Bring more diversity in the radio mode. fixes #54

src/libs/services/recommendation/impl/playlist-constraints/ConsecutiveArtists.cpp

@@ -0,0 +1,97 @@
+/*
+ * 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 "ConsecutiveArtists.hpp"
+
+#include <algorithm>
+
+#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
+{
+	namespace
+	{
+		std::size_t
+		countCommonArtists(const ArtistContainer& artists1, const ArtistContainer& artists2)
+		{
+			ArtistContainer intersection;
+
+			std::set_intersection(std::cbegin(artists1), std::cend(artists1),
+						std::cbegin(artists2), std::cend(artists2),
+						std::back_inserter(intersection));
+
+			return intersection.size();
+		}
+	}
+
+	ConsecutiveArtists::ConsecutiveArtists(Database::Db& db)
+		: _db {db}
+	{}
+
+	float
+	ConsecutiveArtists::computeScore(const std::vector<Database::TrackId>& trackIds, std::size_t trackIndex)
+	{
+		assert(!trackIds.empty());
+		assert(trackIndex <= trackIds.size() - 1);
+
+		const ArtistContainer artists {getArtists(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)
+				score += countCommonArtists(artists, getArtists(trackIds[trackIndex - i])) / static_cast<float>(i);
+
+			if (trackIndex + i < trackIds.size())
+				score += countCommonArtists(artists, getArtists(trackIds[trackIndex + i])) / static_cast<float>(i);
+		}
+
+		return score;
+	}
+
+	ArtistContainer
+	ConsecutiveArtists::getArtists(Database::TrackId trackId)
+	{
+		using namespace Database;
+
+		ArtistContainer res;
+
+		Session& dbSession {_db.getTLSSession()};
+		auto transaction {dbSession.createSharedTransaction()};
+
+		const Track::pointer track {Track::find(dbSession, trackId)};
+		if (!track)
+			return res;
+
+		res = track->getArtistIds({});
+		std::sort(std::begin(res), std::end(res));
+
+		return res;
+	}
+
+
+} // namespace Recommendation
+

src/libs/services/recommendation/impl/playlist-constraints/ConsecutiveArtists.hpp

@@ -0,0 +1,45 @@
+/*
+ * 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/>.
+ */
+
+#pragma once
+
+#include "IConstraint.hpp"
+
+#include "services/database/ReleaseId.hpp"
+
+namespace Database
+{
+	class Db;
+}
+
+namespace Recommendation::PlaylistGeneratorConstraint
+{
+	class ConsecutiveArtists : public IConstraint
+	{
+		public:
+			ConsecutiveArtists(Database::Db& db);
+
+		private:
+			 float computeScore(const TrackContainer& trackIds, std::size_t trackIndex) override;
+			 ArtistContainer getArtists(Database::TrackId trackId);
+
+			 Database::Db& _db;
+	};
+} // namespace Recommendation::PlaylistGeneratorConstraint
+

src/libs/services/recommendation/impl/playlist-constraints/ConsecutiveReleases.cpp

@@ -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
+

src/libs/services/recommendation/impl/playlist-constraints/ConsecutiveReleases.hpp

@@ -0,0 +1,46 @@
+/*
+ * 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/>.
+ */
+
+#pragma once
+
+#include "IConstraint.hpp"
+
+#include "services/database/ReleaseId.hpp"
+
+namespace Database
+{
+	class Db;
+}
+
+namespace Recommendation::PlaylistGeneratorConstraint
+{
+	class ConsecutiveReleases : public IConstraint
+	{
+		public:
+			ConsecutiveReleases(Database::Db& db);
+
+		private:
+			 float computeScore(const std::vector<Database::TrackId>& trackIds, std::size_t trackIndex) override;
+
+			 Database::ReleaseId getReleaseId(Database::TrackId trackId);
+
+			 Database::Db& _db;
+	};
+} // namespace Recommendation
+

src/libs/services/recommendation/impl/playlist-constraints/DuplicateTracks.cpp

@@ -0,0 +1,33 @@
+/*
+ * 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 "DuplicateTracks.hpp"
+
+#include <algorithm>
+
+namespace Recommendation::PlaylistGeneratorConstraint
+{
+	float
+	DuplicateTracks::computeScore(const std::vector<Database::TrackId>& trackIds, std::size_t trackIndex)
+	{
+		const auto count {std::count(std::cbegin(trackIds), std::cend(trackIds), trackIds[trackIndex])};
+		return count == 1 ? 0 : 1000;
+	}
+} // namespace Recommendation
+

src/libs/services/recommendation/impl/playlist-constraints/DuplicateTracks.hpp

@@ -0,0 +1,32 @@
+/*
+ * 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/>.
+ */
+
+#pragma once
+
+#include "IConstraint.hpp"
+
+namespace Recommendation::PlaylistGeneratorConstraint
+{
+	class DuplicateTracks : public IConstraint
+	{
+		private:
+			float computeScore(const std::vector<Database::TrackId>& trackIds, std::size_t trackIndex) override;
+	};
+} // namespace Recommendation::PlaylistGeneratorConstraints
+

src/libs/services/recommendation/impl/playlist-constraints/IConstraint.hpp

@@ -0,0 +1,39 @@
+/*
+ * 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/>.
+ */
+
+#pragma once
+
+#include <vector>
+
+#include "services/recommendation/Types.hpp"
+
+namespace Recommendation::PlaylistGeneratorConstraint
+{
+	class IConstraint
+	{
+		public:
+			virtual ~IConstraint() = default;
+
+			// compute the score of the track at index trackIndex
+			// 0: best
+			// 1: worst
+			// > 1 : violation
+			virtual float computeScore(const TrackContainer& trackIds, std::size_t trackIndex) = 0;
+	};
+} // namespace Recommendation