using System;
using System.Collections.Generic;
using System.Collections.ObjectModel;
using System.IO;

namespace Artemis.Core.LayerEffects
{
    /// <summary>
    ///     Allows you to register one or more <see cref="LayerEffect{T}" />s usable by profile layers.
    /// </summary>
    public abstract class LayerEffectProvider : PluginFeature
    {
        private readonly List<LayerEffectDescriptor> _layerEffectDescriptors;

        /// <summary>
        ///     Allows you to register one or more <see cref="LayerEffect{T}" />s usable by profile layers.
        /// </summary>
        protected LayerEffectProvider()
        {
            _layerEffectDescriptors = new List<LayerEffectDescriptor>();
            LayerEffectDescriptors = new(_layerEffectDescriptors);
            Disabled += OnDisabled;
        }

        /// <summary>
        ///     A read-only collection of all layer effects added with <see cref="RegisterLayerEffectDescriptor{T}" />
        /// </summary>
        public ReadOnlyCollection<LayerEffectDescriptor> LayerEffectDescriptors { get; }

        /// <summary>
        ///     Adds a layer effect descriptor for a given layer effect, so that it appears in the UI.
        ///     <para>Note: You do not need to manually remove these on disable</para>
        /// </summary>
        /// <typeparam name="T">The type of the layer effect you wish to register</typeparam>
        /// <param name="displayName">The name to display in the UI</param>
        /// <param name="description">The description to display in the UI</param>
        /// <param name="icon">
        ///     The Material icon to display in the UI, a full reference can be found <see href="https://materialdesignicons.com">here</see>.
        ///     <para>May also be a path to an SVG file relative to the directory of the plugin.</para>
        /// </param>
        protected void RegisterLayerEffectDescriptor<T>(string displayName, string description, string icon) where T : BaseLayerEffect
        {
            if (!IsEnabled)
                throw new ArtemisPluginFeatureException(this, "Can only add a layer effect descriptor when the plugin is enabled");

            if (icon.ToLower().EndsWith(".svg"))
                icon = Plugin.ResolveRelativePath(icon);
            LayerEffectDescriptor descriptor = new(displayName, description, icon, typeof(T), this);
            _layerEffectDescriptors.Add(descriptor);
            LayerEffectStore.Add(descriptor);
        }

        private void OnDisabled(object? sender, EventArgs e)
        {
            // The store will clean up the registrations by itself, the plugin just needs to clear its own list
            _layerEffectDescriptors.Clear();
        }
    }
}