// Copyright (c) 2007-2019 ppy Pty Ltd <contact@ppy.sh>.
// Licensed under the MIT Licence - https://raw.githubusercontent.com/ppy/osu/master/LICENCE

using System;
using System.Collections.Generic;
using System.Linq;
using osu.Game.Beatmaps;
using osu.Game.Rulesets.Difficulty;
using osu.Game.Rulesets.Mods;
using osu.Game.Rulesets.Scoring;
using osu.Game.Scoring;
using osuTK;

namespace osu.Game.Rulesets.Catch.Difficulty
{
    public class CatchPerformanceCalculator : PerformanceCalculator
    {
        protected new CatchDifficultyAttributes Attributes => (CatchDifficultyAttributes)base.Attributes;

        private Mod[] mods;
        private int countGreat;
        private int countGood;
        private int countMeh;
        private int countMiss;
        private int countKatu;

        public CatchPerformanceCalculator(Ruleset ruleset, WorkingBeatmap beatmap, ScoreInfo score)
            : base(ruleset, beatmap, score) { }

        public override double Calculate(Dictionary<string, double> categoryDifficulty = null)
        {
            mods = Score.Mods;
            countGreat = Convert.ToInt32(Score.Statistics[HitResult.Great]);
            countGood = Convert.ToInt32(Score.Statistics[HitResult.Good]);
            countMeh = Convert.ToInt32(Score.Statistics[HitResult.Meh]);
            countMiss = Convert.ToInt32(Score.Statistics[HitResult.Miss]);
            countKatu = Convert.ToInt32(Score.Statistics[HitResult.Ok]);    // TODO: check

            // Don't count scores made with supposedly unranked mods
            if (mods.Any(m => !m.Ranked))
                return 0;

            // We are heavily relying on aim in catch the beat
            // TODO: replaced Aim with StarRating, not sure if this is correct!
            double value = Math.Pow(5.0f * Math.Max(1.0f, Attributes.StarRating / 0.0049f) - 4.0f, 2.0f) / 100000.0f;

            // Longer maps are worth more. "Longer" means how many hits there are which can contribute to combo
            int numTotalHits = totalComboHits();

            // Longer maps are worth more
            float lengthBonus =
                0.95f + 0.4f * Math.Min(1.0f, numTotalHits / 3000.0f) +
                (numTotalHits > 3000 ? (float)Math.Log10(numTotalHits / 3000.0f) * 0.5f : 0.0f);

            // Longer maps are worth more
            value *= lengthBonus;

            // Penalize misses exponentially. This mainly fixes tag4 maps and the likes until a per-hitobject solution is available
            value *= Math.Pow(0.97f, countMiss);

            // Combo scaling
            float beatmapMaxCombo = Attributes.MaxCombo;
            if (beatmapMaxCombo > 0)
                value *= Math.Min(Math.Pow(Attributes.MaxCombo, 0.8f) / Math.Pow(beatmapMaxCombo, 0.8f), 1.0f);

            float approachRate = (float)Attributes.ApproachRate;
            float approachRateFactor = 1.0f;
            if (approachRate > 9.0f)
                approachRateFactor += 0.1f * (approachRate - 9.0f); // 10% for each AR above 9
            else if (approachRate < 8.0f)
                approachRateFactor += 0.025f * (8.0f - approachRate); // 2.5% for each AR below 8

            value *= approachRateFactor;

            if (mods.Any(m => m is ModHidden))
                // Hiddens gives nothing on max approach rate, and more the lower it is
                value *= 1.05f + 0.075f * (10.0f - Math.Min(10.0f, approachRate)); // 7.5% for each AR below 10

            if (mods.Any(m => m is ModFlashlight))
                // Apply length bonus again if flashlight is on simply because it becomes a lot harder on longer maps.
                value *= 1.35f * lengthBonus;

            // Scale the aim value with accuracy _slightly_
            value *= Math.Pow(accuracy(), 5.5f);

            // Custom multipliers for NoFail. SpunOut is not applicable.
            if (mods.Any(m => m is ModNoFail))
                value *= 0.90f;

            return value;
        }

        private float accuracy() => totalHits() == 0 ? 0 : MathHelper.Clamp((float)totalSuccessfulHits() / totalHits(), 0f, 1f);
        private int totalHits() => countMeh + countGood + countGreat + countMiss + countKatu;
        private int totalSuccessfulHits() => countMeh + countGood + countGreat;
        private int totalComboHits() => countMeh + countGood + countGreat;
    }
}