from contextlib import asynccontextmanager
from pathlib import Path
from fastapi import FastAPI, Request
from fastapi.responses import FileResponse
from fastapi.staticfiles import StaticFiles

from lightsync.devices.registry import DeviceRegistry
from lightsync.store.show_store import ShowStore

# Module-level containers populated in lifespan
registry: DeviceRegistry | None = None
show_store: ShowStore | None = None


@asynccontextmanager
async def lifespan(app: FastAPI):
    global registry, show_store
    # Startup
    registry = DeviceRegistry(Path("devices.json"))
    await registry.load()
    show_store = ShowStore(Path("shows"))
    show_store.ensure_dir()
    yield
    # Shutdown
    await registry.save()


def create_app() -> FastAPI:
    app = FastAPI(title="LightSync", lifespan=lifespan, redirect_slashes=False)

    # API routes (registered before static mount — see Pattern 7)
    from lightsync.api import shows, devices, ws
    app.include_router(shows.router, prefix="/api/shows")
    app.include_router(devices.router, prefix="/api/devices")
    app.include_router(ws.router)

    # Static file serving — no-cache headers to prevent stale JS/CSS
    frontend_dir = Path(__file__).parent / "frontend"

    @app.get("/{filename:path}")
    async def static_files(request: Request, filename: str):
        path = frontend_dir / (filename or "index.html")
        if not path.exists() or not path.is_file():
            path = frontend_dir / "index.html"
        response = FileResponse(path)
        response.headers["Cache-Control"] = "no-cache, no-store, must-revalidate"
        return response

    return app


app = create_app()