// Copyright (c) ppy Pty Ltd <contact@ppy.sh>. Licensed under the MIT Licence.
// See the LICENCE file in the repository root for full licence text.

using System;
using System.Collections.Generic;
using System.Linq;
using osu.Framework.Allocation;
using osu.Framework.Bindables;
using osu.Framework.Graphics;
using osu.Framework.Graphics.Containers;
using osu.Framework.Graphics.Sprites;
using osu.Framework.Graphics.Textures;
using osu.Game.Configuration;
using osu.Game.Graphics.Sprites;
using osu.Game.Overlays.Settings;
using osuTK;

namespace osu.Game.Skinning
{
    /// <summary>
    /// A skinnable element which uses a single texture backing.
    /// </summary>
    public class SkinnableSprite : SkinnableDrawable, ISkinnableDrawable
    {
        protected override bool ApplySizeRestrictionsToDefault => true;

        [Resolved]
        private TextureStore textures { get; set; }

        [SettingSource("Sprite name", "The filename of the sprite", SettingControlType = typeof(SpriteSelectorControl))]
        public Bindable<string> SpriteName { get; } = new Bindable<string>(string.Empty);

        [Resolved]
        private ISkinSource source { get; set; }

        public SkinnableSprite(string textureName, ConfineMode confineMode = ConfineMode.NoScaling)
            : base(new SpriteComponent(textureName), confineMode)
        {
            SpriteName.Value = textureName;
        }

        public SkinnableSprite()
            : base(new SpriteComponent(string.Empty), ConfineMode.NoScaling)
        {
            RelativeSizeAxes = Axes.None;
            AutoSizeAxes = Axes.Both;

            SpriteName.BindValueChanged(name =>
            {
                ((SpriteComponent)Component).LookupName = name.NewValue ?? string.Empty;
                if (IsLoaded)
                    SkinChanged(CurrentSkin);
            });
        }

        protected override Drawable CreateDefault(ISkinComponent component)
        {
            var texture = textures.Get(component.LookupName);

            if (texture == null)
                return new SpriteNotFound(component.LookupName);

            return new Sprite { Texture = texture };
        }

        public bool UsesFixedAnchor { get; set; }

        internal class SpriteComponent : ISkinComponent
        {
            public string LookupName { get; set; }

            public SpriteComponent(string textureName)
            {
                LookupName = textureName;
            }
        }

        public class SpriteSelectorControl : SettingsDropdown<string>
        {
            protected override void LoadComplete()
            {
                base.LoadComplete();

                // Round-about way of getting the user's skin to find available resources.
                // In the future we'll probably want to allow access to resources from the fallbacks, or potentially other skins
                // but that requires further thought.
                var highestPrioritySkin = getHighestPriorityUserSkin(((SkinnableSprite)SettingSourceObject).source.AllSources) as Skin;

                string[] availableFiles = highestPrioritySkin?.SkinInfo.PerformRead(s => s.Files
                                                                                          .Where(f => f.Filename.EndsWith(".png", StringComparison.Ordinal)
                                                                                                      || f.Filename.EndsWith(".jpg", StringComparison.Ordinal))
                                                                                          .Select(f => f.Filename).Distinct()).ToArray();

                if (availableFiles?.Length > 0)
                    Items = availableFiles;

                static ISkin getHighestPriorityUserSkin(IEnumerable<ISkin> skins)
                {
                    foreach (var skin in skins)
                    {
                        if (skin is LegacySkinTransformer transformer && isUserSkin(transformer.Skin))
                            return transformer.Skin;

                        if (isUserSkin(skin))
                            return skin;
                    }

                    return null;
                }

                // Temporarily used to exclude undesirable ISkin implementations
                static bool isUserSkin(ISkin skin)
                    => skin.GetType() == typeof(DefaultSkin)
                       || skin.GetType() == typeof(DefaultLegacySkin)
                       || skin.GetType() == typeof(LegacySkin);
            }
        }

        public class SpriteNotFound : CompositeDrawable
        {
            public SpriteNotFound(string lookup)
            {
                AutoSizeAxes = Axes.Both;

                InternalChildren = new Drawable[]
                {
                    new SpriteIcon
                    {
                        Size = new Vector2(50),
                        Icon = FontAwesome.Solid.QuestionCircle
                    },
                    new OsuSpriteText
                    {
                        Position = new Vector2(25, 50),
                        Text = $"missing: {lookup}",
                        Origin = Anchor.TopCentre,
                    }
                };
            }
        }
    }
}