#include <lcthw/list_algos.h>

int List_bubble_sort(List *list, List_compare cmp)
{
  List_validate(list);

  int swapped = 1;

  while(swapped == 1) {
    swapped = 0;

    LIST_FOREACH(list, first, next, cur) {
      if(cur->next == NULL) {
        continue;
      }

      if(cmp(cur->value, cur->next->value) > 0) {
        List_swap(cur, cur->next);
        swapped = 1;
      }
    }
  }

  return 0;
}

List *_List_merge_sort_merge(List *left, List *right, List_compare cmp)
{
  List *result = List_create();

  while(List_count(left) > 0 && List_count(right) > 0) {
    if(cmp(List_first(left), List_first(right)) <= 0) {
      List_push(result, List_shift(left));
      continue;
    }

    List_push(result, List_shift(right));
  }

  while(List_count(left) > 0) {
    List_push(result, List_shift(left));
  }

  while(List_count(right) > 0) {
    List_push(result, List_shift(right));
  }

  return result;
}

List *List_merge_sort(List *list, List_compare cmp)
{
  if(List_count(list) <= 1) {
    return List_copy(list);;
  }

  int i = 0;
  List *left = List_create();
  List *right = List_create();

  LIST_FOREACH(list, first, next, cur) {
    if(i % 2 == 0) {
      List_push(right, cur->value);
    } else {
      List_push(left, cur->value);
    }
    i++;
  }

  left = List_merge_sort(left, cmp);
  right = List_merge_sort(right, cmp);

  List *result = _List_merge_sort_merge(left, right, cmp);

  List_destroy(left);
  List_destroy(right);

  return result;
}