/*

 * Copyright (C) 2021, Google LLC.

 * Based on diffcore-order.c, which is Copyright (C) 2005, Junio C Hamano

 */

#include "git-compat-util.h"

#include "gettext.h"

#include "diff.h"

#include "diffcore.h"

void diffcore_rotate(struct diff_options *opt)

{

  struct diff_queue_struct *q = &diff_queued_diff;

  struct diff_queue_struct outq = DIFF_QUEUE_INIT;

  int rotate_to, i;

  if (!q->nr)

    return;

  for (i = 0; i < q->nr; i++) {

    int cmp = strcmp(opt->rotate_to, q->queue[i]->two->path);

    if (!cmp)

      break; /* exact match */

    if (!opt->rotate_to_strict && cmp < 0)

      break; /* q->queue[i] is now past the target pathname */

  }

  if (q->nr <= i) {

    /* we did not find the specified path */

    if (opt->rotate_to_strict)

      die(_("No such path '%s' in the diff"), opt->rotate_to);

    return;

  }

  rotate_to = i;

  for (i = rotate_to; i < q->nr; i++)

    diff_q(&outq, q->queue[i]);

  for (i = 0; i < rotate_to; i++) {

    if (opt->skip_instead_of_rotate)

      diff_free_filepair(q->queue[i]);

    else

      diff_q(&outq, q->queue[i]);

  }

  free(q->queue);

  *q = outq;

}