/* Copyright (C) 2004 The glibmm Development Team
 *
 * 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 2.1 of the License, 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, see <http://www.gnu.org/licenses/>.
 */

_DEFS(glibmm,glib)

#include <glibmm/optionentry.h>
#include <glibmm/optiongroup.h>
#include <glibmm/error.h>
#include <sigc++/signal.h>

#ifndef DOXYGEN_SHOULD_SKIP_THIS
extern "C" { typedef struct _GOptionContext GOptionContext; }
#endif


namespace Glib
{

/** Exception class for options.
 */
_WRAP_GERROR(OptionError, GOptionError, G_OPTION_ERROR, NO_GTYPE, decl_prefix GLIBMM_API)

/** An OptionContext defines and parses commandline options, using OptionGroup%s and \link OptionEntry option entries \endlink.
 *
 * It supports short and long commandline options, as shown in the following example:
 *
 * <tt>testtreemodel -r 1 --max-size 20 --rand --display=:1.0 -vb -- file1 file2</tt>
 *
 * The example demonstrates a number of features of the GOption
 * commandline parser:
 * - Options can be single letters, prefixed by a single dash.
 * - Multiple short options can be grouped behind a single dash.
 * - Long options are prefixed by two consecutive dashes.
 * - Options can have an extra argument, which can be a number, a string or
 *   a filename. For long options, the extra argument can be appended with
 *   an equals sign after the option name, which is useful if the extra
 *   argument starts with a dash, which would otherwise cause it to be
 *   interpreted as another option.
 * - Non-option arguments are returned to the application as rest arguments.
 * - An argument consisting solely of two dashes turns off further parsing,
 *   any remaining arguments (even those starting with a dash) are returned
 *   to the application as rest arguments.
 *
 * The OptionContext groups options in OptionGroups, which makes it easy to
 * incorporate options from multiple sources. The intended use for this is
 * to let applications collect option groups from the libraries it uses,
 * add them to their OptionContext, and parse all options by a single call
 * to parse(). See Gtk::Main::add_gtk_option_group(), for an example.
 *
 * Add options by creating OptionEntry instances and appropriately-typed variables,
 * and adding them to an OptionGroup with OptionGroup::add_entry() or
 * OptionGroup::add_entry_filename(). The option group should then be added to
 * the OptionContext with set_main_group() or add_group().
 *
 * You might find it convenient to derive your own class from OptionGroup to
 * contain these OptionEntry instances and member variables.
 *
 * If an option is of type string (see OptionGroup::add_entry()) or filename
 * (see OptionGroup::add_entry_filename()), OptionContext takes
 * care of converting it to the right encoding. strings are returned in
 * UTF-8 encoding and filenames are returned in the GLib filename encoding.
 * Note that this only works if setlocale() has been called before
 * OptionContext::parse().
 *
 * OptionContext can automatically generate nicely formatted help output. Unless it is
 * explicitly turned off with set_help_enabled(), this will recognize
 * the --help, -?, --help-all and --help-groupname options
 * (where groupname is the name of an OptionGroup) and write suitable text to
 * stdout.
 *
 *
 */
class GLIBMM_API OptionContext
{
  _CLASS_GENERIC(OptionContext, GOptionContext)
  _IGNORE(g_option_context_free)
public:

  /** Creates a new option context.
   * @param parameter_string A string which is displayed in the first line of --help output, after programname [OPTION...]
   */
  explicit OptionContext(const Glib::ustring& parameter_string = {});

  //Note that, unlike Glib::wrap(), this would create a second C++ instance for the same C instance,
  //so it should be used carefully. For instance you could not access data in a derived class via this second instance.
  explicit OptionContext(GOptionContext* castitem, bool take_ownership = false);

  OptionContext(const OptionContext& other) = delete;
  OptionContext& operator=(const OptionContext& other) = delete;

  OptionContext(OptionContext&& other) noexcept;
  OptionContext& operator=(OptionContext&& other) noexcept;

  virtual ~OptionContext();

  _WRAP_METHOD(void set_help_enabled(bool help_enabled = true), g_option_context_set_help_enabled)
  _WRAP_METHOD(bool get_help_enabled() const, g_option_context_get_help_enabled)
  _WRAP_METHOD(void set_ignore_unknown_options(bool ignore_unknown = true), g_option_context_set_ignore_unknown_options)
  _WRAP_METHOD(bool get_ignore_unknown_options() const, g_option_context_get_ignore_unknown_options)

  _WRAP_METHOD(void set_strict_posix(bool strict_posix = true), g_option_context_set_strict_posix)
  _WRAP_METHOD(bool get_strict_posix() const, g_option_context_get_strict_posix)

#m4 _CONVERSION(`char**&',`gchar***',`&($3)')
  _WRAP_METHOD(bool parse(int& argc, char**& argv), g_option_context_parse, errthrow "Glib::OptionError, Glib::ConvertError")

  /** Parses the command line arguments.
   *
   * This function is similar to parse(int& argc, char**& argv) except that it
   * respects the normal memory rules when dealing with a strv instead of
   * assuming that the passed-in array is the argv of the main function.
   * In particular, strings that are removed from the arguments list will
   * be freed using g_free().
   *
   * On Windows, the strings are expected to be in UTF-8. This is in
   * contrast to parse(int& argc, char**& argv) which expects them to be in the
   * system codepage, which is how they are passed as @a argv to main().
   * See g_win32_get_command_line() or Gio::ApplicationCommandLine::get_arguments()
   * for a solution.
   *
   * This function is useful if you are trying to use OptionContext with
   * Gio::Application.
   *
   * @newin{2,50}
   *
   * @param[in,out] argv A pointer to the command line arguments
   *   (which must be in UTF-8 on Windows).
   * @return <tt>true</tt> if the parsing was successful,
   *         <tt>false</tt> if an error occurred.
   * @throw Glib::OptionError
   * @throw Glib::ConvertError
   */
  _WRAP_METHOD(bool parse(char**& argv), g_option_context_parse_strv, errthrow)

  //g_option_context_add_main_entries(), just creates a group internally, adds them to it, and does a set_main_group()
  //- a group without callbacks seems to do some simple default parsing.
  _IGNORE(g_option_context_add_main_entries)

  /** Adds an OptionGroup to the context, so that parsing with context will recognize the options in the group.
   * Note that the group will not be copied, so it should exist for as long as the context exists.
   *
   * @param group The group to add.
   */
  void add_group(OptionGroup& group);
  _IGNORE(g_option_context_add_group)

  /** Sets an OptionGroup as the main group of the context. This has the same effect as calling add_group(), the only
   * difference is that the options in the main group are treated differently when generating --help output.
   * Note that the group will not be copied, so it should exist for as long as the context exists.
   *
   * @param group The group to add.
   */
  void set_main_group(OptionGroup& group);
  _IGNORE(g_option_context_set_main_group)

  //We don't need this (hopefully), and the memory management would be really awkward.
  //OptionGroup& get_main_group();
  //const OptionGroup& get_main_group() const;
  _IGNORE(g_option_context_get_main_group)

  #m4 _CONVERSION(`const OptionGroup&',`GOptionGroup*',`const_cast<GOptionGroup*>(($3).gobj())')
  _WRAP_METHOD(Glib::ustring get_help(bool main_help, const OptionGroup& group) const, g_option_context_get_help)

  /** Returns a formatted, translated help text for the given context.
   *
   * - To obtain the text produced by --help, call get_help(true).
   * - To obtain the text produced by --help-all, call get_help(false).
   * - To obtain the help text for an option group, call get_help(false, group).
   *
   * @param main_help If true, only include the main group.
   * @result string containing the help text.
   */
  Glib::ustring get_help(bool main_help = true) const;

  GOptionContext*       gobj()       { return gobject_; }
  const GOptionContext* gobj() const { return gobject_; }

  _WRAP_METHOD(void set_summary(const Glib::ustring& summary), g_option_context_set_summary)
  _WRAP_METHOD(Glib::ustring get_summary() const, g_option_context_get_summary)
  _WRAP_METHOD(void set_description(const Glib::ustring& description), g_option_context_set_description)
  _WRAP_METHOD(Glib::ustring get_description() const, g_option_context_get_description)

  _WRAP_METHOD(void set_translation_domain(const Glib::ustring& domain), g_option_context_set_translation_domain)

  /**
   * This function is used to translate user-visible strings, for --help output.
   * The function takes an untranslated string and returns a translated string
   */
  using SlotTranslate = sigc::slot<Glib::ustring(const Glib::ustring&)>;

  /**
   * Sets the function which is used to translate user-visible
   * strings, for --help output.  Different groups can use different functions.
   *
   * If you are using gettext(), you only need to set the translation domain,
   * see set_translation_domain().
   *
   * @newin{2,14}
   */
  void set_translate_func (const SlotTranslate& slot);
  _IGNORE(g_option_context_set_translate_func)

protected:

  GOptionContext* gobject_;
  bool has_ownership_;
};


} // namespace Glib