Add Contribution view with review and donation buttons

Toki Trainer/Models/TransactionObserver.swift

@@ -0,0 +1,98 @@
+//
+//  Store.swift
+//  Toki Trainer
+//
+//  Created by Madeline Pace on 12/18/23.
+//
+
+import CoreData
+import StoreKit
+
+@MainActor
+final class TransactionObserver: ObservableObject {
+
+    var updates: Task<Void, Never>? = nil
+
+    @Published var donationHearts: Int = 0
+    @Published var hasDonated = false
+
+
+    init() {
+        updates = newTransactionListenerTask()
+        donationHearts = UserDefaults.standard.integer(forKey: K.UserDefaults.donationHearts)
+        hasDonated = UserDefaults.standard.bool(forKey: K.UserDefaults.hasDonated)
+    }
+
+    deinit {
+        updates?.cancel()
+    }
+
+    func addDonationHearts(_ amount: Int) {
+        if hasDonated == false {
+            hasDonated = true
+            UserDefaults.standard.set(hasDonated, forKey: K.UserDefaults.hasDonated)
+        }
+
+        DispatchQueue.main.async {
+            self.donationHearts += amount
+        }
+        UserDefaults.standard.set(donationHearts, forKey: K.UserDefaults.donationHearts)
+    }
+
+    private func newTransactionListenerTask() -> Task<Void, Never> {
+        Task(priority: .background) {
+            for await verificationResult in Transaction.updates {
+                await self.handle(updatedTransaction: verificationResult)
+            }
+        }
+    }
+
+    private func handle(updatedTransaction verificationResult: VerificationResult<Transaction>) async {
+        guard case .verified(let transaction) = verificationResult else {
+            return
+        }
+
+        switch transaction.productType {
+        case Product.ProductType.consumable:
+            processConsumable(transaction.productID)
+        case Product.ProductType.nonRenewable, Product.ProductType.autoRenewable:
+            processSubscription(transaction.productID)
+        default:
+            return
+        }
+
+        print("Finishing transaction")
+        await transaction.finish()
+    }
+
+    func processConsumable(_ productID: String) {
+        print("Consumable ID: \(productID)")
+        switch productID {
+        case K.ConsumableTransactions.TierOne:
+            self.addDonationHearts(100)
+        case K.ConsumableTransactions.TierTwo:
+            self.addDonationHearts(500)
+        case K.ConsumableTransactions.TierThree:
+            self.addDonationHearts(1000)
+        case K.ConsumableTransactions.TierFour:
+            self.addDonationHearts(2000)
+        default:
+            return
+        }
+    }
+
+    func processSubscription(_ productID: String) {
+        // TODO: Write function
+        print("Subscription ID: \(productID)")
+        switch productID {
+        case K.MonthlyTransactions.TierOne:
+            self.addDonationHearts(100)
+        case K.MonthlyTransactions.TierTwo:
+            self.addDonationHearts(500)
+        case K.MonthlyTransactions.TierThree:
+            self.addDonationHearts(1000)
+        default:
+            return
+        }
+    }
+}