Add login flow, session routing, and MainTab shell aligned with reference UI.

Implement token-based root routing, Android-matched login screen, five-slot MainTabBar with scan action, and placeholder tab pages.

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

suixinkan/UI/MainTab/MainTabBarController.swift

@@ -0,0 +1,154 @@
+//
+//  MainTabBarController.swift
+//  suixinkan
+//
+
+import UIKit
+
+/// 主 Tab 容器，展示四个一级入口及中间扫码按钮。
+final class MainTabBarController: UITabBarController {
+
+    private let badgeViewModel = MainTabBadgeViewModel()
+    private var tabNavigationControllers: [AppTab: TabNavigationController] = [:]
+    private var isSyncingTabSelection = false
+
+    /// 测试时可注入扫码点击处理。
+    var onScanTabSelected: (() -> Void)?
+
+    private enum TabSlot: CaseIterable {
+        case home
+        case orders
+        case scan
+        case statistics
+        case profile
+
+        var appTab: AppTab? {
+            switch self {
+            case .home: return .home
+            case .orders: return .orders
+            case .scan: return nil
+            case .statistics: return .statistics
+            case .profile: return .profile
+            }
+        }
+
+        static func index(for tab: AppTab) -> Int? {
+            allCases.firstIndex { $0.appTab == tab }
+        }
+
+        static var scanIndex: Int? {
+            allCases.firstIndex(of: .scan)
+        }
+    }
+
+    override func viewDidLoad() {
+        super.viewDidLoad()
+        delegate = self
+        configureTabBarAppearance()
+        configureTabs()
+        bindBadgeViewModel()
+        badgeViewModel.refreshPendingWriteOffCount()
+    }
+
+    /// 选中指定主 Tab。
+    func selectTab(_ tab: AppTab) {
+        guard let index = TabSlot.index(for: tab) else { return }
+        guard selectedIndex != index else { return }
+        isSyncingTabSelection = true
+        selectedIndex = index
+        isSyncingTabSelection = false
+        if tab == .orders {
+            badgeViewModel.refreshPendingWriteOffCount()
+        }
+    }
+
+    private func configureTabBarAppearance() {
+        tabBar.tintColor = AppColor.primary
+        tabBar.backgroundColor = .white
+        tabBar.shadowImage = UIImage()
+
+        let normalAttributes: [NSAttributedString.Key: Any] = [
+            .foregroundColor: UIColor(hex: 0x7D8DA3),
+            .font: UIFont.systemFont(ofSize: 12, weight: .regular),
+        ]
+        let selectedAttributes: [NSAttributedString.Key: Any] = [
+            .foregroundColor: AppColor.primary,
+            .font: UIFont.systemFont(ofSize: 12, weight: .medium),
+        ]
+
+        let appearance = UITabBarAppearance()
+        appearance.configureWithOpaqueBackground()
+        appearance.backgroundColor = .white
+        appearance.shadowColor = .clear
+        appearance.stackedLayoutAppearance.normal.titleTextAttributes = normalAttributes
+        appearance.stackedLayoutAppearance.selected.titleTextAttributes = selectedAttributes
+        tabBar.standardAppearance = appearance
+        tabBar.scrollEdgeAppearance = appearance
+    }
+
+    private func configureTabs() {
+        tabNavigationControllers.removeAll()
+        viewControllers = TabSlot.allCases.map { slot in
+            if let tab = slot.appTab {
+                let navigationController = TabNavigationController(tab: tab)
+                navigationController.tabBarItem = tab.makeTabBarItem()
+                tabNavigationControllers[tab] = navigationController
+                return navigationController
+            }
+
+            let scannerPlaceholder = UIViewController()
+            scannerPlaceholder.tabBarItem = MainScanTabItem.makeTabBarItem()
+            return scannerPlaceholder
+        }
+    }
+
+    private func bindBadgeViewModel() {
+        badgeViewModel.onChange = { [weak self] in
+            self?.updateOrderBadge()
+        }
+    }
+
+    private func updateOrderBadge() {
+        let badgeValue: String?
+        if let count = badgeViewModel.pendingWriteOffCount, count > 0 {
+            badgeValue = "\(count)"
+        } else {
+            badgeValue = nil
+        }
+        tabNavigationControllers[.orders]?.tabBarItem.badgeValue = badgeValue
+    }
+
+    private func presentGlobalScanner() {
+        guard presentedViewController == nil else { return }
+
+        let scanner = ScanPlaceholderViewController()
+        let navigationController = UINavigationController(rootViewController: scanner)
+        navigationController.modalPresentationStyle = .fullScreen
+        present(navigationController, animated: true)
+    }
+}
+
+extension MainTabBarController: UITabBarControllerDelegate {
+
+    func tabBarController(_ tabBarController: UITabBarController, shouldSelect viewController: UIViewController) -> Bool {
+        guard viewControllers?.firstIndex(of: viewController) == TabSlot.scanIndex else {
+            return true
+        }
+
+        if let onScanTabSelected {
+            onScanTabSelected()
+        } else {
+            presentGlobalScanner()
+        }
+        return false
+    }
+
+    func tabBarController(_ tabBarController: UITabBarController, didSelect viewController: UIViewController) {
+        guard !isSyncingTabSelection,
+              let navigationController = viewController as? TabNavigationController else { return }
+
+        if navigationController.appTab == .orders {
+            badgeViewModel.refreshPendingWriteOffCount()
+        }
+    }
+}