#if os(macOS)
import AppKit
import SwiftUI

// 桌面根界面：NavigationSplitView 侧栏（传输 / 文件 / 消息 / 设备 / 设置）+ 详情 NavigationStack，
// 替代 iOS 的标签栏。离屏无头引擎 WebView 挂在背景保活（同 iOS RootView）。传输 / 文件 / 消息详情为
// 占位（随 Phase 3b 复用 iOS 视图）；设备 / 设置已接引擎真实态（presence / 账号 / 日志），作 3a 引擎
// 联通证明。分区标签暂硬编中文；接入 i18n（t()）待 Phase 3b 复用视图时统一。
struct MacRootView: View
{
    @Environment(EngineController.self) private var engine
    @Environment(AuthManager.self) private var auth
    @State private var quickSend = MacQuickSend.shared
    @State private var selection: MacSection = .transfers

    var body: some View
    {
        NavigationSplitView
        {
            List(selection: $selection)
            {
                brandHeader
                    .listRowInsets(EdgeInsets(top: 10, leading: 8, bottom: 14, trailing: 8))
                    .listRowSeparator(.hidden)
                    .selectionDisabled()
                Section
                {
                    ForEach(MacSection.sidebar)
                    { section in
                        Label(section.title, systemImage: section.icon)
                            .badge(badge(for: section))
                            .tag(section)
                    }
                }
            }
            .navigationSplitViewColumnWidth(min: 200, ideal: 220, max: 280)
            .navigationTitle("Commilitia Drop")
        }
        detail:
        {
            NavigationStack
            {
                detail
            }
        }
        // 引擎离屏 WebView 已由 App 级 MacBackgroundController 挂在常驻隐藏窗口后台续跑（脱离本窗口
        // 生命周期），故关主窗口引擎不销毁；本视图只呈现引擎状态、不再内嵌 WebView。剪贴板 monitor /
        // 全局热键 / App Nap 防护同样上移到 MacBackgroundController（按登录态启停，不随本视图显隐）。
        // 瞬时通知横幅（吊销 / 改名 / 剪贴板 / 登录审批反馈）覆盖窗口顶部。同 iOS RootView。
        .overlay(alignment: .top)
        {
            NoticeOverlay()
        }
        // Quick Send（热键 / 菜单栏触发）：有待发文件即切到「传输」并弹发送表单。
        .onChange(of: quickSend.pending)
        { _, urls in
            if !urls.isEmpty { selection = .transfers }
        }
        .sheet(isPresented: Binding(get: { !quickSend.pending.isEmpty },
                                    set: { if !$0 { quickSend.pending = [] } }))
        {
            MacComposeSheet(urls: quickSend.pending,
                            onCancel: { quickSend.pending = [] },
                            onSend:
                            { device in
                                for url in quickSend.pending { engine.sendFile(to: device, fileURL: url) }
                                quickSend.pending = []
                            })
                .environment(engine)
        }
    }

    @ViewBuilder
    private var detail: some View
    {
        switch selection
        {
        case .transfers:
            MacTransfersView()
        case .files:
            MacFilesView()
        case .messages:
            MacMessagesView()
        case .devices:
            MacDevicesView()
        case .settings:
            MacSettingsView()
        }
    }

    private var brandHeader: some View
    {
        HStack(spacing: 10)
        {
            Image(systemName: "paperplane.fill")
                .font(.title2)
                .foregroundStyle(.tint)
            Text("Commilitia Drop")
                .font(.title3.weight(.semibold))
                .lineLimit(1)
        }
    }

    // 未读红点：消息 / 传输（对齐 iOS RootView 的 badge）。
    private func badge(for section: MacSection) -> Int
    {
        switch section
        {
        case .messages: return engine.unreadMessages
        case .transfers: return engine.unreadTransfers
        default: return 0
        }
    }
}

// 侧栏分区。与 iOS 标签一致：传输 / 文件 / 消息 / 设备 / 设置。
enum MacSection: Hashable, Identifiable, CaseIterable
{
    case transfers, files, messages, devices, settings

    var id: Self { self }

    var title: String
    {
        switch self
        {
        case .transfers: return "传输"
        case .files: return "文件"
        case .messages: return "消息"
        case .devices: return "设备"
        case .settings: return "设置"
        }
    }

    var icon: String
    {
        switch self
        {
        case .transfers: return "arrow.up.arrow.down"
        case .files: return "folder"
        case .messages: return "bubble.left.and.bubble.right"
        case .devices: return "laptopcomputer.and.iphone"
        case .settings: return "gearshape"
        }
    }

    static var sidebar: [MacSection] { MacSection.allCases }
}

// 设备：引擎经桥推来的真实 presence（图标随类型 + 在线态 + 移除设备）。排除本机。
struct MacDevicesView: View
{
    @Environment(EngineController.self) private var engine
    @State private var revokeTarget: DeviceItem?

    private var others: [DeviceItem]
    {
        engine.devices.filter { $0.deviceID != engine.selfDeviceID }
    }

    var body: some View
    {
        Group
        {
            if others.isEmpty
            {
                ContentUnavailableView("暂无其他设备", systemImage: "laptopcomputer.and.iphone",
                                       description: Text("同账户的其他设备将显示在此。"))
            }
            else
            {
                List(others)
                { dev in
                    HStack(spacing: 10)
                    {
                        Image(systemName: macDeviceSymbol(dev.type))
                            .foregroundStyle(dev.online ? Color.green : Color.secondary)
                        VStack(alignment: .leading, spacing: 2)
                        {
                            Text(dev.name)
                            Text(dev.online ? "在线" : "离线")
                                .font(.caption)
                                .foregroundStyle(.secondary)
                        }
                        Spacer()
                    }
                    .contextMenu
                    {
                        Button("移除设备", role: .destructive) { revokeTarget = dev }
                    }
                }
            }
        }
        .navigationTitle("设备")
        .confirmationDialog("移除该设备？",
                            isPresented: Binding(get: { revokeTarget != nil },
                                                 set: { if !$0 { revokeTarget = nil } }),
                            presenting: revokeTarget)
        { dev in
            Button("移除 \(dev.name)", role: .destructive) { engine.revokeDevice(dev.deviceID) }
            Button("取消", role: .cancel) {}
        }
        message:
        { dev in
            Text("将吊销 \(dev.name) 的登录，该设备需重新登录。")
        }
    }
}

// 设置：账号 + 本机设备名（可改）+ 云剪贴板 + 引擎状态 + 引擎日志 + 登出。
struct MacSettingsView: View
{
    @Environment(EngineController.self) private var engine
    @Environment(AuthManager.self) private var auth
    @AppStorage("macClipboardAutoSync") private var autoSync = true
    @AppStorage("macDownloadDir") private var downloadDirPath = ""
    @AppStorage("macHideDock") private var hideDock = false
    @State private var nameDraft = DeviceNameStore.value

    private var signalingLabel: String
    {
        if engine.hubConnected { return "已连接" }
        if engine.hubReconnecting { return "重连中…" }
        return "未连接"
    }

    var body: some View
    {
        Form
        {
            Section("账号")
            {
                LabeledContent("用户", value: auth.session?.user.name ?? "—")
                HStack
                {
                    TextField("本机设备名", text: $nameDraft)
                        .onSubmit { commitRename() }
                    Button("保存") { commitRename() }
                        .disabled(nameDraft.trimmingCharacters(in: .whitespaces).isEmpty)
                }
                Button("登出", role: .destructive)
                {
                    // 引擎复位由 App 级 MacBackgroundController 随登出（会话变 nil）统一处理，此处只登出。
                    auth.logout()
                }
            }
            Section("云剪贴板")
            {
                Toggle("自动同步本机复制（上行）", isOn: $autoSync)
                    .onChange(of: autoSync) { MacBackgroundController.shared.refreshClipboardMonitor() }
                Button("上传本机剪贴板") { engine.uploadClipboard() }
                Button("拉取云剪贴板到本机") { engine.pullClipboard() }
            }
            Section("后台")
            {
                Toggle("隐藏 Dock 图标（仅菜单栏常驻）", isOn: $hideDock)
                    .onChange(of: hideDock) { MacBackgroundController.shared.applyDockPolicy() }
                Text("关闭主窗口后仍在菜单栏后台运行、持续同步；点菜单栏图标可重开窗口。")
                    .font(.caption)
                    .foregroundStyle(.secondary)
            }
            Section("接收")
            {
                LabeledContent("保存到", value: downloadDirDisplay)
                Button("选择目录…") { pickDownloadDir() }
            }
            Section("引擎")
            {
                LabeledContent("状态", value: engine.status)
                LabeledContent("信令", value: signalingLabel)
                LabeledContent("在线设备", value: "\(engine.presenceCount)")
            }
            Section("引擎日志")
            {
                if engine.logs.isEmpty
                {
                    Text("暂无日志").foregroundStyle(.secondary)
                }
                else
                {
                    ForEach(engine.logs.prefix(30))
                    { entry in
                        Text(entry.message)
                            .font(.caption.monospaced())
                            .foregroundStyle(.secondary)
                            .lineLimit(2)
                            .textSelection(.enabled)
                    }
                }
            }
        }
        .formStyle(.grouped)
        .navigationTitle("设置")
    }

    private func commitRename()
    {
        let name = nameDraft.trimmingCharacters(in: .whitespacesAndNewlines)
        guard !name.isEmpty else { return }
        engine.renameSelf(to: name)
    }

    private var downloadDirDisplay: String
    {
        downloadDirPath.isEmpty ? "下载（默认）" : (downloadDirPath as NSString).abbreviatingWithTildeInPath
    }

    private func pickDownloadDir()
    {
        let panel = NSOpenPanel()
        panel.canChooseFiles = false
        panel.canChooseDirectories = true
        panel.allowsMultipleSelection = false
        panel.prompt = "选择"
        if panel.runModal() == .OK, let url = panel.url
        {
            downloadDirPath = url.path
        }
    }
}
#endif