#!/usr/bin/env python3
"""
Initialize pgvector extension in PostgreSQL database.

This script connects to the database specified by DATABASE_URL environment variable
and enables the pgvector extension if not already installed.

Usage:
    python scripts/init_pgvector.py

Environment Variables:
    DATABASE_URL: PostgreSQL connection string (required)

Exit Codes:
    0: Success - pgvector extension is installed and working
    1: Error - connection failed, extension installation failed, or other error
"""

import logging
import os
import sys

import psycopg2  # type: ignore
import psycopg2.extras  # type: ignore


def setup_logging() -> logging.Logger:
    """Setup logging configuration."""
    logging.basicConfig(
        level=logging.INFO,
        format="%(asctime)s - %(levelname)s - %(message)s",
        datefmt="%Y-%m-%d %H:%M:%S",
    )
    return logging.getLogger(__name__)


def get_database_url() -> str:
    """Get DATABASE_URL from environment."""
    database_url = os.getenv("DATABASE_URL")
    if not database_url:
        raise ValueError("DATABASE_URL environment variable is required")
    return database_url


def test_connection(connection_string: str, logger: logging.Logger) -> bool:
    """Test database connection."""
    try:
        with psycopg2.connect(connection_string) as conn:
            with conn.cursor() as cur:
                cur.execute("SELECT 1;")
                result = cur.fetchone()
                if result and result[0] == 1:
                    logger.info("✅ Database connection successful")
                    return True
                else:
                    logger.error("❌ Unexpected result from connection test")
                    return False
    except Exception as e:
        logger.error(f"❌ Database connection failed: {e}")
        return False


def check_postgresql_version(connection_string: str, logger: logging.Logger) -> bool:
    """Check if PostgreSQL version supports pgvector (13+)."""
    try:
        with psycopg2.connect(connection_string) as conn:
            with conn.cursor() as cur:
                cur.execute("SELECT version();")
                result = cur.fetchone()
                if not result:
                    logger.error("❌ Could not get PostgreSQL version")
                    return False

                version_string = str(result[0])

                # Extract major version number
                # Format: "PostgreSQL 15.4 on x86_64-pc-linux-gnu..."
                version_parts = version_string.split()
                if len(version_parts) >= 2:
                    version_number = version_parts[1].split(".")[0]
                    major_version = int(version_number)

                    if major_version >= 13:
                        logger.info(f"✅ PostgreSQL version {major_version} supports pgvector")
                        return True
                    else:
                        logger.error(
                            "❌ PostgreSQL version %s is too old (requires 13+)",
                            major_version,
                        )
                        return False
                else:
                    logger.warning(f"⚠️  Could not parse PostgreSQL version: {version_string}")
                    return True  # Proceed anyway

    except Exception as e:
        logger.error(f"❌ Failed to check PostgreSQL version: {e}")
        return False


def install_pgvector_extension(connection_string: str, logger: logging.Logger) -> bool:
    """Install pgvector extension."""
    try:
        with psycopg2.connect(connection_string) as conn:
            conn.autocommit = True  # Required for CREATE EXTENSION
            with conn.cursor() as cur:
                logger.info("Installing pgvector extension...")
                cur.execute("CREATE EXTENSION IF NOT EXISTS vector;")
                logger.info("✅ pgvector extension installed successfully")
                return True

    except psycopg2.errors.InsufficientPrivilege as e:
        logger.error("❌ Insufficient privileges to install extension: %s", str(e))
        logger.error("Make sure your database user has CREATE privilege or is a superuser")
        return False
    except Exception as e:
        logger.error(f"❌ Failed to install pgvector extension: {e}")
        return False


def verify_pgvector_installation(connection_string: str, logger: logging.Logger) -> bool:
    """Verify pgvector extension is properly installed."""
    try:
        with psycopg2.connect(connection_string) as conn:
            with conn.cursor(cursor_factory=psycopg2.extras.DictCursor) as cur:
                # Check extension is installed
                cur.execute("SELECT extname, extversion FROM pg_extension " "WHERE extname = 'vector';")
                result = cur.fetchone()

                if not result:
                    logger.error("❌ pgvector extension not found in pg_extension")
                    return False

                logger.info(f"✅ pgvector extension version: {result['extversion']}")

                # Test basic vector functionality
                cur.execute("SELECT '[1,2,3]'::vector(3);")
                vector_result = cur.fetchone()
                if vector_result:
                    logger.info("✅ Vector type functioning correctly")
                else:
                    logger.error("❌ Vector type test failed")
                    return False

                # Test vector operations
                cur.execute("SELECT '[1,2,3]'::vector(3) <-> '[1,2,4]'::vector(3);")
                distance_result = cur.fetchone()
                if distance_result and distance_result[0] == 1.0:
                    logger.info("✅ Vector distance operations working")
                    return True
                else:
                    logger.error("❌ Vector distance operations failed")
                    return False

    except Exception as e:
        logger.error(f"❌ Failed to verify pgvector installation: {e}")
        return False


def main() -> int:
    """Main function."""
    logger = setup_logging()

    try:
        logger.info("🚀 Starting pgvector initialization...")

        # Get database connection string
        database_url = get_database_url()
        logger.info("📡 Got DATABASE_URL from environment")

        # Test connection
        if not test_connection(database_url, logger):
            return 1

        # Check PostgreSQL version
        if not check_postgresql_version(database_url, logger):
            return 1

        # Install pgvector extension
        if not install_pgvector_extension(database_url, logger):
            return 1

        # Verify installation
        if not verify_pgvector_installation(database_url, logger):
            return 1

        logger.info("🎉 pgvector initialization completed successfully!")
        logger.info("   Your PostgreSQL database is now ready for vector operations.")
        return 0

    except Exception as e:
        logger.error(f"❌ Unexpected error: {e}")
        return 1


if __name__ == "__main__":
    sys.exit(main())