#!/usr/bin/env bash
set -euo pipefail

readonly GRAPH_API_VERSION="v25.0"
readonly PSID="27511427698460020"
readonly ASID="122111097783118257"
readonly APP_ID="26934819589512827"
readonly APP_SECRET="TODO_APP_SECRET"
readonly PAGE_ACCESS_TOKEN="TODO_PAGE_ACCESS_TOKEN"

appsecret_proof="$(
  node -e '
    const crypto = require("crypto");
    const token = process.argv[1].trim();
    const secret = process.argv[2].trim();
    process.stdout.write(
      crypto.createHmac("sha256", secret).update(token).digest("hex")
    );
  ' "$PAGE_ACCESS_TOKEN" "$APP_SECRET"
)"

response="$(
  curl -sS -G "https://graph.facebook.com/${GRAPH_API_VERSION}/${PSID}/ids_for_apps" \
    --data-urlencode "app=${APP_ID}" \
    --data-urlencode "access_token=${PAGE_ACCESS_TOKEN}" \
    --data-urlencode "appsecret_proof=${appsecret_proof}"
)"

echo "$response"

if echo "$response" | node -e '
  const fs = require("fs");
  const expected = process.argv[1];
  const payload = JSON.parse(fs.readFileSync(0, "utf8"));
  const matched = Array.isArray(payload.data)
    && payload.data.some((item) => item && String(item.id) === expected);
  process.exit(matched ? 0 : 1);
' "$ASID"; then
  echo "Matched: PSID maps to ASID ${ASID}."
  exit 0
fi

echo "Not matched: PSID does not map to ASID ${ASID}."
exit 1