using Microsoft.Maui.Controls;
using System.Net.Http;

namespace VideoDownloader.Mobile;

/// <summary>M1 연결 페이지: QR 스캔(ZXing) + 수동 입력 폴백.</summary>
public sealed class ConnectPage : ContentPage
{
    private readonly Entry _manual = new() { Placeholder = "PC 주소 (예: 192.168.0.223:52100)", Keyboard = Keyboard.Url };
    private readonly Entry _manualToken = new() { Placeholder = "토큰 (QR 못 쓸 때)", IsPassword = true };
    private readonly Label _status = new() { Text = "PC 앱에서 '기기 연결'을 누르고 QR 을 스캔하세요", HorizontalOptions = LayoutOptions.Center, Margin = new Thickness(0, 12) };

    public ConnectPage()
    {
        Title = "연결";

        // 시뮬레이터는 카메라 하드웨어가 없어 세션 시작이 첫 프레임을 막음(UIApplication hang) → 실기기에서만 스캐너
        View scannerArea = new Label
        {
            Text = "📷 시뮬레이터 — 수동 입력을 이용하세요",
            HorizontalOptions = LayoutOptions.Fill, VerticalOptions = LayoutOptions.Center,
            HorizontalTextAlignment = TextAlignment.Center, HeightRequest = 120,
            BackgroundColor = Colors.Black, TextColor = Colors.LightGray,
        };
        if (DeviceInfo.Current.DeviceType == DeviceType.Physical)
        {
            var scanner = new ZXing.Net.Maui.Controls.CameraBarcodeReaderView
            {
                HorizontalOptions = LayoutOptions.Fill,
                HeightRequest = 320,
                Options = new ZXing.Net.Maui.BarcodeReaderOptions
                {
                    Formats = ZXing.Net.Maui.BarcodeFormats.TwoDimensional,
                    AutoRotate = true,
                },
            };
            scanner.BarcodesDetected += (s, e) =>
            {
                var text = e.Results?.FirstOrDefault()?.Value;
                if (string.IsNullOrEmpty(text)) return;
                MainThread.BeginInvokeOnMainThread(() =>
                {
                    if (ApiClient.Instance.Configure(text))
                    {
                        _status.Text = "✅ 연결됨";
                        scanner.IsDetecting = false;
                    }
                });
            };
            scannerArea = scanner;
        }

        var connectBtn = new Button { Text = "수동 연결" };
        connectBtn.Clicked += (_, _) =>
        {
            if (ApiClient.Instance.Configure(_manual.Text, _manualToken.Text)) _status.Text = "✅ 연결됨";
            else _status.Text = "❌ 연결 실패 — 주소/토큰 확인";
        };
        var forgetBtn = new Button { Text = "연결 해제", BackgroundColor = Colors.Gray };
        forgetBtn.Clicked += (_, _) => { ApiClient.Instance.Forget(); _status.Text = "해제됨"; };

        Content = new ScrollView
        {
            Content = new VerticalStackLayout
            {
                Padding = 20, Spacing = 10,
                Children = { _status, scannerArea, _manual, _manualToken, connectBtn, forgetBtn }
            }
        };
    }
}

/// <summary>M1 큐 페이지: 목록(2초 폴링) + URL 추가 + 제어 + U5 완료 알림 + 외부망 안내.</summary>
public sealed class QueuePage : ContentPage
{
    private readonly Entry _url = new() { Placeholder = "YouTube·영상 URL 붙여넣기", Keyboard = Keyboard.Url };
    private readonly Label _summary = new();
    private readonly Label _trouble = new() { FontSize = 12, TextColor = Colors.OrangeRed, IsVisible = false };
    private readonly CollectionView _list = new();
    private readonly IDispatcherTimer _timer;
    private readonly QueueCompletionDetector _completions = new();
    private List<QueueItem> _last = new();

    public QueuePage()
    {
        Title = "다운로드 큐";
        var addBtn = new Button { Text = "PC에서 받기" };
        addBtn.Clicked += async (_, _) =>
        {
            if (string.IsNullOrWhiteSpace(_url.Text)) return;
            _summary.Text = "전송 중…";
            var ok = await ApiClient.Instance.AddAsync(_url.Text.Trim());
            _summary.Text = ok ? "✅ PC 대기열에 추가됨" : "❌ 실패 (연결 확인)";
            if (ok) _url.Text = "";
            await Refresh();
        };

        _list.ItemTemplate = new DataTemplate(() =>
        {
            var title = new Label { FontSize = 14, FontAttributes = FontAttributes.Bold, LineBreakMode = LineBreakMode.TailTruncation };
            title.SetBinding(Label.TextProperty, "Title");
            var status = new Label { FontSize = 12, TextColor = Colors.Gray };
            status.SetBinding(Label.TextProperty, new Binding("Percent", stringFormat: "{0:0}%"));
            var bar = new ProgressBar { HeightRequest = 6 };
            bar.SetBinding(ProgressBar.ProgressProperty, new Binding("Percent", converter: new PercentConverter()));
            var state = new Label { FontSize = 11, TextColor = Colors.Gray };
            state.SetBinding(Label.TextProperty, "Status");

            var pause = new Button { Text = "⏸" };
            var resume = new Button { Text = "▶" };
            var cancel = new Button { Text = "✕", BackgroundColor = Colors.Gray };
                        pause.Clicked += async (_, _) => { if (pause.BindingContext is QueueItem qi) { await ApiClient.Instance.ControlAsync(qi.Id, "pause"); await Refresh(); } };
            resume.Clicked += async (_, _) => { if (resume.BindingContext is QueueItem qi) { await ApiClient.Instance.ControlAsync(qi.Id, "resume"); await Refresh(); } };
            cancel.Clicked += async (_, _) => { if (cancel.BindingContext is QueueItem qi) { await ApiClient.Instance.ControlAsync(qi.Id, "cancel"); await Refresh(); } };

            return new Frame
            {
                Margin = new Thickness(0, 4), Padding = 12, CornerRadius = 10,
                Content = new VerticalStackLayout
                {
                    Spacing = 6,
                    Children = { title, bar, new HorizontalStackLayout { Children = { state, new Label { Text = "  " } } },
                        new HorizontalStackLayout { Spacing = 8, Children = { pause, resume, cancel } } }
                }
            };
        });

        _timer = Dispatcher.CreateTimer();
        _timer.Interval = TimeSpan.FromSeconds(2);
        _timer.Tick += async (_, _) => await Refresh();
        Appearing += (_, _) => _timer.Start();
        Disappearing += (_, _) => _timer.Stop();

        Content = new VerticalStackLayout
        {
            Padding = 16, Spacing = 10,
            Children = { _url, addBtn, _summary, _trouble, _list }
        };
    }

    private async Task Refresh()
    {
        var trouble = ConnectionTroubleshoot.Message(ApiClient.Instance.IsConfigured, ApiClient.Instance.LastError);
        _trouble.Text = trouble;
        _trouble.IsVisible = trouble.Length > 0;
        if (!ApiClient.Instance.IsConfigured) { _summary.Text = "⚠️ 먼저 연결하세요"; _last = new(); return; }
        var items = await ApiClient.Instance.GetQueueAsync();
        _list.ItemsSource = items;

        // U5: 이전 스냅샷 대비 새로 완료된 항목 → 로컬 알림
        var done = _completions.Detect(
            _last.Select(i => (i.Id, i.Status)).ToList(),
            items.Select(i => (i.Id, i.Status)).ToList());
        foreach (var id in done)
        {
            var item = items.First(i => i.Id == id);
            _ = NotifyCompletionAsync(item.Title);
            _summary.Text = $"🔔 완료: {item.Title}";
        }
        _last = items;

        var err = ApiClient.Instance.LastError;
        _summary.Text = err != null ? $"❌ {err}" : items.Count == 0 ? "대기 중인 항목이 없습니다" : $"{items.Count}건";
    }

    /// <summary>U5: 완료 로컬 알림(Android 13+ 는 최초 1회 권한 요청).</summary>
    private static async Task NotifyCompletionAsync(string title)
    {
        try
        {
            if (OperatingSystem.IsAndroidVersionAtLeast(33))
                await Plugin.LocalNotification.LocalNotificationCenter.Current.RequestNotificationPermission();
            Plugin.LocalNotification.LocalNotificationCenter.Current.Show(new Plugin.LocalNotification.NotificationRequest
            {
                Title = "다운로드 완료",
                Description = title,
            });
        }
        catch { }
    }

    private sealed class PercentConverter : IValueConverter
    {
        public object Convert(object? value, Type t, object? p, System.Globalization.CultureInfo c) => Math.Clamp(value is double d ? d / 100.0 : 0, 0, 1);
        public object ConvertBack(object? v, Type t, object? p, System.Globalization.CultureInfo c) => throw new NotSupportedException();
    }
}

/// <summary>M2 라이브러리 페이지: 목록 → 탭하여 스트리밍 재생.</summary>
public sealed class LibraryPage : ContentPage
{
    private readonly CollectionView _list = new();

    public LibraryPage()
    {
        Title = "라이브러리";
        _list.ItemsLayout = new GridItemsLayout(2, ItemsLayoutOrientation.Vertical); // M2 썸네일 그리드
        _list.ItemTemplate = new DataTemplate(() =>
        {
            var thumb = new Image { HeightRequest = 96, Aspect = Aspect.AspectFill, BackgroundColor = Colors.Black };
            thumb.SetBinding(Image.SourceProperty, new Binding(".", converter: new ThumbConverter()));
            var name = new Label { FontSize = 13, FontAttributes = FontAttributes.Bold, LineBreakMode = LineBreakMode.TailTruncation, LineHeight = 1.1 };
            name.SetBinding(Label.TextProperty, "FileName");
            var size = new Label { FontSize = 10, TextColor = Colors.Gray };
            size.SetBinding(Label.TextProperty, new Binding("SizeBytes", stringFormat: "{0:N0} bytes"));

            // U4 폰 저장: 카드 우측 버튼, 진행률을 버튼 텍스트로 표시
            var save = new Button { Text = "💾 저장", FontSize = 12, Padding = new Thickness(10, 4), VerticalOptions = LayoutOptions.Center };
            save.Clicked += async (_, _) => await SaveOffline(save, save.BindingContext as LibraryItem);

            var card = new Frame
            {
                Margin = new Thickness(6, 4), Padding = 8, CornerRadius = 10,
                Content = new VerticalStackLayout { Spacing = 4, Children = { thumb, name, size, save } }
            };
            // CollectionView.SelectionChanged 는 Android 에서 발화 불안정 → 템플릿 카드에 탭 제스처
            var tap = new TapGestureRecognizer();
            tap.Tapped += (_, _) => { if (card.BindingContext is LibraryItem item) OpenPlayer(item); };
            card.GestureRecognizers.Add(tap);
            return card;
        });
        _list.SelectionMode = SelectionMode.None;

        var refresh = new Button { Text = "새로고침" };
        refresh.Clicked += async (_, _) => await Reload();

        Content = new VerticalStackLayout { Padding = 16, Children = { refresh, _list } };
        Appearing += async (_, _) => await Reload();
    }

    /// <summary>U4: 항목을 폰 저장 폴더로 스트리밍 다운로드(진행률 % → 완료 ✓).</summary>
    private static async Task SaveOffline(Button button, LibraryItem? item)
    {
        if (item == null) return;
        if (AppOfflineStore.Default.Exists(item.Id)) { button.Text = "✓ 저장됨"; return; }
        button.Text = "0%";
        try
        {
            var dest = AppOfflineStore.Default.PathFor(item.Id);
            var progress = new Progress<double>(p => MainThread.BeginInvokeOnMainThread(
                () => button.Text = p >= 1 ? "✓ 저장됨" : $"{(int)(p * 100)}%"));
            await ApiClient.Instance.DownloadFileAsync(item, dest, progress, CancellationToken.None);
            AppOfflineStore.Default.Record(item.Id, item.FileName);
            button.Text = "✓ 저장됨";
        }
        catch (Exception e)
        {
            MainThread.BeginInvokeOnMainThread(() => button.Text = $"❌ {e.Message[..Math.Min(20, e.Message.Length)]}");
        }
    }

    private async void OpenPlayer(LibraryItem item)
    {
        // 탭 자식엔 NavigationPage 가 없어 PushAsync 불가 → 루트에서 모달 push (닫기는 상단바 뒤로)
        await Application.Current!.MainPage!.Navigation.PushModalAsync(new NavigationPage(new PlayerPage(item)));
    }

    private async Task Reload()
    {
        if (!ApiClient.Instance.IsConfigured) { _list.ItemsSource = new[] { "먼저 연결하세요" }; return; }
        _list.ItemsSource = await ApiClient.Instance.GetLibraryAsync();
    }
}

/// <summary>M2-U4 저장 탭: 폰에 저장된 항목 목록 — 오프라인 재생/삭제.</summary>
public sealed class DownloadsPage : ContentPage
{
    private readonly CollectionView _list = new();
    private readonly Label _empty = new()
    {
        Text = "저장된 항목이 없습니다 — 라이브러리에서 💾 저장",
        TextColor = Colors.Gray, HorizontalOptions = LayoutOptions.Center, Margin = new Thickness(0, 24),
    };

    public DownloadsPage()
    {
        Title = "저장";
        _list.ItemTemplate = new DataTemplate(() =>
        {
            var name = new Label { FontSize = 14, FontAttributes = FontAttributes.Bold, LineBreakMode = LineBreakMode.TailTruncation };
            name.SetBinding(Label.TextProperty, "FileName");
            var size = new Label { FontSize = 11, TextColor = Colors.Gray };
            size.SetBinding(Label.TextProperty, new Binding("SizeBytes", stringFormat: "{0:N0} bytes — 오프라인"));

            var del = new Button { Text = "🗑", FontSize = 12, Padding = new Thickness(10, 4), VerticalOptions = LayoutOptions.Center };
            del.Clicked += (_, _) =>
            {
                if ((del.BindingContext as OfflineItem) is { } it) { AppOfflineStore.Default.Delete(it.Id); Reload(); }
            };

            var card = new Frame
            {
                Margin = new Thickness(0, 4), Padding = 12, CornerRadius = 10,
                Content = new HorizontalStackLayout { Spacing = 8, Children = { new VerticalStackLayout { Children = { name, size } }, del } }
            };
            var tap = new TapGestureRecognizer();
            tap.Tapped += (_, _) =>
            {
                if ((card.BindingContext as OfflineItem) is { } it)
                    _ = Application.Current!.MainPage!.Navigation.PushModalAsync(
                        new NavigationPage(new PlayerPage(new LibraryItem(it.Id, it.FileName, it.SizeBytes, DateTime.MinValue), AppOfflineStore.Default.PathFor(it.Id))));
            };
            card.GestureRecognizers.Add(tap);
            return card;
        });
        _list.SelectionMode = SelectionMode.None;

        var refresh = new Button { Text = "새로고침" };
        refresh.Clicked += (_, _) => Reload();

        Content = new VerticalStackLayout { Padding = 16, Children = { refresh, _empty, _list } };
        _empty.IsVisible = false;
        Appearing += (_, _) => Reload();
    }

    private void Reload()
    {
        var items = AppOfflineStore.Default.List();
        _list.ItemsSource = items.Count > 0 ? items : null;
        _empty.IsVisible = items.Count == 0;
    }
}

/// <summary>M2 재생 페이지: Range 스트리밍 재생(MediaElement) + 이어보기 위치 동기화(U3). localPath 있으면 오프라인 재생(U4).</summary>
public sealed class PlayerPage : ContentPage
{
    private readonly CommunityToolkit.Maui.Views.MediaElement _media = new()
    {
        Aspect = Aspect.AspectFit,
        ShouldAutoPlay = true,
        ShouldShowPlaybackControls = true,
    };
    private readonly string? _itemId;      // 스트리밍 재생 시 위치 동기화 대상
    private bool _sync;                     // 위치 저장 활성(오프라인 재생은 서버 없이도 동작)

    public PlayerPage(LibraryItem item, string? localPath = null)
    {
        Title = item.FileName;
        if (localPath != null)
        {
            _media.Source = CommunityToolkit.Maui.Views.MediaSource.FromFile(localPath);
        }
        else
        {
            _itemId = item.Id;
            _media.Source = CommunityToolkit.Maui.Views.MediaSource.FromUri(ApiClient.Instance.StreamUrl(item));
            // 열림 시 저장된 위치로 시크 → 5초 주기 동기화(U3)
            _media.MediaOpened += async (_, _) =>
            {
                var saved = await ApiClient.Instance.GetPositionAsync(item.Id);
                if (saved > 1) await _media.SeekTo(TimeSpan.FromSeconds(saved));
                _sync = true;
            };
            Device.StartTimer(TimeSpan.FromSeconds(5), () =>
            {
                if (!_sync || _media.Position <= TimeSpan.Zero) return true;
                _ = ApiClient.Instance.PostPositionAsync(item.Id, _media.Position.TotalSeconds);
                return true; // 페이지가 닫혀도 무해(타이머는 프로세스 수명)
            });
        }
        Content = _media;
        // M2: 재생 중 미디어 알림(ongoing 노티) — 재생은 앱 내(포그라운드) 한정
        StartPlaybackNotification(item.FileName);
    }

    protected override void OnDisappearing()
    {
        if (_sync && _itemId != null && _media.Position > TimeSpan.Zero)
            _ = ApiClient.Instance.PostPositionAsync(_itemId, _media.Position.TotalSeconds);
        StopPlaybackNotification();
        _media.Stop();
        _media.Handler?.DisconnectHandler(); // 재생 리소스 해제
        base.OnDisappearing();
    }

    private const int PlaybackNotificationId = 4711;

    /// <summary>M2: 재생 중 미디어 알림 — ongoing 노티(닫으면 자동 소멸).</summary>
    private static void StartPlaybackNotification(string title)
    {
        try
        {
            Plugin.LocalNotification.LocalNotificationCenter.Current.Show(new Plugin.LocalNotification.NotificationRequest
            {
                NotificationId = PlaybackNotificationId,
                Title = "재생 중",
                Description = title,
                Android =
                {
                    ChannelId = "vd_playback",
                    Ongoing = true,
                    AutoCancel = false,
                },
            });
        }
        catch { }
    }

    private static void StopPlaybackNotification()
    {
        try { Plugin.LocalNotification.LocalNotificationCenter.Current.Cancel(PlaybackNotificationId); } catch { }
    }
}

/// <summary>M2: LibraryItem → 썸네일 URL 변환(바인딩 컨버터).</summary>
public sealed class ThumbConverter : IValueConverter
{
    public object? Convert(object? value, Type t, object? p, System.Globalization.CultureInfo c)
        => value is LibraryItem it && ApiClient.Instance.IsConfigured
            ? Microsoft.Maui.Controls.ImageSource.FromUri(new Uri(ApiClient.Instance.ThumbUrl(it)))
            : null;
    public object ConvertBack(object? v, Type t, object? p, System.Globalization.CultureInfo c) => throw new NotSupportedException();
}