/*
 * Copyright © 2010 Codethink Limited
 *
 * This library 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.
 *
 * Author: Ryan Lortie <desrt@desrt.ca>
 */

#include "config.h"

#include <gio/gio.h>
#include <gi18n.h>
#include <locale.h>
#include <string.h>
#include <stdlib.h>

static gboolean
contained (const gchar * const *items,
           const gchar         *item)
{
  while (*items)
    if (strcmp (*items++, item) == 0)
      return TRUE;

  return FALSE;
}

static gboolean
is_schema (const gchar *schema)
{
  return contained (g_settings_list_schemas (), schema);
}

static gboolean
is_relocatable_schema (const gchar *schema)
{
  return contained (g_settings_list_relocatable_schemas (), schema);
}

static gboolean
check_relocatable_schema (const gchar *schema)
{
  if (is_relocatable_schema (schema))
    return TRUE;

  if (is_schema (schema))
    g_printerr (_("Schema '%s' is not relocatable "
                  "(path must not be specified)\n"),
                schema);

  else
    g_printerr (_("No such schema '%s'\n"), schema);

  return FALSE;
}

static gboolean
check_schema (const gchar *schema)
{
  if (is_schema (schema))
    return TRUE;

  if (is_relocatable_schema (schema))
    g_printerr (_("Schema '%s' is relocatable "
                  "(path must be specified)\n"),
                schema);

  else
    g_printerr (_("No such schema '%s'\n"), schema);

  return FALSE;
}

static gboolean
check_path (const gchar *path)
{
  if (path[0] == '\0')
    {
      g_printerr (_("Empty path given.\n"));
      return FALSE;
    }

  if (path[0] != '/')
    {
      g_printerr (_("Path must begin with a slash (/)\n"));
      return FALSE;
    }

  if (!g_str_has_suffix (path, "/"))
    {
      g_printerr (_("Path must end with a slash (/)\n"));
      return FALSE;
    }

  if (strstr (path, "//"))
    {
      g_printerr (_("Path must not contain two adjacent slashes (//)\n"));
      return FALSE;
    }

  return TRUE;
}

static gboolean
check_key (GSettings   *settings,
           const gchar *key)
{
  gboolean good;
  gchar **keys;

  keys = g_settings_list_keys (settings);
  good = contained ((const gchar **) keys, key);
  g_strfreev (keys);

  if (good)
    return TRUE;

  g_printerr (_("No such key '%s'\n"), key);

  return FALSE;
}

static void
output_list (const gchar * const *list)
{
  gint i;

  for (i = 0; list[i]; i++)
    g_print ("%s\n", list[i]);
}

static void
gsettings_list_schemas (GSettings   *settings,
                        const gchar *key,
                        const gchar *value)
{
  output_list (g_settings_list_schemas ());
}

static void
gsettings_list_relocatable_schemas (GSettings   *settings,
                                    const gchar *key,
                                    const gchar *value)
{
  output_list (g_settings_list_relocatable_schemas ());
}

static void
gsettings_list_keys (GSettings   *settings,
                     const gchar *key,
                     const gchar *value)
{
  gchar **keys;

  keys = g_settings_list_keys (settings);
  output_list ((const gchar **) keys);
  g_strfreev (keys);
}

static void
gsettings_list_children (GSettings   *settings,
                         const gchar *key,
                         const gchar *value)
{
  gchar **children;
  gint max = 0;
  gint i;

  children = g_settings_list_children (settings);
  for (i = 0; children[i]; i++)
    if (strlen (children[i]) > max)
      max = strlen (children[i]);

  for (i = 0; children[i]; i++)
    {
      GSettings *child;
      gchar *schema;
      gchar *path;

      child = g_settings_get_child (settings, children[i]);
      g_object_get (child,
                    "schema", &schema,
                    "path", &path,
                    NULL);

      if (is_schema (schema))
        g_print ("%-*s   %s\n", max, children[i], schema);
      else
        g_print ("%-*s   %s:%s\n", max, children[i], schema, path);

      g_object_unref (child);
      g_free (schema);
      g_free (path);
    }

  g_strfreev (children);
}

static void
enumerate (GSettings *settings)
{
  gchar **keys;
  gchar *schema;
  gint i;

  g_object_get (settings, "schema", &schema, NULL);

  keys = g_settings_list_keys (settings);
  for (i = 0; keys[i]; i++)
    {
      GVariant *value;
      gchar *printed;

      value = g_settings_get_value (settings, keys[i]);
      printed = g_variant_print (value, TRUE);
      g_print ("%s %s %s\n", schema, keys[i], printed);
      g_variant_unref (value);
      g_free (printed);
    }

  g_free (schema);
  g_strfreev (keys);
}

static void
gsettings_list_recursively (GSettings   *settings,
                            const gchar *key,
                            const gchar *value)
{
  gchar **children;
  gint i;

  enumerate (settings);

  children = g_settings_list_children (settings);

  for (i = 0; children[i]; i++)
    {
      GSettings *child;
      gchar *schema;

      child = g_settings_get_child (settings, children[i]);
      g_object_get (child, "schema", &schema, NULL);

      if (is_schema (schema))
        enumerate (child);

      g_object_unref (child);
      g_free (schema);
    }

  g_strfreev (children);
}

static void
gsettings_range (GSettings   *settings,
                 const gchar *key,
                 const gchar *value)
{
  GVariant *range, *detail;
  const gchar *type;

  range = g_settings_get_range (settings, key);
  g_variant_get (range, "(&sv)", &type, &detail);

  if (strcmp (type, "type") == 0)
    g_print ("type %s\n", g_variant_get_type_string (detail) + 1);

  else if (strcmp (type, "range") == 0)
    {
      GVariant *min, *max;
      gchar *smin, *smax;

      g_variant_get (detail, "(**)", &min, &max);
      smin = g_variant_print (min, FALSE);
      smax = g_variant_print (max, FALSE);

      g_print ("range %s %s %s\n",
               g_variant_get_type_string (min), smin, smax);
      g_variant_unref (min);
      g_variant_unref (max);
      g_free (smin);
      g_free (smax);
    }

  else if (strcmp (type, "enum") == 0 || strcmp (type, "flags") == 0)
    {
      GVariantIter iter;
      GVariant *item;

      g_print ("%s\n", type);

      g_variant_iter_init (&iter, detail);
      while (g_variant_iter_loop (&iter, "*", &item))
        {
          gchar *printed;

          printed = g_variant_print (item, FALSE);
          g_print ("%s\n", printed);
          g_free (printed);
        }
    }

  g_variant_unref (detail);
  g_variant_unref (range);
}

static void
gsettings_get (GSettings   *settings,
               const gchar *key,
               const gchar *value_)
{
  GVariant *value;
  gchar *printed;

  value = g_settings_get_value (settings, key);
  printed = g_variant_print (value, TRUE);
  g_print ("%s\n", printed);
  g_variant_unref (value);
  g_free (printed);
}

static void
gsettings_reset (GSettings   *settings,
                 const gchar *key,
                 const gchar *value)
{
  g_settings_reset (settings, key);
  g_settings_sync ();
}

static void
gsettings_writable (GSettings   *settings,
                    const gchar *key,
                    const gchar *value)
{
  g_print ("%s\n",
           g_settings_is_writable (settings, key) ?
           "true" : "false");
}

static void
value_changed (GSettings   *settings,
               const gchar *key,
               gpointer     user_data)
{
  GVariant *value;
  gchar *printed;

  value = g_settings_get_value (settings, key);
  printed = g_variant_print (value, TRUE);
  g_print ("%s: %s\n", key, printed);
  g_variant_unref (value);
  g_free (printed);
}

static void
gsettings_monitor (GSettings   *settings,
                   const gchar *key,
                   const gchar *value)
{
  if (key)
    {
      gchar *name;

      name = g_strdup_printf ("changed::%s", key);
      g_signal_connect (settings, name, G_CALLBACK (value_changed), NULL);
    }
  else
    g_signal_connect (settings, "changed", G_CALLBACK (value_changed), NULL);

  g_main_loop_run (g_main_loop_new (NULL, FALSE));
}

static void
gsettings_set (GSettings   *settings,
               const gchar *key,
               const gchar *value)
{
  const GVariantType *type;
  GError *error = NULL;
  GVariant *existing;
  GVariant *new;
  gchar *freeme = NULL;

  existing = g_settings_get_value (settings, key);
  type = g_variant_get_type (existing);

  new = g_variant_parse (type, value, NULL, NULL, &error);

  /* A common error is to specify a string with single quotes
   * (or use completion for that), and forget that the shell
   * will eat one level of quoting, resulting in 'unknown keyword'
   * error from the gvariant parser.
   * To handle this case, try to parse again with an extra level
   * of quotes.
   */
  if (new == NULL && strstr (error->message, "unknown keyword"))
    {
      value = freeme = g_strdup_printf ("\"%s\"", value);
      new = g_variant_parse (type, value, NULL, NULL, NULL);
      if (new != NULL)
        g_clear_error (&error);
    }

  if (new == NULL)
    {
      g_printerr ("%s\n", error->message);
      exit (1);
    }

  if (!g_settings_range_check (settings, key, new))
    {
      g_printerr (_("The provided value is outside of the valid range\n"));
      g_variant_unref (new);
      exit (1);
    }

  g_settings_set_value (settings, key, new);
  g_variant_unref (existing);
  g_variant_unref (new);

  g_settings_sync ();

  g_free (freeme);
}

static int
gsettings_help (gboolean     requested,
                const gchar *command)
{
  const gchar *description;
  const gchar *synopsis;
  GString *string;

  string = g_string_new (NULL);

  if (command == NULL)
    ;

  else if (strcmp (command, "list-schemas") == 0)
    {
      description = _("List the installed (non-relocatable) schemas");
      synopsis = "";
    }

  else if (strcmp (command, "list-relocatable-schemas") == 0)
    {
      description = _("List the installed relocatable schemas");
      synopsis = "";
    }

  else if (strcmp (command, "list-keys") == 0)
    {
      description = _("Lists the keys in SCHEMA");
      synopsis = N_("SCHEMA[:PATH]");
    }

  else if (strcmp (command, "list-children") == 0)
    {
      description = _("Lists the children of SCHEMA");
      synopsis = N_("SCHEMA[:PATH]");
    }

  else if (strcmp (command, "list-recursively") == 0)
    {
      description = _("List keys and values, recursively");
      synopsis = N_("SCHEMA[:PATH]");
    }

  else if (strcmp (command, "get") == 0)
    {
      description = _("Gets the value of KEY");
      synopsis = N_("SCHEMA[:PATH] KEY");
    }

  else if (strcmp (command, "range") == 0)
    {
      description = _("Queries the range of valid values for KEY");
      synopsis = N_("SCHEMA[:PATH] KEY");
    }

  else if (strcmp (command, "set") == 0)
    {
      description = _("Sets the value of KEY to VALUE");
      synopsis = N_("SCHEMA[:PATH] KEY VALUE");
    }

  else if (strcmp (command, "reset") == 0)
    {
      description = _("Resets KEY to its default value");
      synopsis = N_("SCHEMA[:PATH] KEY");
    }

  else if (strcmp (command, "writable") == 0)
    {
      description = _("Checks if KEY is writable");
      synopsis = N_("SCHEMA[:PATH] KEY");
    }

  else if (strcmp (command, "monitor") == 0)
    {
      description = _("Monitors KEY for changes.\n"
                    "If no KEY is specified, monitor all keys in SCHEMA.\n"
                    "Use ^C to stop monitoring.\n");
      synopsis = N_("SCHEMA[:PATH] [KEY]");
    }
  else
    {
      g_string_printf (string, _("Unknown command %s\n\n"), command);
      requested = FALSE;
      command = NULL;
    }

  if (command == NULL)
    {
      g_string_append (string,
      _("Usage:\n"
        "  gsettings COMMAND [ARGS...]\n"
        "\n"
        "Commands:\n"
        "  help                      Show this information\n"
        "  list-schemas              List installed schemas\n"
        "  list-relocatable-schemas  List relocatable schemas\n"
        "  list-keys                 List keys in a schema\n"
        "  list-children             List children of a schema\n"
        "  list-recursively          List keys and values, recursively\n"
        "  range                     Queries the range of a key\n"
        "  get                       Get the value of a key\n"
        "  set                       Set the value of a key\n"
        "  reset                     Reset the value of a key\n"
        "  writable                  Check if a key is writable\n"
        "  monitor                   Watch for changes\n"
        "\n"
        "Use 'gsettings help COMMAND' to get detailed help.\n\n"));
    }
  else
    {
      g_string_append_printf (string, _("Usage:\n  gsettings %s %s\n\n%s\n\n"),
                              command, _(synopsis), description);

      if (synopsis[0])
        {
          g_string_append (string, _("Arguments:\n"));

          if (strstr (synopsis, "SCHEMA"))
            g_string_append (string,
                           _("  SCHEMA    The name of the schema\n"
                             "  PATH      The path, for relocatable schemas\n"));

          if (strstr (synopsis, "[KEY]"))
            g_string_append (string,
                           _("  KEY       The (optional) key within the schema\n"));

          else if (strstr (synopsis, "KEY"))
            g_string_append (string,
                           _("  KEY       The key within the schema\n"));

          if (strstr (synopsis, "VALUE"))
            g_string_append (string,
                           _("  VALUE     The value to set\n"));

          g_string_append (string, "\n");
        }
    }

  if (requested)
    g_print ("%s", string->str);
  else
    g_printerr ("%s", string->str);

  g_string_free (string, TRUE);

  return requested ? 0 : 1;
}


int
main (int argc, char **argv)
{
  void (* function) (GSettings *, const gchar *, const gchar *);
  GSettings *settings;
  const gchar *key;

  setlocale (LC_ALL, "");

  if (argc < 2)
    return gsettings_help (FALSE, NULL);

  else if (strcmp (argv[1], "help") == 0)
    return gsettings_help (TRUE, argv[2]);

  else if (argc == 2 && strcmp (argv[1], "list-schemas") == 0)
    function = gsettings_list_schemas;

  else if (argc == 2 && strcmp (argv[1], "list-relocatable-schemas") == 0)
    function = gsettings_list_relocatable_schemas;

  else if (argc == 3 && strcmp (argv[1], "list-keys") == 0)
    function = gsettings_list_keys;

  else if (argc == 3 && strcmp (argv[1], "list-children") == 0)
    function = gsettings_list_children;

  else if (argc == 3 && strcmp (argv[1], "list-recursively") == 0)
    function = gsettings_list_recursively;

  else if (argc == 4 && strcmp (argv[1], "range") == 0)
    function = gsettings_range;

  else if (argc == 4 && strcmp (argv[1], "get") == 0)
    function = gsettings_get;

  else if (argc == 5 && strcmp (argv[1], "set") == 0)
    function = gsettings_set;

  else if (argc == 4 && strcmp (argv[1], "reset") == 0)
    function = gsettings_reset;

  else if (argc == 4 && strcmp (argv[1], "writable") == 0)
    function = gsettings_writable;

  else if ((argc == 3 || argc == 4) && strcmp (argv[1], "monitor") == 0)
    function = gsettings_monitor;

  else
    return gsettings_help (FALSE, argv[1]);

  g_type_init ();

  if (argc > 2)
    {
      gchar **parts;

      if (argv[2][0] == '\0')
        {
          g_printerr (_("Empty schema name given"));
          return 1;
        }

      parts = g_strsplit (argv[2], ":", 2);

      if (parts[1])
        {
          if (!check_relocatable_schema (parts[0]) || !check_path (parts[1]))
            return 1;

          settings = g_settings_new_with_path (parts[0], parts[1]);
        }
      else
        {
          if (!check_schema (parts[0]))
            return 1;

          settings = g_settings_new (parts[0]);
        }

      g_strfreev (parts);
    }
  else
    settings = NULL;

  if (argc > 3)
    {
      if (!check_key (settings, argv[3]))
        return 1;

      key = argv[3];
    }
  else
    key = NULL;

  (* function) (settings, key, argc > 4 ? argv[4] : NULL);

  if (settings != NULL)
    g_object_unref (settings);

  return 0;
}