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130 lines
4.7 KiB
C#
130 lines
4.7 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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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.Extensions.IEnumerableExtensions;
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using osu.Framework.Graphics;
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using osu.Game.Online.API;
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using osu.Game.Online.API.Requests;
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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 IRulesetStore rulesets { get; set; }
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[Resolved]
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private Bindable<RulesetInfo> ruleset { get; set; }
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/// <summary>
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/// The user for which the last requests were run.
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/// </summary>
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private int? requestedUserId;
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private readonly Dictionary<IRulesetInfo, double> recommendedDifficultyMapping = new Dictionary<IRulesetInfo, double>();
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private readonly IBindable<APIState> apiState = new Bindable<APIState>();
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[BackgroundDependencyLoader]
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private void load()
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{
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apiState.BindTo(api.State);
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apiState.BindValueChanged(onlineStateChanged, 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 (var 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.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 fetchRecommendedValues()
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{
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if (recommendedDifficultyMapping.Count > 0 && api.LocalUser.Value.Id == requestedUserId)
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return;
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requestedUserId = api.LocalUser.Value.Id;
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// only query API for built-in rulesets
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rulesets.AvailableRulesets.Where(ruleset => ruleset.OnlineID >= 0 && ruleset.OnlineID <= ILegacyRuleset.MAX_LEGACY_RULESET_ID).ForEach(rulesetInfo =>
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{
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var req = new GetUserRequest(api.LocalUser.Value.Id, rulesetInfo);
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req.Success += result =>
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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[rulesetInfo] = Math.Pow((double)(result.Statistics.PP ?? 0), 0.4) * 0.195;
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};
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api.Queue(req);
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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<IRulesetInfo> 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<RulesetInfo>();
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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))
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.Prepend(ruleset.Value);
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}
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}
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private void onlineStateChanged(ValueChangedEvent<APIState> state) => Schedule(() =>
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{
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switch (state.NewValue)
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{
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case APIState.Online:
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fetchRecommendedValues();
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break;
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}
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});
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}
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}
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