# from fastapi import FastAPI, Query, HTTPException
import hmac
import hashlib

from fastapi import FastAPI, Header, HTTPException, Request, Query
from typing import Optional

app = FastAPI()

VERIFY_TOKEN = "lintasmediadanawa"  # Replace with your actual verify token

@app.get("/webhooks")
async def handle_webhook(
    hub_mode: str = Query(..., alias="hub.mode"),
    hub_challenge: int = Query(..., alias="hub.challenge"),
    hub_verify_token: str = Query(..., alias="hub.verify_token")
):
    if hub_mode == "subscribe" and hub_verify_token == VERIFY_TOKEN:
        return int(hub_challenge)
    else:
        raise HTTPException(status_code=403, detail="Verification failed")



@app.post("/webhooks")
async def handle_event_notifications(
    request: Request,
    x_hub_signature_256: Optional[str] = Header(None)  # Header for signature verification
):
    # Read and verify the request body
    body = await request.body()

    # Verify the X-Hub-Signature-256 header
    if not x_hub_signature_256:
        raise HTTPException(status_code=400, detail="Missing X-Hub-Signature-256 header")
    
    # Compute the expected signature
    expected_signature = (
        "sha256="
        + hmac.new(VERIFY_TOKEN.encode(), body, hashlib.sha256).hexdigest()
    )

    if not hmac.compare_digest(expected_signature, x_hub_signature_256):
        raise HTTPException(status_code=403, detail="Signature verification failed")

    # Parse the JSON payload
    payload = await request.json()
    object_type = payload.get("object")
    entries = payload.get("entry", [])

    # Log the received event (or process as needed)
    for entry in entries:
        changes = entry.get("changes", [])
        for change in changes:
            field = change.get("field")
            value = change.get("value")
            # Handle specific fields or values as required
            print(f"Received change for field: {field}, value: {value}")

    # Return a 200 OK response to acknowledge receipt
    return {"status": "ok"}