"""MongoDB client module for play history, activity logs, and analytics."""

import os
from datetime import datetime
from typing import Optional, List, Dict, Any
from motor.motor_asyncio import AsyncIOMotorClient, AsyncIOMotorDatabase
from pymongo import ASCENDING, DESCENDING


# MongoDB configuration from environment variables
MONGO_URI = os.getenv("MONGO_URI", "mongodb://localhost:27017")
MONGO_DB_NAME = os.getenv("MONGO_DB_NAME", "music_memories")

# Global MongoDB client and database instances
_mongo_client: Optional[AsyncIOMotorClient] = None
_mongo_db: Optional[AsyncIOMotorDatabase] = None


def get_mongo_client() -> Optional[AsyncIOMotorClient]:
    """Get the MongoDB client instance."""
    return _mongo_client


def get_mongo_db() -> Optional[AsyncIOMotorDatabase]:
    """Get the MongoDB database instance."""
    return _mongo_db


async def init_mongodb() -> None:
    """Initialize MongoDB connection."""
    global _mongo_client, _mongo_db
    try:
        # Use serverSelectionTimeoutMS to fail fast if MongoDB is not available
        _mongo_client = AsyncIOMotorClient(
            MONGO_URI,
            serverSelectionTimeoutMS=3000,
            connectTimeoutMS=5000,
            socketTimeoutMS=5000
        )
        _mongo_db = _mongo_client[MONGO_DB_NAME]

        # Test connection with ping
        await _mongo_client.admin.command('ping')
        print(f"✓ Connected to MongoDB at {MONGO_URI}")

        # Create indexes for play_history collection
        await _mongo_db.play_history.create_index([("user_id", ASCENDING), ("played_at", DESCENDING)])
        await _mongo_db.play_history.create_index([("song_id", ASCENDING)])
        await _mongo_db.play_history.create_index([("played_at", DESCENDING)])

        # Create indexes for activity_logs collection
        await _mongo_db.activity_logs.create_index([("user_id", ASCENDING), ("timestamp", DESCENDING)])
        await _mongo_db.activity_logs.create_index([("action_type", ASCENDING)])
        await _mongo_db.activity_logs.create_index([("timestamp", DESCENDING)])

        # Create indexes for analytics collection
        await _mongo_db.analytics.create_index([("event_type", ASCENDING), ("timestamp", DESCENDING)])
        await _mongo_db.analytics.create_index([("timestamp", DESCENDING)])

        # Create indexes for search_history collection
        await _mongo_db.search_history.create_index([("query", ASCENDING)])
        await _mongo_db.search_history.create_index([("timestamp", DESCENDING)])

        print("✓ MongoDB indexes created")
    except Exception as e:
        print(f"⚠ MongoDB connection failed: {e}")
        print("⚠ Running without MongoDB (using Redis/SQLite fallback)")
        _mongo_client = None
        _mongo_db = None


async def close_mongodb() -> None:
    """Close MongoDB connection."""
    global _mongo_client, _mongo_db
    if _mongo_client:
        _mongo_client.close()
        _mongo_client = None
        _mongo_db = None


# ============== Play History (MongoDB) ==============

async def store_play_history_mongo(
    user_id: int,
    song_id: int,
    song_title: str = None,
    song_artist: str = None,
    context_id: int = None,
    duration_seconds: int = None,
    completed: bool = True
) -> Dict[str, Any]:
    """Store a play history event in MongoDB."""
    if _mongo_db is None:
        return None
    
    document = {
        "user_id": user_id,
        "song_id": song_id,
        "song_title": song_title,
        "song_artist": song_artist,
        "context_id": context_id,
        "duration_seconds": duration_seconds,
        "completed": completed,
        "played_at": datetime.utcnow(),
        "created_at": datetime.utcnow()
    }
    
    result = await _mongo_db.play_history.insert_one(document)
    return {
        "id": str(result.inserted_id),
        **document
    }


async def get_user_play_history_mongo(
    user_id: int,
    limit: int = 50
) -> List[Dict[str, Any]]:
    """Get play history for a user from MongoDB."""
    if _mongo_db is None:
        return []
    
    cursor = _mongo_db.play_history.find(
        {"user_id": user_id}
    ).sort("played_at", DESCENDING).limit(limit)
    
    results = []
    async for doc in cursor:
        results.append({
            "id": str(doc["_id"]),
            "user_id": doc["user_id"],
            "song_id": doc["song_id"],
            "song_title": doc.get("song_title"),
            "song_artist": doc.get("song_artist"),
            "context_id": doc.get("context_id"),
            "duration_seconds": doc.get("duration_seconds"),
            "completed": doc.get("completed", True),
            "played_at": doc["played_at"].isoformat() if doc.get("played_at") else None
        })
    
    return results


async def get_global_play_history_mongo(
    limit: int = 50
) -> List[Dict[str, Any]]:
    """Get global play history from MongoDB."""
    if _mongo_db is None:
        return []
    
    cursor = _mongo_db.play_history.find({}).sort("played_at", DESCENDING).limit(limit)
    
    results = []
    async for doc in cursor:
        results.append({
            "id": str(doc["_id"]),
            "user_id": doc["user_id"],
            "song_id": doc["song_id"],
            "song_title": doc.get("song_title"),
            "song_artist": doc.get("song_artist"),
            "context_id": doc.get("context_id"),
            "duration_seconds": doc.get("duration_seconds"),
            "completed": doc.get("completed", True),
            "played_at": doc["played_at"].isoformat() if doc.get("played_at") else None
        })
    
    return results


async def get_song_play_count_mongo(song_id: int) -> int:
    """Get total play count for a song."""
    if _mongo_db is None:
        return 0
    
    count = await _mongo_db.play_history.count_documents({"song_id": song_id})
    return count


async def get_top_songs_mongo(limit: int = 10) -> List[Dict[str, Any]]:
    """Get top played songs from MongoDB analytics."""
    if _mongo_db is None:
        return []
    
    pipeline = [
        {"$group": {
            "_id": "$song_id",
            "play_count": {"$sum": 1},
            "song_title": {"$first": "$song_title"},
            "song_artist": {"$first": "$song_artist"}
        }},
        {"$sort": {"play_count": -1}},
        {"$limit": limit}
    ]
    
    results = []
    async for doc in _mongo_db.play_history.aggregate(pipeline):
        results.append({
            "song_id": doc["_id"],
            "song_title": doc.get("song_title"),
            "song_artist": doc.get("song_artist"),
            "play_count": doc["play_count"]
        })
    
    return results


# ============== Activity Logs (MongoDB) ==============

async def log_user_activity(
    user_id: int,
    action_type: str,
    details: Dict[str, Any] = None
) -> Dict[str, Any]:
    """Log a user activity event."""
    if _mongo_db is None:
        return None
    
    document = {
        "user_id": user_id,
        "action_type": action_type,
        "details": details or {},
        "timestamp": datetime.utcnow()
    }
    
    result = await _mongo_db.activity_logs.insert_one(document)
    return {
        "id": str(result.inserted_id),
        **document
    }


async def get_user_activity_mongo(
    user_id: int,
    limit: int = 50,
    action_type: str = None
) -> List[Dict[str, Any]]:
    """Get activity logs for a user."""
    if _mongo_db is None:
        return []
    
    query = {"user_id": user_id}
    if action_type:
        query["action_type"] = action_type
    
    cursor = _mongo_db.activity_logs.find(query).sort("timestamp", DESCENDING).limit(limit)
    
    results = []
    async for doc in cursor:
        results.append({
            "id": str(doc["_id"]),
            "user_id": doc["user_id"],
            "action_type": doc["action_type"],
            "details": doc.get("details", {}),
            "timestamp": doc["timestamp"].isoformat() if doc.get("timestamp") else None
        })
    
    return results


# ============== Analytics Events (MongoDB) ==============

async def track_analytics_event(
    event_type: str,
    properties: Dict[str, Any] = None
) -> Dict[str, Any]:
    """Track an analytics event."""
    if _mongo_db is None:
        return None
    
    document = {
        "event_type": event_type,
        "properties": properties or {},
        "timestamp": datetime.utcnow()
    }
    
    result = await _mongo_db.analytics.insert_one(document)
    return {
        "id": str(result.inserted_id),
        **document
    }


async def get_analytics_summary(
    event_type: str = None,
    hours: int = 24
) -> Dict[str, Any]:
    """Get analytics summary for the last N hours."""
    if _mongo_db is None:
        return {}
    
    from datetime import timedelta
    since = datetime.utcnow() - timedelta(hours=hours)
    
    query = {"timestamp": {"$gte": since}}
    if event_type:
        query["event_type"] = event_type
    
    total_events = await _mongo_db.analytics.count_documents(query)
    
    # Get event type breakdown
    pipeline = [
        {"$match": query},
        {"$group": {
            "_id": "$event_type",
            "count": {"$sum": 1}
        }},
        {"$sort": {"count": -1}}
    ]
    
    breakdown = []
    async for doc in _mongo_db.analytics.aggregate(pipeline):
        breakdown.append({
            "event_type": doc["_id"],
            "count": doc["count"]
        })
    
    return {
        "total_events": total_events,
        "period_hours": hours,
        "breakdown": breakdown
    }


# ============== User Search History (MongoDB) ==============

async def log_search(
    user_id: int = None,
    search_type: str = None,
    query: str = None,
    results_count: int = 0
) -> Dict[str, Any]:
    """Log a search event."""
    if _mongo_db is None:
        return None
    
    document = {
        "user_id": user_id,
        "search_type": search_type,
        "query": query,
        "results_count": results_count,
        "timestamp": datetime.utcnow()
    }
    
    result = await _mongo_db.search_history.insert_one(document)
    return {
        "id": str(result.inserted_id),
        **document
    }


async def get_popular_searches(
    hours: int = 24,
    limit: int = 10
) -> List[Dict[str, Any]]:
    """Get popular search queries."""
    if _mongo_db is None:
        return []
    
    from datetime import timedelta
    since = datetime.utcnow() - timedelta(hours=hours)
    
    pipeline = [
        {"$match": {"timestamp": {"$gte": since}}},
        {"$group": {
            "_id": "$query",
            "count": {"$sum": 1},
            "search_type": {"$first": "$search_type"}
        }},
        {"$sort": {"count": -1}},
        {"$limit": limit}
    ]
    
    results = []
    async for doc in _mongo_db.search_history.aggregate(pipeline):
        results.append({
            "query": doc["_id"],
            "search_type": doc.get("search_type"),
            "count": doc["count"]
        })
    
    return results