"""FastAPI composition root: wiring, lifespan, middleware, routers."""

from collections.abc import AsyncIterator
from contextlib import asynccontextmanager

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

from app.api.errors import register_exception_handlers
from app.api.health import router as health_router
from app.api.middleware import CorrelationIdMiddleware
from app.api.rest import subsonic_router
from app.api.v1 import api_v1_router
from app.core.config import app_version, get_settings
from app.core.logging import configure_logging, get_logger
from app.infrastructure.cache import close_redis
from app.infrastructure.db import dispose_engine

log = get_logger(__name__)


@asynccontextmanager
async def lifespan(_app: FastAPI) -> AsyncIterator[None]:
    settings = get_settings()
    log.info("startup", environment=settings.environment)
    yield
    log.info("shutdown")
    await dispose_engine()
    await close_redis()


def create_app() -> FastAPI:
    settings = get_settings()
    configure_logging(level=settings.log_level, json=settings.log_json)

    app = FastAPI(
        title="mcma-backend",
        version=app_version(),
        summary="Self-hosted, offline-first music service.",
        lifespan=lifespan,
    )

    app.add_middleware(CorrelationIdMiddleware)
    # CORS added last → outermost, so browser preflight (OPTIONS) is answered
    # before anything else. The web UI can connect cross-origin (direct :8000,
    # a LAN IP, 127.0.0.1 vs localhost), which needs these headers. Bearer-token
    # auth (no cookies) → wildcard origins are safe with allow_credentials=False.
    if settings.cors_allow_origins:
        app.add_middleware(
            CORSMiddleware,
            allow_origins=settings.cors_allow_origins,
            allow_credentials=False,
            allow_methods=["*"],
            allow_headers=["*"],
            expose_headers=["Content-Range", "Accept-Ranges", "Content-Length"],
        )
    register_exception_handlers(app)

    app.include_router(health_router)
    app.include_router(api_v1_router)
    app.include_router(subsonic_router, prefix="/rest")

    @app.websocket("/ws")
    async def ws_stub(websocket: WebSocket) -> None:
        await websocket.accept()
        await websocket.close(1001)

    return app


app = create_app()