////////////////////////////////////////////////////////////////////////
//
// Copyright (C) 1996-2021 The Octave Project Developers
//
// See the file COPYRIGHT.md in the top-level directory of this
// distribution or <https://octave.org/copyright/>.
//
// This file is part of Octave.
//
// Octave is free software: you can redistribute it and/or modify it
// under the terms of the GNU General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// Octave 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 General Public License for more details.
//
// You should have received a copy of the GNU General Public License
// along with Octave; see the file COPYING.  If not, see
// <https://www.gnu.org/licenses/>.
//
////////////////////////////////////////////////////////////////////////

#if ! defined (octave_cmd_edit_h)
#define octave_cmd_edit_h 1

#include "octave-config.h"

#include <cstdio>

#include <set>
#include <string>

#include "str-vec.h"

namespace octave
{
  class
  OCTAVE_API
  command_editor
  {
  protected:

    command_editor (void)
      : m_command_number (1), m_rows (24), m_cols (80), m_interrupted (false),
        m_interrupt_event_loop (false), m_initial_input ()
    { }

  public:

    typedef int (*startup_hook_fcn) (void);

    typedef int (*pre_input_hook_fcn) (void);

    typedef int (*event_hook_fcn) (void);

    typedef std::string (*completion_fcn) (const std::string&, int);

    typedef char * (*completion_hook_fcn) ();

    typedef std::string (*quoting_fcn) (const std::string&, int, char);

    typedef std::string (*dequoting_fcn) (const std::string&, int);

    typedef int (*char_is_quoted_fcn) (const std::string&, int);

    typedef void (*user_accept_line_fcn) (const std::string&);

    // No copying!

    command_editor (const command_editor&) = delete;

    command_editor& operator = (const command_editor&) = delete;

    virtual ~command_editor (void) = default;

    static void set_name (const std::string& n);

    static std::string readline (const std::string& prompt);

    static std::string readline (const std::string& prompt, bool& eof);

    static void set_input_stream (FILE *f);

    static FILE * get_input_stream (void);

    static void set_output_stream (FILE *f);

    static FILE * get_output_stream (void);

    static void redisplay (void);

    static int terminal_rows (void);

    static int terminal_cols (void);

    static void clear_screen (bool skip_redisplay = false);

    static void resize_terminal (void);

    static void set_screen_size (int ht, int wd);

    static std::string decode_prompt_string (const std::string& s);

    static void restore_terminal_state (void);

    static void blink_matching_paren (bool flag);

    static bool erase_empty_line (bool flag);

    static void set_basic_word_break_characters (const std::string& s);

    static void set_completer_word_break_characters (const std::string& s);

    static void set_basic_quote_characters (const std::string& s);

    static void set_filename_quote_characters (const std::string& s);

    static void set_completer_quote_characters (const std::string& s);

    static void set_completion_append_character (char c);

    static void set_completion_function (completion_fcn f);

    static void set_quoting_function (quoting_fcn f);

    static void set_dequoting_function (dequoting_fcn f);

    static void set_char_is_quoted_function (char_is_quoted_fcn f);

    static void set_user_accept_line_function (user_accept_line_fcn f);

    static completion_fcn get_completion_function (void);

    static quoting_fcn get_quoting_function (void);

    static dequoting_fcn get_dequoting_function (void);

    static char_is_quoted_fcn get_char_is_quoted_function (void);

    static user_accept_line_fcn get_user_accept_line_function (void);

    static string_vector
    generate_filename_completions (const std::string& text);

    static std::string get_line_buffer (void);

    static std::string get_current_line (void);

    static char get_prev_char (int);

    static void replace_line (const std::string& text, bool clear_undo = true);

    static void kill_full_line (void);

    static void insert_text (const std::string& text);

    static void newline (void);

    static void accept_line (void);

    static bool undo (void);

    static void clear_undo_list (void);

    static void add_startup_hook (startup_hook_fcn f);

    static void remove_startup_hook (startup_hook_fcn f);

    static void add_pre_input_hook (pre_input_hook_fcn f);

    static void remove_pre_input_hook (pre_input_hook_fcn f);

    static void add_event_hook (event_hook_fcn f);

    static void remove_event_hook (event_hook_fcn f);

    static void run_event_hooks (void);

    static void read_init_file (const std::string& file = "");

    static void re_read_init_file (void);

    static bool filename_completion_desired (bool);

    static bool filename_quoting_desired (bool);

    static bool prefer_env_winsize (bool);

    static bool interrupt (bool = true);

    static void interrupt_event_loop (bool flag = true);

    static bool event_loop_interrupted (void);

    static int current_command_number (void);

    static void reset_current_command_number (int n);

    static void increment_current_command_number (void);

    static void force_default_editor (void);

    static void set_initial_input (const std::string& text);

    static int insert_initial_input (void);

  private:

    static bool instance_ok (void);

    static void make_command_editor (void);

    static int startup_handler (void);

    static int pre_input_handler (void);

    static int event_handler (void);

    static void cleanup_instance (void)
    {
      delete s_instance;
      s_instance = nullptr;
    }

    static void handle_interrupt_signal (void);

    //--------

    static command_editor *s_instance;  // the real thing.

    static std::set<startup_hook_fcn> m_startup_hook_set;
    static std::set<pre_input_hook_fcn> m_pre_input_hook_set;
    static std::set<event_hook_fcn> m_event_hook_set;

  protected:

    // To use something other than the GNU readline library, derive a new
    // class from command_editor, overload these functions as
    // necessary, and make instance point to the new class.

    virtual void do_set_name (const std::string&) { }

    std::string do_readline (const std::string& prompt)
    {
      bool eof;

      return do_readline (prompt, eof);
    }

    virtual std::string do_readline (const std::string&, bool&) = 0;

    virtual void do_set_input_stream (FILE *) = 0;

    virtual FILE * do_get_input_stream (void) = 0;

    virtual void do_set_output_stream (FILE *) = 0;

    virtual FILE * do_get_output_stream (void) = 0;

    virtual void do_redisplay (void) { }

    virtual int do_terminal_rows (void) { return m_rows; }

    virtual int do_terminal_cols (void) { return m_cols; }

    virtual void do_clear_screen (bool) { }

    virtual void do_resize_terminal (void) { }

    virtual void do_set_screen_size (int ht, int wd)
    {
      m_rows = ht;
      m_cols = wd;
    }

    virtual std::string do_decode_prompt_string (const std::string&);

    virtual std::string newline_chars (void) { return "\n"; }

    virtual void do_restore_terminal_state (void) { }

    virtual void do_blink_matching_paren (bool) { }

    virtual bool do_erase_empty_line (bool) { return false; }

    virtual void do_set_basic_word_break_characters (const std::string&) { }

    virtual void do_set_completer_word_break_characters (const std::string&) { }

    virtual void do_set_completer_word_break_hook (completion_hook_fcn) { }

    virtual void do_set_basic_quote_characters (const std::string&) { }

    virtual void do_set_filename_quote_characters (const std::string&) { }

    virtual void do_set_completer_quote_characters (const std::string&) { }

    virtual void do_set_completion_append_character (char) { }

    virtual void do_set_completion_function (completion_fcn) { }

    virtual void do_set_quoting_function (quoting_fcn) { }

    virtual void do_set_dequoting_function (dequoting_fcn) { }

    virtual void do_set_char_is_quoted_function (char_is_quoted_fcn) { }

    virtual void do_set_user_accept_line_function (user_accept_line_fcn) { }

    virtual completion_fcn do_get_completion_function (void) const
    { return nullptr; }

    virtual quoting_fcn do_get_quoting_function (void) const
    { return nullptr; }

    virtual dequoting_fcn do_get_dequoting_function (void) const
    { return nullptr; }

    virtual char_is_quoted_fcn do_get_char_is_quoted_function (void) const
    { return nullptr; }

    virtual user_accept_line_fcn do_get_user_accept_line_function (void) const
    { return nullptr; }

    virtual string_vector
    do_generate_filename_completions (const std::string& text) = 0;

    virtual std::string do_get_line_buffer (void) const = 0;

    virtual std::string do_get_current_line (void) const = 0;

    virtual char do_get_prev_char (int) const = 0;

    virtual void
    do_replace_line (const std::string& text, bool clear_undo) = 0;

    virtual void do_kill_full_line (void) = 0;

    virtual void do_insert_text (const std::string& text) = 0;

    virtual void do_newline (void) = 0;

    virtual void do_accept_line (void) = 0;

    virtual bool do_undo (void) { return false; }

    virtual void do_clear_undo_list (void) { }

    virtual void set_startup_hook (startup_hook_fcn) { }

    virtual void restore_startup_hook (void) { }

    virtual void set_pre_input_hook (pre_input_hook_fcn) { }

    virtual void restore_pre_input_hook (void) { }

    virtual void set_event_hook (event_hook_fcn) { }

    virtual void restore_event_hook (void) { }

    virtual void do_read_init_file (const std::string&) { }

    virtual void do_re_read_init_file (void) { }

    virtual bool do_filename_completion_desired (bool) { return false; }

    virtual bool do_filename_quoting_desired (bool) { return false; }

    virtual bool do_prefer_env_winsize (bool) { return false; }

    virtual void do_interrupt (bool) { }

    virtual void do_handle_interrupt_signal (void) { }

    void do_interrupt_event_loop (bool arg) { m_interrupt_event_loop = arg; }

    bool do_event_loop_interrupted (void) const
    { return m_interrupt_event_loop; }

    int do_insert_initial_input (void);

    int read_octal (const std::string& s);

    void error (int);

    void error (const std::string&);

    // The current command number.
    int m_command_number;

    int m_rows;
    int m_cols;

    bool m_interrupted;

    bool m_interrupt_event_loop;

    std::string m_initial_input;
  };
}

#endif