#define USE_THE_REPOSITORY_VARIABLE

#include "git-compat-util.h"

#include "cache-tree.h"

#include "gettext.h"

#include "hex.h"

#include "lockfile.h"

#include "object-name.h"

#include "refs.h"

#include "reset.h"

#include "tree-walk.h"

#include "tree.h"

#include "unpack-trees.h"

#include "hook.h"

static int update_refs(const struct reset_head_opts *opts,

           const struct object_id *oid,

           const struct object_id *head)

{

  unsigned detach_head = opts->flags & RESET_HEAD_DETACH;

  unsigned run_hook = opts->flags & RESET_HEAD_RUN_POST_CHECKOUT_HOOK;

  unsigned update_orig_head = opts->flags & RESET_ORIG_HEAD;

  const struct object_id *orig_head = opts->orig_head;

  const char *switch_to_branch = opts->branch;

  const char *reflog_branch = opts->branch_msg;

  const char *reflog_head = opts->head_msg;

  const char *reflog_orig_head = opts->orig_head_msg;

  const char *default_reflog_action = opts->default_reflog_action;

  struct object_id *old_orig = NULL, oid_old_orig;

  struct strbuf msg = STRBUF_INIT;

  const char *reflog_action;

  size_t prefix_len;

  int ret;

  if ((update_orig_head && !reflog_orig_head) || !reflog_head) {

    if (!default_reflog_action)

      BUG("default_reflog_action must be given when reflog messages are omitted");

    reflog_action = getenv(GIT_REFLOG_ACTION_ENVIRONMENT);

    strbuf_addf(&msg, "%s: ", reflog_action ? reflog_action :

                default_reflog_action);

  }

  prefix_len = msg.len;

  if (update_orig_head) {

    if (!repo_get_oid(the_repository, "ORIG_HEAD", &oid_old_orig))

      old_orig = &oid_old_orig;

    if (head) {

      if (!reflog_orig_head) {

        strbuf_addstr(&msg, "updating ORIG_HEAD");

        reflog_orig_head = msg.buf;

      }

      refs_update_ref(get_main_ref_store(the_repository),

          reflog_orig_head, "ORIG_HEAD",

          orig_head ? orig_head : head,

          old_orig, 0, UPDATE_REFS_MSG_ON_ERR);

    } else if (old_orig)

      refs_delete_ref(get_main_ref_store(the_repository),

          NULL, "ORIG_HEAD", old_orig, 0);

  }

  if (!reflog_head) {

    strbuf_setlen(&msg, prefix_len);

    strbuf_addstr(&msg, "updating HEAD");

    reflog_head = msg.buf;

  }

  if (!switch_to_branch)

    ret = refs_update_ref(get_main_ref_store(the_repository),

              reflog_head, "HEAD", oid, head,

              detach_head ? REF_NO_DEREF : 0,

              UPDATE_REFS_MSG_ON_ERR);

  else {

    ret = refs_update_ref(get_main_ref_store(the_repository),

              reflog_branch ? reflog_branch : reflog_head,

              switch_to_branch, oid, NULL, 0,

              UPDATE_REFS_MSG_ON_ERR);

    if (!ret)

      ret = refs_update_symref(get_main_ref_store(the_repository),

             "HEAD", switch_to_branch,

             reflog_head);

  }

  if (!ret && run_hook)

    run_hooks_l(the_repository, "post-checkout",

          oid_to_hex(head ? head : null_oid()),

          oid_to_hex(oid), "1", NULL);

  strbuf_release(&msg);

  return ret;

}

int reset_head(struct repository *r, const struct reset_head_opts *opts)

{

  const struct object_id *oid = opts->oid;

  const char *switch_to_branch = opts->branch;

  unsigned reset_hard = opts->flags & RESET_HEAD_HARD;

  unsigned refs_only = opts->flags & RESET_HEAD_REFS_ONLY;

  unsigned update_orig_head = opts->flags & RESET_ORIG_HEAD;

  struct object_id *head = NULL, head_oid;

  struct tree_desc desc[2] = { { NULL }, { NULL } };

  struct lock_file lock = LOCK_INIT;

  struct unpack_trees_options unpack_tree_opts = { 0 };

  struct tree *tree;

  const char *action;

  int ret = 0, nr = 0;

  if (switch_to_branch && !starts_with(switch_to_branch, "refs/"))

    BUG("Not a fully qualified branch: '%s'", switch_to_branch);

  if (opts->orig_head_msg && !update_orig_head)

    BUG("ORIG_HEAD reflog message given without updating ORIG_HEAD");

  if (opts->branch_msg && !opts->branch)

    BUG("branch reflog message given without a branch");

  if (!refs_only && repo_hold_locked_index(r, &lock, LOCK_REPORT_ON_ERROR) < 0) {

    ret = -1;

    goto leave_reset_head;

  }

  if (!repo_get_oid(r, "HEAD", &head_oid)) {

    head = &head_oid;

  } else if (!oid || !reset_hard) {

    ret = error(_("could not determine HEAD revision"));

    goto leave_reset_head;

  }

  if (!oid)

    oid = &head_oid;

  if (refs_only)

    return update_refs(opts, oid, head);

  action = reset_hard ? "reset" : "checkout";

  setup_unpack_trees_porcelain(&unpack_tree_opts, action);

  unpack_tree_opts.head_idx = 1;

  unpack_tree_opts.src_index = r->index;

  unpack_tree_opts.dst_index = r->index;

  unpack_tree_opts.fn = reset_hard ? oneway_merge : twoway_merge;

  unpack_tree_opts.update = 1;

  unpack_tree_opts.merge = 1;

  unpack_tree_opts.preserve_ignored = 0; /* FIXME: !overwrite_ignore */

  unpack_tree_opts.skip_cache_tree_update = 1;

  init_checkout_metadata(&unpack_tree_opts.meta, switch_to_branch, oid, NULL);

  if (reset_hard)

    unpack_tree_opts.reset = UNPACK_RESET_PROTECT_UNTRACKED;

  if (repo_read_index_unmerged(r) < 0) {

    ret = error(_("could not read index"));

    goto leave_reset_head;

  }

  if (!reset_hard && !fill_tree_descriptor(r, &desc[nr++], &head_oid)) {

    ret = error(_("failed to find tree of %s"),

          oid_to_hex(&head_oid));

    goto leave_reset_head;

  }

  if (!fill_tree_descriptor(r, &desc[nr++], oid)) {

    ret = error(_("failed to find tree of %s"), oid_to_hex(oid));

    goto leave_reset_head;

  }

  if (unpack_trees(nr, desc, &unpack_tree_opts)) {

    ret = -1;

    goto leave_reset_head;

  }

  tree = parse_tree_indirect(oid);

  if (!tree) {

    ret = error(_("unable to read tree (%s)"), oid_to_hex(oid));

    goto leave_reset_head;

  }

  prime_cache_tree(r, r->index, tree);

  if (write_locked_index(r->index, &lock, COMMIT_LOCK) < 0) {

    ret = error(_("could not write index"));

    goto leave_reset_head;

  }

  if (oid != &head_oid || update_orig_head || switch_to_branch)

    ret = update_refs(opts, oid, head);

leave_reset_head:

  rollback_lock_file(&lock);

  clear_unpack_trees_porcelain(&unpack_tree_opts);

  while (nr)

    free((void *)desc[--nr].buffer);

  return ret;

}