Bring more diversity in the radio mode. fixes #54

2022-10-19 13:56:32 +02:00
parent b85553af34
commit c816b0db45
21 changed files with 750 additions and 104 deletions
@@ -0,0 +1,77 @@
+/*
+ * Copyright (C) 2022 Emeric Poupon
+ *
+ * This file is part of LMS.
+ *
+ * LMS is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * LMS is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with LMS.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include "ConsecutiveReleases.hpp"
+
+#include "services/database/Db.hpp"
+#include "services/database/Release.hpp"
+#include "services/database/Session.hpp"
+#include "services/database/Track.hpp"
+#include "utils/Logger.hpp"
+
+namespace Recommendation::PlaylistGeneratorConstraint
+{
+	ConsecutiveReleases::ConsecutiveReleases(Database::Db& db)
+		: _db {db}
+	{}
+
+	float
+	ConsecutiveReleases::computeScore(const std::vector<Database::TrackId>& trackIds, std::size_t trackIndex)
+	{
+		assert(!trackIds.empty());
+		assert(trackIndex <= trackIds.size() - 1);
+
+		const Database::ReleaseId releaseId {getReleaseId(trackIds[trackIndex])};
+
+		constexpr std::size_t rangeSize{ 3 }; // check up to rangeSize tracks before/after the target track
+		static_assert(rangeSize > 0);
+
+		float score {};
+		for (std::size_t i {1}; i < rangeSize; ++i)
+		{
+			if ((trackIndex >= i) && getReleaseId(trackIds[trackIndex - i]) == releaseId)
+				score += (1.f / static_cast<float>(i));
+
+			if ((trackIndex + i < trackIds.size()) && getReleaseId(trackIds[trackIndex + i]) == releaseId)
+				score += (1.f / static_cast<float>(i));
+		}
+
+		return score;
+	}
+
+	Database::ReleaseId
+	ConsecutiveReleases::getReleaseId(Database::TrackId trackId)
+	{
+		using namespace Database;
+
+		Session& dbSession {_db.getTLSSession()};
+		auto transaction {dbSession.createSharedTransaction()};
+
+		const Track::pointer track {Track::find(dbSession, trackId)};
+		if (!track)
+			return {};
+
+		const Release::pointer release {track->getRelease()};
+		if (!release)
+			return {};
+
+		return release->getId();
+	}
+} // namespace Recommendation
+