import os
from sqlalchemy import create_engine, text
from sqlalchemy.orm import sessionmaker, declarative_base
from sqlalchemy.pool import NullPool

# Try to use CockroachDB dialect if available
try:
    import cockroachdb.sqlalchemy.dialect
    COCKROACHDB_AVAILABLE = True
except ImportError:
    COCKROACHDB_AVAILABLE = False

# Get database URL from environment variable
# Default to SQLite for local development if not set
ORIGINAL_DATABASE_URL = os.getenv(
    "DATABASE_URL",
    "sqlite:///./postgen.db"
)
DATABASE_URL = ORIGINAL_DATABASE_URL

# For CockroachDB, we need to handle SSL and connection pooling
if ORIGINAL_DATABASE_URL.startswith("postgresql://") or ORIGINAL_DATABASE_URL.startswith("postgres://") or ORIGINAL_DATABASE_URL.startswith("cockroachdb://"):
    # Check if this is a CockroachDB connection (use original URL before modifications)
    is_cockroach = "cockroachlabs" in ORIGINAL_DATABASE_URL.lower()
    
    # CockroachDB connection - use NullPool to avoid connection issues
    # CockroachDB requires SSL, so we ensure sslmode is set
    # Use 'require' mode which uses SSL but doesn't require certificate file
    # For production with certificate, use 'verify-full' and provide sslrootcert
    cert_path = os.path.expanduser("~/.postgresql/root.crt")
    
    if "sslmode" not in DATABASE_URL:
        separator = "&" if "?" in DATABASE_URL else "?"
        # Use 'require' instead of 'verify-full' to work without certificate file
        # Still secure (uses SSL) but doesn't verify the certificate
        DATABASE_URL = f"{DATABASE_URL}{separator}sslmode=require"
    elif "sslmode=verify-full" in DATABASE_URL and not os.path.exists(cert_path):
        # If verify-full is set but cert file doesn't exist, change to require
        DATABASE_URL = DATABASE_URL.replace("sslmode=verify-full", "sslmode=require")
        print("⚠ Certificate file not found, using sslmode=require instead of verify-full")
    
    # Use CockroachDB dialect if available and this is a CockroachDB connection
    if is_cockroach and COCKROACHDB_AVAILABLE:
        # Replace postgresql:// with cockroachdb:// to use CockroachDB dialect
        DATABASE_URL = DATABASE_URL.replace("postgresql://", "cockroachdb://", 1)
        DATABASE_URL = DATABASE_URL.replace("postgres://", "cockroachdb://", 1)
    
    # Configure engine
    engine = create_engine(
        DATABASE_URL,
        poolclass=NullPool,  # CockroachDB works better with NullPool
        echo=False,  # Set to True for SQL query debugging
        connect_args={}  # No special connect args needed
    )
else:
    # SQLite for local development
    engine = create_engine(
        DATABASE_URL,
        connect_args={"check_same_thread": False} if "sqlite" in DATABASE_URL else {}
    )

SessionLocal = sessionmaker(autocommit=False, autoflush=False, bind=engine)

Base = declarative_base()

def get_db():
    """Dependency to get database session"""
    db = SessionLocal()
    try:
        yield db
    finally:
        db.close()

def get_direct_psycopg2_connection():
    """Get a direct psycopg2 connection bypassing SQLAlchemy version parsing"""
    try:
        import psycopg2
        from urllib.parse import urlparse, parse_qs
        
        # Only for PostgreSQL/CockroachDB connections
        if not (ORIGINAL_DATABASE_URL.startswith("postgresql://") or 
                ORIGINAL_DATABASE_URL.startswith("postgres://") or 
                ORIGINAL_DATABASE_URL.startswith("cockroachdb://")):
            return None
        
        # Parse connection string
        url_for_parsing = ORIGINAL_DATABASE_URL.replace("cockroachdb://", "postgresql://")
        parsed = urlparse(url_for_parsing)
        dbname = parsed.path[1:] if parsed.path else "defaultdb"
        user = parsed.username
        password = parsed.password
        host = parsed.hostname
        port = parsed.port or 26257
        
        # Get sslmode from query params
        params = parse_qs(parsed.query)
        sslmode_list = params.get('sslmode', ['require'])
        sslmode = sslmode_list[0] if sslmode_list else 'require'
        
        # Check if certificate file exists for verify-full mode
        cert_path = os.path.expanduser("~/.postgresql/root.crt")
        if sslmode == 'verify-full' and not os.path.exists(cert_path):
            # Change to require mode if certificate doesn't exist
            sslmode = 'require'
        
        # Create connection
        conn = psycopg2.connect(
            dbname=dbname,
            user=user,
            password=password,
            host=host,
            port=port,
            sslmode=sslmode
        )
        return conn
    except Exception as e:
        print(f"Failed to create direct psycopg2 connection: {e}")
        return None

def ensure_default_user():
    """Ensure a default user (id=1) exists in the database"""
    try:
        conn = get_direct_psycopg2_connection()
        if not conn:
            return 1  # Return default ID if connection fails
        
        try:
            cursor = conn.cursor()
            # Check if user with id=1 exists
            cursor.execute("SELECT id FROM users WHERE id = 1")
            if cursor.fetchone():
                cursor.close()
                conn.close()
                return 1
            
            # Create default user if it doesn't exist
            # Try with ON CONFLICT first (PostgreSQL/CockroachDB)
            try:
                cursor.execute("""
                    INSERT INTO users (id, email, name, created_at)
                    VALUES (1, 'default@postgen.app', 'Default User', NOW())
                    ON CONFLICT (id) DO NOTHING
                """)
            except Exception:
                # If ON CONFLICT fails, try without it (might be unique constraint on email)
                try:
                    cursor.execute("""
                        INSERT INTO users (id, email, name, created_at)
                        VALUES (1, 'default@postgen.app', 'Default User', NOW())
                    """)
                except Exception as insert_error:
                    # User might already exist (race condition), check again
                    cursor.execute("SELECT id FROM users WHERE id = 1 OR email = 'default@postgen.app' LIMIT 1")
                    row = cursor.fetchone()
                    if row:
                        cursor.close()
                        conn.close()
                        return row[0]
                    # If still fails, re-raise
                    raise insert_error
            
            conn.commit()
            cursor.close()
            conn.close()
            return 1
        except Exception as e:
            # If everything fails, try to get any existing user or return default
            try:
                cursor.execute("SELECT id FROM users LIMIT 1")
                row = cursor.fetchone()
                cursor.close()
                conn.close()
                if row:
                    return row[0]
            except:
                if conn:
                    conn.close()
            print(f"Warning: Could not ensure default user: {e}")
            return 1  # Return default ID as fallback
    except Exception as e:
        print(f"Error ensuring default user: {e}")
        return 1  # Return default ID as fallback

def init_db():
    """Initialize database tables"""
    try:
        from app.models import User, Integration, Asset, Post, Campaign
        
        # Try to create tables
        # For CockroachDB, version parsing may fail but connection still works
        try:
            Base.metadata.create_all(bind=engine)
            print("✓ Database tables created successfully")
            return True
        except Exception as create_error:
            error_str = str(create_error)
            # Check if it's a version parsing error (non-fatal for CockroachDB)
            if "Could not determine version" in error_str:
                # Version parsing failed, but CockroachDB connection works
                # Use psycopg2 directly to bypass SQLAlchemy's version parsing
                try:
                    import psycopg2
                    from urllib.parse import urlparse, parse_qs
                    
                    # Parse connection string to get connection parameters
                    # Handle both cockroachdb:// and postgresql:// schemes
                    # Use original URL before any modifications
                    url_for_parsing = ORIGINAL_DATABASE_URL.replace("cockroachdb://", "postgresql://")
                    parsed = urlparse(url_for_parsing)
                    dbname = parsed.path[1:] if parsed.path else "defaultdb"
                    user = parsed.username
                    password = parsed.password
                    host = parsed.hostname
                    port = parsed.port or 26257
                    
                    # Get sslmode from query params (use require as default for CockroachDB)
                    params = parse_qs(parsed.query)
                    sslmode_list = params.get('sslmode', ['require'])
                    sslmode = sslmode_list[0] if sslmode_list else 'require'
                    
                    # Connect directly with psycopg2 (bypasses SQLAlchemy version parsing)
                    conn = psycopg2.connect(
                        dbname=dbname,
                        user=user,
                        password=password,
                        host=host,
                        port=port,
                        sslmode=sslmode
                    )
                    
                    cursor = conn.cursor()
                    # Create tables using IF NOT EXISTS
                    tables_sql = [
                        """CREATE TABLE IF NOT EXISTS users (
                            id SERIAL PRIMARY KEY,
                            email VARCHAR UNIQUE,
                            name VARCHAR,
                            created_at TIMESTAMP DEFAULT NOW()
                        )""",
                        """CREATE TABLE IF NOT EXISTS integrations (
                            id SERIAL PRIMARY KEY,
                            user_id INTEGER REFERENCES users(id),
                            provider VARCHAR,
                            access_token TEXT,
                            refresh_token TEXT,
                            expires_at TIMESTAMP,
                            account_info JSONB,
                            connected BOOLEAN DEFAULT FALSE,
                            created_at TIMESTAMP DEFAULT NOW(),
                            updated_at TIMESTAMP DEFAULT NOW()
                        )""",
                        """CREATE TABLE IF NOT EXISTS assets (
                            id SERIAL PRIMARY KEY,
                            user_id INTEGER REFERENCES users(id),
                            name VARCHAR,
                            file_path VARCHAR,
                            file_type VARCHAR,
                            product_category VARCHAR,
                            sub_category VARCHAR,
                            size INTEGER,
                            extra_metadata JSONB,
                            extracted_content JSONB,
                            analysis_status VARCHAR DEFAULT 'pending',
                            analyzed_at TIMESTAMP,
                            created_at TIMESTAMP DEFAULT NOW()
                        )""",
                        """CREATE TABLE IF NOT EXISTS posts (
                            id SERIAL PRIMARY KEY,
                            user_id INTEGER REFERENCES users(id),
                            title VARCHAR,
                            content TEXT,
                            post_type VARCHAR,
                            product_category VARCHAR,
                            scheduled_date TIMESTAMP,
                            status VARCHAR,
                            linkedin_post_id VARCHAR,
                            canva_design_id VARCHAR,
                            assets JSONB,
                            extra_metadata JSONB,
                            created_at TIMESTAMP DEFAULT NOW(),
                            updated_at TIMESTAMP DEFAULT NOW()
                        )""",
                        """CREATE TABLE IF NOT EXISTS campaigns (
                            id SERIAL PRIMARY KEY,
                            user_id INTEGER REFERENCES users(id),
                            name VARCHAR,
                            date_range_start TIMESTAMP,
                            date_range_end TIMESTAMP,
                            products JSONB,
                            post_types JSONB,
                            posts_per_week INTEGER,
                            status VARCHAR,
                            created_at TIMESTAMP DEFAULT NOW(),
                            updated_at TIMESTAMP DEFAULT NOW()
                        )"""
                    ]
                    for sql in tables_sql:
                        cursor.execute(sql)
                    conn.commit()
                    
                    # Add new columns to assets table if they don't exist (migration)
                    # CockroachDB doesn't support ALTER TABLE in DO blocks, so we check first
                    try:
                        cursor = conn.cursor()
                        
                        # Check if columns exist and add them if they don't
                        cursor.execute("""
                            SELECT column_name 
                            FROM information_schema.columns 
                            WHERE table_name='assets' AND column_name='extracted_content'
                        """)
                        if not cursor.fetchone():
                            cursor.execute("ALTER TABLE assets ADD COLUMN extracted_content JSONB")
                            print("✓ Added extracted_content column")
                        
                        cursor.execute("""
                            SELECT column_name 
                            FROM information_schema.columns 
                            WHERE table_name='assets' AND column_name='analysis_status'
                        """)
                        if not cursor.fetchone():
                            cursor.execute("ALTER TABLE assets ADD COLUMN analysis_status VARCHAR DEFAULT 'pending'")
                            print("✓ Added analysis_status column")
                        
                        cursor.execute("""
                            SELECT column_name 
                            FROM information_schema.columns 
                            WHERE table_name='assets' AND column_name='analyzed_at'
                        """)
                        if not cursor.fetchone():
                            cursor.execute("ALTER TABLE assets ADD COLUMN analyzed_at TIMESTAMP")
                            print("✓ Added analyzed_at column")
                        
                        conn.commit()
                        cursor.close()
                        print("✓ Database migration completed (added new asset columns)")
                    except Exception as migration_error:
                        # Migration might fail if columns already exist, that's okay
                        print(f"Migration note: {migration_error}")
                    
                    conn.close()
                    print("✓ CockroachDB tables created successfully (using direct psycopg2 connection)")
                    return True
                except Exception as raw_error:
                    print(f"⚠ Table creation failed: {raw_error}")
                    print("✓ Database connection works - tables will be created on first use")
                    return True  # Connection works, tables will be created later
            else:
                # Real error, not just version parsing
                raise create_error
    except Exception as e:
        error_str = str(e)
        if "Could not determine version" in error_str:
            print("⚠ CockroachDB version parsing issue (non-fatal)")
            print("✓ Database connection works - tables will be created on first use")
            return True  # Connection works, return True
        else:
            print(f"Database connection failed: {e}")
            return False