import logging
from contextlib import asynccontextmanager
from fastapi import FastAPI
from fastapi.middleware.cors import CORSMiddleware

from app.core.config import settings
from app.core.database import init_db
from app.core.logging_config import setup_logging
from app.core.middleware import RequestLoggingMiddleware, ErrorLoggingMiddleware
from app.api.router import api_router

# Initialize logging configuration
setup_logging()
logger = logging.getLogger(__name__)


@asynccontextmanager
async def lifespan(app: FastAPI):
    """Application lifespan handler."""
    # Startup
    logger.info("Starting Patherly API server...")
    logger.info(f"Environment: {'Development' if settings.DEBUG else 'Production'}")
    logger.info(f"ALLOW_RAILWAY_ORIGINS: {settings.ALLOW_RAILWAY_ORIGINS}")
    # Note: In production, use Alembic migrations instead of init_db
    # await init_db()
    yield
    # Shutdown
    logger.info("Shutting down Patherly API server...")


app = FastAPI(
    title=settings.APP_NAME,
    description="Patherly - Take the path MOST traveled. Guided troubleshooting with automatic documentation.",
    version="1.0.0",
    docs_url="/api/docs",
    redoc_url="/api/redoc",
    openapi_url="/api/openapi.json",
    lifespan=lifespan
)

# Add logging middleware (BEFORE CORS to log all requests)
app.add_middleware(ErrorLoggingMiddleware)
app.add_middleware(RequestLoggingMiddleware)

# Configure CORS
# Note: When ALLOW_RAILWAY_ORIGINS is True, we use allow_origin_regex for Railway domains
# PLUS the explicit allowed_origins list (for custom domains like app.patherly.com)
if settings.ALLOW_RAILWAY_ORIGINS:
    app.add_middleware(
        CORSMiddleware,
        allow_origins=settings.allowed_origins,
        allow_origin_regex=r"https://.*\.up\.railway\.app",
        allow_credentials=True,
        allow_methods=["*"],
        allow_headers=["*"],
    )
else:
    app.add_middleware(
        CORSMiddleware,
        allow_origins=settings.allowed_origins,
        allow_credentials=True,
        allow_methods=["*"],
        allow_headers=["*"],
    )

# Include API router
app.include_router(api_router, prefix=settings.API_V1_PREFIX)


@app.get("/")
async def root():
    """Root endpoint."""
    return {
        "message": "Patherly API",
        "docs": "/api/docs",
        "version": "1.0.0"
    }


@app.get("/health")
async def health_check():
    """Health check endpoint."""
    return {"status": "healthy"}


@app.get("/debug/cors")
async def debug_cors():
    """Debug endpoint to check CORS configuration."""
    return {
        "allow_railway_origins": settings.ALLOW_RAILWAY_ORIGINS,
        "cors_mode": "regex + list" if settings.ALLOW_RAILWAY_ORIGINS else "list",
        "allowed_origins": settings.allowed_origins,
        "railway_regex": r"https://.*\.up\.railway\.app" if settings.ALLOW_RAILWAY_ORIGINS else None
    }