// Copyright (c) 2007-2018 ppy Pty Ltd <contact@ppy.sh>.
// Licensed under the MIT Licence - https://raw.githubusercontent.com/ppy/osu/master/LICENCE

using System;
using System.Linq;
using osu.Framework.Graphics;
using osu.Game.Rulesets.Objects.Drawables;
using osu.Game.Rulesets.Scoring;
using osu.Game.Rulesets.Taiko.Objects.Drawables.Pieces;

namespace osu.Game.Rulesets.Taiko.Objects.Drawables
{
    public abstract class DrawableHit : DrawableTaikoHitObject<Hit>
    {
        /// <summary>
        /// A list of keys which can result in hits for this HitObject.
        /// </summary>
        public abstract TaikoAction[] HitActions { get; }

        /// <summary>
        /// The action that caused this <see cref="DrawableHit"/> to be hit.
        /// </summary>
        public TaikoAction? HitAction { get; private set; }

        private bool validActionPressed;

        private bool pressHandledThisFrame;

        protected DrawableHit(Hit hit)
            : base(hit)
        {
            FillMode = FillMode.Fit;
        }

        protected override void CheckForResult(bool userTriggered, double timeOffset)
        {
            if (!userTriggered)
            {
                if (!HitObject.HitWindows.CanBeHit(timeOffset))
                    ApplyResult(r => r.Type = HitResult.Miss);
                return;
            }

            var result = HitObject.HitWindows.ResultFor(timeOffset);
            if (result == HitResult.None)
                return;

            if (!validActionPressed)
                ApplyResult(r => r.Type = HitResult.Miss);
            else
                ApplyResult(r => r.Type = result);
        }

        public override bool OnPressed(TaikoAction action)
        {
            if (pressHandledThisFrame)
                return true;

            if (Judged)
                return false;

            validActionPressed = HitActions.Contains(action);

            // Only count this as handled if the new judgement is a hit
            var result = UpdateResult(true);

            if (IsHit)
                HitAction = action;

            // Regardless of whether we've hit or not, any secondary key presses in the same frame should be discarded
            // E.g. hitting a non-strong centre as a strong should not fall through and perform a hit on the next note
            pressHandledThisFrame = true;

            return result;
        }

        public override bool OnReleased(TaikoAction action)
        {
            if (action == HitAction)
                HitAction = null;
            return base.OnReleased(action);
        }

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

            // The input manager processes all input prior to us updating, so this is the perfect time
            // for us to remove the extra press blocking, before input is handled in the next frame
            pressHandledThisFrame = false;

            Size = BaseSize * Parent.RelativeChildSize;
        }

        protected override void UpdateState(ArmedState state)
        {
            var circlePiece = MainPiece as CirclePiece;
            circlePiece?.FlashBox.FinishTransforms();

            var offset = !AllJudged ? 0 : Time.Current - HitObject.StartTime;
            using (BeginDelayedSequence(HitObject.StartTime - Time.Current + offset, true))
            {
                switch (State.Value)
                {
                    case ArmedState.Idle:
                        validActionPressed = false;

                        UnproxyContent();
                        this.Delay(HitObject.HitWindows.HalfWindowFor(HitResult.Miss)).Expire();
                        break;
                    case ArmedState.Miss:
                        this.FadeOut(100)
                            .Expire();
                        break;
                    case ArmedState.Hit:
                        // If we're far enough away from the left stage, we should bring outselves in front of it
                        ProxyContent();

                        var flash = circlePiece?.FlashBox;
                        if (flash != null)
                        {
                            flash.FadeTo(0.9f);
                            flash.FadeOut(300);
                        }

                        const float gravity_time = 300;
                        const float gravity_travel_height = 200;

                        this.ScaleTo(0.8f, gravity_time * 2, Easing.OutQuad);

                        this.MoveToY(-gravity_travel_height, gravity_time, Easing.Out)
                            .Then()
                            .MoveToY(gravity_travel_height * 2, gravity_time * 2, Easing.In);

                        this.FadeOut(800)
                            .Expire();

                        break;
                }
            }
        }

        protected override DrawableStrongNestedHit CreateStrongHit(StrongHitObject hitObject) => new StrongNestedHit(hitObject, this);

        private class StrongNestedHit : DrawableStrongNestedHit
        {
            /// <summary>
            /// The lenience for the second key press.
            /// This does not adjust by map difficulty in ScoreV2 yet.
            /// </summary>
            private const double second_hit_window = 30;

            public new DrawableHit MainObject => (DrawableHit)base.MainObject;

            public StrongNestedHit(StrongHitObject strong, DrawableHit hit)
                : base(strong, hit)
            {
            }

            protected override void CheckForResult(bool userTriggered, double timeOffset)
            {
                if (!MainObject.Result.HasResult)
                {
                    base.CheckForResult(userTriggered, timeOffset);
                    return;
                }

                if (!MainObject.Result.IsHit)
                {
                    ApplyResult(r => r.Type = HitResult.Miss);
                    return;
                }

                if (!userTriggered)
                {
                    if (timeOffset - MainObject.Result.TimeOffset > second_hit_window)
                        ApplyResult(r => r.Type = HitResult.Miss);
                    return;
                }

                if (Math.Abs(timeOffset - MainObject.Result.TimeOffset) <= second_hit_window)
                    ApplyResult(r => r.Type = MainObject.Result.Type);
            }

            public override bool OnPressed(TaikoAction action)
            {
                // Don't process actions until the main hitobject is hit
                if (!MainObject.IsHit)
                    return false;

                // Don't process actions if the pressed button was released
                if (MainObject.HitAction == null)
                    return false;

                // Don't handle invalid hit action presses
                if (!MainObject.HitActions.Contains(action))
                    return false;

                return UpdateResult(true);
            }
        }
    }
}