"""
Production Database Initialization
Sets up MongoDB with proper indexes and collections
"""
from typing import Optional
from pymongo import MongoClient, ASCENDING, DESCENDING, TEXT
from pymongo.errors import CollectionInvalid
from config import settings
from utils.crypto_utils import encrypt_secret, is_encrypted
import base64


_client: Optional[MongoClient] = None


def get_client() -> MongoClient:
    """Get MongoDB client (singleton) with connection pooling"""
    global _client
    if _client is None:
        # Mask credentials in URI for logging
        uri = settings.MONGODB_URI
        masked = uri
        try:
            if "@" in uri and "://" in uri:
                scheme_sep = uri.split("://", 1)
                scheme, rest = scheme_sep[0], scheme_sep[1]
                if "@" in rest:
                    creds, host = rest.split("@", 1)
                    masked_creds = "***:***" if ":" in creds else "***"
                    masked = f"{scheme}://{masked_creds}@{host}"
        except Exception:
            masked = "<redacted>"
        print(f"[DB] Connecting to MongoDB: {masked}")
        
        # Connection pool configuration for production workloads
        _client = MongoClient(
            settings.MONGODB_URI,
            maxPoolSize=50,           # Maximum connections in pool
            minPoolSize=5,            # Minimum connections to maintain
            maxIdleTimeMS=30000,      # Close idle connections after 30s
            serverSelectionTimeoutMS=5000,  # Fast fail on connection issues
            connectTimeoutMS=10000,   # Connection timeout
            retryWrites=True,         # Auto-retry on transient errors
        )
        # Test connection
        _client.admin.command('ping')
        print("[DB] [SUCCESS] MongoDB connection successful (pool: 5-50)")
    return _client


def get_db():
    """Get database instance"""
    client = get_client()
    return client[settings.MONGODB_DB_NAME]


def get_mongo():
    """Generator for FastAPI dependency injection"""
    db = get_db()
    try:
        yield db
    finally:
        pass  # Connection pooling handles cleanup


def get_next_sequence(db, name: str) -> int:
    """
    Get the next sequence number for auto-incrementing IDs.
    Used for generating unique sequential identifiers.
    
    Args:
        db: Database connection
        name: Name of the sequence (e.g., 'property_id', 'user_id')
    
    Returns:
        Next sequence number
    """
    from pymongo import ReturnDocument
    doc = db.counters.find_one_and_update(
        {"_id": name},
        {"$inc": {"seq": 1}},
        upsert=True,
        return_document=ReturnDocument.AFTER,
    )
    return int(doc.get("seq", 1))


def create_collections(db):
    """Create all required collections"""
    print("[DB] Creating collections...")
    
    collections = [
        'users', 'wallets', 'properties', 'property_specifications',
        'amenities', 'property_images', 'investments', 'transactions',
        'portfolios', 'documents', 'secondary_market_transactions',
        'otps', 'sessions', 'certificates', 'rent_distributions', 
        'rent_payments', 'counters', 'tokens', 'funded_properties'
    ]
    
    existing = db.list_collection_names()
    
    for coll_name in collections:
        if coll_name not in existing:
            try:
                db.create_collection(coll_name)
                print(f"[DB] [SUCCESS] Created collection: {coll_name}")
            except CollectionInvalid:
                pass  # Collection already exists


def ensure_indexes(db):
    """Create all database indexes for performance and uniqueness"""
    print("[DB] Creating indexes...")
    
    # ========================================================================
    # USERS COLLECTION
    # ========================================================================
    db.users.create_index([("email", ASCENDING)], unique=True, name="idx_email_unique")
    db.users.create_index([("role", ASCENDING)], name="idx_role")
    db.users.create_index([("is_active", ASCENDING)], name="idx_is_active")
    db.users.create_index([("deleted", ASCENDING)], name="idx_deleted")
    db.users.create_index([("created_at", DESCENDING)], name="idx_created_at")
    print("[DB] [SUCCESS] Users indexes created")
    
    # ========================================================================
    # OTPs COLLECTION (for email verification)
    # ========================================================================
    db.otps.create_index([("email", ASCENDING), ("purpose", ASCENDING)], name="idx_email_purpose")
    # TTL index: automatically deletes OTPs after they expire
    db.otps.create_index([("expires_at", ASCENDING)], name="idx_expires_at_ttl", expireAfterSeconds=0)
    db.otps.create_index([("verified", ASCENDING)], name="idx_verified")
    db.otps.create_index([("created_at", DESCENDING)], name="idx_created_at")
    print("[DB] [SUCCESS] OTPs indexes created (with TTL)")
    
    # ========================================================================
    # WALLETS COLLECTION
    # ========================================================================
    db.wallets.create_index([("user_id", ASCENDING)], unique=True, name="idx_user_id_unique")
    db.wallets.create_index([("is_active", ASCENDING)], name="idx_is_active")
    print("[DB] [SUCCESS] Wallets indexes created")
    
    # ========================================================================
    # PROPERTIES COLLECTION
    # ========================================================================
    db.properties.create_index([("title", TEXT)], name="idx_title_text")
    db.properties.create_index([("location", ASCENDING)], name="idx_location")
    db.properties.create_index([("property_type", ASCENDING)], name="idx_property_type")
    db.properties.create_index([("is_active", ASCENDING)], name="idx_is_active")
    db.properties.create_index([("deleted", ASCENDING)], name="idx_deleted")
    db.properties.create_index([("created_by", ASCENDING)], name="idx_created_by")
    db.properties.create_index([("created_at", DESCENDING)], name="idx_created_at")
    db.properties.create_index([("funded_date", DESCENDING)], name="idx_funded_date")
    db.properties.create_index([("available_tokens", ASCENDING)], name="idx_available_tokens")
    print("[DB] [SUCCESS] Properties indexes created")
    
    # ========================================================================
    # PROPERTY SPECIFICATIONS COLLECTION
    # ========================================================================
    db.property_specifications.create_index(
        [("property_id", ASCENDING)], 
        unique=True, 
        name="idx_property_id_unique"
    )
    print("[DB] [SUCCESS] Property specifications indexes created")
    
    # ========================================================================
    # AMENITIES COLLECTION
    # ========================================================================
    db.amenities.create_index([("property_id", ASCENDING)], name="idx_property_id")
    db.amenities.create_index([("is_active", ASCENDING)], name="idx_is_active")
    print("[DB] [SUCCESS] Amenities indexes created")
    
    # ========================================================================
    # PROPERTY IMAGES COLLECTION
    # ========================================================================
    db.property_images.create_index([("property_id", ASCENDING)], name="idx_property_id")
    db.property_images.create_index([("is_main", ASCENDING)], name="idx_is_main")
    db.property_images.create_index([("is_active", ASCENDING)], name="idx_is_active")
    print("[DB] [SUCCESS] Property images indexes created")
    
    # ========================================================================
    # INVESTMENTS COLLECTION
    # ========================================================================
    db.investments.create_index([("user_id", ASCENDING)], name="idx_user_id")
    db.investments.create_index([("property_id", ASCENDING)], name="idx_property_id")
    db.investments.create_index(
        [("user_id", ASCENDING), ("property_id", ASCENDING)],
        name="idx_user_property"
    )
    db.investments.create_index([("status", ASCENDING)], name="idx_status")
    db.investments.create_index([("created_at", DESCENDING)], name="idx_created_at")
    print("[DB] [SUCCESS] Investments indexes created")
    
    # ========================================================================
    # TRANSACTIONS COLLECTION
    # ========================================================================
    db.transactions.create_index([("user_id", ASCENDING)], name="idx_user_id")
    db.transactions.create_index([("wallet_id", ASCENDING)], name="idx_wallet_id")
    db.transactions.create_index([("property_id", ASCENDING)], name="idx_property_id")
    db.transactions.create_index([("type", ASCENDING)], name="idx_type")
    db.transactions.create_index([("status", ASCENDING)], name="idx_status")
    db.transactions.create_index([("created_at", DESCENDING)], name="idx_created_at")
    db.transactions.create_index(
        [("user_id", ASCENDING), ("type", ASCENDING)],
        name="idx_user_type"
    )
    print("[DB] [SUCCESS] Transactions indexes created")
    
    # ========================================================================
    # PORTFOLIOS COLLECTION
    # ========================================================================
    db.portfolios.create_index([("user_id", ASCENDING)], unique=True, name="idx_user_id_unique")
    db.portfolios.create_index([("updated_at", DESCENDING)], name="idx_updated_at")
    print("[DB] [SUCCESS] Portfolios indexes created")
    
    # ========================================================================
    # DOCUMENTS COLLECTION
    # ========================================================================
    db.documents.create_index([("property_id", ASCENDING)], name="idx_property_id")
    db.documents.create_index([("file_type", ASCENDING)], name="idx_file_type")
    db.documents.create_index([("uploaded_by", ASCENDING)], name="idx_uploaded_by")
    print("[DB] [SUCCESS] Documents indexes created")
    
    # ========================================================================
    # SECONDARY MARKET TRANSACTIONS COLLECTION
    # ========================================================================
    db.secondary_market_transactions.create_index(
        [("transaction_id", ASCENDING)], 
        unique=True, 
        name="idx_transaction_id_unique"
    )
    db.secondary_market_transactions.create_index(
        [("seller_id", ASCENDING)], 
        name="idx_seller_id"
    )
    db.secondary_market_transactions.create_index(
        [("buyer_id", ASCENDING)], 
        name="idx_buyer_id"
    )
    db.secondary_market_transactions.create_index(
        [("property_id", ASCENDING)], 
        name="idx_property_id"
    )
    db.secondary_market_transactions.create_index(
        [("status", ASCENDING)], 
        name="idx_status"
    )
    db.secondary_market_transactions.create_index(
        [("transaction_type", ASCENDING)], 
        name="idx_transaction_type"
    )
    db.secondary_market_transactions.create_index(
        [("initiated_at", DESCENDING)], 
        name="idx_initiated_at"
    )
    db.secondary_market_transactions.create_index(
        [("seller_id", ASCENDING), ("status", ASCENDING)],
        name="idx_seller_status"
    )
    db.secondary_market_transactions.create_index(
        [("property_id", ASCENDING), ("status", ASCENDING)],
        name="idx_property_status"
    )
    db.secondary_market_transactions.create_index(
        [("blockchain_tx_hash", ASCENDING)], 
        name="idx_blockchain_tx"
    )
    print("[DB] [SUCCESS] Secondary market transactions indexes created")
    
    # ========================================================================
    # SESSIONS COLLECTION (Device-bound Authentication)
    # ========================================================================
    db.sessions.create_index([("session_id", ASCENDING)], unique=True, name="idx_session_id_unique")
    db.sessions.create_index([("user_id", ASCENDING)], name="idx_user_id")
    db.sessions.create_index([("expires_at", ASCENDING)], name="idx_expires_at_ttl", expireAfterSeconds=0)
    db.sessions.create_index(
        [("user_id", ASCENDING), ("device_fingerprint", ASCENDING)],
        name="idx_user_device"
    )
    db.sessions.create_index([("is_active", ASCENDING)], name="idx_is_active")
    print("[DB] [SUCCESS] Sessions indexes created (with TTL)")
    
    # ========================================================================
    # CERTIFICATES COLLECTION (Ownership Certificates)
    # ========================================================================
    db.certificates.create_index([("certificate_id", ASCENDING)], unique=True, name="idx_certificate_id_unique")
    db.certificates.create_index([("user_id", ASCENDING)], name="idx_user_id")
    db.certificates.create_index(
        [("user_id", ASCENDING), ("property_details.property_id", ASCENDING)],
        name="idx_user_property"
    )
    db.certificates.create_index([("issued_date", ASCENDING)], name="idx_issued_date")
    db.certificates.create_index([("is_valid", ASCENDING)], name="idx_is_valid")
    print("[DB] [SUCCESS] Certificates indexes created")
    
    # ========================================================================
    # RENT DISTRIBUTIONS COLLECTION
    # ========================================================================
    db.rent_distributions.create_index([("property_id", ASCENDING)], name="idx_property_id")
    db.rent_distributions.create_index([("distribution_date", DESCENDING)], name="idx_distribution_date")
    db.rent_distributions.create_index([("status", ASCENDING)], name="idx_status")
    db.rent_distributions.create_index([("created_at", DESCENDING)], name="idx_created_at")
    db.rent_distributions.create_index(
        [("property_id", ASCENDING), ("status", ASCENDING)],
        name="idx_property_status"
    )
    print("[DB] [SUCCESS] Rent distributions indexes created")
    
    # ========================================================================
    # RENT PAYMENTS COLLECTION
    # ========================================================================
    db.rent_payments.create_index([("distribution_id", ASCENDING)], name="idx_distribution_id")
    db.rent_payments.create_index([("user_id", ASCENDING)], name="idx_user_id")
    db.rent_payments.create_index([("property_id", ASCENDING)], name="idx_property_id")
    db.rent_payments.create_index(
        [("user_id", ASCENDING), ("property_id", ASCENDING)],
        name="idx_user_property"
    )
    db.rent_payments.create_index([("payment_date", DESCENDING)], name="idx_payment_date")
    db.rent_payments.create_index([("payment_status", ASCENDING)], name="idx_payment_status")
    print("[DB] [SUCCESS] Rent payments indexes created")
    
    # ========================================================================
    # TOKENS COLLECTION (Property Tokens)
    # ========================================================================
    db.tokens.create_index([("property_id", ASCENDING)], unique=True, name="idx_property_id_unique")
    db.tokens.create_index([("is_active", ASCENDING)], name="idx_is_active")
    print("[DB] [SUCCESS] Tokens indexes created")
    
    # ========================================================================
    # FUNDED PROPERTIES COLLECTION (Fully Funded Properties Archive)
    # ========================================================================
    db.funded_properties.create_index([("property_id", ASCENDING)], unique=True, name="idx_property_id_unique")
    db.funded_properties.create_index([("funded_date", DESCENDING)], name="idx_funded_date")
    db.funded_properties.create_index([("funding_status", ASCENDING)], name="idx_funding_status")
    db.funded_properties.create_index([("is_active", ASCENDING)], name="idx_is_active")
    db.funded_properties.create_index([("created_at", DESCENDING)], name="idx_created_at")
    print("[DB] [SUCCESS] Funded properties indexes created")
    
    print("[DB] ✅ All indexes created successfully")


def init_mongo(app=None):
    """Initialize MongoDB database"""
    print("\n" + "="*80)
    print("INITIALIZING MONGODB DATABASE")
    print("="*80 + "\n")
    
    try:
        db = get_db()
        
        # Create collections
        create_collections(db)
        
        # Create indexes
        ensure_indexes(db)

        # Optional: migrate legacy wallet seeds to encrypted form if encryption enabled
        try:
            if settings.encryption_enabled():
                wallets = db.wallets.find({"xrp_seed": {"$exists": True, "$ne": None}})
                migrated = 0
                for w in wallets:
                    seed_val = w.get("xrp_seed")
                    if not seed_val or is_encrypted(seed_val):
                        continue
                    # Detect base64 vs plain: attempt decode
                    try:
                        decoded = base64.b64decode(seed_val).decode()
                        candidate = decoded if decoded.startswith("s") else seed_val
                    except Exception:
                        candidate = seed_val
                    new_enc = encrypt_secret(candidate, settings.ENCRYPTION_KEY)
                    db.wallets.update_one({"_id": w["_id"]}, {"$set": {"xrp_seed": new_enc}})
                    migrated += 1
                if migrated:
                    print(f"[DB] [SUCCESS] Migrated {migrated} wallet seeds to encrypted format")
        except Exception as mig_err:
            print(f"[DB][WARNING] Seed encryption migration skipped: {mig_err}")
        
        # Attach to FastAPI app if provided
        if app:
            app.state.mongo = db
            print("[DB] [SUCCESS] Database attached to FastAPI app")
        
        print("\n[DB] ✅ Database initialization complete!")
        print("="*80 + "\n")
        
        return db
        
    except Exception as e:
        print(f"\n[DB] [ERROR] ERROR during initialization: {str(e)}")
        import traceback
        traceback.print_exc()
        raise


def close_mongo():
    """Close MongoDB connection"""
    global _client
    if _client:
        _client.close()
        _client = None
        print("[DB] Connection closed")


# Optional: Database health check
def check_db_health():
    """Check database connectivity and health"""
    try:
        client = get_client()
        # Ping the database
        client.admin.command('ping')
        
        # Check database exists
        db = get_db()
        collections = db.list_collection_names()
        
        return {
            "status": "healthy",
            "database": settings.MONGODB_DB_NAME,
            "collections": len(collections),
            "collection_names": collections
        }
    except Exception as e:
        return {
            "status": "unhealthy",
            "error": str(e)
        }