/*
 * Copyright 2013 (c) Anna Schumaker.
 *
 * Queues are lists of tracks that the user has requested to play next.
 * Users of queues are expected to implement their own save and load functions,
 * and to provide a filled out queue_ops structure during initialization.
 */
#ifndef OCARINA_CORE_QUEUE_H
#define OCARINA_CORE_QUEUE_H

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

struct queue;


struct queue_ops {
	/* Called to tell a higher layer that a queue has been initialized. */
	void *(*qop_init)(struct queue *, void *);

	/* Called to tell a higher layer that a queue is deinitializing. */
	void (*qop_deinit)(struct queue *);
};


struct queue {
	GQueue         q_tracks;  /* The queue's list of tracks.             */
	void          *q_private; /* The queue's private data.               */

	const struct queue_ops *q_ops; /* The queue's operations vector.     */
};


/* Called to initialize a queue. */
void queue_init(struct queue *, const struct queue_ops *, void *);

/* Called to deinitialize a queue. */
void queue_deinit(struct queue *);


/* Called to access the queued track at a given index. */
static inline struct track *queue_at(struct queue *queue, unsigned int index)
{
	return (struct track *)g_queue_peek_nth(&queue->q_tracks, index);
}

#endif /* OCARINA_CORE_QUEUE_H */