app/main.py

"""Main FastAPI application for the multi-utility server."""

import time
from contextlib import asynccontextmanager

from fastapi import FastAPI, Request
from fastapi.responses import JSONResponse
from fastapi.middleware.cors import CORSMiddleware
from slowapi import _rate_limit_exceeded_handler
from slowapi.errors import RateLimitExceeded

from app.core.config import settings
from app.core.logging import setup_logging, get_logger
from app.core.exceptions import MultiUtilityServerException
from app.middleware import APIKeyMiddleware, limiter
from app.apis.subtitles.router import router as subtitles_router
from app.apis.embeddings.router import router as embeddings_router

setup_logging()
logger = get_logger(__name__)


@asynccontextmanager
async def lifespan(app: FastAPI):
    """Application lifespan manager."""
    logger.info("Starting multi-utility server...")
    logger.info(f"Log level: {settings.log_level}")
    logger.info(f"API keys configured: {len(settings.api_keys_set)}")
    logger.info(f"CORS origins: {settings.cors_origins_list}")
    yield
    logger.info("Shutting down multi-utility server...")


app = FastAPI(
    title="Multi-Utility Server",
    description="Centralized FastAPI server providing reusable APIs for different projects",
    version="1.0.0",
    docs_url="/docs",
    redoc_url="/redoc",
    lifespan=lifespan
)

app.state.limiter = limiter
app.add_exception_handler(RateLimitExceeded, _rate_limit_exceeded_handler)

app.add_middleware(
    CORSMiddleware,
    allow_origins=settings.cors_origins_list,
    allow_credentials=True if settings.cors_origins else False,
    allow_methods=["GET", "POST", "PUT", "DELETE"],
    allow_headers=["*"],
)

app.add_middleware(APIKeyMiddleware)


@app.exception_handler(MultiUtilityServerException)
async def custom_exception_handler(request: Request, exc: MultiUtilityServerException):
    """Handle custom application exceptions."""
    logger.error(f"Application error: {exc.message}")
    return JSONResponse(
        status_code=exc.status_code,
        content={"status": "error", "message": exc.message}
    )


@app.exception_handler(Exception)
async def global_exception_handler(request: Request, exc: Exception):
    """Handle unexpected exceptions."""
    logger.error(f"Unexpected error: {str(exc)}", exc_info=True)
    return JSONResponse(
        status_code=500,
        content={"status": "error", "message": "An unexpected error occurred"}
    )


@app.middleware("http")
async def log_requests(request: Request, call_next):
    """Log all HTTP requests."""
    start_time = time.time()
    logger.info(f"Request: {request.method} {request.url.path}")
    
    response = await call_next(request)
    
    process_time = time.time() - start_time
    logger.info(
        f"Response: {response.status_code} | "
        f"Time: {process_time:.4f}s | "
        f"Path: {request.url.path}"
    )
    
    return response

@app.head("/health")
@app.get("/health")
async def health_check():
    """Health check endpoint."""
    return {
        "status": "healthy",
        "service": "multi-utility-server",
        "version": "1.0.0"
    }


@app.get("/")
async def root():
    """Root endpoint with API information."""
    return {
        "message": "Multi-Utility FastAPI Server",
        "version": "1.0.0",
        "docs": "/docs",
        "health": "/health",
        "apis": {
            "subtitles": "/api/v1/subtitles",
            "embeddings": "/api/v1/embeddings"
        }
    }


app.include_router(subtitles_router)
app.include_router(embeddings_router)


if __name__ == "__main__":
    import uvicorn
    uvicorn.run(
        "app.main:app",
        host=settings.host,
        port=settings.port,
        reload=settings.reload,
        log_level=settings.log_level.lower()
    )