ocarina/include/core/queue.h

/**
 * @file
 * Copyright 2013 (c) Anna Schumaker.
 */
#ifndef OCARINA_CORE_QUEUE_H
#define OCARINA_CORE_QUEUE_H

#include <core/file.h>
#include <core/tags/track.h>

#include <vector>
#include <list>

/**
 * Enum defining queue flags.
 */
enum queue_flags {
	/** Queue is enabled. */
	Q_ENABLED	= (1 << 0),

	/** Queue will pick songs randomly. */
	Q_RANDOM	= (1 << 1),

	/** Queue will not remove songs when picked.  */
	Q_REPEAT	= (1 << 2),

	/** Queue will not be sorted. */
	Q_NO_SORT	= (1 << 3),
};


/**
 * Mask of valid flags.
 */
static const unsigned int Q_FLAG_MASK = Q_ENABLED | Q_RANDOM | Q_REPEAT | Q_NO_SORT;


/**
 * Track fields that can be compared.
 */
enum sort_t {
	/** Artist name */
	SORT_ARTIST,
	/** Album name */
	SORT_ALBUM,
	/** Play count */
	SORT_COUNT,
	/** Genre */
	SORT_GENRE,
	/** Track length */
	SORT_LENGTH,
	/** Date the track was last played */
	SORT_PLAYED,
	/** Track title */
	SORT_TITLE,
	/** Track number */
	SORT_TRACK,
	/** Track year */
	SORT_YEAR,
};


/**
 * Struct for passing sort parameters.
 */
struct sort_info {
	sort_t field;
	bool   ascending;
};


/**
 * Class defining playback queues.
 */
class Queue {
protected:
	std :: vector <Track *> _tracks;
	std :: vector <struct sort_info> _sort_order;
	unsigned int _cur;
	unsigned int _flags;
	unsigned int _length;

	unsigned int find_sorted_id(Track *);
	unsigned int _add_at(Track *, unsigned int);
	void _del_at(Track *, unsigned int);

public:
	/**
	 * Default queue constructor.
	 */
	Queue();

	/**
	 * Alternat queue constructor.
	 * @param  f  Create a queue with flags set to f.
	 */
	Queue(unsigned int);

	/**
	 * Queue destructor.
	 */
	~Queue();

	/**
	 * Write a queue to disk.
	 * @param  f  File queue data will be written to.
	 */
	void write(File &);

	/**
	 * Read a queue from disk.
	 * @param  f  File to read queue data from.
	 */
	void read(File &);


	/**
	 * Set a queue flag.
	 * @param  f  queue_flag to set.
	 */
	virtual void set_flag(queue_flags);

	/**
	 * Clear a queue flag.
	 * @param  f  queue_flag to clear.
	 */
	virtual void unset_flag(queue_flags);

	/**
	 * Check if a queue has a specific flag set.
	 * @param  f  queue_flag to check.
	 * @return true if queue_flag is set.
	 */
	bool has_flag(queue_flags);


	/**
	 * Add a track to the queue.
	 * @param  track  Track to add to the queue.
	 * @return The index of the track in the queue.
	 */
	virtual unsigned int add(Track *);

	/**
	 * Remove all instances of a track from the queue.
	 * @param  track Track to remove from the queue.
	 */
	virtual void del(Track *);

	/**
	 * Remove a track based on its queue index.
	 * @param  index  Track index to remove from the queue.
	 */
	virtual void del(unsigned int);

	/**
	 * Signal to the queue that a track has been updated.
	 * @param  track  The track that has been modified.
	 */
	void updated(Track *);

	/**
	 * Pick the next track from the queue.
	 * @return The next Track on the queue.
	 */
	Track *next();


	/**
	 * Find the size of the queue.
	 * @return The number of tracks on the queue.
	 */
	unsigned int size();

	/**
	 * Find the size of the queue, as a string.
	 * @return The number of tracks on the queue, in string form.
	 */
	const std::string size_str();

	/**
	 * Find the runtime of the queue.
	 * @return The runtime of the queue, as a string.
	 */
	const std::string length_str();


	/**
	 * Add a new parameter for sorting the queue.
	 * @param  field  Field to sort by.
	 * @param  reset  Set to true if current sort data should be discarded.
	 */
	virtual void sort(sort_t, bool);

	/**
	 * Access a track by index.
	 * @param  index  The index to look up.
	 * @return  The track found at the requested index.
	 */
	Track *operator[](unsigned int);

	/**
	 * Tell the queue that a track has been selected for playback without
	 * calling Queue :: next().
	 * @param  index  The index that is now playing.
	 */
	void track_selected(unsigned int);
};

#endif /* OCARINA_CORE_QUEUE_H */