#nullable enable
using System.Globalization;
using System.Text.Json.Serialization;

namespace Terminal.Gui;

/// <summary>
///     Holds the <see cref="ColorScheme"/>s that define the <see cref="Attribute"/>s that are used by views to render
///     themselves.
/// </summary>
public static class Colors
{
    static Colors ()
    {
        Reset ();
    }

    /// <summary>Gets a dictionary of defined <see cref="ColorScheme"/> objects.</summary>
    /// <remarks>
    ///     <para>
    ///         The <see cref="ColorSchemes"/> dictionary includes the following keys, by default:
    ///         <list type="table">
    ///             <listheader>
    ///                 <term>Built-in Color Scheme</term> <description>Description</description>
    ///             </listheader>
    ///             <item>
    ///                 <term>Base</term> <description>The base color scheme used for most Views.</description>
    ///             </item>
    ///             <item>
    ///                 <term>TopLevel</term>
    ///                 <description>The application Toplevel color scheme; used for the <see cref="Toplevel"/> View.</description>
    ///             </item>
    ///             <item>
    ///                 <term>Dialog</term>
    ///                 <description>
    ///                     The dialog color scheme; used for <see cref="Dialog"/>, <see cref="MessageBox"/>, and
    ///                     other views dialog-like views.
    ///                 </description>
    ///             </item>
    ///             <item>
    ///                 <term>Menu</term>
    ///                 <description>
    ///                     The menu color scheme; used for <see cref="MenuBar"/>, <see cref="ContextMenu"/>, and
    ///                     <see cref="StatusBar"/>.
    ///                 </description>
    ///             </item>
    ///             <item>
    ///                 <term>Error</term>
    ///                 <description>
    ///                     The color scheme for showing errors, such as in
    ///                     <see cref="MessageBox.ErrorQuery(string, string, string[])"/>.
    ///                 </description>
    ///             </item>
    ///         </list>
    ///     </para>
    ///     <para>Changing the values of an entry in this dictionary will affect all views that use the scheme.</para>
    ///     <para>
    ///         <see cref="ConfigurationManager"/> can be used to override the default values for these schemes and add
    ///         additional schemes. See <see cref="ConfigurationManager.Themes"/>.
    ///     </para>
    /// </remarks>
    [SerializableConfigurationProperty (Scope = typeof (ThemeScope), OmitClassName = true)]
    [JsonConverter (typeof (DictionaryJsonConverter<ColorScheme>))]
    public static Dictionary<string, ColorScheme>
        ColorSchemes { get; private set; } // Serialization requires this to have a setter (private set;)

    /// <summary>Resets the <see cref="ColorSchemes"/> dictionary to the default values.</summary>
    public static Dictionary<string, ColorScheme> Reset ()
    {
        ColorSchemes ??= new Dictionary<string, ColorScheme> (
                                                              5,
                                                              CultureInfo.InvariantCulture.CompareInfo
                                                                         .GetStringComparer (
                                                                                             CompareOptions.IgnoreCase
                                                                                            )
                                                             );
        ColorSchemes.Clear ();
        ColorSchemes.Add ("TopLevel", new ColorScheme ());
        ColorSchemes.Add ("Base", new ColorScheme ());
        ColorSchemes.Add ("Dialog", new ColorScheme ());
        ColorSchemes.Add ("Menu", new ColorScheme ());
        ColorSchemes.Add ("Error", new ColorScheme ());

        return ColorSchemes;
    }

    private class SchemeNameComparerIgnoreCase : IEqualityComparer<string>
    {
        public bool Equals (string x, string y)
        {
            if (x is { } && y is { })
            {
                return string.Equals (x, y, StringComparison.InvariantCultureIgnoreCase);
            }

            return false;
        }

        public int GetHashCode (string obj) { return obj.ToLowerInvariant ().GetHashCode (); }
    }
}