/* -*- mode: C; c-file-style: "gnu"; indent-tabs-mode: nil; -*-
 *
 * Copyright (C) 2014 Colin Walters <walters@verbum.org>
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU Lesser General Public License as published
 * by the Free Software Foundation; either version 2 of the licence or (at
 * your option) any later version.
 *
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General
 * Public License along with this library; if not, write to the
 * Free Software Foundation, Inc., 59 Temple Place, Suite 330,
 * Boston, MA 02111-1307, USA.
 */

#include "config.h"

#include <string.h>
#include <glib-unix.h>

#include "rpmostree-builtins.h"
#include "rpmostree-treepkgdiff.h"

#include "libgsystem.h"

static gboolean opt_reboot;

static GOptionEntry option_entries[] = {
  { "reboot", 'r', 0, G_OPTION_ARG_NONE, &opt_reboot, "Initiate a reboot after rollback is prepared", NULL },
  { NULL }
};

gboolean
rpmostree_builtin_rollback (int             argc,
                            char          **argv,
                            GCancellable   *cancellable,
                            GError        **error)
{
  gboolean ret = FALSE;
  GOptionContext *context = g_option_context_new ("- Revert to the previously booted tree");
  gs_unref_object OstreeSysroot *sysroot = NULL;
  gs_free char *origin_description = NULL;
  gs_unref_ptrarray GPtrArray *deployments = NULL;
  gs_unref_ptrarray GPtrArray *new_deployments =
    g_ptr_array_new_with_free_func (g_object_unref);
  OstreeDeployment *booted_deployment = NULL;
  guint i;
  guint booted_index;
  guint index_to_prepend;
  
  g_option_context_add_main_entries (context, option_entries, NULL);

  if (!g_option_context_parse (context, &argc, &argv, error))
    goto out;

  sysroot = ostree_sysroot_new_default ();
  if (!ostree_sysroot_load (sysroot, cancellable, error))
    goto out;

  booted_deployment = ostree_sysroot_get_booted_deployment (sysroot);
  if (booted_deployment == NULL)
    {
      g_set_error_literal (error, G_IO_ERROR, G_IO_ERROR_FAILED,
                           "Not currently booted into an OSTree system");
      goto out;
    }

  deployments = ostree_sysroot_get_deployments (sysroot);
  if (deployments->len < 2)
    {
      g_set_error (error, G_IO_ERROR, G_IO_ERROR_FAILED,
                   "Found %u deployments, at least 2 required for rollback",
                   deployments->len);
      goto out;
    }

  g_assert (booted_deployment != NULL);
  for (booted_index = 0; booted_index < deployments->len; booted_index++)
    {
      if (deployments->pdata[booted_index] == booted_deployment)
        break;
    }
  g_assert (booted_index < deployments->len);
  g_assert (deployments->pdata[booted_index] == booted_deployment);
  
  if (booted_index != 0)
    {
      /* There is an earlier deployment, let's assume we want to just
       * insert the current one in front.
       */
      index_to_prepend = booted_index;
    }
  else
    {
      /* We're booted into the first, let's roll back to the previous */
      index_to_prepend = 1;
    }
  
  g_ptr_array_add (new_deployments, g_object_ref (deployments->pdata[index_to_prepend]));
  for (i = 0; i < deployments->len; i++)
    {
      if (i == index_to_prepend)
        continue;
      g_ptr_array_add (new_deployments, g_object_ref (deployments->pdata[i]));
    }

  g_print ("Moving '%s.%d' to be first deployment\n",
           ostree_deployment_get_csum (deployments->pdata[index_to_prepend]),
           ostree_deployment_get_deployserial (deployments->pdata[index_to_prepend]));

  if (!ostree_sysroot_write_deployments (sysroot, new_deployments, cancellable,
                                         error))
    goto out;

  if (!ostree_sysroot_cleanup (sysroot, cancellable, error))
    goto out;

  if (opt_reboot)
    gs_subprocess_simple_run_sync (NULL, GS_SUBPROCESS_STREAM_DISPOSITION_INHERIT,
                                   cancellable, error,
                                   "systemctl", "reboot", NULL);
  else
    {
#ifdef HAVE_PATCHED_HAWKEY_AND_LIBSOLV
      if (!rpmostree_print_treepkg_diff (sysroot, cancellable, error))
        goto out;
#endif

      g_print ("Sucessfully reset deployment order; run \"systemctl reboot\" to start a reboot\n");
    }

  if (opt_reboot)
  ret = TRUE;
 out:
  return ret;
}