// 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.Colour;
using osu.Framework.Graphics.Containers;
using osu.Framework.Graphics.Cursor;
using osu.Framework.Graphics.Shapes;
using osu.Framework.Graphics.UserInterface;
using osu.Framework.Input.Events;
using osu.Framework.Localisation;
using osu.Game.Beatmaps;
using osu.Game.Beatmaps.Drawables;
using osu.Game.Graphics;
using osu.Game.Graphics.Sprites;
using osu.Game.Graphics.UserInterface;
using osu.Game.Overlays;
using osu.Game.Rulesets;
using osuTK;
using osuTK.Graphics;

namespace osu.Game.Screens.Select.Carousel
{
    public class DrawableCarouselBeatmapSet : DrawableCarouselItem, IHasContextMenu
    {
        private Action<BeatmapSetInfo> restoreHiddenRequested;
        private Action<int> viewDetails;

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

        private readonly BeatmapSetInfo beatmapSet;

        public DrawableCarouselBeatmapSet(CarouselBeatmapSet set)
            : base(set)
        {
            beatmapSet = set.BeatmapSet;
        }

        [BackgroundDependencyLoader(true)]
        private void load(BeatmapManager manager, BeatmapSetOverlay beatmapOverlay)
        {
            restoreHiddenRequested = s => s.Beatmaps.ForEach(manager.Restore);
            if (beatmapOverlay != null)
                viewDetails = beatmapOverlay.FetchAndShowBeatmapSet;

            Children = new Drawable[]
            {
                new DelayedLoadUnloadWrapper(() =>
                    {
                        var background = new PanelBackground(manager.GetWorkingBeatmap(beatmapSet.Beatmaps.FirstOrDefault()))
                        {
                            RelativeSizeAxes = Axes.Both,
                        };

                        background.OnLoadComplete += d => d.FadeInFromZero(1000, Easing.OutQuint);

                        return background;
                    }, 300, 5000
                ),
                new FillFlowContainer
                {
                    Direction = FillDirection.Vertical,
                    Padding = new MarginPadding { Top = 5, Left = 18, Right = 10, Bottom = 10 },
                    AutoSizeAxes = Axes.Both,
                    Children = new Drawable[]
                    {
                        new OsuSpriteText
                        {
                            Text = new LocalisedString((beatmapSet.Metadata.TitleUnicode, beatmapSet.Metadata.Title)),
                            Font = OsuFont.GetFont(weight: FontWeight.Bold, size: 22, italics: true),
                            Shadow = true,
                        },
                        new OsuSpriteText
                        {
                            Text = new LocalisedString((beatmapSet.Metadata.ArtistUnicode, beatmapSet.Metadata.Artist)),
                            Font = OsuFont.GetFont(weight: FontWeight.SemiBold, size: 17, italics: true),
                            Shadow = true,
                        },
                        new FillFlowContainer
                        {
                            Direction = FillDirection.Horizontal,
                            AutoSizeAxes = Axes.Both,
                            Margin = new MarginPadding { Top = 5 },
                            Children = new Drawable[]
                            {
                                new BeatmapSetOnlineStatusPill
                                {
                                    Origin = Anchor.CentreLeft,
                                    Anchor = Anchor.CentreLeft,
                                    Margin = new MarginPadding { Right = 5 },
                                    TextSize = 11,
                                    TextPadding = new MarginPadding { Horizontal = 8, Vertical = 2 },
                                    Status = beatmapSet.Status
                                },
                                new FillFlowContainer<DifficultyIcon>
                                {
                                    AutoSizeAxes = Axes.Both,
                                    Spacing = new Vector2(3),
                                    ChildrenEnumerable = getDifficultyIcons(),
                                },
                            }
                        }
                    }
                }
            };
        }

        private const int maximum_difficulty_icons = 18;

        private IEnumerable<DifficultyIcon> getDifficultyIcons()
        {
            var beatmaps = ((CarouselBeatmapSet)Item).Beatmaps.ToList();

            return beatmaps.Count > maximum_difficulty_icons
                ? (IEnumerable<DifficultyIcon>)beatmaps.GroupBy(b => b.Beatmap.Ruleset).Select(group => new FilterableGroupedDifficultyIcon(group.ToList(), group.Key))
                : beatmaps.Select(b => new FilterableDifficultyIcon(b));
        }

        public MenuItem[] ContextMenuItems
        {
            get
            {
                List<MenuItem> items = new List<MenuItem>();

                if (Item.State.Value == CarouselItemState.NotSelected)
                    items.Add(new OsuMenuItem("Expand", MenuItemType.Highlighted, () => Item.State.Value = CarouselItemState.Selected));

                if (beatmapSet.OnlineBeatmapSetID != null)
                    items.Add(new OsuMenuItem("Details...", MenuItemType.Standard, () => viewDetails?.Invoke(beatmapSet.OnlineBeatmapSetID.Value)));

                if (beatmapSet.Beatmaps.Any(b => b.Hidden))
                    items.Add(new OsuMenuItem("Restore all hidden", MenuItemType.Standard, () => restoreHiddenRequested?.Invoke(beatmapSet)));

                items.Add(new OsuMenuItem("Delete", MenuItemType.Destructive, () => dialogOverlay?.Push(new BeatmapDeleteDialog(beatmapSet))));

                return items.ToArray();
            }
        }

        private class PanelBackground : BufferedContainer
        {
            public PanelBackground(WorkingBeatmap working)
            {
                CacheDrawnFrameBuffer = true;
                RedrawOnScale = false;

                Children = new Drawable[]
                {
                    new BeatmapBackgroundSprite(working)
                    {
                        RelativeSizeAxes = Axes.Both,
                        Anchor = Anchor.Centre,
                        Origin = Anchor.Centre,
                        FillMode = FillMode.Fill,
                    },
                    new FillFlowContainer
                    {
                        Depth = -1,
                        RelativeSizeAxes = Axes.Both,
                        Direction = FillDirection.Horizontal,
                        // This makes the gradient not be perfectly horizontal, but diagonal at a ~40° angle
                        Shear = new Vector2(0.8f, 0),
                        Alpha = 0.5f,
                        Children = new[]
                        {
                            // The left half with no gradient applied
                            new Box
                            {
                                RelativeSizeAxes = Axes.Both,
                                Colour = Color4.Black,
                                Width = 0.4f,
                            },
                            // Piecewise-linear gradient with 3 segments to make it appear smoother
                            new Box
                            {
                                RelativeSizeAxes = Axes.Both,
                                Colour = ColourInfo.GradientHorizontal(Color4.Black, new Color4(0f, 0f, 0f, 0.9f)),
                                Width = 0.05f,
                            },
                            new Box
                            {
                                RelativeSizeAxes = Axes.Both,
                                Colour = ColourInfo.GradientHorizontal(new Color4(0f, 0f, 0f, 0.9f), new Color4(0f, 0f, 0f, 0.1f)),
                                Width = 0.2f,
                            },
                            new Box
                            {
                                RelativeSizeAxes = Axes.Both,
                                Colour = ColourInfo.GradientHorizontal(new Color4(0f, 0f, 0f, 0.1f), new Color4(0, 0, 0, 0)),
                                Width = 0.05f,
                            },
                        }
                    },
                };
            }
        }

        public class FilterableDifficultyIcon : DifficultyIcon
        {
            private readonly BindableBool filtered = new BindableBool();

            public bool IsFiltered => filtered.Value;

            public readonly CarouselBeatmap Item;

            public FilterableDifficultyIcon(CarouselBeatmap item)
                : base(item.Beatmap)
            {
                filtered.BindTo(item.Filtered);
                filtered.ValueChanged += isFiltered => Schedule(() => this.FadeTo(isFiltered.NewValue ? 0.1f : 1, 100));
                filtered.TriggerChange();

                Item = item;
            }

            protected override bool OnClick(ClickEvent e)
            {
                Item.State.Value = CarouselItemState.Selected;
                return true;
            }
        }

        public class FilterableGroupedDifficultyIcon : GroupedDifficultyIcon
        {
            public readonly List<CarouselBeatmap> Items;

            public FilterableGroupedDifficultyIcon(List<CarouselBeatmap> items, RulesetInfo ruleset)
                : base(items.Select(i => i.Beatmap).ToList(), ruleset, Color4.White)
            {
                Items = items;

                foreach (var item in items)
                    item.Filtered.BindValueChanged(_ => Scheduler.AddOnce(updateFilteredDisplay));

                updateFilteredDisplay();
            }

            protected override bool OnClick(ClickEvent e)
            {
                Items.First().State.Value = CarouselItemState.Selected;
                return true;
            }

            private void updateFilteredDisplay()
            {
                // for now, fade the whole group based on the ratio of hidden items.
                this.FadeTo(1 - 0.9f * ((float)Items.Count(i => i.Filtered.Value) / Items.Count), 100);
            }
        }
    }
}