import json

from fastapi import FastAPI, Request, HTTPException


MAX_WEBHOOK_BODY_BYTES = 1 * 1024 * 1024
DEFAULT_WEBHOOK_PATH = "/api/channel/webex/webhook"


def create_webhook_app(
    verify_signature,
    handle_webhook,
    webhook_path: str = DEFAULT_WEBHOOK_PATH,
) -> FastAPI:

    app = FastAPI(title="Cisco Webex Webhook", docs_url=None, redoc_url=None)

    @app.post(webhook_path)
    async def webhook_endpoint(request: Request):
        body = await request.body()

        if len(body) > MAX_WEBHOOK_BODY_BYTES:
            raise HTTPException(status_code=413, detail="Payload too large")

        x_spark_signature = request.headers.get("X-Spark-Signature", "")
        if not verify_signature(body, x_spark_signature):
            raise HTTPException(status_code=401, detail="Invalid signature")

        payload = json.loads(body.decode())
        result = await handle_webhook(payload)
        return result

    @app.get(webhook_path)
    async def health_check():
        return {"status": "healthy", "channel": "webex"}

    return app