from contextlib import asynccontextmanager

from fastapi import FastAPI
from fastapi.middleware.cors import CORSMiddleware
from fastapi.openapi.utils import get_openapi
from fastapi_pagination import add_pagination

from app.api.router import router as api_router
from app.config import settings
from app.core.redis_sse_bridge import RedisSSEBridge
from app.core.throttle import GlobalRateLimitMiddleware
from app.utils.helpers import create_initial_admin
from shared.logging import get_logger

logger = get_logger(__name__)
redis_sse_bridge = RedisSSEBridge(settings.redis_url)


@asynccontextmanager
async def lifespan(_app: FastAPI):
    logger.info("Starting Backend...")
    try:
        await create_initial_admin()
        await redis_sse_bridge.start()
    except Exception as e:
        logger.exception("Failed to initialize the application: %s", e)
        raise e
    yield
    logger.info("Shutting down reNgine Backend...")
    await redis_sse_bridge.stop()


app = FastAPI(
    title=settings.APP_NAME,
    version=settings.APP_VERSION,
    lifespan=lifespan,
)


add_pagination(app)


def custom_openapi():
    if app.openapi_schema:
        return app.openapi_schema

    openapi_schema = get_openapi(
        title=settings.APP_NAME,
        version=settings.APP_VERSION,
        description="reNgine 3.0 - Attack Surface Management Platform",
        routes=app.routes,
    )

    openapi_schema["components"]["securitySchemes"] = {
        "BearerAuth": {
            "type": "http",
            "scheme": "bearer",
            "bearerFormat": "JWT",
            "description": "Enter your JWT token from /auth/login",
        }
    }

    app.openapi_schema = openapi_schema
    return app.openapi_schema


app.openapi = custom_openapi

if "*" in settings.CORS_ORIGINS:
    msg = "CORS_ORIGINS must be an explicit allowlist (no '*') when credentials are enabled"
    raise ValueError(msg)

app.add_middleware(GlobalRateLimitMiddleware)
app.add_middleware(
    CORSMiddleware,
    allow_origins=settings.CORS_ORIGINS,
    allow_credentials=True,
    allow_methods=["*"],
    allow_headers=["*"],
)

app.include_router(api_router, prefix=settings.API_V1_PREFIX)


@app.get("/")
async def root():
    logger.debug("Root endpoint accessed")
    return {
        "message": "Welcome to reNgine API",
        "version": settings.APP_VERSION,
        "docs": "/docs",
    }