import os
import uuid
import datetime
from typing import Dict, List, Optional, Any
from pymongo import MongoClient
from bson.objectid import ObjectId

class MongoDBHelper:
    """Helper class for MongoDB operations"""
    
    def __init__(self, connection_string: Optional[str] = None):
        """Initialize the MongoDB client"""
        # Get connection string from env var or use provided one
        self.connection_string = connection_string or os.getenv('MONGODB_URI')
        
        if not self.connection_string:
            raise ValueError("MongoDB connection string not provided. Set MONGODB_URI environment variable or pass it to constructor.")
            
        self.client = MongoClient(self.connection_string)
        self.db = self.client.get_database("pyscout_ai")
        
        # Collections
        self.api_keys_collection = self.db.api_keys
        self.usage_collection = self.db.usage
        self.users_collection = self.db.users
        self.conversations_collection = self.db.conversations
        self.messages_collection = self.db.messages
        
        self._create_indexes()
    
    def _create_indexes(self):
        # API Keys indexes
        self.api_keys_collection.create_index("key", unique=True)
        self.api_keys_collection.create_index("user_id")
        self.api_keys_collection.create_index("created_at")
        
        # Usage indexes
        self.usage_collection.create_index("api_key")
        self.usage_collection.create_index("timestamp")
        
        # Users indexes
        self.users_collection.create_index("email", unique=True)
        
        # Conversations indexes
        self.conversations_collection.create_index("user_id")
        self.conversations_collection.create_index("created_at")
        
        # Messages indexes
        self.messages_collection.create_index("conversation_id")
        self.messages_collection.create_index("timestamp")

    def create_user(self, email: str, name: str, organization: str = None) -> str:
        user_id = str(ObjectId())
        self.users_collection.insert_one({
            "_id": ObjectId(user_id),
            "email": email,
            "name": name,
            "organization": organization,
            "created_at": datetime.datetime.utcnow(),
            "last_active": datetime.datetime.utcnow()
        })
        return user_id

    def create_conversation(self, user_id: str, system_prompt: str = None) -> str:
        conversation_id = str(ObjectId())
        self.conversations_collection.insert_one({
            "_id": ObjectId(conversation_id),
            "user_id": user_id,
            "system_prompt": system_prompt,
            "created_at": datetime.datetime.utcnow(),
            "last_message_at": datetime.datetime.utcnow(),
            "is_active": True
        })
        return conversation_id

    def add_message(self, conversation_id: str, role: str, content: str, 
                   model: str = None, tokens: int = 0) -> str:
        message_id = str(ObjectId())
        self.messages_collection.insert_one({
            "_id": ObjectId(message_id),
            "conversation_id": conversation_id,
            "role": role,
            "content": content,
            "model": model,
            "tokens": tokens,
            "timestamp": datetime.datetime.utcnow()
        })
        
        # Update conversation last_message_at
        self.conversations_collection.update_one(
            {"_id": ObjectId(conversation_id)},
            {"$set": {"last_message_at": datetime.datetime.utcnow()}}
        )
        
        return message_id

    def get_conversation_history(self, conversation_id: str) -> List[Dict]:
        return list(self.messages_collection.find(
            {"conversation_id": conversation_id},
            {"_id": 0}
        ).sort("timestamp", 1))

    def get_user_conversations(self, user_id: str, limit: int = 10) -> List[Dict]:
        conversations = list(self.conversations_collection.find(
            {"user_id": user_id},
            {"_id": 1, "system_prompt": 1, "created_at": 1, "last_message_at": 1}
        ).sort("last_message_at", -1).limit(limit))
        
        # Convert ObjectId to string
        for conv in conversations:
            conv["_id"] = str(conv["_id"])
        return conversations

    def generate_api_key(self, user_id: str, name: str = "Default API Key") -> str:
        """Generate a new API key for a user"""
        # Format: PyScoutAI-{uuid4-hex}
        api_key = f"PyScoutAI-{uuid.uuid4().hex}"
        
        # Store in database
        self.api_keys_collection.insert_one({
            "key": api_key,
            "user_id": user_id,
            "name": name,
            "created_at": datetime.datetime.utcnow(),
            "last_used": None,
            "is_active": True,
            "rate_limit": {
                "requests_per_day": 1000,
                "tokens_per_day": 1000000
            }
        })
        
        return api_key
    
    def validate_api_key(self, api_key: str) -> Dict[str, Any]:
        """
        Validate an API key
        
        Returns:
            Dict with user info if valid, None otherwise
        """
        if not api_key:
            return None
            
        # Find the API key in the database
        key_data = self.api_keys_collection.find_one({"key": api_key, "is_active": True})
        if not key_data:
            return None
            
        # Update last used timestamp
        self.api_keys_collection.update_one(
            {"_id": key_data["_id"]},
            {"$set": {"last_used": datetime.datetime.utcnow()}}
        )
        
        return key_data
    
    def log_api_usage(self, api_key: str, endpoint: str, tokens: int = 0, 
                     model: str = None, conversation_id: str = None):
        usage_data = {
            "api_key": api_key,
            "endpoint": endpoint,
            "tokens": tokens,
            "model": model,
            "timestamp": datetime.datetime.utcnow()
        }
        if conversation_id:
            usage_data["conversation_id"] = conversation_id
            
        self.usage_collection.insert_one(usage_data)

    def get_user_api_keys(self, user_id: str) -> List[Dict[str, Any]]:
        """Get all API keys for a user"""
        keys = list(self.api_keys_collection.find({"user_id": user_id}))
        # Convert ObjectId to string for JSON serialization
        for key in keys:
            key["_id"] = str(key["_id"])
        return keys
    
    def revoke_api_key(self, api_key: str) -> bool:
        """Revoke an API key"""
        result = self.api_keys_collection.update_one(
            {"key": api_key},
            {"$set": {"is_active": False}}
        )
        return result.modified_count > 0
    
    def check_rate_limit(self, api_key: str) -> Dict[str, Any]:
        """
        Check if the API key has exceeded its rate limits
        
        Returns:
            Dict with rate limit info and allowed status
        """
        key_data = self.api_keys_collection.find_one({"key": api_key, "is_active": True})
        if not key_data:
            return {"allowed": False, "reason": "Invalid API key"}
            
        # Get rate limit settings
        rate_limit = key_data.get("rate_limit", {})
        requests_per_day = rate_limit.get("requests_per_day", 1000)
        tokens_per_day = rate_limit.get("tokens_per_day", 1000000)
        
        # Calculate usage for today
        today_start = datetime.datetime.combine(
            datetime.datetime.utcnow().date(),
            datetime.time.min
        )
        
        # Count requests today
        requests_today = self.usage_collection.count_documents({
            "api_key": api_key,
            "timestamp": {"$gte": today_start}
        })
        
        # Sum tokens used today
        tokens_pipeline = [
            {"$match": {"api_key": api_key, "timestamp": {"$gte": today_start}}},
            {"$group": {"_id": None, "total_tokens": {"$sum": "$tokens"}}}
        ]
        tokens_result = list(self.usage_collection.aggregate(tokens_pipeline))
        tokens_today = tokens_result[0]["total_tokens"] if tokens_result else 0
        
        # Check if limits are exceeded
        if requests_today >= requests_per_day:
            return {
                "allowed": False,
                "reason": "Daily request limit exceeded",
                "limit": requests_per_day,
                "used": requests_today
            }
            
        if tokens_today >= tokens_per_day:
            return {
                "allowed": False,
                "reason": "Daily token limit exceeded",
                "limit": tokens_per_day,
                "used": tokens_today
            }
            
        return {
            "allowed": True,
            "requests": {
                "limit": requests_per_day,
                "used": requests_today,
                "remaining": requests_per_day - requests_today
            },
            "tokens": {
                "limit": tokens_per_day,
                "used": tokens_today,
                "remaining": tokens_per_day - tokens_today
            }
        }

    def get_user_stats(self, user_id: str) -> Dict:
        pipeline = [
            {"$match": {"user_id": user_id}},
            {"$group": {
                "_id": None,
                "total_conversations": {"$sum": 1},
                "total_messages": {"$sum": "$message_count"},
                "total_tokens": {"$sum": "$total_tokens"}
            }}
        ]
        stats = list(self.conversations_collection.aggregate(pipeline))
        return stats[0] if stats else {"total_conversations": 0, "total_messages": 0, "total_tokens": 0}