using MusicBridge.Agent.Network;

namespace MusicBridge.Agent;

internal sealed class PairingWindowHost(PairingService pairing, string fingerprint, Func<Uri[]> endpoints, bool visible = true) : IDisposable
{
    private readonly object gate = new();
    private Thread? thread;
    private Form? form;
    private bool disposed;
    public string? Error { get; private set; }

    public void Open()
    {
        lock (gate)
        {
            if (disposed) return;
            if (thread?.IsAlive == true)
            {
                if (form is { IsHandleCreated: true } active)
                {
                    try { active.BeginInvoke(() => { active.WindowState = FormWindowState.Normal; active.Activate(); }); }
                    catch (InvalidOperationException) { }
                }
                return;
            }
            thread = new Thread(Run) { IsBackground = true, Name = "MusicBridge QR" };
            thread.SetApartmentState(ApartmentState.STA);
            thread.Start();
        }
    }

    private void Run()
    {
        try
        {
            using var window = new Form
            {
                Text = "MusicBridge — подключение iPhone", ClientSize = new Size(620, 740),
                MinimumSize = new Size(440, 560), StartPosition = FormStartPosition.CenterScreen,
                AutoScaleMode = AutoScaleMode.Dpi, ShowInTaskbar = visible, Opacity = visible ? 1 : 0
            };
            using var layout = new TableLayoutPanel { Dock = DockStyle.Fill, ColumnCount = 1, RowCount = 4, Padding = new Padding(16) };
            layout.RowStyles.Add(new RowStyle(SizeType.Absolute, 58));
            layout.RowStyles.Add(new RowStyle(SizeType.Absolute, 40));
            layout.RowStyles.Add(new RowStyle(SizeType.Percent, 100));
            layout.RowStyles.Add(new RowStyle(SizeType.Absolute, 72));
            var title = new Label { Text = "Подключение к компьютеру\nВыбери адрес домашней сети", Dock = DockStyle.Fill };
            var selector = new ComboBox { Dock = DockStyle.Fill, DropDownStyle = ComboBoxStyle.DropDownList };
            var picture = new PictureBox { Dock = DockStyle.Fill, SizeMode = PictureBoxSizeMode.Zoom, BackColor = Color.White };
            var status = new Label { Dock = DockStyle.Fill, TextAlign = ContentAlignment.MiddleCenter };
            layout.Controls.Add(title); layout.Controls.Add(selector); layout.Controls.Add(picture); layout.Controls.Add(status);
            window.Controls.Add(layout);
            string? renderedPayload = null;
            void ClearImage()
            {
                var old = picture.Image;
                picture.Image = null;
                old?.Dispose();
                renderedPayload = null;
            }
            void RefreshQr()
            {
                try
                {
                    var choices = endpoints().Select(u => u.GetLeftPart(UriPartial.Authority)).ToArray();
                    if (!selector.Items.Cast<string>().SequenceEqual(choices))
                    {
                        var selected = selector.SelectedItem as string;
                        selector.Items.Clear();
                        selector.Items.AddRange(choices);
                        if (choices.Length > 0) selector.SelectedIndex = Math.Max(0, Array.IndexOf(choices, selected));
                    }
                    var now = DateTimeOffset.UtcNow;
                    var current = pairing.Current;
                    if (current is null || selector.SelectedItem is not string address)
                    {
                        ClearImage();
                        status.Text = current is null ? "Сопряжение закрыто. Нажми B в консоли для нового кода."
                            : "Нет адреса домашней сети. Запусти агент с --lan.";
                        return;
                    }
                    var invitation = ConnectionInvitation.Create(new Uri(address), fingerprint, current, now);
                    var payload = invitation.ToQrPayload();
                    if (renderedPayload != payload)
                    {
                        ClearImage();
                        using var stream = new MemoryStream(PairingQr.Render(invitation));
                        using var decoded = Image.FromStream(stream);
                        picture.Image = new Bitmap(decoded);
                        renderedPayload = payload;
                    }
                    status.Text = $"Код: {current.Code} • действует до {current.ExpiresAt.ToLocalTime():HH:mm:ss}\nСканирование предназначено для будущего приложения MusicBridge.";
                }
                catch (Exception ex) { ClearImage(); status.Text = $"QR недоступен: {ex.Message}"; }
            }
            using var timer = new System.Windows.Forms.Timer { Interval = 500 };
            timer.Tick += (_, _) => RefreshQr();
            window.Shown += (_, _) =>
            {
                lock (gate) { if (disposed) { window.Close(); return; } }
                RefreshQr(); timer.Start();
            };
            window.FormClosed += (_, _) => { timer.Stop(); ClearImage(); };
            lock (gate)
            {
                if (disposed) return;
                form = window;
            }
            Application.Run(window);
        }
        catch (Exception ex) { Error = ex.Message; }
        finally { lock (gate) form = null; }
    }

    public void Dispose()
    {
        Thread? running;
        lock (gate)
        {
            disposed = true;
            running = thread;
            if (form is { IsHandleCreated: true } active)
            {
                try { active.BeginInvoke(() => active.Close()); }
                catch (InvalidOperationException) { }
            }
        }
        running?.Join(TimeSpan.FromSeconds(2));
    }
}