// 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 System.Threading;
using osuTK;
using osuTK.Graphics;
using osu.Framework.Allocation;
using osu.Framework.Bindables;
using osu.Framework.Extensions.Color4Extensions;
using osu.Framework.Graphics;
using osu.Framework.Graphics.Colour;
using osu.Framework.Graphics.Containers;
using osu.Framework.Utils;
using osu.Game.Beatmaps;
using osu.Game.Beatmaps.Drawables;
using osu.Game.Graphics;
using osu.Game.Graphics.Sprites;
using osu.Framework.Graphics.Shapes;
using osu.Framework.Graphics.Cursor;
using osu.Framework.Graphics.Effects;
using osu.Framework.Graphics.Sprites;
using osu.Framework.Localisation;
using osu.Framework.Logging;
using osu.Game.Configuration;
using osu.Game.Rulesets;
using osu.Game.Rulesets.Mods;
using osu.Game.Rulesets.UI;
using osu.Game.Screens.Ranking.Expanded;

namespace osu.Game.Screens.Select
{
    public class BeatmapInfoWedge : VisibilityContainer
    {
        private const float shear_width = 36.75f;

        private static readonly Vector2 wedged_container_shear = new Vector2(shear_width / SongSelect.WEDGE_HEIGHT, 0);

        [Resolved]
        private IBindable<RulesetInfo> ruleset { get; set; }

        [Resolved]
        private IBindable<IReadOnlyList<Mod>> mods { get; set; }

        [Resolved]
        private BeatmapDifficultyCache difficultyCache { get; set; }

        private IBindable<StarDifficulty?> beatmapDifficulty;

        protected BufferedWedgeInfo Info;

        public BeatmapInfoWedge()
        {
            Shear = wedged_container_shear;
            Masking = true;
            BorderColour = new Color4(221, 255, 255, 255);
            BorderThickness = 2.5f;
            Alpha = 0;
            EdgeEffect = new EdgeEffectParameters
            {
                Type = EdgeEffectType.Glow,
                Colour = new Color4(130, 204, 255, 150),
                Radius = 20,
                Roundness = 15,
            };
        }

        [BackgroundDependencyLoader]
        private void load()
        {
            ruleset.BindValueChanged(_ => updateDisplay());
        }

        protected override void PopIn()
        {
            this.MoveToX(0, 800, Easing.OutQuint);
            this.RotateTo(0, 800, Easing.OutQuint);
            this.FadeIn(250);
        }

        protected override void PopOut()
        {
            this.MoveToX(-100, 800, Easing.In);
            this.RotateTo(10, 800, Easing.In);
            this.FadeOut(500, Easing.In);
        }

        private WorkingBeatmap beatmap;

        private CancellationTokenSource cancellationSource;

        public WorkingBeatmap Beatmap
        {
            get => beatmap;
            set
            {
                if (beatmap == value) return;

                beatmap = value;
                cancellationSource?.Cancel();
                cancellationSource = new CancellationTokenSource();

                beatmapDifficulty?.UnbindAll();
                beatmapDifficulty = difficultyCache.GetBindableDifficulty(beatmap.BeatmapInfo, cancellationSource.Token);
                beatmapDifficulty.BindValueChanged(_ => updateDisplay());

                updateDisplay();
            }
        }

        public override bool IsPresent => base.IsPresent || Info == null; // Visibility is updated in the LoadComponentAsync callback

        private BufferedWedgeInfo loadingInfo;

        private void updateDisplay()
        {
            Scheduler.AddOnce(perform);

            void perform()
            {
                void removeOldInfo()
                {
                    State.Value = beatmap == null ? Visibility.Hidden : Visibility.Visible;

                    Info?.FadeOut(250);
                    Info?.Expire();
                    Info = null;
                }

                if (beatmap == null)
                {
                    removeOldInfo();
                    return;
                }

                LoadComponentAsync(loadingInfo = new BufferedWedgeInfo(beatmap, ruleset.Value, mods.Value, beatmapDifficulty.Value ?? new StarDifficulty())
                {
                    Shear = -Shear,
                    Depth = Info?.Depth + 1 ?? 0
                }, loaded =>
                {
                    // ensure we are the most recent loaded wedge.
                    if (loaded != loadingInfo) return;

                    removeOldInfo();
                    Add(Info = loaded);
                });
            }
        }

        protected override void Dispose(bool isDisposing)
        {
            base.Dispose(isDisposing);
            cancellationSource?.Cancel();
        }

        public class BufferedWedgeInfo : BufferedContainer
        {
            public OsuSpriteText VersionLabel { get; private set; }
            public OsuSpriteText TitleLabel { get; private set; }
            public OsuSpriteText ArtistLabel { get; private set; }
            public BeatmapSetOnlineStatusPill StatusPill { get; private set; }
            public FillFlowContainer MapperContainer { get; private set; }

            private ILocalisedBindableString titleBinding;
            private ILocalisedBindableString artistBinding;
            private FillFlowContainer infoLabelContainer;
            private Container bpmLabelContainer;

            private readonly WorkingBeatmap beatmap;
            private readonly RulesetInfo ruleset;
            private readonly IReadOnlyList<Mod> mods;
            private readonly StarDifficulty starDifficulty;

            private ModSettingChangeTracker settingChangeTracker;

            public BufferedWedgeInfo(WorkingBeatmap beatmap, RulesetInfo userRuleset, IReadOnlyList<Mod> mods, StarDifficulty difficulty)
                : base(pixelSnapping: true)
            {
                this.beatmap = beatmap;
                ruleset = userRuleset ?? beatmap.BeatmapInfo.Ruleset;
                this.mods = mods;
                starDifficulty = difficulty;
            }

            [BackgroundDependencyLoader]
            private void load(LocalisationManager localisation)
            {
                var beatmapInfo = beatmap.BeatmapInfo;
                var metadata = beatmapInfo.Metadata ?? beatmap.BeatmapSetInfo?.Metadata ?? new BeatmapMetadata();

                CacheDrawnFrameBuffer = true;
                RelativeSizeAxes = Axes.Both;

                titleBinding = localisation.GetLocalisedString(new RomanisableString(metadata.TitleUnicode, metadata.Title));
                artistBinding = localisation.GetLocalisedString(new RomanisableString(metadata.ArtistUnicode, metadata.Artist));

                Children = new Drawable[]
                {
                    // We will create the white-to-black gradient by modulating transparency and having
                    // a black backdrop. This results in an sRGB-space gradient and not linear space,
                    // transitioning from white to black more perceptually uniformly.
                    new Box
                    {
                        RelativeSizeAxes = Axes.Both,
                        Colour = Color4.Black,
                    },
                    // We use a container, such that we can set the colour gradient to go across the
                    // vertices of the masked container instead of the vertices of the (larger) sprite.
                    new Container
                    {
                        RelativeSizeAxes = Axes.Both,
                        Colour = ColourInfo.GradientVertical(Color4.White, Color4.White.Opacity(0.3f)),
                        Children = new[]
                        {
                            // Zoomed-in and cropped beatmap background
                            new BeatmapBackgroundSprite(beatmap)
                            {
                                RelativeSizeAxes = Axes.Both,
                                Anchor = Anchor.Centre,
                                Origin = Anchor.Centre,
                                FillMode = FillMode.Fill,
                            },
                        },
                    },
                    new DifficultyColourBar(starDifficulty)
                    {
                        RelativeSizeAxes = Axes.Y,
                        Width = 20,
                    },
                    new FillFlowContainer
                    {
                        Name = "Topleft-aligned metadata",
                        Anchor = Anchor.TopLeft,
                        Origin = Anchor.TopLeft,
                        Direction = FillDirection.Vertical,
                        Padding = new MarginPadding { Top = 10, Left = 25, Right = shear_width * 2.5f },
                        AutoSizeAxes = Axes.Y,
                        RelativeSizeAxes = Axes.X,
                        Children = new Drawable[]
                        {
                            VersionLabel = new OsuSpriteText
                            {
                                Text = beatmapInfo.Version,
                                Font = OsuFont.GetFont(size: 24, italics: true),
                                RelativeSizeAxes = Axes.X,
                                Truncate = true,
                            },
                        }
                    },
                    new FillFlowContainer
                    {
                        Name = "Topright-aligned metadata",
                        Anchor = Anchor.TopRight,
                        Origin = Anchor.TopRight,
                        Direction = FillDirection.Vertical,
                        Padding = new MarginPadding { Top = 14, Right = shear_width / 2 },
                        AutoSizeAxes = Axes.Both,
                        Shear = wedged_container_shear,
                        Children = new[]
                        {
                            createStarRatingDisplay(starDifficulty).With(display =>
                            {
                                display.Anchor = Anchor.TopRight;
                                display.Origin = Anchor.TopRight;
                                display.Shear = -wedged_container_shear;
                            }),
                            StatusPill = new BeatmapSetOnlineStatusPill
                            {
                                Anchor = Anchor.TopRight,
                                Origin = Anchor.TopRight,
                                Shear = -wedged_container_shear,
                                TextSize = 11,
                                TextPadding = new MarginPadding { Horizontal = 8, Vertical = 2 },
                                Status = beatmapInfo.Status,
                            }
                        }
                    },
                    new FillFlowContainer
                    {
                        Name = "Centre-aligned metadata",
                        Anchor = Anchor.CentreLeft,
                        Origin = Anchor.TopLeft,
                        Y = -7,
                        Direction = FillDirection.Vertical,
                        Padding = new MarginPadding { Left = 25, Right = shear_width },
                        AutoSizeAxes = Axes.Y,
                        RelativeSizeAxes = Axes.X,
                        Children = new Drawable[]
                        {
                            TitleLabel = new OsuSpriteText
                            {
                                Font = OsuFont.GetFont(size: 28, italics: true),
                                RelativeSizeAxes = Axes.X,
                                Truncate = true,
                            },
                            ArtistLabel = new OsuSpriteText
                            {
                                Font = OsuFont.GetFont(size: 17, italics: true),
                                RelativeSizeAxes = Axes.X,
                                Truncate = true,
                            },
                            MapperContainer = new FillFlowContainer
                            {
                                Margin = new MarginPadding { Top = 10 },
                                Direction = FillDirection.Horizontal,
                                AutoSizeAxes = Axes.Both,
                                Children = getMapper(metadata)
                            },
                            infoLabelContainer = new FillFlowContainer
                            {
                                Margin = new MarginPadding { Top = 20 },
                                Spacing = new Vector2(20, 0),
                                AutoSizeAxes = Axes.Both,
                            }
                        }
                    }
                };

                titleBinding.BindValueChanged(_ => setMetadata(metadata.Source));
                artistBinding.BindValueChanged(_ => setMetadata(metadata.Source), true);

                // no difficulty means it can't have a status to show
                if (beatmapInfo.Version == null)
                    StatusPill.Hide();

                addInfoLabels();
            }

            private static Drawable createStarRatingDisplay(StarDifficulty difficulty) => difficulty.Stars > 0
                ? new StarRatingDisplay(difficulty)
                {
                    Margin = new MarginPadding { Bottom = 5 }
                }
                : Empty();

            private void setMetadata(string source)
            {
                ArtistLabel.Text = artistBinding.Value;
                TitleLabel.Text = string.IsNullOrEmpty(source) ? titleBinding.Value : source + " — " + titleBinding.Value;
                ForceRedraw();
            }

            private void addInfoLabels()
            {
                if (beatmap.Beatmap?.HitObjects?.Any() != true)
                    return;

                infoLabelContainer.Children = new Drawable[]
                {
                    new InfoLabel(new BeatmapStatistic
                    {
                        Name = "Length",
                        CreateIcon = () => new BeatmapStatisticIcon(BeatmapStatisticsIconType.Length),
                        Content = TimeSpan.FromMilliseconds(beatmap.BeatmapInfo.Length).ToString(@"m\:ss"),
                    }),
                    bpmLabelContainer = new Container
                    {
                        AutoSizeAxes = Axes.Both,
                    },
                    new FillFlowContainer
                    {
                        AutoSizeAxes = Axes.Both,
                        Spacing = new Vector2(20, 0),
                        Children = getRulesetInfoLabels()
                    }
                };

                settingChangeTracker = new ModSettingChangeTracker(mods);
                settingChangeTracker.SettingChanged += _ => refreshBPMLabel();

                refreshBPMLabel();
            }

            private InfoLabel[] getRulesetInfoLabels()
            {
                try
                {
                    IBeatmap playableBeatmap;

                    try
                    {
                        // Try to get the beatmap with the user's ruleset
                        playableBeatmap = beatmap.GetPlayableBeatmap(ruleset, Array.Empty<Mod>());
                    }
                    catch (BeatmapInvalidForRulesetException)
                    {
                        // Can't be converted to the user's ruleset, so use the beatmap's own ruleset
                        playableBeatmap = beatmap.GetPlayableBeatmap(beatmap.BeatmapInfo.Ruleset, Array.Empty<Mod>());
                    }

                    return playableBeatmap.GetStatistics().Select(s => new InfoLabel(s)).ToArray();
                }
                catch (Exception e)
                {
                    Logger.Error(e, "Could not load beatmap successfully!");
                }

                return Array.Empty<InfoLabel>();
            }

            private void refreshBPMLabel()
            {
                var b = beatmap.Beatmap;
                if (b == null)
                    return;

                // this doesn't consider mods which apply variable rates, yet.
                double rate = 1;
                foreach (var mod in mods.OfType<IApplicableToRate>())
                    rate = mod.ApplyToRate(0, rate);

                double bpmMax = b.ControlPointInfo.BPMMaximum * rate;
                double bpmMin = b.ControlPointInfo.BPMMinimum * rate;
                double mostCommonBPM = 60000 / b.GetMostCommonBeatLength() * rate;

                string labelText = Precision.AlmostEquals(bpmMin, bpmMax)
                    ? $"{bpmMin:0}"
                    : $"{bpmMin:0}-{bpmMax:0} (mostly {mostCommonBPM:0})";

                bpmLabelContainer.Child = new InfoLabel(new BeatmapStatistic
                {
                    Name = "BPM",
                    CreateIcon = () => new BeatmapStatisticIcon(BeatmapStatisticsIconType.Bpm),
                    Content = labelText
                });

                ForceRedraw();
            }

            private OsuSpriteText[] getMapper(BeatmapMetadata metadata)
            {
                if (string.IsNullOrEmpty(metadata.Author?.Username))
                    return Array.Empty<OsuSpriteText>();

                return new[]
                {
                    new OsuSpriteText
                    {
                        Text = "mapped by ",
                        Font = OsuFont.GetFont(size: 15),
                    },
                    new OsuSpriteText
                    {
                        Text = metadata.Author.Username,
                        Font = OsuFont.GetFont(weight: FontWeight.Bold, size: 15),
                    }
                };
            }

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

            public class InfoLabel : Container, IHasTooltip
            {
                public string TooltipText { get; }

                public InfoLabel(BeatmapStatistic statistic)
                {
                    TooltipText = statistic.Name;
                    AutoSizeAxes = Axes.Both;

                    Children = new Drawable[]
                    {
                        new Container
                        {
                            Anchor = Anchor.CentreLeft,
                            Origin = Anchor.CentreLeft,
                            Size = new Vector2(20),
                            Children = new[]
                            {
                                new SpriteIcon
                                {
                                    Anchor = Anchor.Centre,
                                    Origin = Anchor.Centre,
                                    RelativeSizeAxes = Axes.Both,
                                    Colour = Color4Extensions.FromHex(@"441288"),
                                    Icon = FontAwesome.Solid.Square,
                                    Rotation = 45,
                                },
                                new SpriteIcon
                                {
                                    Anchor = Anchor.Centre,
                                    Origin = Anchor.Centre,
                                    RelativeSizeAxes = Axes.Both,
                                    Colour = Color4Extensions.FromHex(@"f7dd55"),
                                    Icon = FontAwesome.Regular.Circle,
                                    Size = new Vector2(0.8f)
                                },
                                statistic.CreateIcon().With(i =>
                                {
                                    i.Anchor = Anchor.Centre;
                                    i.Origin = Anchor.Centre;
                                    i.RelativeSizeAxes = Axes.Both;
                                    i.Colour = Color4Extensions.FromHex(@"f7dd55");
                                    i.Size = new Vector2(0.64f);
                                }),
                            }
                        },
                        new OsuSpriteText
                        {
                            Anchor = Anchor.CentreLeft,
                            Origin = Anchor.CentreLeft,
                            Colour = new Color4(255, 221, 85, 255),
                            Font = OsuFont.GetFont(weight: FontWeight.Bold, size: 17),
                            Margin = new MarginPadding { Left = 30 },
                            Text = statistic.Content,
                        }
                    };
                }
            }

            private class DifficultyColourBar : Container
            {
                private readonly StarDifficulty difficulty;

                public DifficultyColourBar(StarDifficulty difficulty)
                {
                    this.difficulty = difficulty;
                }

                [BackgroundDependencyLoader]
                private void load(OsuColour colours)
                {
                    const float full_opacity_ratio = 0.7f;

                    var difficultyColour = colours.ForDifficultyRating(difficulty.DifficultyRating);

                    Children = new Drawable[]
                    {
                        new Box
                        {
                            RelativeSizeAxes = Axes.Both,
                            Colour = difficultyColour,
                            Width = full_opacity_ratio,
                        },
                        new Box
                        {
                            RelativeSizeAxes = Axes.Both,
                            RelativePositionAxes = Axes.Both,
                            Colour = difficultyColour,
                            Alpha = 0.5f,
                            X = full_opacity_ratio,
                            Width = 1 - full_opacity_ratio,
                        }
                    };
                }
            }
        }
    }
}