fix: 优化相册素材状态与删除保护

suixinkan/Features/TravelAlbum/ViewModels/TravelAlbumDetailViewModel.swift

@@ -48,6 +48,7 @@ final class TravelAlbumDetailViewModel {
     private(set) var isRefreshing = false
     private(set) var isSelectionMode = false
     private(set) var selectedMaterialIds: Set<Int> = []
+    private var selectedMaterialPurchaseStates: [Int: Bool] = [:]
 
     var onStateChange: (() -> Void)?
     var onShowMessage: ((String) -> Void)?
@@ -142,12 +143,29 @@ final class TravelAlbumDetailViewModel {
         selectedTab == .all ? allPhotoCount : purchasedPhotoCount
     }
 
+    /// 当前选中素材中的已购买数量。
+    var selectedPurchasedMaterialCount: Int {
+        selectedMaterialIds.count - selectedDeletableMaterialIds.count
+    }
+
+    /// 删除确认弹窗文案；选中已购素材时明确说明保护规则与实际删除数量。
+    var deleteSelectedConfirmationMessage: String {
+        let selectedCount = selectedMaterialIds.count
+        let purchasedCount = selectedPurchasedMaterialCount
+        guard purchasedCount > 0 else {
+            return "确定删除选中的 \(selectedCount) 张素材吗？"
+        }
+        let deletableCount = selectedCount - purchasedCount
+        return "已选择 \(selectedCount) 张素材，其中 \(purchasedCount) 张已购买。"
+            + "不会删除已购买的项目，只会删除 \(deletableCount) 张未购买的项目。"
+    }
+
     /// 切换素材 tab。
     func selectTab(_ tab: Tab, api: any TravelAlbumServing) async {
         guard selectedTab != tab else { return }
         selectedTab = tab
         isSelectionMode = false
-        selectedMaterialIds = []
+        clearMaterialSelection()
         notifyStateChange()
         await loadMaterials(reset: true, api: api)
     }
@@ -223,10 +241,9 @@ final class TravelAlbumDetailViewModel {
 
     /// 切换选择模式。
     func toggleSelectionMode() {
-        guard selectedTab == .all else { return }
         isSelectionMode.toggle()
         if !isSelectionMode {
-            selectedMaterialIds = []
+            clearMaterialSelection()
         }
         notifyStateChange()
     }
@@ -234,14 +251,12 @@ final class TravelAlbumDetailViewModel {
     /// 切换素材选中状态。
     func toggleMaterialSelection(_ material: TravelAlbumMaterial) {
         guard isSelectionMode else { return }
-        guard material.status == 1 else {
-            onShowMessage?("仅未购买素材可删除")
-            return
-        }
         if selectedMaterialIds.contains(material.id) {
             selectedMaterialIds.remove(material.id)
+            selectedMaterialPurchaseStates.removeValue(forKey: material.id)
         } else {
             selectedMaterialIds.insert(material.id)
+            selectedMaterialPurchaseStates[material.id] = material.isPurchased
         }
         notifyStateChange()
     }
@@ -249,7 +264,7 @@ final class TravelAlbumDetailViewModel {
     /// AI 修图任务提交成功后退出选择模式并清空当前选择。
     func completeAIRetouchSubmission() {
         isSelectionMode = false
-        selectedMaterialIds = []
+        clearMaterialSelection()
         notifyStateChange()
     }
 
@@ -264,6 +279,7 @@ final class TravelAlbumDetailViewModel {
         guard let index = materials.firstIndex(where: { $0.id == id }) else { return }
         let material = materials.remove(at: index)
         selectedMaterialIds.remove(id)
+        selectedMaterialPurchaseStates.removeValue(forKey: id)
         allPhotoCount = max(0, allPhotoCount - 1)
         if material.isPurchased {
             purchasedPhotoCount = max(0, purchasedPhotoCount - 1)
@@ -273,16 +289,20 @@ final class TravelAlbumDetailViewModel {
 
     /// 删除已选素材。
     func deleteSelectedMaterials(api: any TravelAlbumServing) async {
-        let ids = selectedMaterialIds.sorted()
-        guard !ids.isEmpty else {
+        guard !selectedMaterialIds.isEmpty else {
             onShowMessage?("请选择要删除的素材")
             return
         }
+        let ids = selectedDeletableMaterialIds
+        guard !ids.isEmpty else {
+            onShowMessage?("选中的素材均已购买，未删除任何项目")
+            return
+        }
         do {
             try await api.batchDeleteMaterials(ids: ids)
             onShowMessage?("删除成功")
             isSelectionMode = false
-            selectedMaterialIds = []
+            clearMaterialSelection()
             await refreshAll(api: api)
         } catch is CancellationError {
             return
@@ -307,4 +327,18 @@ final class TravelAlbumDetailViewModel {
     private func notifyStateChange() {
         onStateChange?()
     }
+
+    private func clearMaterialSelection() {
+        selectedMaterialIds = []
+        selectedMaterialPurchaseStates = [:]
+    }
+
+    private var selectedDeletableMaterialIds: [Int] {
+        selectedMaterialIds
+            .filter { id in
+                guard selectedMaterialPurchaseStates[id] == false else { return false }
+                return materials.first(where: { $0.id == id })?.isPurchased != true
+            }
+            .sorted()
+    }
 }