"""
Apl_GS API — FastAPI Application Entry Point

Run:
    python app.py

Or directly with uvicorn:
    uvicorn app:app --host 0.0.0.0 --port 5000 --reload

API Docs:
    http://localhost:5000/docs      (Swagger UI)
    http://localhost:5000/redoc     (ReDoc)

Architecture Reference:
    insights/architecture_rule.md
"""

import os
import logging
from contextlib import asynccontextmanager

from fastapi import FastAPI
from fastapi.middleware.cors import CORSMiddleware
from fastapi.responses import JSONResponse
from dotenv import load_dotenv

# Load environment variables FIRST (before any config imports)
load_dotenv()

from web.route import router
from config.rate_limiter import rate_limit_middleware
from config.database_config import init_db, close_db

# ── Logging ──
logging.basicConfig(
    level=os.getenv("LOG_LEVEL", "INFO"),
    format="%(asctime)s — %(name)s — %(levelname)s — %(message)s",
)
logger = logging.getLogger(__name__)

# ── App Metadata ──
APP_NAME = os.getenv("APP_NAME", "Apl_GS API")
APP_VERSION = "1.0.0"
APP_ENV = os.getenv("APP_ENV", "development")
APP_DEBUG = os.getenv("APP_DEBUG", "False").lower() == "true"


# ── Lifespan (startup + shutdown) ──
@asynccontextmanager
async def lifespan(app: FastAPI):
    """Application lifecycle — runs on startup and shutdown."""
    # ── STARTUP ──
    logger.info(f"🚀 Starting {APP_NAME} v{APP_VERSION}")
    logger.info(f"📍 Environment: {APP_ENV}")
    logger.info(f"🔧 Debug mode: {APP_DEBUG}")
    logger.info(f"🌐 Port: {os.getenv('PORT', '5000')}")

    # Initialize database tables
    try:
        await init_db()
        logger.info("✅ Database initialized successfully")
    except Exception as e:
        logger.error(f"❌ Database initialization failed: {e}")
        logger.warning("⚠️  API will start but database operations will fail")
        logger.warning("⚠️  Make sure PostgreSQL 15+ is installed and running!")

    yield  # Application runs here

    # ── SHUTDOWN ──
    logger.info("🛑 Shutting down Apl_GS API")
    await close_db()


# ── Create FastAPI Instance ──
app = FastAPI(
    title=APP_NAME,
    version=APP_VERSION,
    description=(
        "Apl_GS Backend API — Visit & Checklist Management System.\n\n"
        "**No authentication required** — protected by rate limiter.\n\n"
        "Built with FastAPI + PostgreSQL 15+.\n\n"
        "📖 Architecture Reference: `insights/architecture_rule.md`"
    ),
    docs_url="/docs",
    redoc_url="/redoc",
    openapi_url="/openapi.json",
    lifespan=lifespan,
)

# ── CORS Middleware ──
cors_origins = os.getenv(
    "CORS_ORIGINS", "http://localhost"
).split(",")

app.add_middleware(
    CORSMiddleware,
    allow_origins=[origin.strip() for origin in cors_origins],
    allow_credentials=True,
    allow_methods=["*"],
    allow_headers=["*"],
)

# ── Rate Limiter Middleware ──
app.middleware("http")(rate_limit_middleware)

# ── Include API Routes ──
app.include_router(router)


# ── Root Endpoint ──
@app.get("/", tags=["Root"], summary="API root — basic info and links")
async def root():
    """
    Root endpoint — returns API info, version, and documentation links.
    """
    return {
        "status": "success",
        "data": {
            "name": APP_NAME,
            "version": APP_VERSION,
            "environment": APP_ENV,
            "docs": "/docs",
            "redoc": "/redoc",
            "health": "/api/v1/health",
        },
        "message": "Apl_GS API is running",
    }


# ── Global Exception Handler ──
@app.exception_handler(Exception)
async def global_exception_handler(request, exc):
    """Handle unexpected exceptions gracefully."""
    logger.error(f"Unhandled exception: {exc}", exc_info=True)
    return JSONResponse(
        status_code=500,
        content={
            "status": "error",
            "error": {
                "code": "INTERNAL_ERROR",
                "message": "An unexpected error occurred",
                "details": str(exc) if APP_DEBUG else None,
            },
        },
    )


# ── Run with Uvicorn ──
if __name__ == "__main__":
    import uvicorn

    host = os.getenv("HOST", "0.0.0.0")
    port = int(os.getenv("PORT", "5000"))

    logger.info(f"🌟 Running on http://{host}:{port}")
    logger.info(f"📚 Swagger UI:  http://{host}:{port}/docs")
    logger.info(f"📚 ReDoc:       http://{host}:{port}/redoc")

    uvicorn.run(
        "app:app",
        host=host,
        port=port,
        reload=(APP_ENV == "development"),
        log_level=os.getenv("LOG_LEVEL", "info").lower(),
    )