using System.Drawing;
using System.Text.Json.Serialization;
using CommunityToolkit.Mvvm.ComponentModel;

namespace CursorLang.Core.Models;

/// <summary>
/// The application settings, as the settings window writes them to settings.json.
/// </summary>
/// <remarks>
/// The colours are <see cref="System.Drawing.Color"/> rather than
/// <c>System.Windows.Media.Color</c>. The former lives in System.Drawing.Primitives,
/// which is part of the base runtime and brings neither WPF nor GDI+ along; the latter
/// is WindowsBase, and this type is read by the agent, which must stay clear of it.
/// The settings window turns them into brushes in its converters.
///
/// Both processes hold an instance of this, but only the settings window writes: the
/// agent re-reads the file and pours the fresh values into the instance it already has,
/// so everything subscribed to it stays subscribed. See <see cref="CopyFrom"/>.
/// </remarks>
public sealed partial class AppSettings : ObservableObject
{
    /// <summary>The interface language as a culture code: "ru", "en".</summary>
    [ObservableProperty]
    private string _language = "en";

    /// <summary>The look of the settings window.</summary>
    [ObservableProperty]
    private AppTheme _theme = AppTheme.System;

    /// <summary>Where the popup is shown: at the cursor, at the caret or at a fixed point.</summary>
    [ObservableProperty]
    private PopupPlacementMode _placementMode = PopupPlacementMode.AtCursor;

    // The side and the offset are stored per mode: the cursor and the caret call for
    // different settings, and switching the mode does not reset them

    /// <summary>The side of the cursor the popup is put on.</summary>
    [ObservableProperty]
    private AnchorSide _cursorSide = AnchorSide.BottomRight;

    /// <summary>The offset from the cursor in WPF units.</summary>
    [ObservableProperty]
    private double _cursorOffset = 16;

    /// <summary>The side of the caret the popup is put on.</summary>
    [ObservableProperty]
    private AnchorSide _caretSide = AnchorSide.BottomRight;

    /// <summary>The offset from the caret in WPF units.</summary>
    [ObservableProperty]
    private double _caretOffset = 16;

    /// <summary>
    /// The place on the monitor for the <see cref="PopupPlacementMode.FixedPoint"/> mode.
    /// </summary>
    [ObservableProperty]
    private ScreenPosition _screenPosition = ScreenPosition.BottomRight;

    /// <summary>The offset from the monitor edge in WPF units.</summary>
    [ObservableProperty]
    private double _screenMargin = 24;

    /// <summary>The size of the layout name in the popup, in WPF units.</summary>
    [ObservableProperty]
    private double _fontSize = 20;

    /// <summary>The popup opacity: 1.0 is fully opaque.</summary>
    [ObservableProperty]
    private double _opacity = 0.9;

    /// <summary>How long the popup stays on screen, in milliseconds.</summary>
    [ObservableProperty]
    private double _durationMilliseconds = 500;

    /// <summary>
    /// Intercept Caps Lock and switch the layout with it instead of changing the case.
    /// Off by default: the application must not change the behaviour of the system
    /// until it is asked to.
    /// </summary>
    [ObservableProperty]
    private bool _useCapsLockHotkey;

    /// <summary>
    /// After how long a Caps Lock hold cancels the switch, in milliseconds.
    /// </summary>
    [ObservableProperty]
    private double _capsLockHoldMilliseconds = 300;

    /// <summary>The fill of the popup. The opacity is set by <see cref="Opacity"/>.</summary>
    [ObservableProperty]
    private Color _backgroundColor = Color.FromArgb(0xFF, 0x20, 0x20, 0x20);

    /// <summary>The colour of the layout name in the popup.</summary>
    [ObservableProperty]
    private Color _foregroundColor = Color.FromArgb(0xFF, 0xFF, 0xFF, 0xFF);

    /// <summary><see cref="DurationMilliseconds"/> as a <see cref="TimeSpan"/>.</summary>
    [JsonIgnore]
    public TimeSpan Duration => TimeSpan.FromMilliseconds(DurationMilliseconds);

    /// <summary><see cref="CapsLockHoldMilliseconds"/> as a <see cref="TimeSpan"/>.</summary>
    [JsonIgnore]
    public TimeSpan CapsLockHoldDelay => TimeSpan.FromMilliseconds(CapsLockHoldMilliseconds);

    /// <summary>
    /// Takes the values of another instance over, raising a change notification for
    /// every property that has actually moved.
    /// </summary>
    /// <remarks>
    /// This is how the agent learns about an edit: the settings window is a separate
    /// process, so the fresh values arrive as a freshly parsed instance and are poured
    /// into the one everything is already bound to, rather than replacing it.
    /// </remarks>
    public void CopyFrom(AppSettings other)
    {
        Language = other.Language;
        Theme = other.Theme;
        PlacementMode = other.PlacementMode;
        CursorSide = other.CursorSide;
        CursorOffset = other.CursorOffset;
        CaretSide = other.CaretSide;
        CaretOffset = other.CaretOffset;
        ScreenPosition = other.ScreenPosition;
        ScreenMargin = other.ScreenMargin;
        FontSize = other.FontSize;
        Opacity = other.Opacity;
        DurationMilliseconds = other.DurationMilliseconds;
        UseCapsLockHotkey = other.UseCapsLockHotkey;
        CapsLockHoldMilliseconds = other.CapsLockHoldMilliseconds;
        BackgroundColor = other.BackgroundColor;
        ForegroundColor = other.ForegroundColor;
    }
}