from flask import Flask, request, Response
import hmac

app = Flask(__name__)
psk = bytes.fromhex('redacted secret')


@app.route('/webhook', methods=['POST'])
def respond():
    content_len = request.headers['Content-Length']
    received_signature = request.headers['X-Ztc-Signature']
    print(f'\n{received_signature=}')

    sig_parts = received_signature.split(',')
    t = sig_parts[0].split('=')[1]
    v1 = sig_parts[1].split('=')[1]

    h = hmac.new(key=psk, digestmod='sha256')
    h.update(t.encode())
    h.update(b',')
    h.update(request.data)  # bytes
    hexdigest = h.hexdigest()

    print(f'Received hash  : {v1}')
    print(f'Calculated hash: {hexdigest}')
    print(f'Compare hashes result: {hmac.compare_digest(v1, hexdigest)}')
    print(f'Content length from header: {int(content_len)}')
    print(f'Content length from request body: {len(request.data)}')
    print()

    return Response(status=200)