount}, new balance: {new_balance}")
            return True
            
        except Exception as e:
            logger.error(f"Error updating wallet balance for user {customer_id}: {str(e)}")
            return False
    
    @staticmethod
    async def get_transaction_history(customer_id: str, page: int = 1, per_page: int = 20) -> Dict[str, Any]:
        """Get paginated transaction history for a user"""
        try:
            skip = (page - 1) * per_page
            
            # Get transactions with pagination
            cursor = WalletModel.transaction_collection.find(
                {"customer_id": customer_id}
            ).sort("timestamp", -1).skip(skip).limit(per_page)
            
            transactions = []
            async for transaction in cursor:
                # Convert ObjectId to string for JSON serialization
                transaction["_id"] = str(transaction["_id"])
                transactions.append(transaction)
            
            # Get total count
            total_count = await WalletModel.transaction_collection.count_documents({"customer_id": customer_id})
            
            return {
                "transactions": transactions,
                "total_count": total_count,
                "page": page,
                "per_page": per_page,
                "total_pages": (total_count + per_page - 1) // per_page
            }
            
        except Exception as e:
            logger.error(f"Error getting transaction history for user {customer_id}: {str(e)}")
            return {
                "transactions": [],
                "total_count": 0,
                "page": page,
                "per_page": per_page,
                "total_pages": 0
            }
    
    @staticmethod
    async def get_wallet_summary(customer_id: str) -> Dict[str, Any]:
        """Get wallet summary including balance and recent transactions"""
        try:
            balance = await WalletModel.get_wallet_balance(customer_id)
            recent_transactions = await WalletModel.get_transaction_history(customer_id, page=1, per_page=5)
            
            return {
                "balance": balance,
                "recent_transactions": recent_transactions["transactions"]
            }
            
        except Exception as e:
            logger.error(f"Error getting wallet summary for user {customer_id}: {str(e)}")
            return {
                "balance": 0.0,
                "recent_transactions": []
            }