// 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 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.Framework.Utils;
using osu.Game.Screens.Play.HUD;
using osu.Game.Utils;
using osuTK;
using osuTK.Graphics;

namespace osu.Game.Skinning
{
    public partial class LegacyHealthDisplay : HealthDisplay, ISerialisableDrawable
    {
        private const double epic_cutoff = 0.5;

        private LegacyHealthPiece fill;
        private LegacyHealthPiece marker;

        private float maxFillWidth;

        private bool isNewStyle;

        public bool UsesFixedAnchor { get; set; }

        [BackgroundDependencyLoader]
        private void load(ISkinSource source)
        {
            AutoSizeAxes = Axes.Both;

            var skin = source.FindProvider(s => getTexture(s, "bg") != null);

            // the marker lookup to decide which display style must be performed on the source of the bg, which is the most common element.
            isNewStyle = getTexture(skin, "marker") != null;

            // background implementation is the same for both versions.
            AddInternal(new Sprite { Texture = getTexture(skin, "bg") });

            if (isNewStyle)
            {
                AddRangeInternal(new[]
                {
                    fill = new LegacyNewStyleFill(skin),
                    marker = new LegacyNewStyleMarker(skin),
                });
            }
            else
            {
                AddRangeInternal(new[]
                {
                    fill = new LegacyOldStyleFill(skin),
                    marker = new LegacyOldStyleMarker(skin),
                });
            }

            fill.Current.BindTo(Current);
            marker.Current.BindTo(Current);

            maxFillWidth = fill.Width;
            fill.Width = 0;
        }

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

            fill.Width = Interpolation.ValueAt(
                Math.Clamp(Clock.ElapsedFrameTime, 0, 200),
                fill.Width, (float)Current.Value * maxFillWidth, 0, 200, Easing.OutQuint);

            marker.Position = fill.Position + new Vector2(fill.DrawWidth, isNewStyle ? fill.DrawHeight / 2 : 0);
        }

        protected override void HealthChanged(bool increase)
        {
            if (increase)
                marker.Bulge();
            base.HealthChanged(increase);
        }

        protected override void Flash() => marker.Flash(Current.Value >= epic_cutoff);

        private static Texture getTexture(ISkin skin, string name) => skin?.GetTexture($"scorebar-{name}");

        private static Color4 getFillColour(double hp)
        {
            if (hp < 0.2)
                return LegacyUtils.InterpolateNonLinear(0.2 - hp, Color4.Black, Color4.Red, 0, 0.2);

            if (hp < epic_cutoff)
                return LegacyUtils.InterpolateNonLinear(0.5 - hp, Color4.White, Color4.Black, 0, 0.5);

            return Color4.White;
        }

        public partial class LegacyOldStyleMarker : LegacyMarker
        {
            private readonly Texture normalTexture;
            private readonly Texture dangerTexture;
            private readonly Texture superDangerTexture;

            public LegacyOldStyleMarker(ISkin skin)
            {
                normalTexture = getTexture(skin, "ki");
                dangerTexture = getTexture(skin, "kidanger");
                superDangerTexture = getTexture(skin, "kidanger2");
            }

            public override Sprite CreateSprite() => new Sprite
            {
                Texture = normalTexture,
                Origin = Anchor.Centre,
            };

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

                if (Current.Value < 0.2f)
                    Main.Texture = superDangerTexture;
                else if (Current.Value < epic_cutoff)
                    Main.Texture = dangerTexture;
                else
                    Main.Texture = normalTexture;
            }
        }

        public partial class LegacyNewStyleMarker : LegacyMarker
        {
            private readonly ISkin skin;

            public LegacyNewStyleMarker(ISkin skin)
            {
                this.skin = skin;
            }

            public override Sprite CreateSprite() => new Sprite
            {
                Texture = getTexture(skin, "marker"),
                Origin = Anchor.Centre,
            };

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

                Main.Colour = getFillColour(Current.Value);
                Main.Blending = Current.Value < epic_cutoff ? BlendingParameters.Inherit : BlendingParameters.Additive;
            }
        }

        internal abstract partial class LegacyFill : LegacyHealthPiece
        {
            protected LegacyFill(ISkin skin)
            {
                // required for sizing correctly..
                var firstFrame = getTexture(skin, "colour-0");

                if (firstFrame == null)
                {
                    InternalChild = new Sprite { Texture = getTexture(skin, "colour") };
                    Size = InternalChild.Size;
                }
                else
                {
                    InternalChild = skin.GetAnimation("scorebar-colour", true, true, startAtCurrentTime: false, applyConfigFrameRate: true) ?? Empty();
                    Size = new Vector2(firstFrame.DisplayWidth, firstFrame.DisplayHeight);
                }

                Masking = true;
            }
        }

        internal partial class LegacyOldStyleFill : LegacyFill
        {
            public LegacyOldStyleFill(ISkin skin)
                : base(skin)
            {
                Position = new Vector2(3, 10) * 1.6f;
            }
        }

        internal partial class LegacyNewStyleFill : LegacyFill
        {
            public LegacyNewStyleFill(ISkin skin)
                : base(skin)
            {
                Position = new Vector2(7.5f, 7.8f) * 1.6f;
            }

            protected override void Update()
            {
                base.Update();
                Colour = getFillColour(Current.Value);
            }
        }

        public abstract partial class LegacyMarker : LegacyHealthPiece
        {
            protected Sprite Main;

            private Sprite explode;

            protected LegacyMarker()
            {
                Origin = Anchor.Centre;
            }

            [BackgroundDependencyLoader]
            private void load()
            {
                InternalChildren = new Drawable[]
                {
                    Main = CreateSprite(),
                    explode = CreateSprite().With(s =>
                    {
                        s.Alpha = 0;
                        s.Blending = BlendingParameters.Additive;
                    }),
                };
            }

            public abstract Sprite CreateSprite();

            public override void Flash(bool isEpic)
            {
                Bulge();
                explode.Texture = Main.Texture;
                explode.Blending = isEpic ? BlendingParameters.Additive : BlendingParameters.Inherit;
                explode.ScaleTo(1).Then().ScaleTo(isEpic ? 2 : 1.6f, 120, Easing.Out);
                explode.FadeOutFromOne(120, Easing.Out);
            }

            public override void Bulge()
            {
                base.Bulge();
                Main.ScaleTo(1.2f).Then().ScaleTo(0.8f, 150);
            }
        }

        public partial class LegacyHealthPiece : CompositeDrawable
        {
            public Bindable<double> Current { get; } = new Bindable<double>();

            public virtual void Bulge()
            {
            }

            public virtual void Flash(bool isEpic)
            {
            }
        }
    }
}
