// 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.Linq;
using osu.Game.Beatmaps;
using osu.Game.Rulesets.Judgements;
using osu.Game.Rulesets.Scoring;
using osu.Game.Rulesets.Taiko.Judgements;
using osu.Game.Rulesets.Taiko.Objects;
using osu.Game.Rulesets.UI;

namespace osu.Game.Rulesets.Taiko.Scoring
{
    internal class TaikoScoreProcessor : ScoreProcessor<TaikoHitObject>
    {
        /// <summary>
        /// The HP awarded by a <see cref="HitResult.Great"/> hit.
        /// </summary>
        private const double hp_hit_great = 0.03;

        /// <summary>
        /// The HP awarded for a <see cref="HitResult.Good"/> hit.
        /// </summary>
        private const double hp_hit_good = 0.011;

        /// <summary>
        /// The minimum HP deducted for a <see cref="HitResult.Miss"/>.
        /// This occurs when HP Drain = 0.
        /// </summary>
        private const double hp_miss_min = -0.0018;

        /// <summary>
        /// The median HP deducted for a <see cref="HitResult.Miss"/>.
        /// This occurs when HP Drain = 5.
        /// </summary>
        private const double hp_miss_mid = -0.0075;

        /// <summary>
        /// The maximum HP deducted for a <see cref="HitResult.Miss"/>.
        /// This occurs when HP Drain = 10.
        /// </summary>
        private const double hp_miss_max = -0.12;

        /// <summary>
        /// The HP awarded for a <see cref="DrumRollTick"/> hit.
        /// <para>
        /// <see cref="DrumRollTick"/> hits award less HP as they're more spammable, although in hindsight
        /// this probably awards too little HP and is kept at this value for now for compatibility.
        /// </para>
        /// </summary>
        private const double hp_hit_tick = 0.00000003;

        /// <summary>
        /// Taiko fails at the end of the map if the player has not half-filled their HP bar.
        /// </summary>
        protected override bool DefaultFailCondition => JudgedHits == MaxHits && Health.Value <= 0.5;

        private double hpIncreaseTick;
        private double hpIncreaseGreat;
        private double hpIncreaseGood;
        private double hpIncreaseMiss;

        public TaikoScoreProcessor()
        {
        }

        public TaikoScoreProcessor(RulesetContainer<TaikoHitObject> rulesetContainer)
            : base(rulesetContainer)
        {
        }

        protected override void SimulateAutoplay(Beatmap<TaikoHitObject> beatmap)
        {
            double hpMultiplierNormal = 1 / (hp_hit_great * beatmap.HitObjects.FindAll(o => o is Hit).Count * BeatmapDifficulty.DifficultyRange(beatmap.BeatmapInfo.BaseDifficulty.DrainRate, 0.5, 0.75, 0.98));

            hpIncreaseTick = hp_hit_tick;
            hpIncreaseGreat = hpMultiplierNormal * hp_hit_great;
            hpIncreaseGood = hpMultiplierNormal * hp_hit_good;
            hpIncreaseMiss = BeatmapDifficulty.DifficultyRange(beatmap.BeatmapInfo.BaseDifficulty.DrainRate, hp_miss_min, hp_miss_mid, hp_miss_max);

            foreach (var obj in beatmap.HitObjects)
            {
                switch (obj)
                {
                    case Hit _:
                        AddJudgement(new TaikoJudgement { Result = HitResult.Great });
                        if (obj.IsStrong)
                            AddJudgement(new TaikoStrongHitJudgement());
                        break;
                    case DrumRoll drumRoll:
                        var count = drumRoll.NestedHitObjects.OfType<DrumRollTick>().Count();
                        for (int i = 0; i < count; i++)
                        {
                            AddJudgement(new TaikoDrumRollTickJudgement { Result = HitResult.Great });

                            if (obj.IsStrong)
                                AddJudgement(new TaikoStrongHitJudgement());
                        }

                        AddJudgement(new TaikoJudgement { Result = HitResult.Great });

                        if (obj.IsStrong)
                            AddJudgement(new TaikoStrongHitJudgement());
                        break;
                    case Swell _:
                        AddJudgement(new TaikoJudgement { Result = HitResult.Great });
                        break;
                }
            }
        }

        protected override void OnNewJudgement(Judgement judgement)
        {
            base.OnNewJudgement(judgement);

            bool isTick = judgement is TaikoDrumRollTickJudgement;

            // Apply HP changes
            switch (judgement.Result)
            {
                case HitResult.Miss:
                    // Missing ticks shouldn't drop HP
                    if (!isTick)
                        Health.Value += hpIncreaseMiss;
                    break;
                case HitResult.Good:
                    Health.Value += hpIncreaseGood;
                    break;
                case HitResult.Great:
                    if (isTick)
                        Health.Value += hpIncreaseTick;
                    else
                        Health.Value += hpIncreaseGreat;
                    break;
            }
        }

        protected override void Reset(bool storeResults)
        {
            base.Reset(storeResults);

            Health.Value = 0;
        }
    }
}