mirror of https://github.com/ppy/osu
99 lines
3.6 KiB
C#
99 lines
3.6 KiB
C#
// Copyright (c) ppy Pty Ltd <contact@ppy.sh>. Licensed under the MIT Licence.
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// See the LICENCE file in the repository root for full licence text.
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#nullable disable
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using System;
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using System.Collections.Generic;
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using System.Linq;
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using JetBrains.Annotations;
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using osu.Framework.Allocation;
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using osu.Framework.Bindables;
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using osu.Framework.Graphics;
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using osu.Game.Online.API;
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using osu.Game.Rulesets;
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namespace osu.Game.Beatmaps
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{
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/// <summary>
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/// A class which will recommend the most suitable difficulty for the local user from a beatmap set.
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/// This requires the user to be logged in, as it sources from the user's online profile.
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/// </summary>
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public class DifficultyRecommender : Component
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{
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[Resolved]
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private IAPIProvider api { get; set; }
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[Resolved]
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private Bindable<RulesetInfo> ruleset { get; set; }
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private readonly Dictionary<string, double> recommendedDifficultyMapping = new Dictionary<string, double>();
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[BackgroundDependencyLoader]
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private void load()
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{
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api.LocalUser.BindValueChanged(_ => populateValues(), true);
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}
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/// <summary>
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/// Find the recommended difficulty from a selection of available difficulties for the current local user.
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/// </summary>
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/// <remarks>
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/// This requires the user to be online for now.
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/// </remarks>
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/// <param name="beatmaps">A collection of beatmaps to select a difficulty from.</param>
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/// <returns>The recommended difficulty, or null if a recommendation could not be provided.</returns>
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[CanBeNull]
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public BeatmapInfo GetRecommendedBeatmap(IEnumerable<BeatmapInfo> beatmaps)
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{
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foreach (string r in orderedRulesets)
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{
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if (!recommendedDifficultyMapping.TryGetValue(r, out double recommendation))
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continue;
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BeatmapInfo beatmapInfo = beatmaps.Where(b => b.Ruleset.ShortName.Equals(r)).OrderBy(b =>
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{
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double difference = b.StarRating - recommendation;
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return difference >= 0 ? difference * 2 : difference * -1; // prefer easier over harder
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}).FirstOrDefault();
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if (beatmapInfo != null)
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return beatmapInfo;
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}
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return null;
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}
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private void populateValues()
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{
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if (api.LocalUser.Value.RulesetsStatistics == null)
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return;
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foreach (var kvp in api.LocalUser.Value.RulesetsStatistics)
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{
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// algorithm taken from https://github.com/ppy/osu-web/blob/e6e2825516449e3d0f3f5e1852c6bdd3428c3437/app/Models/User.php#L1505
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recommendedDifficultyMapping[kvp.Key] = Math.Pow((double)(kvp.Value.PP ?? 0), 0.4) * 0.195;
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}
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}
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/// <returns>
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/// Rulesets ordered descending by their respective recommended difficulties.
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/// The currently selected ruleset will always be first.
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/// </returns>
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private IEnumerable<string> orderedRulesets
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{
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get
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{
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if (LoadState < LoadState.Ready || ruleset.Value == null)
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return Enumerable.Empty<string>();
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return recommendedDifficultyMapping
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.OrderByDescending(pair => pair.Value)
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.Select(pair => pair.Key)
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.Where(r => !r.Equals(ruleset.Value.ShortName))
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.Prepend(ruleset.Value.ShortName);
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}
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}
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}
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}
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