import StoreKit

let productIDs = [
    "com.app.coins_100",
    "com.app.premium",
    "com.app.pro_monthly"
]

let products = try await Product.products(for: productIDs)

let products = try await Product.products(for: productIDs)

// Check what loaded
let loadedIDs = Set(products.map { $0.id })
let missingIDs = Set(productIDs).subtracting(loadedIDs)

if !missingIDs.isEmpty {
    print("Missing products: \(missingIDs)")
    // Products not configured in App Store Connect or .storekit file
}

let product: Product

product.id // "com.app.premium"
product.displayName // "Premium Upgrade"
product.description // "Unlock all features"
product.displayPrice // "$4.99"
product.price // Decimal(4.99)
product.type // .nonConsumable

switch product.type {
case .consumable:
    // Coins, hints, boosts
case .nonConsumable:
    // Premium features, level packs
case .autoRenewable:
    // Monthly/annual subscriptions
case .nonRenewing:
    // Seasonal passes
@unknown default:
    break
}

if let subscriptionInfo = product.subscription {
    // Product is auto-renewable subscription
    let groupID = subscriptionInfo.subscriptionGroupID
    let period = subscriptionInfo.subscriptionPeriod
}

let period = product.subscription?.subscriptionPeriod

switch period?.unit {
case .day:
    print("\(period?.value ?? 0) days")
case .week:
    print("\(period?.value ?? 0) weeks")
case .month:
    print("\(period?.value ?? 0) months")
case .year:
    print("\(period?.value ?? 0) years")
default:
    break
}

if let introOffer = product.subscription?.introductoryOffer {
    print("Free trial: \(introOffer.period.value) \(introOffer.period.unit)")
    print("Price: \(introOffer.displayPrice)")

    switch introOffer.paymentMode {
    case .freeTrial:
        print("Free trial - no charge")
    case .payAsYouGo:
        print("Discounted price per period")
    case .payUpFront:
        print("One-time discounted price")
    @unknown default:
        break
    }
}

let offers = product.subscription?.promotionalOffers ?? []

for offer in offers {
    print("Offer ID: \(offer.id)")
    print("Price: \(offer.displayPrice)")
    print("Period: \(offer.period.value) \(offer.period.unit)")
}

let product: Product
let scene: UIWindowScene

let result = try await product.purchase(confirmIn: scene)

let accountToken = UUID()

let result = try await product.purchase(
    confirmIn: scene,
    options: [
        .appAccountToken(accountToken)
    ]
)

let jwsSignature: String // From your server

let result = try await product.purchase(
    confirmIn: scene,
    options: [
        .promotionalOffer(offerID: "promo_winback", signature: jwsSignature)
    ]
)

let jwsSignature: String // From your server

let result = try await product.purchase(
    confirmIn: scene,
    options: [
        .introductoryOfferEligibility(signature: jwsSignature)
    ]
)

struct ProductView: View {
    let product: Product
    @Environment(\.purchase) private var purchase

    var body: some View {
        Button("Buy \(product.displayPrice)") {
            Task {
                do {
                    let result = try await purchase(product)
                    // Handle result
                } catch {
                    print("Purchase failed: \(error)")
                }
            }
        }
    }
}

let result = try await product.purchase(confirmIn: scene)

switch result {
case .success(let verificationResult):
    // Purchase succeeded - verify transaction
    guard let transaction = try? verificationResult.payloadValue else {
        print("Transaction verification failed")
        return
    }

    // Grant entitlement
    await grantEntitlement(for: transaction)
    await transaction.finish()

case .userCancelled:
    // User tapped "Cancel" in payment sheet
    print("User cancelled purchase")

case .pending:
    // Purchase requires action (Ask to Buy, payment issue)
    // Transaction will arrive via Transaction.updates when approved
    print("Purchase pending approval")

@unknown default:
    break
}

let transaction: Transaction
let appTransactionID = transaction.appTransactionID
// Unique ID for app download (same across all purchases by same Apple Account)

if let offerPeriod = transaction.offer?.period {
    print("Offer duration: \(offerPeriod)")
    // ISO 8601 duration format (e.g., "P1M" for 1 month)
}

if let advancedInfo = transaction.advancedCommerceInfo {
    // Only present for Advanced Commerce API purchases
    // nil for standard IAP
}

let transaction: Transaction

transaction.id // Unique transaction ID
transaction.originalID // Original transaction ID (consistent across renewals)
transaction.productID // "com.app.pro_monthly"
transaction.productType // .autoRenewable
transaction.purchaseDate // Date of purchase
transaction.appAccountToken // UUID set at purchase time (if provided)

transaction.expirationDate // When subscription expires
transaction.isUpgraded // true if user upgraded to higher tier
transaction.revocationDate // Date of refund (nil if not refunded)
transaction.revocationReason // .developerIssue or .other

if let offer = transaction.offer {
    offer.type // .introductory or .promotional or .code
    offer.id // Offer identifier from App Store Connect
    offer.paymentMode // .freeTrial, .payAsYouGo, .payUpFront, .oneTime
}

var purchasedProductIDs: Set<String> = []

for await result in Transaction.currentEntitlements {
    guard let transaction = try? result.payloadValue else {
        continue
    }

    // Only include non-refunded transactions
    if transaction.revocationDate == nil {
        purchasedProductIDs.insert(transaction.productID)
    }
}

let productID = "com.app.premium"

for await result in Transaction.currentEntitlements(for: productID) {
    if let transaction = try? result.payloadValue,
       transaction.revocationDate == nil {
        // User owns this product
        return true
    }
}

// ❌ Deprecated in iOS 18.4
let entitlement = await Transaction.currentEntitlement(for: productID)

// ✅ Use this instead (returns sequence, handles Family Sharing)
for await result in Transaction.currentEntitlements(for: productID) {
    // ...
}

for await result in Transaction.all {
    guard let transaction = try? result.payloadValue else {
        continue
    }

    print("Transaction: \(transaction.productID) on \(transaction.purchaseDate)")
}

for await result in Transaction.all(matching: productID) {
    guard let transaction = try? result.payloadValue else {
        continue
    }

    // All transactions for this product
}

func listenForTransactions() -> Task<Void, Never> {
    Task.detached {
        for await verificationResult in Transaction.updates {
            await handleTransaction(verificationResult)
        }
    }
}

func handleTransaction(_ result: VerificationResult<Transaction>) async {
    guard let transaction = try? result.payloadValue else {
        return
    }

    // Grant or revoke entitlement
    if transaction.revocationDate != nil {
        await revokeEntitlement(for: transaction.productID)
    } else {
        await grantEntitlement(for: transaction)
    }

    // CRITICAL: Always finish transaction
    await transaction.finish()
}

let result: VerificationResult<Transaction>

switch result {
case .verified(let transaction):
    // ✅ Transaction signed by App Store
    await grantEntitlement(for: transaction)
    await transaction.finish()

case .unverified(let transaction, let error):
    // ❌ Transaction signature invalid
    print("Unverified: \(error)")
    // DO NOT grant entitlement
    await transaction.finish() // Still finish to clear queue
}

await transaction.finish()

let appTransaction = try await AppTransaction.shared

switch appTransaction {
case .verified(let transaction):
    let appTransactionID = transaction.appTransactionID
    // Globally unique ID for this Apple Account + app
    // Same value appears in Transaction and RenewalInfo

case .unverified(_, let error):
    print("AppTransaction verification failed: \(error)")
}

if let appTransaction = try? await AppTransaction.shared.payloadValue {
    let platform = appTransaction.originalPlatform

    switch platform {
    case .iOS:
        print("Originally downloaded on iPhone/iPad")
    case .macOS:
        print("Originally downloaded on Mac")
    case .tvOS:
        print("Originally downloaded on Apple TV")
    case .visionOS:
        print("Originally downloaded on Vision Pro")
    @unknown default:
        break
    }
}

let appTransaction: AppTransaction

appTransaction.appVersion // "1.2.3"
appTransaction.originalAppVersion // "1.0.0"
appTransaction.originalPurchaseDate // First download date
appTransaction.bundleID // "com.company.app"
appTransaction.deviceVerification // UUID for device
appTransaction.deviceVerificationNonce // Nonce for verification

if let appTransaction = try? await AppTransaction.shared.payloadValue {
    if appTransaction.appVersion != currentVersion {
        // Prompt user to update
    }
}

// Moving from paid app to free app with IAP
if appTransaction.originalPlatform == .iOS,
   appTransaction.originalPurchaseDate < migrationDate {
    // User paid for app before migration - grant premium
    await grantPremiumAccess()
}

let renewalInfo: RenewalInfo
let appTransactionID = renewalInfo.appTransactionID

if let offerPeriod = renewalInfo.offerPeriod {
    print("Next renewal offer period: \(offerPeriod)")
    // ISO 8601 duration (applies at next renewal)
}

if let token = renewalInfo.appAccountToken {
    // UUID associating subscription with your server account
}

if let advancedInfo = renewalInfo.advancedCommerceInfo {
    // Only for Advanced Commerce API subscriptions
}

let renewalInfo: RenewalInfo

renewalInfo.willAutoRenew // true if subscription will renew
renewalInfo.autoRenewPreference // Product ID customer will renew to
renewalInfo.expirationReason // Why subscription expired (if expired)

switch renewalInfo.expirationReason {
case .autoRenewDisabled:
    // User turned off auto-renewal
case .billingError:
    // Payment method issue
case .didNotConsentToPriceIncrease:
    // User didn't accept price increase - show win-back offer!
case .productUnavailable:
    // Product no longer available
case .unknown:
    // Unknown reason
@unknown default:
    break
}

if let gracePeriodExpiration = renewalInfo.gracePeriodExpirationDate {
    // Subscription in grace period - billing issue
    // Show update payment method UI
}

if let consentStatus = renewalInfo.priceIncreaseStatus {
    switch consentStatus {
    case .agreed:
        // User accepted price increase
    case .notYetResponded:
        // User hasn't responded - show consent UI
    @unknown default:
        break
    }
}

let statuses = try await Product.SubscriptionInfo.status(for: groupID)

for status in statuses {
    switch status.renewalInfo {
    case .verified(let renewalInfo):
        print("Will renew: \(renewalInfo.willAutoRenew)")
    case .unverified(_, let error):
        print("Renewal info verification failed: \(error)")
    }
}

let status: Product.SubscriptionInfo.Status

switch status.state {
case .subscribed:
    // User has active subscription - full access

case .expired:
    // Subscription expired - show resubscribe/win-back offer

case .inGracePeriod:
    // Billing issue but access maintained - show update payment UI

case .inBillingRetryPeriod:
    // Apple retrying payment - maintain access

case .revoked:
    // Family Sharing access removed - revoke access

@unknown default:
    break
}

let groupID = "pro_tier"

let statuses = try await Product.SubscriptionInfo.status(for: groupID)

// Find highest service level
let activeStatus = statuses
    .filter { $0.state == .subscribed }
    .max { $0.transaction.productID < $1.transaction.productID }

let transactionID = transaction.id

let status = try await Product.SubscriptionInfo.status(for: transactionID)

for await statuses in Product.SubscriptionInfo.Status.updates(for: groupID) {
    // Process updated statuses
    for status in statuses {
        print("Status: \(status.state)")
    }
}

let status: Product.SubscriptionInfo.Status

status.state // .subscribed, .expired, etc.
status.transaction // VerificationResult<Transaction>
status.renewalInfo // VerificationResult<RenewalInfo>

import StoreKit

struct ContentView: View {
    let productID = "com.app.premium"

    var body: some View {
        ProductView(id: productID)
    }
}

struct ContentView: View {
    let product: Product

    var body: some View {
        ProductView(for: product)
    }
}

ProductView(id: productID) {
    Image(systemName: "star.fill")
        .foregroundStyle(.yellow)
}

ProductView(id: productID)
    .productViewStyle(.regular)  // Default

ProductView(id: productID)
    .productViewStyle(.compact)  // Smaller

ProductView(id: productID)
    .productViewStyle(.large)  // Prominent

struct ContentView: View {
    let productIDs = [
        "com.app.coins_100",
        "com.app.coins_500",
        "com.app.coins_1000"
    ]

    var body: some View {
        StoreView(ids: productIDs)
    }
}

struct ContentView: View {
    let products: [Product]

    var body: some View {
        StoreView(products: products)
    }
}

struct SubscriptionView: View {
    let groupID = "pro_tier"

    var body: some View {
        SubscriptionStoreView(groupID: groupID) {
            // Marketing content above subscription options
            VStack {
                Image("app-icon")
                Text("Go Pro")
                    .font(.largeTitle.bold())
                Text("Unlock all features")
            }
        }
    }
}

SubscriptionStoreView(groupID: groupID) {
    // Marketing content
}
.subscriptionStoreControlStyle(.automatic)    // Default
.subscriptionStoreControlStyle(.picker)       // Horizontal picker
.subscriptionStoreControlStyle(.buttons)      // Stacked buttons
.subscriptionStoreControlStyle(.prominentPicker) // Large picker (iOS 18.4+)