"""
FastAPI application entry point for Delphi Database.

This module initializes the FastAPI application, sets up database connections,
and provides the main application instance.
"""

import logging
from contextlib import asynccontextmanager

from fastapi import FastAPI, Depends
from sqlalchemy.orm import Session

from .database import create_tables, get_db, get_database_url
from .models import User


# Configure logging
logging.basicConfig(level=logging.INFO)
logger = logging.getLogger(__name__)


@asynccontextmanager
async def lifespan(app: FastAPI):
    """
    Lifespan context manager for FastAPI application.

    Handles startup and shutdown events:
    - Creates database tables on startup
    - Logs database connection info
    """
    # Startup
    logger.info("Starting Delphi Database application...")

    # Create database tables
    create_tables()
    logger.info("Database tables created/verified")

    # Log database connection info
    db_url = get_database_url()
    logger.info(f"Database connected: {db_url}")

    yield

    # Shutdown
    logger.info("Shutting down Delphi Database application...")


# Create FastAPI application with lifespan management
app = FastAPI(
    title="Delphi Database",
    description="Legal case management database application",
    version="1.0.0",
    lifespan=lifespan
)


@app.get("/")
async def root():
    """
    Root endpoint - health check.
    """
    return {"message": "Delphi Database API is running"}


@app.get("/health")
async def health_check(db: Session = Depends(get_db)):
    """
    Health check endpoint that verifies database connectivity.
    """
    try:
        # Test database connection by querying user count
        user_count = db.query(User).count()
        return {
            "status": "healthy",
            "database": "connected",
            "users": user_count
        }
    except Exception as e:
        logger.error(f"Health check failed: {e}")
        return {
            "status": "unhealthy",
            "database": "error",
            "error": str(e)
        }