from contextlib import asynccontextmanager

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

from app.api.middleware.rate_limit import TierRateLimitMiddleware
from app.api.middleware.sanitizer import SanitizerMiddleware
from app.config.settings import settings


@asynccontextmanager
async def lifespan(app: FastAPI):
    # Startup: initialise DB connection pool and agent registry
    from app.core.agent_registry import registry  # noqa: F401 — triggers module load
    import app.agents  # noqa: F401 — triggers @registry.register decorators

    yield

    # Shutdown: dispose SQLAlchemy connection pool
    from app.db import engine
    await engine.dispose()


def create_app() -> FastAPI:
    app = FastAPI(
        title="Adiuva Cloud API",
        version="0.1.0",
        docs_url="/docs" if settings.ENV == "dev" else None,
        redoc_url=None,
        lifespan=lifespan,
    )

    app.add_middleware(
        CORSMiddleware,
        allow_origins=settings.CORS_ORIGINS,
        allow_credentials=True,
        allow_methods=["*"],
        allow_headers=["*"],
    )
    # Middleware stack (Starlette inserts at position 0, so last-added = outermost).
    # Request flow:  TierRateLimit → Sanitizer → CORS → Router
    # Response flow: Router → CORS → Sanitizer → TierRateLimit
    app.add_middleware(SanitizerMiddleware)
    app.add_middleware(TierRateLimitMiddleware)

    from app.api.routes import agents, auth, backup, billing, chat, device_ws, plans, plugins, storage, vectors

    app.include_router(auth.router,       prefix="/api/v1")
    app.include_router(chat.router,       prefix="/api/v1")
    app.include_router(plans.router,      prefix="/api/v1")
    app.include_router(storage.router,    prefix="/api/v1")
    app.include_router(vectors.router,    prefix="/api/v1")
    app.include_router(backup.router,     prefix="/api/v1")
    app.include_router(plugins.router,    prefix="/api/v1")
    app.include_router(billing.router,    prefix="/api/v1")
    app.include_router(agents.router,     prefix="/api/v1")
    app.include_router(device_ws.router,  prefix="/api/v1")

    @app.get("/api/v1/health", tags=["health"])
    async def health() -> dict:
        return {"status": "ok", "version": app.version}

    return app


app = create_app()