import SwiftUI
import GhosttyTerminal
import TXCore

struct ContentView: View {
    @StateObject private var model = SSHTerminalModel()
    @Environment(\.scenePhase) private var scenePhase

    var body: some View {
        // M1 纯自检分支：仅 -txTsnetKey（无 -txHost）时跑 tsnet 加入+对端枚举自检。
        // 若同时有 -txHost，则走正常终端流程（model 经 tsnet fd 桥连接）。
        if let tsnetKey = UserDefaults.standard.string(forKey: "txTsnetKey"), !tsnetKey.isEmpty,
           (UserDefaults.standard.string(forKey: "txHost") ?? "").isEmpty {
            TsnetProbeView(authKey: tsnetKey)
        } else {
            Group {
                if model.showsTerminal {
                    TerminalScreen(model: model)
                } else {
                    ConnectionForm(model: model)
                }
            }
            .onAppear { model.autoConnectIfConfigured() }
            .onChange(of: scenePhase) { _, phase in
                switch phase {
                case .background: model.enterBackground()
                case .active: model.enterForeground()
                default: break
                }
            }
        }
    }
}

/// M0 连接表单：SSH 直连（不过 tsnet）。真实运维即输入自己的服务器。
struct ConnectionForm: View {
    @ObservedObject var model: SSHTerminalModel
    @State private var host = ""
    @State private var port = "22"
    @State private var username = ""
    @State private var password = ""

    var body: some View {
        NavigationStack {
            Form {
                Section("SSH 直连 (M0)") {
                    TextField("主机 / IP", text: $host)
                        .autocorrectionDisabled()
                        .textInputAutocapitalization(.never)
                    TextField("端口", text: $port)
                        .keyboardType(.numberPad)
                    TextField("用户名", text: $username)
                        .autocorrectionDisabled()
                        .textInputAutocapitalization(.never)
                    SecureField("密码", text: $password)
                }
                Section {
                    Button {
                        model.connect(host: host, port: Int(port) ?? 22,
                                      username: username, password: password)
                    } label: {
                        Text("连接").frame(maxWidth: .infinity)
                    }
                    .disabled(host.isEmpty || username.isEmpty)
                }
                Section("状态") {
                    Text(model.phaseText)
                        .foregroundStyle(model.phaseText.hasPrefix("失败") ? .red : .secondary)
                    if !model.banner.isEmpty {
                        Text(model.banner).font(.caption).foregroundStyle(.secondary)
                    }
                }
            }
            .navigationTitle("terminalX")
        }
    }
}

struct TerminalScreen: View {
    @ObservedObject var model: SSHTerminalModel

    var body: some View {
        if let tmux = model.tmuxController {
            TmuxTabbedView(controller: tmux)       // tmux -CC → 原生 tab
        } else {
            RawTerminalView(model: model)           // 普通单终端
        }
    }
}

/// 普通（非 tmux）单终端视图。
struct RawTerminalView: View {
    @ObservedObject var model: SSHTerminalModel
    @FocusState private var focused: Bool

    var body: some View {
        TerminalSurfaceView(context: model.state)
            .terminalFocusOnAppear($focused)
            .overlay(alignment: .top) {
                if model.phaseText != "已连接", !model.banner.isEmpty {
                    Text(model.banner)
                        .font(.caption)
                        .padding(.horizontal, 10).padding(.vertical, 6)
                        .background(.thinMaterial, in: Capsule())
                        .padding(.top, 6)
                }
            }
            .task {
                for _ in 0 ..< 300 where model.state.surfaceSize == nil {
                    try? await Task.sleep(nanoseconds: 30_000_000)
                }
                model.markSurfaceReady()
            }
    }
}

/// tmux control-mode：window 映射为原生 tab 条 + 活动 window 终端。
struct TmuxTabbedView: View {
    @ObservedObject var controller: TmuxController

    var body: some View {
        VStack(spacing: 0) {
            ScrollView(.horizontal, showsIndicators: false) {
                HStack(spacing: 6) {
                    ForEach(controller.windows) { win in
                        TmuxTabChip(window: win,
                                    isActive: win.id == controller.activeWindowID) {
                            controller.selectWindow(win.id)
                        }
                    }
                    Button { controller.newWindow() } label: {
                        Image(systemName: "plus").padding(.horizontal, 6)
                    }
                }
                .padding(.horizontal, 8).padding(.vertical, 6)
            }
            .background(.thinMaterial)
            Divider()
            if let win = controller.activeWindow {
                TmuxWindowView(window: win, controller: controller)
                    .id(win.id.raw)
            } else {
                Spacer(); Text("无 tmux 窗口").foregroundStyle(.secondary); Spacer()
            }
        }
    }
}

struct TmuxTabChip: View {
    @ObservedObject var window: TmuxWindow
    let isActive: Bool
    let onTap: () -> Void

    var body: some View {
        Button(action: onTap) {
            Text(window.title)
                .font(.caption).lineLimit(1)
                .padding(.horizontal, 12).padding(.vertical, 6)
                .background(isActive ? Color.accentColor.opacity(0.25) : Color.gray.opacity(0.12),
                            in: RoundedRectangle(cornerRadius: 8))
        }
        .buttonStyle(.plain)
    }
}

/// 一个 window：按 tmux 可见布局树把多 pane 绝对定位为分屏（每 pane 一 surface）。
struct TmuxWindowView: View {
    @ObservedObject var window: TmuxWindow
    let controller: TmuxController
    @Environment(\.displayScale) private var displayScale

    var body: some View {
        GeometryReader { geo in
            Group {
                if let layout = window.visibleLayout {
                    let root = layout.root.rect
                    let cw = geo.size.width / CGFloat(max(1, root.width))
                    let ch = geo.size.height / CGFloat(max(1, root.height))
                    ZStack(alignment: .topLeading) {
                        ForEach(leaves(layout.root), id: \.pane.raw) { item in
                            if let surface = window.panes[item.pane] {
                                TmuxPaneView(
                                    surface: surface,
                                    isActive: window.activePane == item.pane,
                                    onTap: { controller.selectPane(item.pane, in: window.id) },
                                    onReady: { controller.markPaneReady(item.pane) }
                                )
                                .frame(width: CGFloat(item.rect.width) * cw,
                                       height: CGFloat(item.rect.height) * ch)
                                .position(x: (CGFloat(item.rect.x) + CGFloat(item.rect.width) / 2) * cw,
                                          y: (CGFloat(item.rect.y) + CGFloat(item.rect.height) / 2) * ch)
                            }
                        }
                    }
                } else {
                    Color.clear
                }
            }
            // iPadOS 可自由拖拽窗口尺寸 → 容器变化即重算总格子并 refresh-client -C（controller 内 debounce）。
            .onAppear { controller.containerResized(widthPt: geo.size.width, heightPt: geo.size.height, scale: displayScale) }
            .onChange(of: geo.size) { _, s in
                controller.containerResized(widthPt: s.width, heightPt: s.height, scale: displayScale)
            }
        }
    }

    /// 收集布局树叶子（pane + 绝对 rect），identity 只用 paneID → 布局变化不重建 surface view。
    private func leaves(_ node: TmuxLayout.Node) -> [(pane: TmuxPaneID, rect: TmuxLayout.Rect)] {
        switch node {
        case .leaf(let p, let r): return [(p, r)]
        case .horizontal(let cs, _), .vertical(let cs, _): return cs.flatMap(leaves)
        }
    }
}

/// 单个 pane 的终端面 + 焦点边框 + 点击选中。
struct TmuxPaneView: View {
    @ObservedObject var surface: TmuxPaneSurface
    let isActive: Bool
    let onTap: () -> Void
    let onReady: () -> Void
    @FocusState private var focused: Bool

    var body: some View {
        TerminalSurfaceView(context: surface.state)
            .terminalFocusOnAppear($focused)
            .overlay(
                Rectangle().stroke(isActive ? Color.accentColor : Color.gray.opacity(0.35),
                                   lineWidth: isActive ? 2 : 0.5)
            )
            // 非活动 pane 叠透明 tap-catcher（TerminalSurfaceView 会吞触摸）；活动 pane 直通终端。
            .overlay {
                if !isActive {
                    Color.black.opacity(0.04).contentShape(Rectangle()).onTapGesture { onTap() }
                }
            }
            .onChange(of: isActive) { _, active in focused = active }
            .task {
                for _ in 0 ..< 300 where surface.state.surfaceSize == nil {
                    try? await Task.sleep(nanoseconds: 30_000_000)
                }
                onReady()
            }
    }
}