# app/core/lifespan.py
"""Application lifespan management - Clean Migration Approach.

This module provides classes and functions for:
- Application startup and shutdown events
- Logging setup
- Default user creation
- NO database table creation (handled by Alembic)
"""

import logging
from contextlib import asynccontextmanager

from fastapi import FastAPI
from sqlalchemy import text

from middleware.auth import AuthManager
# Remove this import if not needed: from models.database.base import Base

from .database import SessionLocal, engine
from .logging import setup_logging

logger = logging.getLogger(__name__)
auth_manager = AuthManager()


@asynccontextmanager
async def lifespan(app: FastAPI):
    """Application lifespan events - Clean migration approach."""

    # === STARTUP ===
    app_logger = setup_logging()
    app_logger.info("Starting up ecommerce API")
    logger.info("[OK] Application startup completed")

    yield

    # === SHUTDOWN ===
    app_logger.info("Shutting down ecommerce API")
    # Add cleanup tasks here if needed


# === NEW HELPER FUNCTION ===
def check_database_ready():
    """Check if database is ready (migrations have been run)."""
    try:
        with engine.connect() as conn:
            # Try to query a table that should exist
            result = conn.execute(text("SELECT name FROM sqlite_master WHERE type='table' LIMIT 1"))
            tables = result.fetchall()
            return len(tables) > 0
    except Exception:
        return False


def get_migration_status():
    """Get current Alembic migration status."""
    try:
        from alembic import command
        from alembic.config import Config

        alembic_cfg = Config("alembic.ini")

        # This would need more implementation to actually check status
        # For now, just return a placeholder
        return "Migration status check not implemented"
    except Exception as e:
        logger.warning(f"Could not check migration status: {e}")
        return "Unknown"


# === STARTUP VERIFICATION (Optional) ===
def verify_startup_requirements():
    """Verify that all startup requirements are met."""

    issues = []

    # Check if database exists and has tables
    if not check_database_ready():
        issues.append("Database not ready - run 'make migrate-up' first")

    # Add other checks as needed
    # - Configuration validation
    # - External service connectivity
    # - Required environment variables

    if issues:
        logger.error("[ERROR] Startup verification failed:")
        for issue in issues:
            logger.error(f"   - {issue}")
        return False

    logger.info("[OK] Startup verification passed")
    return True

# You can call this in your main.py if desired:
# if not verify_startup_requirements():
#     raise RuntimeError("Application startup requirements not met")