using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Text.Json.Nodes;
using System.Threading;
using System.Threading.Tasks;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Input;
using System.Windows.Media;
using System.Windows.Media.Imaging;
using System.Windows.Threading;
using JJServiceManager.Remote;

namespace JJServiceManager
{
    /// <summary>대상 PC: 원격 화면 연결 승인 창 (30초 안에 답하지 않으면 거부)</summary>
    public sealed class ApprovalWindow : Window
    {
        private readonly TaskCompletionSource<bool> _result = new TaskCompletionSource<bool>();
        private readonly DispatcherTimer _timer;
        private readonly TextBlock _countdown;
        private int _left = 30;

        private ApprovalWindow(string who, bool control)
        {
            Title = "원격관리 연결 요청" + AppInstance.TitleTag;
            Width = 460;
            SizeToContent = SizeToContent.Height;
            ResizeMode = ResizeMode.NoResize;
            WindowStartupLocation = WindowStartupLocation.CenterScreen;
            Topmost = true;
            FontFamily = new FontFamily("Malgun Gothic");
            FontSize = 13;
            Background = Brushes2.Make("#FAFAFA");
            AppIcon.Apply(this);

            var root = new StackPanel { Margin = new Thickness(20, 18, 20, 16) };
            root.Children.Add(new TextBlock
            {
                Text = control ? "원격 화면 보기 + 키보드·마우스 제어 요청" : "원격 화면 보기 요청",
                FontSize = 15,
                FontWeight = FontWeights.Bold,
                Foreground = Brushes2.Make(control ? "#B71C1C" : "#155E75"),
                Margin = new Thickness(0, 0, 0, 10)
            });
            root.Children.Add(new TextBlock
            {
                Text = $"관리 PC [{who}] 가 이 PC 화면을 {(control ? "보고 조작" : "보")}려고 합니다.\n허용할까요?",
                TextWrapping = TextWrapping.Wrap,
                Margin = new Thickness(0, 0, 0, 10)
            });
            _countdown = new TextBlock { Foreground = Brushes.Gray };
            root.Children.Add(_countdown);

            var buttons = new StackPanel { Orientation = Orientation.Horizontal, HorizontalAlignment = HorizontalAlignment.Right, Margin = new Thickness(0, 12, 0, 0) };
            var allow = new Button { Content = "허용", MinWidth = 90, FontWeight = FontWeights.Bold };
            var deny = new Button { Content = "거부", MinWidth = 90, IsCancel = true };
            allow.Click += (s, e) => Finish(true);
            deny.Click += (s, e) => Finish(false);
            buttons.Children.Add(allow);
            buttons.Children.Add(deny);
            root.Children.Add(buttons);
            Content = root;

            _timer = new DispatcherTimer { Interval = TimeSpan.FromSeconds(1) };
            _timer.Tick += (s, e) =>
            {
                _left--;
                UpdateCountdown();
                if (_left <= 0) Finish(false);
            };
            UpdateCountdown();
            Closed += (s, e) => { _timer.Stop(); _result.TrySetResult(false); };
            Loaded += (s, e) => { _timer.Start(); Activate(); };
        }

        private void UpdateCountdown() => _countdown.Text = $"{_left}초 뒤 자동으로 거부됩니다.";

        private void Finish(bool ok)
        {
            _result.TrySetResult(ok);
            Close();
        }

        /// <summary>UI 스레드에서 호출</summary>
        public static Task<bool> AskAsync(string who, bool control)
        {
            var w = new ApprovalWindow(who, control);
            w.Show();
            return w._result.Task;
        }
    }

    /// <summary>대상 PC: 원격 화면 연결 중 화면 위쪽 표시줄 (항상 표시)</summary>
    public sealed class RemoteIndicatorWindow : Window
    {
        private readonly TextBlock _text;
        private readonly Border _bar;

        public event Action DisconnectRequested;

        public RemoteIndicatorWindow()
        {
            WindowStyle = WindowStyle.None;
            ResizeMode = ResizeMode.NoResize;
            AllowsTransparency = true;
            Background = Brushes.Transparent;
            Topmost = true;
            ShowInTaskbar = false;
            ShowActivated = false;
            SizeToContent = SizeToContent.WidthAndHeight;
            FontFamily = new FontFamily("Malgun Gothic");
            FontSize = 13;

            _bar = new Border
            {
                CornerRadius = new CornerRadius(0, 0, 8, 8),
                Padding = new Thickness(14, 6, 8, 6),
                Background = Brushes2.Make("#E65100")
            };
            var panel = new StackPanel { Orientation = Orientation.Horizontal };
            _text = new TextBlock { Foreground = Brushes.White, FontWeight = FontWeights.Bold, VerticalAlignment = VerticalAlignment.Center };
            var stop = new Button
            {
                Content = "연결 끊기",
                Margin = new Thickness(12, 0, 0, 0),
                MinWidth = 0,
                MinHeight = 0,
                Padding = new Thickness(8, 2, 8, 2),
                Background = Brushes.White
            };
            stop.Click += (s, e) => DisconnectRequested?.Invoke();
            panel.Children.Add(_text);
            panel.Children.Add(stop);
            _bar.Child = panel;
            Content = _bar;

            SizeChanged += (s, e) => Reposition();
        }

        public void Update(IReadOnlyList<ScreenViewer> viewers)
        {
            if (viewers.Count == 0)
            {
                Hide();
                return;
            }
            bool control = viewers.Any(v => v.Control);
            _bar.Background = Brushes2.Make(control ? "#C62828" : "#E65100");
            _text.Text = $"● 원격 {(control ? "제어" : "보기")} 중: {string.Join(", ", viewers.Select(v => v.Who).Distinct())}";
            if (!IsVisible) Show();
            Reposition();
        }

        private void Reposition()
        {
            var wa = SystemParameters.WorkArea;
            Left = wa.Left + (wa.Width - ActualWidth) / 2;
            Top = wa.Top;
        }
    }

    /// <summary>관리 PC: 원격 화면 창 (보기 / 제어)</summary>
    public sealed class RemoteViewerWindow : Window
    {
        private readonly RemoteClient _client;
        private readonly string _label;
        private readonly Image _image;
        private readonly TextBlock _status, _overlay;
        private readonly StackPanel _monitorButtons;
        private readonly HashSet<int> _pressedKeys = new HashSet<int>();
        private int _sid;
        private bool _control;
        private bool _ended;
        private int _monitor = 1;
        private int _frames;
        private DateTime _fpsStart = DateTime.UtcNow;
        private int _decoding;
        private DateTime _lastMove = DateTime.MinValue;

        public string ViewerKey { get; }

        public RemoteViewerWindow(string key, RemoteClient client, string label)
        {
            ViewerKey = key;
            _client = client;
            _label = label;

            Title = $"원격관리 - {label}" + AppInstance.TitleTag;
            Width = 1280;
            Height = 800;
            WindowStartupLocation = WindowStartupLocation.CenterScreen;
            FontFamily = new FontFamily("Malgun Gothic");
            FontSize = 13;
            Background = Brushes2.Make("#263238");
            AppIcon.Apply(this);
            // 한글 입력기는 대상 PC에서 처리하도록 이 창에서는 끔
            InputMethod.SetIsInputMethodEnabled(this, false);

            var root = new DockPanel();

            // ── 도구 모음
            var bar = new DockPanel { Background = Brushes2.Make("#ECEFF1") };
            DockPanel.SetDock(bar, Dock.Top);
            var close = new Button { Content = "연결 끊기" };
            close.Click += (s, e) => Close();
            DockPanel.SetDock(close, Dock.Right);
            bar.Children.Add(close);
            _status = new TextBlock { VerticalAlignment = VerticalAlignment.Center, Margin = new Thickness(12, 0, 12, 0), Foreground = Brushes2.Make("#37474F") };
            DockPanel.SetDock(_status, Dock.Right);
            bar.Children.Add(_status);
            _monitorButtons = new StackPanel { Orientation = Orientation.Horizontal, Margin = new Thickness(4) };
            bar.Children.Add(_monitorButtons);
            root.Children.Add(bar);

            // ── 화면
            var stage = new Grid { Background = Brushes.Black, ClipToBounds = true };
            _image = new Image
            {
                Stretch = Stretch.Uniform,
                HorizontalAlignment = HorizontalAlignment.Center,
                VerticalAlignment = VerticalAlignment.Center,
                Focusable = true,
                Cursor = Cursors.Arrow
            };
            RenderOptions.SetBitmapScalingMode(_image, BitmapScalingMode.HighQuality);
            _overlay = new TextBlock
            {
                Text = "연결 중…",
                Foreground = Brushes.White,
                FontSize = 16,
                HorizontalAlignment = HorizontalAlignment.Center,
                VerticalAlignment = VerticalAlignment.Center,
                TextAlignment = TextAlignment.Center,
                TextWrapping = TextWrapping.Wrap
            };
            stage.Children.Add(_image);
            stage.Children.Add(_overlay);
            root.Children.Add(stage);
            Content = root;

            _image.MouseMove += OnMouseMove;
            _image.MouseDown += OnMouseDown;
            _image.MouseUp += OnMouseUp;
            _image.MouseWheel += OnMouseWheel;
            PreviewKeyDown += OnKey;
            PreviewKeyUp += OnKey;
            Deactivated += (s, e) => ReleaseKeys();

            _client.ScreenEvent += OnScreenEvent;
            Loaded += async (s, e) => await StartAsync();
            Closed += (s, e) => Stop();
        }

        // ───────────────────────── 시작 / 끝 ─────────────────────────

        private async Task StartAsync()
        {
            try
            {
                _overlay.Text = "대상 PC 정보를 확인하는 중…";
                var info = await _client.RequestAsync("screenInfo", null, TimeSpan.FromSeconds(15));
                if (!Json.Bool(info, "allowView"))
                {
                    End("대상 PC에서 화면 보기를 허용하지 않았습니다.\n(대상 PC 설정 → 원격 접속 허용 → 화면 보기 허용)");
                    return;
                }

                var monitors = (info["monitors"] as JsonArray)?.OfType<JsonObject>().ToList() ?? new List<JsonObject>();
                var primary = monitors.FirstOrDefault(m => Json.Bool(m, "primary"));
                _monitor = primary != null ? Json.Int(primary, "index", 1) : 1;
                foreach (var m in monitors)
                {
                    int idx = Json.Int(m, "index", 1);
                    AddMonitorButton($"모니터 {idx}" + (Json.Bool(m, "primary") ? " (주)" : ""), idx,
                        $"{Json.Int(m, "width")} × {Json.Int(m, "height")}");
                }
                if (monitors.Count > 1) AddMonitorButton("전체", 0, "모든 모니터를 한 화면에");
                HighlightMonitor();

                _overlay.Text = "대상 PC의 승인을 기다리는 중…";
                var r = await _client.RequestAsync("screenStart", new JsonObject { ["monitor"] = _monitor }, TimeSpan.FromSeconds(45));
                _sid = Json.Int(r, "sid");
                _control = Json.Bool(r, "control");
                _overlay.Text = "";
                UpdateStatus();
                _image.Cursor = _control ? Cursors.Cross : Cursors.Arrow;
                _image.Focus();
            }
            catch (Exception ex)
            {
                End(RemoteClient.Friendly(ex));
            }
        }

        private void AddMonitorButton(string text, int index, string tip)
        {
            var b = new Button { Content = text, Tag = index, ToolTip = tip, MinWidth = 70 };
            b.Click += async (s, e) =>
            {
                _monitor = index;
                HighlightMonitor();
                try { await _client.RequestAsync("screenMonitor", new JsonObject { ["monitor"] = index }, TimeSpan.FromSeconds(10)); }
                catch { }
                _image.Focus();
            };
            _monitorButtons.Children.Add(b);
        }

        private void HighlightMonitor()
        {
            foreach (Button b in _monitorButtons.Children)
            {
                bool on = (int)b.Tag == _monitor;
                b.FontWeight = on ? FontWeights.Bold : FontWeights.Normal;
                b.Background = on ? Brushes2.Make("#BBDEFB") : Brushes.White;
            }
        }

        private void End(string reason)
        {
            _ended = true;
            _overlay.Text = reason;
            _status.Text = "연결 끝";
            _image.Cursor = Cursors.Arrow;
        }

        private void Stop()
        {
            _client.ScreenEvent -= OnScreenEvent;
            ReleaseKeys();
            if (_sid > 0 && !_ended)
                _ = _client.RequestAsync("screenStop", null, TimeSpan.FromSeconds(5)).ContinueWith(t => { _ = t.Exception; });
        }

        private void UpdateStatus()
        {
            var secs = (DateTime.UtcNow - _fpsStart).TotalSeconds;
            double fps = secs > 0 ? _frames / secs : 0;
            if (secs > 3) { _frames = 0; _fpsStart = DateTime.UtcNow; }
            _status.Text = $"{(_control ? "● 제어 중" : "보기 전용")} · {fps:0.0}장/초";
            _status.Foreground = _control ? Brushes2.Stopped : Brushes2.Make("#37474F");
        }

        // ───────────────────────── 화면 받기 ─────────────────────────

        private void OnScreenEvent(JsonObject msg)
        {
            var ev = Json.Str(msg, "event");
            int sid = Json.Int(msg, "sid");
            if (ev == "screenEnd")
            {
                if (sid == 0 || sid == _sid)
                {
                    var reason = Json.Str(msg, "reason");
                    Dispatcher.BeginInvoke(new Action(() => End("원격 화면 연결이 끝났습니다.\n" + reason)));
                }
                return;
            }
            if (ev != "frame" || sid != _sid || _ended) return;

            // 화면 그리기가 밀리면 이전 장면은 건너뜀
            if (Interlocked.Exchange(ref _decoding, 1) == 1) return;
            try
            {
                var bytes = Convert.FromBase64String(Json.Str(msg, "data"));
                var bmp = new BitmapImage();
                bmp.BeginInit();
                bmp.CacheOption = BitmapCacheOption.OnLoad;
                bmp.StreamSource = new MemoryStream(bytes);
                bmp.EndInit();
                bmp.Freeze();
                Dispatcher.BeginInvoke(new Action(() =>
                {
                    _image.Source = bmp;
                    _frames++;
                    UpdateStatus();
                    Interlocked.Exchange(ref _decoding, 0);
                }), DispatcherPriority.Render);
            }
            catch
            {
                Interlocked.Exchange(ref _decoding, 0);
            }
        }

        // ───────────────────────── 입력 보내기 ─────────────────────────

        private bool CanControl => _control && !_ended && _sid > 0;

        private (double x, double y) Norm(MouseEventArgs e)
        {
            var p = e.GetPosition(_image);
            double w = Math.Max(1, _image.ActualWidth), h = Math.Max(1, _image.ActualHeight);
            return (Math.Clamp(p.X / w, 0, 1), Math.Clamp(p.Y / h, 0, 1));
        }

        private void SendMouse(MouseEventArgs e, string action, string button = "", int delta = 0)
        {
            var (x, y) = Norm(e);
            _client.SendNoReply(new JsonObject
            {
                ["op"] = "input",
                ["kind"] = "mouse",
                ["action"] = action,
                ["button"] = button,
                ["x"] = Math.Round(x, 5),
                ["y"] = Math.Round(y, 5),
                ["delta"] = delta
            });
        }

        private static string ButtonName(MouseButton b) => b switch
        {
            MouseButton.Right => "right",
            MouseButton.Middle => "middle",
            _ => "left"
        };

        private void OnMouseMove(object sender, MouseEventArgs e)
        {
            if (!CanControl) return;
            // 너무 자주 보내지 않도록 (약 30회/초)
            if ((DateTime.UtcNow - _lastMove).TotalMilliseconds < 33) return;
            _lastMove = DateTime.UtcNow;
            SendMouse(e, "move");
        }

        private void OnMouseDown(object sender, MouseButtonEventArgs e)
        {
            _image.Focus();
            if (!CanControl) return;
            _image.CaptureMouse();
            SendMouse(e, "down", ButtonName(e.ChangedButton));
            e.Handled = true;
        }

        private void OnMouseUp(object sender, MouseButtonEventArgs e)
        {
            if (!CanControl) return;
            SendMouse(e, "up", ButtonName(e.ChangedButton));
            if (Mouse.LeftButton == MouseButtonState.Released && Mouse.RightButton == MouseButtonState.Released && Mouse.MiddleButton == MouseButtonState.Released)
                _image.ReleaseMouseCapture();
            e.Handled = true;
        }

        private void OnMouseWheel(object sender, MouseWheelEventArgs e)
        {
            if (!CanControl) return;
            SendMouse(e, "wheel", "", e.Delta);
            e.Handled = true;
        }

        private void OnKey(object sender, KeyEventArgs e)
        {
            if (!CanControl) return;
            var key = e.Key switch
            {
                Key.System => e.SystemKey,
                Key.ImeProcessed => e.ImeProcessedKey,
                Key.DeadCharProcessed => e.DeadCharProcessedKey,
                _ => e.Key
            };
            int vk = KeyInterop.VirtualKeyFromKey(key);
            if (vk <= 0) return;
            bool down = e.RoutedEvent == Keyboard.PreviewKeyDownEvent;
            if (down) _pressedKeys.Add(vk); else _pressedKeys.Remove(vk);
            _client.SendNoReply(new JsonObject { ["op"] = "input", ["kind"] = "key", ["vk"] = vk, ["down"] = down });
            e.Handled = true;
        }

        /// <summary>창을 벗어나면 눌린 키가 대상 PC에 남지 않도록 모두 뗌</summary>
        private void ReleaseKeys()
        {
            if (_pressedKeys.Count == 0) return;
            foreach (var vk in _pressedKeys.ToList())
                _client.SendNoReply(new JsonObject { ["op"] = "input", ["kind"] = "key", ["vk"] = vk, ["down"] = false });
            _pressedKeys.Clear();
        }
    }
}