[Woo POS] Coupons: Show error when coupons are disabled in core

WooCommerce/Classes/POS/Controllers/PointOfSaleCouponsController.swift

@@ -1,5 +1,6 @@
 import Observation
 import enum Yosemite.POSItem
+import enum Yosemite.PointOfSaleCouponServiceError
 import protocol Yosemite.PointOfSaleItemServiceProtocol
 import protocol Yosemite.PointOfSaleCouponServiceProtocol
 
@@ -20,7 +21,8 @@ import protocol Yosemite.PointOfSaleCouponServiceProtocol
     @MainActor
     func loadItems(base: ItemListBaseItem) async {
         // TODO:
-        // Handle unhappy path
+        // Handle unhappy path:
+        // Depending on the error type (failed to load vs coupons disabled) we want to show a different CTA choice
         await loadFirstPage()
     }
 
@@ -49,7 +51,16 @@ private extension PointOfSaleCouponsController {
                                             itemsStack: .init(root: .loaded(coupons, hasMoreItems: false),
                                                               itemStates: [:]))
         } catch {
-            debugPrint(error)
+            if let couponError = error as? PointOfSaleCouponServiceError {
+                switch couponError {
+                case .couponsLoadingError:
+                    itemsViewState = ItemsViewState(containerState: .error(.errorOnLoadingCoupons()),
+                                                    itemsStack: .init(root: .loaded([], hasMoreItems: false), itemStates: [:]))
+                case .couponsDisabled:
+                    itemsViewState = ItemsViewState(containerState: .error(.errorCouponsDisabled()),
+                                                    itemsStack: .init(root: .loaded([], hasMoreItems: false), itemStates: [:]))
+                }
+            }
         }
     }
 }

WooCommerce/Classes/POS/Models/PointOfSaleErrorState.swift

@@ -29,6 +29,14 @@ struct PointOfSaleErrorState: Equatable {
                               buttonText: Constants.failedToLoadVariationsNextPageButtonTitle)
     }
 
+    static func errorOnLoadingCoupons() -> Self {
+        PointOfSaleErrorState(title: "Error loading coupons", subtitle: "Error loading coupons", buttonText: "Retry")
+    }
+
+    static func errorCouponsDisabled() -> Self {
+        PointOfSaleErrorState(title: "Error loading coupons", subtitle: "Please enable coupons in WooCommerce Settings, and tap Retry", buttonText: "Retry")
+    }
+
     enum Constants {
         static let failedToLoadProductsTitle = NSLocalizedString(
             "pos.itemList.failedToLoadProductsTitle",

Yosemite/Yosemite/PointOfSale/PointOfSaleCouponService.swift

@@ -5,6 +5,11 @@ import class WooFoundation.CurrencyFormatter
 import class WooFoundation.CurrencySettings
 import Storage
 
+public enum PointOfSaleCouponServiceError: Error {
+    case couponsLoadingError
+    case couponsDisabled
+}
+
 public protocol PointOfSaleCouponServiceProtocol {
     func providePointOfSaleCoupons(pageNumber: Int) async throws -> PagedItems<POSItem>
 }
@@ -42,6 +47,11 @@ public final class PointOfSaleCouponService: PointOfSaleCouponServiceProtocol {
 
     @MainActor
     public func providePointOfSaleCoupons(pageNumber: Int) async throws -> PagedItems<POSItem> {
+        let couponsEnabled = await checkStoreCouponSettings()
+        if !couponsEnabled {
+            throw PointOfSaleCouponServiceError.couponsDisabled
+        }
+
         let coupons = await providePointOfSaleCoupons()
 
         if !coupons.isEmpty {
@@ -109,4 +119,40 @@ private extension PointOfSaleCouponService {
             }
         }
     }
+
+    private func checkStoreCouponSettings() async -> Bool {
+        await withCheckedContinuation { continuation in
+            let action = SettingAction.retrieveCouponSetting(siteID: siteID) { result in
+                switch result {
+                case let .success(isEnabled):
+                    debugPrint("Coupons enabled? \(isEnabled)")
+                    continuation.resume(returning: isEnabled)
+                case let .failure(error):
+                    debugPrint("Coupons settings error: \(error)")
+                    continuation.resume(returning: false)
+                }
+            }
+            Task { @MainActor in
+                stores?.dispatch(action)
+            }
+        }
+    }
+
+    private func enableStoreCouponSettings() async -> Bool {
+        await withCheckedContinuation { continuation in
+            let action = SettingAction.enableCouponSetting(siteID: siteID) { result in
+                switch result {
+                case .success:
+                    debugPrint("Coupons enabled")
+                    continuation.resume(returning: true)
+                case let .failure(error):
+                    debugPrint("Error when attempting to enable Coupons: \(error)")
+                    continuation.resume(returning: false)
+                }
+            }
+            Task { @MainActor in
+                stores?.dispatch(action)
+            }
+        }
+    }
 }