from fastapi import FastAPI
from fastapi.middleware.cors import CORSMiddleware

from app.api import health
from app.api.router import api_router
from app.core.config import settings
from app.core.errors import register_exception_handlers


def create_app() -> FastAPI:
    """应用工厂：创建 FastAPI 实例并挂载中间件、路由和异常处理器。"""
    app = FastAPI(
        title=settings.app_name,
        debug=settings.app_debug,
        version="0.1.0",
        root_path=settings.app_root_path,
        docs_url="/docs",
        redoc_url="/redoc",
    )

    app.add_middleware(
        CORSMiddleware,
        allow_origins=settings.cors_allow_origins,
        allow_origin_regex=settings.cors_allow_origin_regex or None,
        allow_credentials=True,
        allow_methods=["*"],
        allow_headers=["*"],
    )

    app.include_router(health.router, prefix="/health", tags=["health"])
    app.include_router(api_router, prefix=settings.api_v1_prefix)
    register_exception_handlers(app)
    return app


app = create_app()