from contextlib import asynccontextmanager
from collections.abc import AsyncIterator

from fastapi import FastAPI
from fastapi.middleware.cors import CORSMiddleware
from starlette.middleware.trustedhost import TrustedHostMiddleware

from app.api.routes import auth, exports, generation, health, history, images, materials, questions, templates
from app.core.config import get_settings
from app.core.errors import register_exception_handlers
from app.core.middleware import RateLimitMiddleware, RequestSizeLimitMiddleware
from app.core.security_headers import SecurityHeadersMiddleware
from app.db.init_db import init_db


@asynccontextmanager
async def lifespan(_: FastAPI) -> AsyncIterator[None]:
    init_db()
    yield


def create_app() -> FastAPI:
    settings = get_settings()
    app = FastAPI(title=settings.app_name, lifespan=lifespan)

    # CORS debe ser el middleware más externo (añadirlo al final) para que
    # las peticiones OPTIONS (preflight) respondan antes que rate limit, etc.
    app.add_middleware(RequestSizeLimitMiddleware, settings=settings)
    app.add_middleware(RateLimitMiddleware, settings=settings)
    app.add_middleware(SecurityHeadersMiddleware, settings=settings)
    if settings.trusted_hosts_list:
        app.add_middleware(TrustedHostMiddleware, allowed_hosts=settings.trusted_hosts_list)
    app.add_middleware(
        CORSMiddleware,
        allow_origins=settings.cors_origins,
        allow_credentials=True,
        allow_methods=["GET", "POST", "PATCH", "DELETE", "OPTIONS"],
        allow_headers=["Authorization", "Content-Type", "X-API-Key", "Accept"],
        expose_headers=["Content-Disposition"],
    )

    register_exception_handlers(app)

    app.include_router(health.router)
    app.include_router(auth.router)
    app.include_router(templates.router, prefix="/exam")
    app.include_router(generation.router, prefix="/exam")
    app.include_router(exports.router, prefix="/exam")
    app.include_router(history.router, prefix="/exam")
    app.include_router(materials.router, prefix="/exam")
    app.include_router(images.router, prefix="/exam")
    app.include_router(questions.router, prefix="/exam")

    return app


app = create_app()