// 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 osu.Framework.Bindables;
using osu.Framework.Graphics;
using osu.Game.Skinning;
using osuTK;

namespace osu.Game.Rulesets.Osu.Skinning.Legacy
{
    public class OsuLegacySkinTransformer : LegacySkinTransformer
    {
        private Lazy<bool> hasHitCircle;

        /// <summary>
        /// On osu-stable, hitcircles have 5 pixels of transparent padding on each side to allow for shadows etc.
        /// Their hittable area is 128px, but the actual circle portion is 118px.
        /// We must account for some gameplay elements such as slider bodies, where this padding is not present.
        /// </summary>
        public const float LEGACY_CIRCLE_RADIUS = 64 - 5;

        public OsuLegacySkinTransformer(ISkinSource source)
            : base(source)
        {
            Source.SourceChanged += sourceChanged;
            sourceChanged();
        }

        private void sourceChanged()
        {
            hasHitCircle = new Lazy<bool>(() => Source.GetTexture("hitcircle") != null);
        }

        public override Drawable GetDrawableComponent(ISkinComponent component)
        {
            if (component is OsuSkinComponent osuComponent)
            {
                switch (osuComponent.Component)
                {
                    case OsuSkinComponents.FollowPoint:
                        return this.GetAnimation(component.LookupName, true, false, true, startAtCurrentTime: false);

                    case OsuSkinComponents.SliderFollowCircle:
                        var followCircle = this.GetAnimation("sliderfollowcircle", true, true, true);
                        if (followCircle != null)
                            // follow circles are 2x the hitcircle resolution in legacy skins (since they are scaled down from >1x
                            followCircle.Scale *= 0.5f;
                        return followCircle;

                    case OsuSkinComponents.SliderBall:
                        var sliderBallContent = this.GetAnimation("sliderb", true, true, animationSeparator: "");

                        // todo: slider ball has a custom frame delay based on velocity
                        // Math.Max((150 / Velocity) * GameBase.SIXTY_FRAME_TIME, GameBase.SIXTY_FRAME_TIME);

                        if (sliderBallContent != null)
                            return new LegacySliderBall(sliderBallContent);

                        return null;

                    case OsuSkinComponents.SliderBody:
                        if (hasHitCircle.Value)
                            return new LegacySliderBody();

                        return null;

                    case OsuSkinComponents.SliderTailHitCircle:
                        if (hasHitCircle.Value)
                            return new LegacyMainCirclePiece("sliderendcircle", false);

                        return null;

                    case OsuSkinComponents.SliderHeadHitCircle:
                        if (hasHitCircle.Value)
                            return new LegacyMainCirclePiece("sliderstartcircle");

                        return null;

                    case OsuSkinComponents.HitCircle:
                        if (hasHitCircle.Value)
                            return new LegacyMainCirclePiece();

                        return null;

                    case OsuSkinComponents.Cursor:
                        if (Source.GetTexture("cursor") != null)
                            return new LegacyCursor();

                        return null;

                    case OsuSkinComponents.CursorTrail:
                        if (Source.GetTexture("cursortrail") != null)
                            return new LegacyCursorTrail();

                        return null;

                    case OsuSkinComponents.HitCircleText:
                        if (!this.HasFont(LegacyFont.HitCircle))
                            return null;

                        return new LegacySpriteText(LegacyFont.HitCircle)
                        {
                            // stable applies a blanket 0.8x scale to hitcircle fonts
                            Scale = new Vector2(0.8f),
                        };

                    case OsuSkinComponents.SpinnerBody:
                        bool hasBackground = Source.GetTexture("spinner-background") != null;

                        if (Source.GetTexture("spinner-top") != null && !hasBackground)
                            return new LegacyNewStyleSpinner();
                        else if (hasBackground)
                            return new LegacyOldStyleSpinner();

                        return null;
                }
            }

            return Source.GetDrawableComponent(component);
        }

        public override IBindable<TValue> GetConfig<TLookup, TValue>(TLookup lookup)
        {
            switch (lookup)
            {
                case OsuSkinColour colour:
                    return Source.GetConfig<SkinCustomColourLookup, TValue>(new SkinCustomColourLookup(colour));

                case OsuSkinConfiguration osuLookup:
                    switch (osuLookup)
                    {
                        case OsuSkinConfiguration.SliderPathRadius:
                            if (hasHitCircle.Value)
                                return SkinUtils.As<TValue>(new BindableFloat(LEGACY_CIRCLE_RADIUS));

                            break;

                        case OsuSkinConfiguration.HitCircleOverlayAboveNumber:
                            // See https://osu.ppy.sh/help/wiki/Skinning/skin.ini#%5Bgeneral%5D
                            // HitCircleOverlayAboveNumer (with typo) should still be supported for now.
                            return Source.GetConfig<OsuSkinConfiguration, TValue>(OsuSkinConfiguration.HitCircleOverlayAboveNumber) ??
                                   Source.GetConfig<OsuSkinConfiguration, TValue>(OsuSkinConfiguration.HitCircleOverlayAboveNumer);
                    }

                    break;
            }

            return Source.GetConfig<TLookup, TValue>(lookup);
        }
    }
}