using System.Globalization;
using Avalonia;
using Avalonia.Controls;
using Avalonia.Layout;
using Avalonia.Markup.Xaml;
using IBKRTrader.App.Shell;
using IBKRTrader.App.ViewModels;
using IBKRTrader.Core.Modularity;
using IBKRTrader.Core.Settings;
using IBKRTrader.Core.Time;

namespace IBKRTrader.App.Views;

/// <summary>
/// Core-Ansicht: Einstellungen. Ersetzt das <c>PropertyGrid</c> der WinForms-Fassung durch eine
/// aus den Attributen erzeugte Maske (siehe <see cref="SettingsModelBuilder"/>).
///
/// <para>Geändert wird direkt auf dem <c>AppSettings</c>-Objekt; „Speichern" schreibt es nach
/// <c>settings.json</c>, „Verwerfen" lädt die Datei neu. Zahlen werden ausdrücklich gegen
/// <see cref="CultureInfo.InvariantCulture"/> gelesen – die Datei ist maschinenlesbar und darf
/// nicht von der Kultur des Rechners abhängen.</para>
/// </summary>
public partial class SettingsWindow : Window
{
    private readonly SettingsService _settings;

    public SettingsWindow(IModuleUiHost uiHost, SettingsService settings)
    {
        _settings = settings;

        InitializeComponent();
        WindowMenu.Wire(this.FindControl<Menu>("WindowMenuBar")!, uiHost, "core.settings");

        this.FindControl<Button>("SaveButton")!.Click += (_, _) =>
        {
            try
            {
                _settings.Save();
                SetStatus("Gespeichert. Zeitzonen-Änderungen greifen erst nach einem Neustart.");
            }
            catch (Exception ex) { SetStatus($"Speichern fehlgeschlagen: {ex.Message}"); }
        };

        this.FindControl<Button>("ReloadButton")!.Click += (_, _) =>
        {
            _settings.Load();
            BuildForm();
            SetStatus("Gespeicherte Werte neu geladen.");
        };

        BuildForm();
        SetStatus("Bereit.");
    }

    private void InitializeComponent() => AvaloniaXamlLoader.Load(this);

    private void BuildForm()
    {
        var panel = this.FindControl<StackPanel>("SectionPanel")!;
        panel.Children.Clear();

        foreach (var section in SettingsModelBuilder.Build(_settings.Settings))
        {
            var grid = new Grid
            {
                ColumnDefinitions = new ColumnDefinitions("240,*"),
                Margin            = new Thickness(4, 4, 4, 12)
            };

            for (var i = 0; i < section.Fields.Count; i++)
            {
                var field = section.Fields[i];
                grid.RowDefinitions.Add(new RowDefinition(GridLength.Auto));

                var label = new TextBlock
                {
                    Text              = field.DisplayName,
                    Margin            = new Thickness(0, 6, 10, 6),
                    VerticalAlignment = VerticalAlignment.Center
                };
                if (!string.IsNullOrWhiteSpace(field.Description))
                    ToolTip.SetTip(label, field.Description);

                var editor = CreateEditor(field);
                editor.Margin = new Thickness(0, 4, 0, 4);
                if (!string.IsNullOrWhiteSpace(field.Description))
                    ToolTip.SetTip(editor, field.Description);

                Grid.SetRow(label, i);  Grid.SetColumn(label, 0);
                Grid.SetRow(editor, i); Grid.SetColumn(editor, 1);
                grid.Children.Add(label);
                grid.Children.Add(editor);
            }

            panel.Children.Add(new Expander
            {
                Header      = section.Title,
                IsExpanded  = true,
                Content     = grid,
                Margin      = new Thickness(0, 0, 0, 6),
                HorizontalContentAlignment = HorizontalAlignment.Stretch
            });
        }
    }

    /// <summary>Wählt das Eingabeelement passend zum Typ des Feldes.</summary>
    private static Control CreateEditor(SettingsField field)
    {
        if (field.ValueType == typeof(bool))
        {
            var check = new CheckBox { IsChecked = (bool?)field.Get() };
            check.IsCheckedChanged += (_, _) => field.Set(check.IsChecked == true);
            return check;
        }

        if (field.ValueType.IsEnum)
        {
            var combo = new ComboBox
            {
                ItemsSource   = Enum.GetValues(field.ValueType),
                SelectedItem  = field.Get(),
                HorizontalAlignment = HorizontalAlignment.Left,
                MinWidth      = 200
            };
            combo.SelectionChanged += (_, _) => { if (combo.SelectedItem is not null) field.Set(combo.SelectedItem); };
            return combo;
        }

        if (field.ValueType == typeof(int) || field.ValueType == typeof(long) ||
            field.ValueType == typeof(double) || field.ValueType == typeof(decimal))
        {
            var numeric = new NumericUpDown
            {
                Value               = ToDecimal(field.Get()),
                Increment           = field.ValueType == typeof(double) || field.ValueType == typeof(decimal) ? 0.5m : 1m,
                FormatString        = field.ValueType == typeof(double) || field.ValueType == typeof(decimal) ? "0.###" : "0",
                HorizontalAlignment = HorizontalAlignment.Left,
                MinWidth            = 200
            };
            numeric.ValueChanged += (_, _) =>
            {
                if (numeric.Value is not { } v) return;
                field.Set(Convert.ChangeType(v, field.ValueType, CultureInfo.InvariantCulture));
            };
            return numeric;
        }

        var box = new TextBox { Text = field.Get()?.ToString() ?? "" };
        // Kennwortfelder (DB-Passwort, Flex-Token) nicht im Klartext anzeigen.
        if (field.IsPassword) box.PasswordChar = '•';
        box.TextChanged += (_, _) => field.Set(box.Text ?? "");
        return box;
    }

    private static decimal ToDecimal(object? value) =>
        value is null ? 0m : Convert.ToDecimal(value, CultureInfo.InvariantCulture);

    private void SetStatus(string text) =>
        this.FindControl<TextBlock>("StatusText")!.Text = $"{text}  |  {AppTimeZone.Now:HH:mm:ss}";
}