text: /****************************************************************************
   *
   *   Copyright (C) 2015-2016 PX4 Development Team. All rights reserved.
   *
   * Redistribution and use in source and binary forms, with or without
   * modification, are permitted provided that the following conditions
   * are met:
   *
   * 1. Redistributions of source code must retain the above copyright
   *    notice, this list of conditions and the following disclaimer.
   * 2. Redistributions in binary form must reproduce the above copyright
   *    notice, this list of conditions and the following disclaimer in
   *    the documentation and/or other materials provided with the
   *    distribution.
   * 3. Neither the name PX4 nor the names of its contributors may be
   *    used to endorse or promote products derived from this software
   *    without specific prior written permission.
   *
   * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
   * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
   * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
   * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
   * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
   * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
   * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
   * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
   * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
   * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
   * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
   * POSSIBILITY OF SUCH DAMAGE.
   *
   ****************************************************************************/
  /**
   * @file pxh.cpp
   *
   * This is a simple PX4 shell implementation used to start modules.
   *
   * @author Mark Charlebois <charlebm@gmail.com>
   * @author Roman Bapst <bapstroman@gmail.com>
   * @author Julian Oes <julian@oes.ch>
   */
  
  #include <string>
  #include <sstream>
  #include <vector>
  #include <stdio.h>
  
  #include "pxh.h"
  
  namespace px4_daemon
  {
  
  Pxh *Pxh::_instance = nullptr;
  
  apps_map_type Pxh::_apps = {};
  
  
  Pxh::Pxh()
  {
  	_history.try_to_add("commander takeoff"); // for convenience
  	_history.reset_to_end();
  	_instance = this;
  }
  
  Pxh::~Pxh()
  {
  	_instance = nullptr;
  }
  
  int Pxh::process_line(const std::string &line, bool silently_fail)
  {
  	if (line.empty()) {
  		return 0;
  	}
  
  	if (_apps.empty()) {
  		init_app_map(_apps);
  	}
  
  	std::stringstream line_stream(line);
  	std::string word;
  	std::vector<std::string> words;
  
  	// First arg should be the command.
  	while (line_stream >> word) {
  		words.push_back(word);
  	}
  
  	if (words.empty()) {
  		return 0;
  	}
  
  	const std::string &command(words.front());
  
  	if (_apps.find(command) != _apps.end()) {
  
  		// Note that argv[argc] always needs to be a nullptr.
  		// Therefore add one more entry.
  		const char *arg[words.size() + 1];
  
  		for (unsigned i = 0; i < words.size(); ++i) {
  			arg[i] = (char *)words[i].c_str();
  		}
  
  		// Explicitly set this nullptr.
  		arg[words.size()] = nullptr;
  
  		int retval = _apps[command](words.size(), (char **)arg);
  
  		if (retval) {
  			if (!silently_fail) {
  				printf("Command '%s' failed, returned %d.\n", command.c_str(), retval);
  			}
  		}
  
  		return retval;
  
  	} else if (command == "help") {
  		list_builtins(_apps);
  		return 0;
  
  	} else if (command.length() == 0 || command[0] == '#') {
  		// Do nothing
  		return 0;
  
  	} else if (!silently_fail) {
  		//std::cout << "Invalid command: " << command << "\ntype 'help' for a list of commands" << endl;
  		printf("Invalid command: %s\ntype 'help' for a list of commands\n", command.c_str());
  		return -1;
  
  	} else {
  		return -1;
  	}
  }
  
  
  void Pxh::run_pxh()
  {
  	_should_exit = false;
  
  	_setup_term();
  
  	std::string mystr;
  	int cursor_position = 0; // position of the cursor from right to left
  	// (0: all the way to the right, mystr.length: all the way to the left)
  
  	_print_prompt();
  
  	while (!_should_exit) {
  
  		int c = getchar();
  		std::string add_string; // string to add at current cursor position
  		bool update_prompt = true;
  
  		switch (c) {
  		case EOF:
  			_should_exit = true;
  			break;
  
  		case 127:	// backslash
  			if ((int)mystr.length() - cursor_position > 0) {
  				mystr.erase(mystr.length() - cursor_position - 1, 1);
  			}
  
  			break;
  
  		case '\n':	// user hit enter
  			_history.try_to_add(mystr);
  			_history.reset_to_end();
  
  			printf("\n");
  			process_line(mystr, false);
  			// reset string and cursor position
  			mystr = "";
  			cursor_position = 0;
  
  			update_prompt = false;
  			_print_prompt();
  			break;
  
  		case '\033': {	// arrow keys
  				c = getchar();	// skip first one, does not have the info
  				c = getchar();
  
  				if (c == 'A') { // arrow up
  					_history.try_to_save_current_line(mystr);
  					_history.get_previous(mystr);
  					cursor_position = 0; // move cursor to end of line
  
  				} else if (c == 'B') { // arrow down
  					_history.get_next(mystr);
  					cursor_position = 0; // move cursor to end of line
  
  				} else if (c == 'C') { // arrow right
  					if (cursor_position > 0) {
  						cursor_position--;
  					}
  
  				} else if (c == 'D') { // arrow left
  					if (cursor_position < (int)mystr.length()) {
  						cursor_position++;
  					}
  
  				} else if (c == 'H') { // Home (go to the beginning of the command)
  					cursor_position = mystr.length();
  
  				} else if (c == '1') { // Home (go to the beginning of the command, Editing key)
  					(void)getchar(); // swallow '~'
  					cursor_position = mystr.length();
  
  				} else if (c == 'F') { // End (go to the end of the command)
  					cursor_position = 0;
  
  				} else if (c == '4') { // End (go to the end of the command, Editing key)
  					(void)getchar(); // swallow '~'
  					cursor_position = 0;
  				}
  
  				break;
  			}
  
  		default:	// any other input
  			if (c > 3) {
  				add_string += (char)c;
  
  			} else {
  				update_prompt = false;
  			}
  
  			break;
  		}
  
  
  		if (update_prompt) {
  			// reprint prompt with mystr
  			mystr.insert(mystr.length() - cursor_position, add_string);
  			_clear_line();
  			_print_prompt();
  			printf("%s", mystr.c_str());
  
  			// Move the cursor to its position
  			if (cursor_position > 0) {
  				_move_cursor(cursor_position);
  			}
  		}
  
  	}
  }
  
  void Pxh::stop()
  {
  	_restore_term();
  
  	if (_instance) {
  		_instance->_should_exit = true;
  	}
  }
  
  void Pxh::_setup_term()
  {
  	// Make sure we restore terminal at exit.
  	tcgetattr(0, &_orig_term);
  	atexit(Pxh::_restore_term);
  
  	// change input mode so that we can manage shell
  	struct termios term;
  	tcgetattr(0, &term);
  	term.c_lflag &= ~ICANON;
  	term.c_lflag &= ~ECHO;
  	tcsetattr(0, TCSANOW, &term);
  	setbuf(stdin, nullptr);
  }
  
  void Pxh::_restore_term()
  {
  	if (_instance) {
  		tcsetattr(0, TCSANOW, &_instance->_orig_term);
  	}
  }
  
  void Pxh::_print_prompt()
  {
  	fflush(stdout);
  	printf("pxh> ");
  	fflush(stdout);
  }
  
  void Pxh::_clear_line()
  {
  	printf("%c[2K%c", (char)27, (char)13);
  }
  void Pxh::_move_cursor(int position)
  {
  	printf("\033[%dD", position);
  }
  
  } // namespace px4_daemon
  