#define _GNU_SOURCE

#include "block_range.h"
#include <stdio.h>

struct block_range *new_block_range(blk64_t start, blk64_t end)
{
	struct block_range *range = malloc(sizeof(*range));
	range->start = start;
	range->end = end;
	range->next = NULL;
	return range;
}

void add_blocks_to_range(struct block_range_list *list, blk64_t blk_start,
			 blk64_t blk_end)
{
	if (list->head == NULL)
		list->head = list->tail = new_block_range(blk_start, blk_end);
	else if (list->tail->end + 1 == blk_start)
		list->tail->end += (blk_end - blk_start + 1);
	else {
		struct block_range *range = new_block_range(blk_start, blk_end);
		list->tail->next = range;
		list->tail = range;
	}
}

static void remove_head(struct block_range_list *list)
{
	struct block_range *next_range = list->head->next;

	free(list->head);
	if (next_range == NULL)
		list->head = list->tail = NULL;
	else
		list->head = next_range;
}

void delete_block_ranges(struct block_range_list *list)
{
	while (list->head)
		remove_head(list);
}

int write_block_ranges(FILE *f, struct block_range *range,
				     char *sep)
{
	int len;
	char *buf;

	while (range) {
		if (range->start == range->end)
			len = asprintf(&buf, "%llu%s", range->start, sep);
		else
			len = asprintf(&buf, "%llu-%llu%s", range->start,
				       range->end, sep);
		if (fwrite(buf, 1, len, f) != (size_t)len) {
			free(buf);
			return -1;
		}
		free(buf);
		range = range->next;
	}

	len = strlen(sep);
	if (fseek(f, -len, SEEK_CUR) == -len)
		return -1;
	return 0;
}

blk64_t consume_next_block(struct block_range_list *list)
{
	blk64_t ret = list->head->start;

	list->head->start += 1;
	if (list->head->start > list->head->end)
		remove_head(list);
	return ret;
}