In-App Purchase

const result = await startiapp.InAppPurchase.purchaseProduct(
  "com.example.premium",
  "nonconsumable"
);

if (result.success) {
  console.log("Transaction ID:", result.value.transactionIdentifier);
} else {
  console.error("Purchase failed:", result.errorMessage);
}

const result = await startiapp.InAppPurchase.getProduct(
  "com.example.premium",
  "nonconsumable"
);

if (result.success) {
  console.log(`${result.value.name} - ${result.value.localizedPrice}`);
} else {
  console.error("Failed to load product:", result.errorMessage);
}

// New subscription
const result = await startiapp.InAppPurchase.subscribe("com.example.monthly");

if (result.success) {
  console.log("Subscribed! Transaction:", result.value.transactionId);

  // IMPORTANT: Validate on your backend first, then finish the transaction
  const validated = await fetch("/api/validate-subscription", {
    method: "POST",
    headers: { "Content-Type": "application/json" },
    body: JSON.stringify(result.value)
  }).then(r => r.ok);

  if (validated) {
    await startiapp.InAppPurchase.finishTransaction(result.value.transactionId);
  }
}

// Upgrade from monthly to yearly
const result = await startiapp.InAppPurchase.subscribe("com.example.yearly", {
  oldProductId: "com.example.monthly",
  upgradePolicy: "immediate"
});

// After your backend confirms the subscription is valid:
const result = await startiapp.InAppPurchase.finishTransaction(transactionId);

if (result.success) {
  console.log("Transaction acknowledged");
}

const result = await startiapp.InAppPurchase.getSubscriptionProducts([
  "com.example.monthly",
  "com.example.yearly"
]);

if (result.success) {
  result.value.forEach(product => {
    console.log(`${product.name}: ${product.localizedPrice}/${product.subscriptionPeriod}`);

    if (product.introductoryOffer) {
      console.log(`  Trial: ${product.introductoryOffer.localizedPrice} for ${product.introductoryOffer.period}`);
    }
  });
}

const result = await startiapp.InAppPurchase.getActiveSubscriptions();

if (result.success) {
  const active = result.value.filter(s => s.state === "subscribed");
  if (active.length > 0) {
    console.log("User has active subscription:", active[0].productId);
    console.log("Will renew:", active[0].willAutoRenew);
  }
}

const result = await startiapp.InAppPurchase.restorePurchases();

if (result.success) {
  console.log("Restored", result.value.length, "subscriptions");
}

await startiapp.InAppPurchase.manageSubscriptions();

// Check for any active subscription
if (await startiapp.InAppPurchase.isSubscribed()) {
  unlockPremiumFeatures();
}

// Check for a specific product
const hasYearly = await startiapp.InAppPurchase.isSubscribed("com.example.yearly");

await startiapp.initialize();

startiapp.InAppPurchase.addEventListener("unfinishedTransaction", async (event) => {
  const transaction = event.detail;

  // Validate on your backend, then finish the transaction
  const validated = await fetch("/api/validate-subscription", {
    method: "POST",
    headers: { "Content-Type": "application/json" },
    body: JSON.stringify(transaction)
  }).then(r => r.ok);

  if (validated) {
    await startiapp.InAppPurchase.finishTransaction(transaction.transactionId);
  }
});

type InApPurchasePurchaseType = "nonconsumable" | "consumable";

type InAppPurchaseResponse<T> =
  | { success: true;  value: T }
  | { success: false; errorMessage: string };

type InAppPurchaseProductResponse = {
  transactionIdentifier: string;
};

type InAppPurchaseGetProductResponse = {
  name: string;
  description: string;
  localizedPrice: string;
  currencyCode: string;
};

type SubscribeOptions = {
  oldProductId?: string;
  upgradePolicy?: "immediate" | "deferred";
  offerId?: string;
  resolveOffer?: (productId: string, offerId: string) => Promise<OfferSignature>;
};

type OfferSignature = {
  signature: string;
  nonce: string;
  timestamp: string;
  keyId: string;
};

type SubscribeResponse = {
  /** Pass this to finishTransaction() after backend validation. */
  transactionId: string;
  originalTransactionId: string;
  productId: string;
  purchaseDate: string;
};

type SubscriptionProduct = {
  productId: string;
  name: string;
  description: string;
  localizedPrice: string;
  currencyCode: string;
  /** Human-readable billing period, e.g. "1 month", "1 year", "3 months". null if not available. */
  subscriptionPeriod: string | null;
  introductoryOffer?: SubscriptionOffer;
  promotionalOffers?: SubscriptionOffer[];
};

type SubscriptionOffer = {
  id?: string;
  localizedPrice: string;
  period: string;
  periodCount: number;
  paymentMode: "freeTrial" | "payAsYouGo" | "payUpFront";
};

type SubscriptionStatus = {
  productId: string;
  transactionId: string;
  originalTransactionId: string;
  purchaseDate: string;
  state: "subscribed" | "expired";
  willAutoRenew: boolean;
};