// 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 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.Graphics;
using osu.Game.Graphics.Sprites;
using osu.Game.Rulesets.Objects.Drawables;
using osu.Game.Rulesets.Osu.Objects;
using osu.Game.Skinning;
using osuTK;
using osuTK.Graphics;
using static osu.Game.Skinning.LegacySkinConfiguration;

namespace osu.Game.Rulesets.Osu.Skinning
{
    public class LegacyMainCirclePiece : CompositeDrawable
    {
        private readonly string priorityLookup;
        private readonly bool hasNumber;

        public LegacyMainCirclePiece(string priorityLookup = null, bool hasNumber = true)
        {
            this.priorityLookup = priorityLookup;
            this.hasNumber = hasNumber;

            Size = new Vector2(OsuHitObject.OBJECT_RADIUS * 2);
        }

        private Container<Sprite> circleSprites;
        private Sprite hitCircleSprite;
        private Sprite hitCircleOverlay;

        private SkinnableSpriteText hitCircleText;

        private readonly IBindable<ArmedState> state = new Bindable<ArmedState>();
        private readonly Bindable<Color4> accentColour = new Bindable<Color4>();
        private readonly IBindable<int> indexInCurrentCombo = new Bindable<int>();

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

        [BackgroundDependencyLoader]
        private void load(DrawableHitObject drawableObject)
        {
            OsuHitObject osuObject = (OsuHitObject)drawableObject.HitObject;

            Texture baseTexture;
            Texture overlayTexture;
            bool allowFallback = false;

            // attempt lookup using priority specification
            baseTexture = getTextureWithFallback(string.Empty);

            // if the base texture was not found without a fallback, switch on fallback mode and re-perform the lookup.
            if (baseTexture == null)
            {
                allowFallback = true;
                baseTexture = getTextureWithFallback(string.Empty);
            }

            // at this point, any further texture fetches should be correctly using the priority source if the base texture was retrieved using it.
            // the flow above handles the case where a sliderendcircle.png is retrieved from the skin, but sliderendcircleoverlay.png doesn't exist.
            // expected behaviour in this scenario is not showing the overlay, rather than using hitcircleoverlay.png (potentially from the default/fall-through skin).
            overlayTexture = getTextureWithFallback("overlay");

            InternalChildren = new Drawable[]
            {
                circleSprites = new Container<Sprite>
                {
                    Anchor = Anchor.Centre,
                    Origin = Anchor.Centre,
                    RelativeSizeAxes = Axes.Both,
                    Children = new[]
                    {
                        hitCircleSprite = new Sprite
                        {
                            Texture = baseTexture,
                            Anchor = Anchor.Centre,
                            Origin = Anchor.Centre,
                        },
                        hitCircleOverlay = new Sprite
                        {
                            Texture = overlayTexture,
                            Anchor = Anchor.Centre,
                            Origin = Anchor.Centre,
                        }
                    }
                },
            };

            if (hasNumber)
            {
                AddInternal(hitCircleText = new SkinnableSpriteText(new OsuSkinComponent(OsuSkinComponents.HitCircleText), _ => new OsuSpriteText
                {
                    Font = OsuFont.Numeric.With(size: 40),
                    UseFullGlyphHeight = false,
                }, confineMode: ConfineMode.NoScaling)
                {
                    Anchor = Anchor.Centre,
                    Origin = Anchor.Centre,
                });
            }

            bool overlayAboveNumber = skin.GetConfig<OsuSkinConfiguration, bool>(OsuSkinConfiguration.HitCircleOverlayAboveNumber)?.Value ?? true;

            if (overlayAboveNumber)
                AddInternal(hitCircleOverlay.CreateProxy());

            state.BindTo(drawableObject.State);
            accentColour.BindTo(drawableObject.AccentColour);
            indexInCurrentCombo.BindTo(osuObject.IndexInCurrentComboBindable);

            Texture getTextureWithFallback(string name)
            {
                Texture tex = null;

                if (!string.IsNullOrEmpty(priorityLookup))
                {
                    tex = skin.GetTexture($"{priorityLookup}{name}");

                    if (!allowFallback)
                        return tex;
                }

                return tex ?? skin.GetTexture($"hitcircle{name}");
            }
        }

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

            state.BindValueChanged(updateState, true);
            accentColour.BindValueChanged(colour => hitCircleSprite.Colour = LegacyColourCompatibility.DisallowZeroAlpha(colour.NewValue), true);
            if (hasNumber)
                indexInCurrentCombo.BindValueChanged(index => hitCircleText.Text = (index.NewValue + 1).ToString(), true);
        }

        private void updateState(ValueChangedEvent<ArmedState> state)
        {
            const double legacy_fade_duration = 240;

            switch (state.NewValue)
            {
                case ArmedState.Hit:
                    circleSprites.FadeOut(legacy_fade_duration, Easing.Out);
                    circleSprites.ScaleTo(1.4f, legacy_fade_duration, Easing.Out);

                    if (hasNumber)
                    {
                        var legacyVersion = skin.GetConfig<LegacySetting, decimal>(LegacySetting.Version)?.Value;

                        if (legacyVersion >= 2.0m)
                            // legacy skins of version 2.0 and newer only apply very short fade out to the number piece.
                            hitCircleText.FadeOut(legacy_fade_duration / 4, Easing.Out);
                        else
                        {
                            // old skins scale and fade it normally along other pieces.
                            hitCircleText.FadeOut(legacy_fade_duration, Easing.Out);
                            hitCircleText.ScaleTo(1.4f, legacy_fade_duration, Easing.Out);
                        }
                    }

                    break;
            }
        }
    }
}