/*
 * Copyright 2008-2013 Various Authors
 * Copyright 2006 Timo Hirvonen
 *
 * This program 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 2 of the
 * License, or (at your option) any later version.
 *
 * This program 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 this program; if not, see <http://www.gnu.org/licenses/>.
 */

#include "track.h"
#include "lib.h"
#include "iter.h"
#include "search_mode.h"
#include "window.h"
#include "options.h"
#include "uchar.h"
#include "xmalloc.h"
#include "debug.h"
#include "misc.h"

#include <string.h>

void simple_track_init(struct simple_track *track, struct track_info *ti)
{
	track->info = ti;
	track->marked = 0;
	RB_CLEAR_NODE(&track->tree_node);
}

struct simple_track *simple_track_new(struct track_info *ti)
{
	struct simple_track *t = xnew(struct simple_track, 1);

	track_info_ref(ti);
	simple_track_init(t, ti);
	return t;
}

GENERIC_ITER_PREV(simple_track_get_prev, struct simple_track, node)
GENERIC_ITER_NEXT(simple_track_get_next, struct simple_track, node)

int simple_track_search_get_current(void *data, struct iter *iter)
{
	return window_get_sel(data, iter);
}

int _simple_track_search_matches(struct iter *iter, const char *text)
{
	unsigned int flags = TI_MATCH_TITLE;
	struct simple_track *track = iter_to_simple_track(iter);

	if (!search_restricted)
		flags |= TI_MATCH_ARTIST | TI_MATCH_ALBUM | TI_MATCH_ALBUMARTIST;

	return track_info_matches(track->info, text, flags);
}

int simple_track_search_matches(void *data, struct iter *iter, const char *text)
{
	int rc = _simple_track_search_matches(iter, text);
	if (rc)
		window_set_sel(data, iter);
	return rc;
}

void shuffle_insert(struct rb_root *root, struct shuffle_info *previous, struct shuffle_info *next)
{
	BUG_ON(root == NULL);
	BUG_ON(next == NULL);

	if (previous == next)
		return;
	rb_erase(&next->tree_node, root);

	struct rb_node *parent = previous ? &previous->tree_node : NULL;
	struct rb_node **new = parent ? &parent->rb_right : &root->rb_node;
	while (*new) {
		parent = *new;
		new = &(*new)->rb_left;
	}

	rb_link_node(&next->tree_node, parent, new);
	rb_insert_color(&next->tree_node, root);
}

struct shuffle_info *shuffle_list_get_next(struct rb_root *root, struct shuffle_info *cur,
		int (*filter_callback)(const struct album *))
{
	struct rb_node *node;

	if (!cur) {
		if (auto_reshuffle)
			shuffle_list_reshuffle(root);
		return tree_node_to_shuffle_info(rb_first(root));
	}

	node = rb_next(&cur->tree_node);
again:
	while (node) {
		struct shuffle_info *track = tree_node_to_shuffle_info(node);

		if (filter_callback == NULL || filter_callback(track->album))
			return track;
		node = rb_next(node);
	}
	if (repeat) {
		if (auto_reshuffle)
			shuffle_list_reshuffle(root);
		node = rb_first(root);
		goto again;
	}
	return NULL;
}

struct shuffle_info *shuffle_list_get_prev(struct rb_root *root, struct shuffle_info *cur,
		int (*filter_callback)(const struct album *))
{
	struct rb_node *node;

	if (!cur) {
		if (auto_reshuffle)
			shuffle_list_reshuffle(root);
		return tree_node_to_shuffle_info(rb_last(root));
	}

	node = rb_prev(&cur->tree_node);
again:
	while (node) {
		struct shuffle_info *track = tree_node_to_shuffle_info(node);

		if (filter_callback == NULL || filter_callback(track->album))
			return track;
		node = rb_prev(node);
	}
	if (repeat) {
		if (auto_reshuffle)
			shuffle_list_reshuffle(root);
		node = rb_last(root);
		goto again;
	}
	return NULL;
}

struct simple_track *simple_list_get_next(struct list_head *head, struct simple_track *cur,
		int (*filter_callback)(const struct album *), bool allow_repeat)
{
	struct list_head *item;

	if (cur == NULL) {
		if (!allow_repeat)
			return NULL;
		return to_simple_track(head->next);
	}

	item = cur->node.next;
again:
	while (item != head) {
		struct simple_track *track = to_simple_track(item);

		if (filter_callback == NULL || filter_callback(((struct tree_track *)track)->album))
			return track;
		item = item->next;
	}
	item = head->next;
	if (allow_repeat && repeat)
		goto again;
	return NULL;
}

struct simple_track *simple_list_get_prev(struct list_head *head, struct simple_track *cur,
		int (*filter_callback)(const struct album *), bool allow_repeat)
{
	struct list_head *item;

	if (cur == NULL) {
		if (!allow_repeat)
			return NULL;
		return to_simple_track(head->prev);
	}

	item = cur->node.prev;
again:
	while (item != head) {
		struct simple_track *track = to_simple_track(item);

		if (filter_callback == NULL || filter_callback(((struct tree_track *)track)->album))
			return track;
		item = item->prev;
	}
	item = head->prev;
	if (allow_repeat && repeat)
		goto again;
	return NULL;
}

void sorted_list_add_track(struct list_head *head, struct rb_root *tree_root, struct simple_track *track,
		const sort_key_t *keys, int tiebreak)
{
	struct rb_node **new = &(tree_root->rb_node), *parent = NULL, *curr, *next;
	struct list_head *node;
	int result = 0;

	/* try to locate track in tree */
	while (*new) {
		const struct simple_track *t = tree_node_to_simple_track(*new);
		result = track_info_cmp(track->info, t->info, keys);

		parent = *new;
		if (result < 0)
			new = &(parent->rb_left);
		else if (result > 0)
			new = &(parent->rb_right);
		else
			break;
	}

	/* duplicate is present in the tree */
	if (parent && result == 0) {
		if (tiebreak < 0) {
			node = &(tree_node_to_simple_track(parent)->node);
			rb_replace_node(parent, &track->tree_node, tree_root);
			RB_CLEAR_NODE(parent);
		} else {
			next = rb_next(parent);
			node = next ? &(tree_node_to_simple_track(next)->node) : head;
		}
	} else {
		rb_link_node(&track->tree_node, parent, new);
		curr = *new;
		rb_insert_color(&track->tree_node, tree_root);
		if (result < 0) {
			node = &(tree_node_to_simple_track(parent)->node);
		} else if (result > 0) {
			next = rb_next(curr);
			node = next ? &(tree_node_to_simple_track(next)->node) : head;
		} else {
			/* rbtree was empty, just add after list head */
			node = head;
		}
	}
	list_add(&track->node, node->prev);
}

void sorted_list_remove_track(struct list_head *head, struct rb_root *tree_root, struct simple_track *track)
{
	struct simple_track *next_track;
	struct rb_node *tree_next;

	if (!RB_EMPTY_NODE(&track->tree_node)) {
		next_track = (track->node.next != head) ? to_simple_track(track->node.next) : NULL;
		tree_next = rb_next(&track->tree_node);

		if (next_track && (!tree_next || tree_node_to_simple_track(tree_next) != next_track)) {
			rb_replace_node(&track->tree_node, &next_track->tree_node, tree_root);
			RB_CLEAR_NODE(&track->tree_node);
		} else
			rb_erase(&track->tree_node, tree_root);
	}
	list_del(&track->node);
}

void rand_list_rebuild(struct list_head *head, struct rb_root *tree_root)
{
	struct list_head *item, *tmp;
	struct rb_root tmp_tree = RB_ROOT;
	struct simple_track **track_array;
	static const sort_key_t empty_sort_keys[] = { SORT_INVALID };

	unsigned int len = 0, track_cnt = 0;

	list_for_each(item, head) {
		len++;
	}
	track_array = xmalloc(len * sizeof(track_array[0]));

	LIST_HEAD(tmp_head);
	list_for_each_safe(item, tmp, head) {
		struct simple_track *track = to_simple_track(item);
		sorted_list_remove_track(head, tree_root, track);
		track_array[track_cnt] = track;
		track_cnt++;
	}
	shuffle_array(track_array, len, sizeof(track_array[0]));
	for (unsigned int i=0; i<len; i++) {
		sorted_list_add_track(&tmp_head, &tmp_tree, track_array[i], empty_sort_keys, 0);
	}
	free(track_array);

	tree_root->rb_node = tmp_tree.rb_node;
	_list_add(head, tmp_head.prev, tmp_head.next);
}

void sorted_list_rebuild(struct list_head *head, struct rb_root *tree_root, const sort_key_t *keys)
{
	struct list_head *item, *tmp;
	struct rb_root tmp_tree = RB_ROOT;
	LIST_HEAD(tmp_head);

	list_for_each_safe(item, tmp, head) {
		struct simple_track *track = to_simple_track(item);
		sorted_list_remove_track(head, tree_root, track);
		sorted_list_add_track(&tmp_head, &tmp_tree, track, keys, 0);
	}
	tree_root->rb_node = tmp_tree.rb_node;
	_list_add(head, tmp_head.prev, tmp_head.next);
}

static int compare_rand(const struct rb_node *a, const struct rb_node *b)
{
	struct shuffle_info *tr_a = tree_node_to_shuffle_info(a);
	struct shuffle_info *tr_b = tree_node_to_shuffle_info(b);

	if (tr_a->rand < tr_b->rand)
		return -1;
	if (tr_a->rand > tr_b->rand)
		return +1;

	return 0;
}

static void shuffle_info_init(struct shuffle_info *info, struct album *album)
{
	info->rand = rand() / ((double) RAND_MAX + 1);
	info->album = album;
}

void shuffle_list_add(struct shuffle_info *track, struct rb_root *tree_root, struct album *album)
{
	struct rb_node **new = &(tree_root->rb_node), *parent = NULL;

	shuffle_info_init(track, album);

	/* try to locate track in tree */
	while (*new) {
		int result = compare_rand(&track->tree_node, *new);

		parent = *new;
		if (result < 0)
			new = &((*new)->rb_left);
		else if (result > 0)
			new = &((*new)->rb_right);
		else {
			/* very unlikely, try again! */
			shuffle_list_add(track, tree_root, album);
			return;
		}
	}

	rb_link_node(&track->tree_node, parent, new);
	rb_insert_color(&track->tree_node, tree_root);
}

void shuffle_list_reshuffle(struct rb_root *tree_root)
{
	struct rb_node *node, *tmp;
	struct rb_root tmptree = RB_ROOT;

	rb_for_each_safe(node, tmp, tree_root) {
		struct shuffle_info *track = tree_node_to_shuffle_info(node);
		struct album *album = track->album;
		rb_erase(node, tree_root);
		shuffle_list_add(track, &tmptree, album);
	}

	tree_root->rb_node = tmptree.rb_node;
}

/* expensive */
void list_add_rand(struct list_head *head, struct list_head *node, int nr)
{
	struct list_head *item;
	int pos;

	pos = rand() % (nr + 1);
	item = head;
	if (pos <= nr / 2) {
		while (pos) {
			item = item->next;
			pos--;
		}
		/* add after item */
		list_add(node, item);
	} else {
		pos = nr - pos;
		while (pos) {
			item = item->prev;
			pos--;
		}
		/* add before item */
		list_add_tail(node, item);
	}
}

int simple_list_for_each_marked(struct list_head *head, track_info_cb cb,
		void *data, int reverse)
{
	struct simple_track *t;
	int rc = 0;

	if (reverse) {
		list_for_each_entry_reverse(t, head, node) {
			if (t->marked) {
				rc = cb(data, t->info);
				if (rc)
					break;
			}
		}
	} else {
		list_for_each_entry(t, head, node) {
			if (t->marked) {
				rc = cb(data, t->info);
				if (rc)
					break;
			}
		}
	}
	return rc;
}

int simple_list_for_each(struct list_head *head, track_info_cb cb, void *data,
		int reverse)
{
	struct simple_track *t;
	int rc = 0;

	if (reverse) {
		list_for_each_entry_reverse(t, head, node) {
			if ((rc = cb(data, t->info)))
				break;
		}
	} else {
		list_for_each_entry(t, head, node) {
			if ((rc = cb(data, t->info)))
				break;
		}
	}

	return rc;
}
