Initial commit: suixinkan_ios UIKit rewrite project.

Co-authored-by: Cursor <cursoragent@cursor.com>

suixinkan_ios/Features/MessageCenter/ViewModels/MessageCenterViewModel.swift

@@ -0,0 +1,169 @@
+//
+//  MessageCenterViewModel.swift
+//  suixinkan
+//
+//  Created by Codex on 2026/6/25.
+//
+
+import Foundation
+
+@MainActor
+/// 消息中心 ViewModel，负责消息分页、筛选、已读和删除。
+final class MessageCenterViewModel {
+    var onChange: (() -> Void)?
+    var messages: [MessageItem] = [] { didSet { onChange?() } }
+    var selectedFilter: MessageFilter = .all { didSet { onChange?() } }
+    var isLoading = false { didSet { onChange?() } }
+    var isLoadingMore = false { didSet { onChange?() } }
+    var loadFailed = false { didSet { onChange?() } }
+    var loadFailureReason: String? { didSet { onChange?() } }
+    var message: String? { didSet { onChange?() } }
+
+    private(set) var hasMoreMessages = false { didSet { onChange?() } }
+    private(set) var lastId = 0 { didSet { onChange?() } }
+    private let pageSize = 20
+
+    /// 未读消息数量。
+    var unreadCount: Int {
+        messages.filter { !$0.isRead }.count
+    }
+
+    /// 当前筛选说明。
+    var filterDescription: String {
+        selectedFilter == .all ? "显示全部消息" : "仅显示未读消息"
+    }
+
+    /// 切换筛选并重新加载首屏。
+    func selectFilter(_ filter: MessageFilter, api: any MessageCenterServing) async {
+        guard selectedFilter != filter else { return }
+        selectedFilter = filter
+        await reloadFirstPage(api: api)
+    }
+
+    /// 重新加载首屏消息，失败时清空旧数据。
+    func reloadFirstPage(api: any MessageCenterServing) async {
+        isLoading = true
+        loadFailed = false
+        loadFailureReason = nil
+        message = nil
+        defer { isLoading = false }
+
+        do {
+            let response = try await api.messageList(lastId: 0, limit: pageSize, unread: selectedFilter.rawValue)
+            messages = mapMessages(response.items)
+            hasMoreMessages = response.hasMore
+            lastId = response.lastId
+        } catch {
+            clearMessages()
+            loadFailed = true
+            loadFailureReason = error.localizedDescription
+            message = error.localizedDescription
+        }
+    }
+
+    /// 加载更多消息，失败时保留当前数据和分页状态。
+    func loadMore(api: any MessageCenterServing) async {
+        guard hasMoreMessages, !isLoadingMore, !isLoading else { return }
+        isLoadingMore = true
+        message = nil
+        defer { isLoadingMore = false }
+
+        do {
+            let response = try await api.messageList(lastId: lastId, limit: pageSize, unread: selectedFilter.rawValue)
+            messages.append(contentsOf: mapMessages(response.items))
+            messages = deduplicatedAndSorted(messages)
+            hasMoreMessages = response.hasMore
+            lastId = response.lastId
+        } catch {
+            message = error.localizedDescription
+        }
+    }
+
+    /// 标记单条消息为已读，接口成功后再更新本地状态。
+    func markAsRead(api: any MessageCenterServing, item: MessageItem) async throws {
+        guard !item.isRead, let msgId = item.msgId else { return }
+        try await api.messageRead(id: msgId)
+        guard let index = messages.firstIndex(where: { $0.id == item.id }) else { return }
+        messages[index].isRead = true
+    }
+
+    /// 将当前列表中的未读消息逐条标记为已读。
+    func markAllAsRead(api: any MessageCenterServing) async throws {
+        let original = messages
+        do {
+            for item in messages where !item.isRead {
+                if let msgId = item.msgId {
+                    try await api.messageRead(id: msgId)
+                }
+            }
+            messages = messages.map { item in
+                var next = item
+                next.isRead = true
+                return next
+            }
+        } catch {
+            messages = original
+            throw error
+        }
+    }
+
+    /// 删除消息，接口成功后再移除本地列表。
+    func deleteMessage(api: any MessageCenterServing, item: MessageItem) async throws {
+        if let msgId = item.msgId {
+            try await api.messageDelete(id: msgId)
+        }
+        messages.removeAll { $0.id == item.id }
+    }
+
+    /// 将后端实体转换为页面展示实体。
+    func mapMessages(_ source: [MessageEntity]) -> [MessageItem] {
+        source.map { item in
+            MessageItem(
+                id: "msg_\(item.id)",
+                msgId: item.id,
+                title: item.title.trimmingCharacters(in: .whitespacesAndNewlines).nonEmpty
+                    ?? item.typeName.trimmingCharacters(in: .whitespacesAndNewlines).nonEmpty
+                    ?? "系统通知",
+                detail: item.content,
+                time: item.pushAt.trimmingCharacters(in: .whitespacesAndNewlines).nonEmpty
+                    ?? item.createdAt.trimmingCharacters(in: .whitespacesAndNewlines).nonEmpty
+                    ?? "0000-00-00 00:00",
+                isRead: item.isRead,
+                type: Self.messageType(from: item.type)
+            )
+        }
+    }
+
+    /// 将后端类型映射为页面消息类型。
+    static func messageType(from value: Int) -> MessageType {
+        switch value {
+        case 1:
+            return .order
+        case 2:
+            return .writeOff
+        default:
+            return .system
+        }
+    }
+
+    private func deduplicatedAndSorted(_ source: [MessageItem]) -> [MessageItem] {
+        var unique: [String: MessageItem] = [:]
+        for item in source {
+            unique[item.id] = item
+        }
+        return unique.values.sorted { $0.time > $1.time }
+    }
+
+    private func clearMessages() {
+        messages = []
+        hasMoreMessages = false
+        lastId = 0
+        isLoadingMore = false
+    }
+}
+
+private extension String {
+    var nonEmpty: String? {
+        isEmpty ? nil : self
+    }
+}