/*
 * Copyright 2016 (c) Anna Schumaker.
 *
 * NOTE: The playlist_iter type is defined in include/core/playlists/playlist.h
 */
#ifndef OCARINA_CORE_PLAYLISTS_ITERATOR_H
#define OCARINA_CORE_PLAYLISTS_ITERATOR_H
#include <core/playlists/playlist.h>

/* Called to set the playlist iterator to a specific position. */
static inline playlist_iter playlist_iter_get(struct playlist *playlist,
					      unsigned int     n)
{
	return playlist ? g_queue_peek_nth_link(&playlist->pl_tracks, n) : NULL;
}

/* Called to advance the requested playlist iterator. */
static inline playlist_iter playlist_iter_next(playlist_iter iter)
{
	return g_list_next(iter);
}

/* Called to get a pointer to the track at the requested iterator. */
static inline struct track *playlist_iter_track(playlist_iter iter)
{
	return iter ? iter->data : NULL;
}

/* Called to find the playlist index of the requested iterator. */
static inline int playlist_iter_index(struct playlist *playlist,
				      playlist_iter    iter)
{
	return (playlist && iter) ? g_queue_link_index(&playlist->pl_tracks, iter) : -1;
}

/* Called to iterate over the entire playlist. */
#define playlist_for_each(playlist, it)				\
	for (it = playlist_iter_get(playlist, 0); it; it = playlist_iter_next(it))


/* Called to set the index of the current track. */
static inline bool playlist_current_set(struct playlist *playlist,
					unsigned int     n)
{
	if (playlist)
		playlist->pl_current = playlist_iter_get(playlist, n);
	return playlist && playlist->pl_current;
}

/* Called to advance the current track. */
static inline bool playlist_current_next(struct playlist *playlist)
{
	if (playlist)
		playlist->pl_current = playlist_iter_next(playlist->pl_current);
	return playlist && playlist->pl_current;
}

/* Called to rewind the current track. */
static inline bool playlist_current_previous(struct playlist *playlist)
{
	if (playlist)
		playlist->pl_current = g_list_previous(playlist->pl_current);
	return playlist && playlist->pl_current;
}

/* Called to get a pointer to the current track. */
static inline struct track *playlist_current_track(struct playlist *playlist)
{
	return playlist ? playlist_iter_track(playlist->pl_current) : NULL;
}

/* Called to get the playlist index of the current track. */
static inline int playlist_current_index(struct playlist *playlist)
{
	return playlist ? playlist_iter_index(playlist, playlist->pl_current) : -1;
}

/* Called to find the nth track on a playlist. */
static inline struct track *playlist_at(struct playlist *playlist, unsigned int n)
{
	return playlist_iter_track(playlist_iter_get(playlist, n));
}
#endif /* OCARINA_CORE_PLAYLISTS_ITERATOR_H */