#include "builtin.h"

#include "config.h"

#include "commit.h"

#include "gettext.h"

#include "hex.h"

#include "object-name.h"

#include "parse-options.h"

#include "repository.h"

#include "commit-reach.h"

static int show_merge_base(struct commit **rev, int rev_nr, int show_all)

{

  struct commit_list *result = NULL, *r;

  if (repo_get_merge_bases_many_dirty(the_repository, rev[0],

              rev_nr - 1, rev + 1, &result) < 0) {

    free_commit_list(result);

    return -1;

  }

  if (!result)

    return 1;

  for (r = result; r; r = r->next) {

    printf("%s\n", oid_to_hex(&r->item->object.oid));

    if (!show_all)

      break;

  }

  free_commit_list(result);

  return 0;

}

static const char * const merge_base_usage[] = {

  N_("git merge-base [-a | --all] <commit> <commit>..."),

  N_("git merge-base [-a | --all] --octopus <commit>..."),

  N_("git merge-base --is-ancestor <commit> <commit>"),

  N_("git merge-base --independent <commit>..."),

  N_("git merge-base --fork-point <ref> [<commit>]"),

  NULL

};

static struct commit *get_commit_reference(const char *arg)

{

  struct object_id revkey;

  struct commit *r;

  if (repo_get_oid(the_repository, arg, &revkey))

    die("Not a valid object name %s", arg);

  r = lookup_commit_reference(the_repository, &revkey);

  if (!r)

    die("Not a valid commit name %s", arg);

  return r;

}

static int handle_independent(int count, const char **args)

{

  struct commit_list *revs = NULL, *rev;

  int i;

  for (i = count - 1; i >= 0; i--)

    commit_list_insert(get_commit_reference(args[i]), &revs);

  reduce_heads_replace(&revs);

  if (!revs)

    return 1;

  for (rev = revs; rev; rev = rev->next)

    printf("%s\n", oid_to_hex(&rev->item->object.oid));

  free_commit_list(revs);

  return 0;

}

static int handle_octopus(int count, const char **args, int show_all)

{

  struct commit_list *revs = NULL;

  struct commit_list *result = NULL, *rev;

  int i;

  for (i = count - 1; i >= 0; i--)

    commit_list_insert(get_commit_reference(args[i]), &revs);

  if (get_octopus_merge_bases(revs, &result) < 0) {

    free_commit_list(revs);

    free_commit_list(result);

    return 128;

  }

  free_commit_list(revs);

  reduce_heads_replace(&result);

  if (!result)

    return 1;

  for (rev = result; rev; rev = rev->next) {

    printf("%s\n", oid_to_hex(&rev->item->object.oid));

    if (!show_all)

      break;

  }

  free_commit_list(result);

  return 0;

}

static int handle_is_ancestor(int argc, const char **argv)

{

  struct commit *one, *two;

  int ret;

  if (argc != 2)

    die("--is-ancestor takes exactly two commits");

  one = get_commit_reference(argv[0]);

  two = get_commit_reference(argv[1]);

  ret = repo_in_merge_bases(the_repository, one, two);

  if (ret < 0)

    exit(128);

  if (ret)

    return 0;

  else

    return 1;

}

static int handle_fork_point(int argc, const char **argv)

{

  struct object_id oid;

  struct commit *derived, *fork_point;

  const char *commitname;

  commitname = (argc == 2) ? argv[1] : "HEAD";

  if (repo_get_oid(the_repository, commitname, &oid))

    die("Not a valid object name: '%s'", commitname);

  derived = lookup_commit_reference(the_repository, &oid);

  fork_point = get_fork_point(argv[0], derived);

  if (!fork_point)

    return 1;

  printf("%s\n", oid_to_hex(&fork_point->object.oid));

  return 0;

}

int cmd_merge_base(int argc, const char **argv, const char *prefix)

{

  struct commit **rev;

  int rev_nr = 0;

  int show_all = 0;

  int cmdmode = 0;

  int ret;

  struct option options[] = {

    OPT_BOOL('a', "all", &show_all, N_("output all common ancestors")),

    OPT_CMDMODE(0, "octopus", &cmdmode,

          N_("find ancestors for a single n-way merge"), 'o'),

    OPT_CMDMODE(0, "independent", &cmdmode,

          N_("list revs not reachable from others"), 'r'),

    OPT_CMDMODE(0, "is-ancestor", &cmdmode,

          N_("is the first one ancestor of the other?"), 'a'),

    OPT_CMDMODE(0, "fork-point", &cmdmode,

          N_("find where <commit> forked from reflog of <ref>"), 'f'),

    OPT_END()

  };

  git_config(git_default_config, NULL);

  argc = parse_options(argc, argv, prefix, options, merge_base_usage, 0);

  if (cmdmode == 'a') {

    if (argc < 2)

      usage_with_options(merge_base_usage, options);

    if (show_all)

      die(_("options '%s' and '%s' cannot be used together"),

          "--is-ancestor", "--all");

    return handle_is_ancestor(argc, argv);

  }

  if (cmdmode == 'r' && show_all)

    die(_("options '%s' and '%s' cannot be used together"),

        "--independent", "--all");

  if (cmdmode == 'o')

    return handle_octopus(argc, argv, show_all);

  if (cmdmode == 'r')

    return handle_independent(argc, argv);

  if (cmdmode == 'f') {

    if (argc < 1 || 2 < argc)

      usage_with_options(merge_base_usage, options);

    return handle_fork_point(argc, argv);

  }

  if (argc < 2)

    usage_with_options(merge_base_usage, options);

  ALLOC_ARRAY(rev, argc);

  while (argc-- > 0)

    rev[rev_nr++] = get_commit_reference(*argv++);

  ret = show_merge_base(rev, rev_nr, show_all);

  free(rev);

  return ret;

}