// 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.

#nullable disable

using System;
using System.Collections.Generic;
using System.Linq;
using JetBrains.Annotations;
using osu.Framework.Allocation;
using osu.Framework.Bindables;
using osu.Framework.Graphics;
using osu.Framework.Graphics.Sprites;
using osu.Framework.Localisation;
using osu.Framework.Logging;
using osu.Framework.Platform;
using osu.Game.Database;
using osu.Game.Graphics.UserInterface;
using osu.Game.Localisation;
using osu.Game.Screens.Select;
using osu.Game.Skinning;
using osu.Game.Skinning.Editor;
using Realms;

namespace osu.Game.Overlays.Settings.Sections
{
    public class SkinSection : SettingsSection
    {
        private SkinSettingsDropdown skinDropdown;

        public override LocalisableString Header => SkinSettingsStrings.SkinSectionHeader;

        public override Drawable CreateIcon() => new SpriteIcon
        {
            Icon = FontAwesome.Solid.PaintBrush
        };

        private static readonly Live<SkinInfo> random_skin_info = new SkinInfo
        {
            ID = SkinInfo.RANDOM_SKIN,
            Name = "<Random Skin>",
        }.ToLiveUnmanaged();

        private readonly List<Live<SkinInfo>> dropdownItems = new List<Live<SkinInfo>>();

        [Resolved]
        private SkinManager skins { get; set; }

        [Resolved]
        private RealmAccess realm { get; set; }

        private IDisposable realmSubscription;

        [BackgroundDependencyLoader(permitNulls: true)]
        private void load([CanBeNull] SkinEditorOverlay skinEditor)
        {
            Children = new Drawable[]
            {
                skinDropdown = new SkinSettingsDropdown
                {
                    LabelText = SkinSettingsStrings.CurrentSkin,
                    Current = skins.CurrentSkinInfo,
                    Keywords = new[] { @"skins" }
                },
                new SettingsButton
                {
                    Text = SkinSettingsStrings.SkinLayoutEditor,
                    Action = () => skinEditor?.ToggleVisibility(),
                },
                new ExportSkinButton(),
                new DeleteSkinButton(),
            };
        }

        protected override void LoadComplete()
        {
            base.LoadComplete();

            realmSubscription = realm.RegisterForNotifications(_ => realm.Realm.All<SkinInfo>()
                                                                         .Where(s => !s.DeletePending)
                                                                         .OrderByDescending(s => s.Protected) // protected skins should be at the top.
                                                                         .ThenBy(s => s.Name, StringComparer.OrdinalIgnoreCase), skinsChanged);

            skinDropdown.Current.BindValueChanged(skin =>
            {
                if (skin.NewValue == random_skin_info)
                {
                    // before selecting random, set the skin back to the previous selection.
                    // this is done because at this point it will be random_skin_info, and would
                    // cause SelectRandomSkin to be unable to skip the previous selection.
                    skins.CurrentSkinInfo.Value = skin.OldValue;
                    skins.SelectRandomSkin();
                }
            });
        }

        private void skinsChanged(IRealmCollection<SkinInfo> sender, ChangeSet changes, Exception error)
        {
            // This can only mean that realm is recycling, else we would see the protected skins.
            // Because we are using `Live<>` in this class, we don't need to worry about this scenario too much.
            if (!sender.Any())
                return;

            int protectedCount = sender.Count(s => s.Protected);

            // For simplicity repopulate the full list.
            // In the future we should change this to properly handle ChangeSet events.
            dropdownItems.Clear();
            foreach (var skin in sender)
                dropdownItems.Add(skin.ToLive(realm));
            dropdownItems.Insert(protectedCount, random_skin_info);

            Schedule(() => skinDropdown.Items = dropdownItems);
        }

        protected override void Dispose(bool isDisposing)
        {
            base.Dispose(isDisposing);

            realmSubscription?.Dispose();
        }

        private class SkinSettingsDropdown : SettingsDropdown<Live<SkinInfo>>
        {
            protected override OsuDropdown<Live<SkinInfo>> CreateDropdown() => new SkinDropdownControl();

            private class SkinDropdownControl : DropdownControl
            {
                protected override LocalisableString GenerateItemText(Live<SkinInfo> item) => item.ToString();
            }
        }

        public class ExportSkinButton : SettingsButton
        {
            [Resolved]
            private SkinManager skins { get; set; }

            [Resolved]
            private Storage storage { get; set; }

            private Bindable<Skin> currentSkin;

            [BackgroundDependencyLoader]
            private void load()
            {
                Text = SkinSettingsStrings.ExportSkinButton;
                Action = export;
            }

            protected override void LoadComplete()
            {
                base.LoadComplete();

                currentSkin = skins.CurrentSkin.GetBoundCopy();
                currentSkin.BindValueChanged(skin => Enabled.Value = skin.NewValue.SkinInfo.PerformRead(s => !s.Protected), true);
            }

            private void export()
            {
                try
                {
                    currentSkin.Value.SkinInfo.PerformRead(s => new LegacySkinExporter(storage).Export(s));
                }
                catch (Exception e)
                {
                    Logger.Log($"Could not export current skin: {e.Message}", level: LogLevel.Error);
                }
            }
        }

        public class DeleteSkinButton : DangerousSettingsButton
        {
            [Resolved]
            private SkinManager skins { get; set; }

            [Resolved(CanBeNull = true)]
            private IDialogOverlay dialogOverlay { get; set; }

            private Bindable<Skin> currentSkin;

            [BackgroundDependencyLoader]
            private void load()
            {
                Text = SkinSettingsStrings.DeleteSkinButton;
                Action = delete;
            }

            protected override void LoadComplete()
            {
                base.LoadComplete();

                currentSkin = skins.CurrentSkin.GetBoundCopy();
                currentSkin.BindValueChanged(skin => Enabled.Value = skin.NewValue.SkinInfo.PerformRead(s => !s.Protected), true);
            }

            private void delete()
            {
                dialogOverlay?.Push(new SkinDeleteDialog(currentSkin.Value));
            }
        }
    }
}