import SwiftUI

/// 主界面：未连接时显示设置面板，连接成功后显示远程控制面板。
struct ContentView: View {
    @StateObject private var viewModel = ControllerViewModel()

    var body: some View {
        ZStack {
            if viewModel.isControlling {
                ControlPanelView(viewModel: viewModel)
            } else {
                SetupPanelView(viewModel: viewModel)
            }
        }
        .sheet(isPresented: $viewModel.showAuthSheet) {
            AuthSheetView { authType, authValue in
                viewModel.connect(authType: authType, authValue: authValue)
            }
        }
        .alert("提示", isPresented: Binding(
            get: { viewModel.alertMessage != nil },
            set: { if !$0 { viewModel.alertMessage = nil } })) {
            Button("确定", role: .cancel) { viewModel.alertMessage = nil }
        } message: {
            Text(viewModel.alertMessage ?? "")
        }
    }
}

// MARK: - 设置面板

private struct SetupPanelView: View {
    @ObservedObject var viewModel: ControllerViewModel

    var body: some View {
        NavigationView {
            Form {
                Section("本机信息") {
                    HStack {
                        Text("本机设备 ID")
                        Spacer()
                        Text(viewModel.myDeviceId)
                            .font(.system(.body, design: .monospaced))
                            .foregroundColor(.secondary)
                            .textSelection(.enabled)
                    }
                }

                Section("连接设置") {
                    TextField("信令服务器地址 (wss://...)", text: $viewModel.serverUrl)
                        .keyboardType(.URL)
                        .autocapitalization(.none)
                        .disableAutocorrection(true)
                    TextField("目标设备 ID", text: $viewModel.targetDeviceId)
                        .autocapitalization(.allCharacters)
                        .disableAutocorrection(true)
                }

                Section {
                    Button {
                        viewModel.requestConnect()
                    } label: {
                        HStack {
                            Spacer()
                            if viewModel.isConnecting {
                                ProgressView()
                                    .padding(.trailing, 8)
                            }
                            Text(viewModel.isConnecting ? "连接中..." : "连接")
                                .fontWeight(.semibold)
                            Spacer()
                        }
                    }
                    .disabled(viewModel.isConnecting)

                    if viewModel.isConnecting {
                        Button(role: .destructive) {
                            viewModel.disconnect()
                        } label: {
                            HStack {
                                Spacer()
                                Text("取消")
                                Spacer()
                            }
                        }
                    }
                } footer: {
                    Text(viewModel.statusText)
                }
            }
            .navigationTitle("WebRTC 控制端")
        }
        .navigationViewStyle(.stack)
    }
}

// MARK: - 控制面板

private struct ControlPanelView: View {
    @ObservedObject var viewModel: ControllerViewModel

    var body: some View {
        VStack(spacing: 0) {
            topBar
            videoArea
            statsView
            navButtons
        }
        .background(Color.black.ignoresSafeArea())
    }

    private var topBar: some View {
        HStack(spacing: 12) {
            Text(viewModel.statusText)
                .font(.footnote)
                .foregroundColor(.green)
                .lineLimit(1)

            Spacer()

            // 串流模式切换（WebRTC / 自编码）
            Toggle(isOn: Binding(
                get: { viewModel.streamMode == .selfCodec },
                set: { viewModel.toggleStreamMode($0) })) {
                Text("自编码")
                    .font(.footnote)
                    .foregroundColor(.white)
            }
            .toggleStyle(.switch)
            .fixedSize()

            // 分辨率选择
            Menu {
                ForEach(ResolutionOption.all) { option in
                    Button {
                        viewModel.selectResolution(option)
                    } label: {
                        if option == viewModel.selectedResolution {
                            Label(option.title, systemImage: "checkmark")
                        } else {
                            Text(option.title)
                        }
                    }
                }
            } label: {
                Label(viewModel.selectedResolution.title, systemImage: "rectangle.compress.vertical")
                    .font(.footnote)
            }

            Button(role: .destructive) {
                viewModel.disconnect()
            } label: {
                Text("断开")
                    .font(.footnote)
                    .fontWeight(.semibold)
            }
            .buttonStyle(.borderedProminent)
            .tint(.red)
            .controlSize(.small)
        }
        .padding(.horizontal, 12)
        .padding(.vertical, 6)
        .background(Color(white: 0.1))
    }

    /// 视频区域：按远端画面宽高比自适应，触控层与画面精确对齐
    private var videoArea: some View {
        GeometryReader { _ in
            ZStack {
                Color.black
                ZStack {
                    // WebRTC 视频渲染（UIKit RTCMTLVideoView）
                    RemoteVideoView(videoView: viewModel.remoteVideoView)
                        .opacity(viewModel.streamMode == .webrtc ? 1 : 0)
                    // 自编码 H.264 硬解渲染（UIKit AVSampleBufferDisplayLayer）
                    SelfCodecDisplayViewRepresentable(view: viewModel.selfCodecView)
                        .opacity(viewModel.streamMode == .selfCodec ? 1 : 0)
                    // UIKit 触控捕获层
                    TouchOverlay(
                        onMotionEvent: { action, x, y in
                            viewModel.sendMotionEvent(action: action, x: x, y: y)
                        },
                        onSwipe: { x1, y1, x2, y2, duration in
                            viewModel.sendSwipe(x1: x1, y1: y1, x2: x2, y2: y2, duration: duration)
                        })
                }
                .aspectRatio(viewModel.videoAspect, contentMode: .fit)
                .frame(maxWidth: .infinity, maxHeight: .infinity)
            }
        }
    }

    private var statsView: some View {
        HStack {
            Text(viewModel.statsText)
                .font(.system(size: 11, design: .monospaced))
                .foregroundColor(Color(white: 0.75))
                .multilineTextAlignment(.leading)
            Spacer()
        }
        .padding(.horizontal, 12)
        .padding(.vertical, 4)
        .background(Color(white: 0.08))
    }

    private var navButtons: some View {
        HStack(spacing: 24) {
            navButton(title: "返回", systemImage: "arrow.uturn.backward") {
                viewModel.sendKey(ControllerViewModel.AndroidKey.back)
            }
            navButton(title: "主页", systemImage: "circle") {
                viewModel.sendKey(ControllerViewModel.AndroidKey.home)
            }
            navButton(title: "多任务", systemImage: "square.on.square") {
                viewModel.sendKey(ControllerViewModel.AndroidKey.appSwitch)
            }
        }
        .padding(.vertical, 8)
        .frame(maxWidth: .infinity)
        .background(Color(white: 0.1))
    }

    private func navButton(title: String, systemImage: String, action: @escaping () -> Void) -> some View {
        Button(action: action) {
            VStack(spacing: 2) {
                Image(systemName: systemImage)
                    .font(.system(size: 18))
                Text(title)
                    .font(.caption2)
            }
            .foregroundColor(.white)
            .frame(width: 64)
        }
    }
}