@using Sandbox;
@using Sandbox.UI;
@inherits PanelComponent
@namespace Sandbox

<root>
    <HudCanvas @ref="Canvas" Layer=@this />
</root>

@code
{
    /// <summary>
    /// The HUD colour when nothing has set one, also what the HUD panels fall back to without a layer
    /// </summary>
    public static readonly Color DefaultTint = new Color( 0.97f, 0.77f, 0.302f );

    /// <summary>
    /// Colour multiplied into every HUD element
    /// </summary>
    [Property] public Color Tint { get; set; } = DefaultTint;

    /// <summary>
    /// HDR color exponent for highlighted HUD elements like digits or selected hotbar slots
    /// </summary>
    [Property, Group( "Effects" ), Range( 0, 6 )] public float DigitExponent { get; set; } = 0.75f;

    /// <summary>
    /// HDR color exponent for regular HUD text
    /// </summary>
    [Property, Group( "Effects" ), Range( 0, 6 )] public float TextExponent { get; set; } = 0.16f;

    /// <summary>
    /// HDR multipliers from <see cref="DigitExponent"/> and <see cref="TextExponent"/>
    /// </summary>
    public float DigitGain => MathF.Pow( 2, DigitExponent );
    public float TextGain => MathF.Pow( 2, TextExponent );

    [Property, Group( "Effects" ), Range( 0, 1 )] public float GlowStrength { get; set; } = 0.22f;

    [Property, Group( "Effects" ), Range( 0, 48 )] public float GlowRadius { get; set; } = 20;

    [Property, Group( "Effects" ), Range( 0, 1 )] public float ScanlineIntensity { get; set; } = 0.46f;

    /// <summary>
    /// Scanline frequency in pixels
    /// </summary>
    [Property, Group( "Effects" ), Range( 2, 12 )] public float ScanlinePeriod { get; set; } = 3.7f;

    [Property, Group( "Effects" ), Range( 0, 1 )] public float ScanlineThickness { get; set; } = 0.55f;

    [Property, Group( "Effects" ), Range( 0, 1 )] public float ScanlineSoftness { get; set; } = 0.04f;

    public HudCanvas Canvas { get; private set; }

    /// <summary>
    /// The scene's HUD layer. With <paramref name="create"/> it is added next to the screen panel <paramref name="from"/> lives under if there isn't one yet
    /// </summary>
    public static HudLayer Find( Component from, bool create = true )
    {
        var layer = from.Scene?.Get<HudLayer>();
        if ( layer.IsValid() || !create ) return layer;

        var screen = from.Components.GetInAncestorsOrSelf<ScreenPanel>();
        return screen.IsValid() ? screen.GameObject.Components.GetOrCreate<HudLayer>() : null;
    }

    /// <summary>
    /// A section of the scene's HUD layer. Hand back the previous result to skip the scene lookup while its canvas is still alive
    /// </summary>
    public static T FindSection<T>( Component from, T cached ) where T : HudSection, new()
        => cached?.Canvas is { } canvas && canvas.IsValid() ? cached : Find( from )?.Canvas?.Section<T>();

    protected override int BuildHash() => 0;
}