WIP: Add playlists/queues and add support for Sailfish back

core/include/JellyfinQt/model/shuffle.h

@@ -0,0 +1,166 @@
+/*
+ * Sailfin: a Jellyfin client written using Qt
+ * Copyright (C) 2021 Chris Josten and the Sailfin Contributors.
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * This library 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
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
+ */
+#ifndef JELLYFIN_MODEL_SHUFFLE_H
+#define JELLYFIN_MODEL_SHUFFLE_H
+
+#include "playlist.h"
+#include "../model/item.h"
+
+
+namespace Jellyfin {
+namespace Model {
+
+/**
+ * @brief Interface for an algorithm shuffling a playlist.
+ */
+class Shuffle {
+public:
+    Shuffle(const Playlist *parent) : m_playlist(parent) {}
+
+    /**
+     * @brief If this Shuffle implementation shuffles the entire list in advance.
+     * @return True if this shuffle class shuffles the entire list in advance
+     *
+     * Some shuffle implementations may only shuffle the next item as they go.
+     */
+    virtual bool canShuffleInAdvance() { return true; }
+
+    /**
+     * @brief Shuffle the list in advance. Should only be called if canShuffleInAdvance()
+     * is called.
+     */
+    virtual void shuffleInAdvance() {}
+
+    /**
+     * @brief The shuffle should determine the next item.
+     */
+    virtual void next() {};
+
+    /**
+     * @brief The shuffle should determine the previous item.
+     */
+    virtual void previous() {};
+
+    /**
+     * @brief Set the index of the now playing item.
+     * @param i
+     */
+    virtual void setIndex(int i) {};
+
+    /**
+     * @return the index of the currently playing item
+     */
+    virtual int currentItem() const { return -1; }
+
+    /**
+     * @brief Determine the item index at at the shuffled index
+     * @param index The shuffled index
+     * @return The actual index
+     *
+     * If canShuffleInAdvance() returns false, a new implemention is not needed
+     * or -1 may be returned. This function should not even be called in that case.
+     */
+    virtual int itemAt(int index) const { return -1; }
+
+    /**
+     * @return the index of the next item
+     */
+    virtual int nextItem() const { return -1; }
+
+    /**
+     * @brief Sets whether the shuffler to loop over the list if all items are played.
+     */
+    void setRepeatAll(bool repeatAll) { m_repeatAll = repeatAll; }
+protected:
+    /// Playlist that can be used to gather information about the songs if needed for the algorithm
+    const Playlist *m_playlist;
+    bool m_repeatAll = false;
+    static int random(int max, int min = 0);
+};
+
+/**
+ * @brief A shuffler that does not shuffle.
+ */
+class NoShuffle : public Shuffle {
+public:
+    NoShuffle(const Playlist *parent);
+
+    virtual int currentItem() const override;
+    virtual int nextItem() const override;
+
+    virtual void previous() override;
+    virtual void next() override;
+    virtual void setIndex(int i) override;
+protected:
+    int nextIndex() const;
+    int previousIndex() const;
+    int m_index = 0;
+
+};
+
+/**
+ * @brief Base class for shuffles that shuffle the entire list in advance
+ */
+class ListShuffleBase : public NoShuffle {
+public:
+    ListShuffleBase(const Playlist *parent);
+    virtual int currentItem() const override;
+    virtual int nextItem() const override;
+protected:
+    QVector<int> m_map;
+};
+
+/**
+ * @brief A simple shuffler which shuffles each item in the list in advance
+ */
+class SimpleListShuffle : public ListShuffleBase {
+public:
+    SimpleListShuffle(const Playlist *parent);
+    virtual void shuffleInAdvance() override;
+};
+
+/**
+ * @brief A shuffler that is pretty random. Does not care about repeating items in a list.
+ */
+class RandomShuffle : public Shuffle {
+public:
+    RandomShuffle(const Playlist *parent);
+    bool canShuffleInAdvance() override;
+    virtual int currentItem() const override;
+    virtual int nextItem() const override;
+    virtual void previous() override;
+    virtual void next() override;
+protected:
+    int m_previous, m_current, m_next = -1;
+};
+
+/**
+ * @brief A smart shuffler that shuffles a list with a few constraints to make it appear "more random" to an user.
+ *
+ * This shuffler tries to place to avoid placing tracks of the same album, artist, and genre next to each other.
+ * This way, the user may perceive the list as more random
+ */
+class VariedListShuffle {
+
+};
+
+} // NS Model
+} // NS Jellyfin
+
+#endif // SHUFFLE_H