const { onCall, HttpsError } = require("firebase-functions/v2/https");
const { onMessagePublished } = require("firebase-functions/v2/pubsub");
const admin = require("firebase-admin");
const { AccessToken } = require("livekit-server-sdk");
const { CloudBillingClient } = require("@google-cloud/billing");

admin.initializeApp();

// ── Hard billing cutoff ───────────────────────────────────────────────────────
exports.stopBilling = onMessagePublished("billing-cutoff", async (event) => {
  const data = JSON.parse(
    Buffer.from(event.data.message.data, "base64").toString()
  );

  if (data.costAmount >= data.budgetAmount) {
    const projectId     = process.env.GCLOUD_PROJECT;
    const billingClient = new CloudBillingClient();

    const [projectInfo] = await billingClient.getProjectBillingInfo({
      name: `projects/${projectId}`,
    });

    if (!projectInfo.billingEnabled) {
      console.log("Billing already disabled.");
      return;
    }

    await billingClient.updateProjectBillingInfo({
      name: `projects/${projectId}`,
      projectBillingInfo: { billingAccountName: "" },
    });

    console.log(`Billing DISABLED for ${projectId} — budget exceeded.`);
  }
});

// ── Livekit token ─────────────────────────────────────────────────────────────
exports.getLivekitToken = onCall(async (request) => {
  if (!request.auth) {
    throw new HttpsError("unauthenticated", "Must be signed in.");
  }

  const { roomName, participantName } = request.data;

  if (!roomName || !participantName) {
    throw new HttpsError("invalid-argument", "roomName and participantName required.");
  }

  const apiKey    = process.env.LIVEKIT_API_KEY;
  const apiSecret = process.env.LIVEKIT_API_SECRET;
  const url       = process.env.LIVEKIT_URL;

  if (!apiKey || !apiSecret) {
    throw new HttpsError("internal", "Livekit credentials not configured.");
  }

  const at = new AccessToken(apiKey, apiSecret, {
    identity: request.auth.uid,
    name:     participantName,
    ttl:      "4h",
  });

  at.addGrant({
    roomJoin:          true,
    room:              roomName,
    canPublish:        true,
    canSubscribe:      true,
    canPublishData:    true,
    canUpdateOwnMetadata: true,
  });

  const token = await at.toJwt();
  return { token, url };
});