//
// FLUID main entry for the Fast Light Tool Kit (FLTK).
//
// Copyright 1998-2023 by Bill Spitzak and others.
//
// This library is free software. Distribution and use rights are outlined in
// the file "COPYING" which should have been included with this file.  If this
// file is missing or damaged, see the license at:
//
//     https://www.fltk.org/COPYING.php
//
// Please see the following page on how to report bugs and issues:
//
//     https://www.fltk.org/bugs.php
//

// in progress:
// FLUID comes with example shell commands to build the current project file
// and run the project. This is accomplished by calling `fltk-config` on the
// files generated by FLUID, and by calling the executable directly.
//
// If the user wants more complex commands, he can add or modify them in the
// "Shell" settings panel. Modified shell commands are saved with the .fl
// file.

// The Shell panel has a list of shell commands in the upper half. Under the
// list are buttons to add, duplicate, and delete shell commands. A popup
// menu offers import and export functionality and a list of sample scripts.
// We may want to add up and down buttons, so the user can change the
// order of commands.

// Selecting any shell command in the list fills in and activates a list of
// options in the lower half of the panel. Those settings are:
//  - Name: the name of the shell command in the list
//  - Label: the label in the pulldown menu (could be the same as name?)
//  - Shortcut: shortcut key to launch the command
//  - Storage: where to store this shell command
//  - Condition: pulldown menu to make the entry conditional for various
//    target platforms, for example, a "Windows only" entry would only be added
//    to the Shell menu on a Windows machine. Other options could be:
//     - Linux only, macOS only, never (to make a list header!?), inactive?
//  - Command: a multiline input for the actual shell command
//  - Variables: a pulldown menu that insert variable names like $<sourcefile>
//  - options to save project, code, and strings before running
//  - test-run button

// TODO: add @APPDIR@?
// TODO: get a macro to find `fltk-config` @FLTK_CONFIG@
// TODO:   add an input field so the user can insert their preferred file and path for fltk-config (user setting)
//        `fltk-config` is actually tricky to find
//        for live builds, we could check the program launch directory
//          if we know where build/Xcode/bin/Debug/fluid is, we
//          may or may not find ./build/Xcode/fltk-config
//        on macOS with homebrew, we find /opt/homebrew/bin/fltk-config but the user
//        can set their own install path.
//        We can query the shell path, but that requires knowing the users shell (echo $SHELL).
//        We can run the shell as a login shell with `-l`, so the user $PTH is set: /bin/bash -l -c 'fltk-config'
//        The shell should output the path of the fltk-config that it found and why it is using that one.
//        This can also output the fltk-config version.
// TODO: add a bunch of sensible sample shell commands
// TODO: when this new feature is used for the very first time, import two or three samples as initial user setting
// TODO: make the settings dialog resizable
// TODO: make g_shell_config static, not a pointer, but don't load anything in batch mode

// FEATURE: Fd_Tool_Store icons are currently redundant with @file and @save and could be improved
// FEATURE: hostname, username, getenv support?
// FEATURE: add the files ./fluid.prefs and ./fluid.user.prefs as tool locations
// FEATURE: interpret compiler output, for example: clang, and highlight errors and warnings
//          `.../shell_command.cxx:71:2: error: test`
//          `71 | #error test`
//          `clang++: error: no such file or directory: '.../shell_command.o'`
//          would make the error message clickable in the shell window and could select the widget,
//          open the matching editor in the widget panel, and highlight the line in SourceView.

/*
 Some ideas:

 default shell is in $SHELL on linux and macOS

 On macOS, we can write Apple Scripts:

 #!/usr/bin/env osascript
 say "@BASENAME@"

 osascript <<EOD
 say "spark"
 EOD

  osascript <<EOD
    tell application "Xcode"
      build workspace document 1
    end tell
  EOD

  powershell -c "$wshell = New-Object -ComObject wscript.shell; $wshell.SendKeys('^{ESCAPE}')
 */

#include "shell_command.h"

#include "fluid.h"
#include "file.h"
#include "settings_panel.h"

#include <FL/Fl_Double_Window.H>
#include <FL/Fl_Menu_Bar.H>
#include <FL/fl_message.H>
#include <FL/fl_string_functions.h>

#include <errno.h>

static Fl_String fltk_config_cmd;
static Fl_Process s_proc;

/**
 See if shell command is running (public)
 */
bool shell_command_running() {
  return s_proc.desc() ? true : false;
}

/**
 Reads an entry from the group. A default value must be
 supplied. The return value indicates if the value was available
 (non-zero) or the default was used (0).

 \param[in] prefs preference group
 \param[in] key name of entry
 \param[out] value returned from preferences or default value if none was set
 \param[in] defaultValue default value to be used if no preference was set
 \return 0 if the default value was used
 */
char preferences_get(Fl_Preferences &prefs, const char *key, Fl_String &value, const Fl_String &defaultValue) {
  char *v = NULL;
  char ret = prefs.get(key, v, defaultValue.c_str());
  value = v;
  ::free(v);
  return ret;
}

/**
 Sets an entry (name/value pair). The return value indicates if there
 was a problem storing the data in memory. However it does not
 reflect if the value was actually stored in the preference file.

 \param[in] prefs preference group
 \param[in] entry name of entry
 \param[in] value set this entry to value (stops at the first nul character).
 \return 0 if setting the value failed
 */
char preferences_set(Fl_Preferences &prefs, const char *key, const Fl_String &value) {
  return prefs.set(key, value.c_str());
}


/** \class Fl_Process
 Launch an external shell command.
 */

/**
 Create a process manager
 */
Fl_Process::Fl_Process() {
  _fpt= NULL;
}

/**
 Destroy the project manager.
 */
Fl_Process::~Fl_Process() {
  // TODO: check what we need to do if a task is still running
  if (_fpt) close();
}

/**
 Open a process.

 \param[in] cmd the shell command that we want to run
 \param[in] mode "r" or "w" for creating a stream that can read or write
 \return a stream that is redirected from the shell command stdout
 */
FILE * Fl_Process::popen(const char *cmd, const char *mode) {
#if defined(_WIN32)  && !defined(__CYGWIN__)
  // PRECONDITIONS
  if (!mode || !*mode || (*mode!='r' && *mode!='w') ) return NULL;
  if (_fpt) close(); // close first before reuse

  ptmode = *mode;
  pin[0] = pin[1] = pout[0] = pout[1] = perr[0] = perr[1] = INVALID_HANDLE_VALUE;
  // stderr to stdout wanted ?
  int fusion = (strstr(cmd,"2>&1") !=NULL);

  // Create windows pipes
  if (!createPipe(pin) || !createPipe(pout) || (!fusion && !createPipe(perr) ) )
    return freeHandles(); // error

  // Initialize Startup Info
  ZeroMemory(&si, sizeof(STARTUPINFO));
  si.cb           = sizeof(STARTUPINFO);
  si.dwFlags    = STARTF_USESTDHANDLES;
  si.hStdInput    = pin[0];
  si.hStdOutput   = pout[1];
  si.hStdError  = fusion ? pout[1] : perr [1];

  if ( CreateProcess(NULL, (LPTSTR) cmd,NULL,NULL,TRUE,
                     DETACHED_PROCESS,NULL,NULL, &si, &pi)) {
    // don't need theses handles inherited by child process:
    clean_close(pin[0]); clean_close(pout[1]); clean_close(perr[1]);
    HANDLE & h = *mode == 'r' ? pout[0] : pin[1];
    _fpt = _fdopen(_open_osfhandle((fl_intptr_t) h,_O_BINARY),mode);
    h= INVALID_HANDLE_VALUE;  // reset the handle pointer that is shared
    // with _fpt so we don't free it twice
  }

  if (!_fpt)  freeHandles();
  return _fpt;
#else
  _fpt=::popen(cmd,mode);
  return _fpt;
#endif
}

/**
 Close the current process.
 */
int Fl_Process::close() {
#if defined(_WIN32)  && !defined(__CYGWIN__)
  if (_fpt) {
    fclose(_fpt);
    clean_close(perr[0]);
    clean_close(pin[1]);
    clean_close(pout[0]);
    _fpt = NULL;
    return 0;
  }
  return -1;
#else
  int ret = ::pclose(_fpt);
  _fpt=NULL;
  return ret;
#endif
}

/**
 non-null if file is open.

 \return the current file descriptor of the process' stdout
 */
FILE *Fl_Process::desc() const {
  return _fpt;
}

/**
 Receive a single line from the current process.

 \param[out] line buffer to receive the line
 \param[in] s size of the provided buffer
 \return NULL if an error occurred, otherwise a pointer to the string
 */
char *Fl_Process::get_line(char * line, size_t s) const {
  return _fpt ? fgets(line, (int)s, _fpt) : NULL;
}

// returns fileno(FILE*):
// (file must be open, i.e. _fpt must be non-null)
// *FIXME* we should find a better solution for the 'fileno' issue
// non null if file is open
int Fl_Process::get_fileno() const {
#ifdef _MSC_VER
    return _fileno(_fpt); // suppress MSVC warning
#else
    return fileno(_fpt);
#endif
}

#if defined(_WIN32)  && !defined(__CYGWIN__)

bool Fl_Process::createPipe(HANDLE * h, BOOL bInheritHnd) {
  SECURITY_ATTRIBUTES sa;
  sa.nLength = sizeof(sa);
  sa.lpSecurityDescriptor = NULL;
  sa.bInheritHandle = bInheritHnd;
  return CreatePipe (&h[0],&h[1],&sa,0) ? true : false;
}

FILE *Fl_Process::freeHandles()  {
  clean_close(pin[0]);    clean_close(pin[1]);
  clean_close(pout[0]);   clean_close(pout[1]);
  clean_close(perr[0]);   clean_close(perr[1]);
  return NULL; // convenient for error management
}

void Fl_Process::clean_close(HANDLE& h) {
  if (h!= INVALID_HANDLE_VALUE) CloseHandle(h);
  h = INVALID_HANDLE_VALUE;
}

#endif


/**
 Prepare FLUID for running a shell command according to the command flags.

 \param[in] flags set various flags to save the project, code, and string before running the command
 \return false if the previous command is still running
 */
static bool prepare_shell_command(int flags)  {
//  settings_window->hide();
  if (s_proc.desc()) {
    fl_alert("Previous shell command still running!");
    return false;
  }
  if (flags & Fd_Shell_Command::SAVE_PROJECT) {
    save_cb(0, 0);
  }
  if (flags & Fd_Shell_Command::SAVE_SOURCECODE) {
    write_code_files(true);
  }
  if (flags & Fd_Shell_Command::SAVE_STRINGS) {
    write_strings_cb(0, 0);
  }
  return true;
}

/**
 Called by the file handler when the command is finished.
 */
void shell_proc_done() {
  shell_run_terminal->append("... END SHELL COMMAND ...\n");
  shell_run_button->activate();
  shell_run_window->label("FLUID Shell");
  fl_beep();
}

void shell_timer_cb(void*) {
  if (!s_proc.desc()) {
    shell_proc_done();
  } else {
    Fl::add_timeout(0.25, shell_timer_cb);
  }
}

// Support the full piped shell command...
void shell_pipe_cb(FL_SOCKET, void*) {
  char  line[1024]="";          // Line from command output...

  if (s_proc.get_line(line, sizeof(line)) != NULL) {
    // Add the line to the output list...
    shell_run_terminal->append(line);
  } else {
    // End of file; tell the parent...
    Fl::remove_timeout(shell_timer_cb);
    Fl::remove_fd(s_proc.get_fileno());
    s_proc.close();
    shell_proc_done();
  }
}

/** Find the script `fltk-config` that most closely relates to this version of FLUID.
 This is not implemented yet.
 */
//static void find_fltk_config() {
//
//}

static void expand_macro(Fl_String &cmd, const Fl_String &macro, const Fl_String &content) {
  for (int i=0;;) {
    i = cmd.find(macro, i);
    if (i==Fl_String::npos) break;
    cmd.replace(i, macro.size(), content);
  }
}

static void expand_macros(Fl_String &cmd) {
  expand_macro(cmd, "@BASENAME@",         g_project.basename());
  expand_macro(cmd, "@PROJECTFILE_PATH@", g_project.projectfile_path());
  expand_macro(cmd, "@PROJECTFILE_NAME@", g_project.projectfile_name());
  expand_macro(cmd, "@CODEFILE_PATH@",    g_project.codefile_path());
  expand_macro(cmd, "@CODEFILE_NAME@",    g_project.codefile_name());
  expand_macro(cmd, "@HEADERFILE_PATH@",  g_project.headerfile_path());
  expand_macro(cmd, "@HEADERFILE_NAME@",  g_project.headerfile_name());
  expand_macro(cmd, "@TEXTFILE_PATH@",    g_project.stringsfile_path());
  expand_macro(cmd, "@TEXTFILE_NAME@",    g_project.stringsfile_name());
//  TODO: implement finding the script `fltk-config` for all platforms
//  if (cmd.find("@FLTK_CONFIG@") != Fl_String::npos) {
//    find_fltk_config();
//    expand_macro(cmd, "@FLTK_CONFIG@",      fltk_config_cmd.c_str());
//  }
  if (cmd.find("@TMPDIR@") != Fl_String::npos)
    expand_macro(cmd, "@TMPDIR@",           get_tmpdir());
}

/**
 Show the terminal window where it was last positioned.
 */
void show_terminal_window() {
  Fl_Preferences pos(fluid_prefs, "shell_run_Window_pos");
  int x, y, w, h;
  pos.get("x", x, -1);
  pos.get("y", y, 0);
  pos.get("w", w, 640);
  pos.get("h", h, 480);
  if (x!=-1) {
    shell_run_window->resize(x, y, w, h);
  }
  shell_run_window->show();
}

/**
 Prepare for and run a shell command.

 \param[in] cmd the command that is sent to `/bin/sh -c ...` or `cmd.exe` on Windows machines
 \param[in] flags various flags in preparation of the command
 */
void run_shell_command(const Fl_String &cmd, int flags) {
  if (cmd.empty()) {
    fl_alert("No shell command entered!");
    return;
  }

  if (!prepare_shell_command(flags)) return;

  Fl_String expanded_cmd = cmd;
  expand_macros(expanded_cmd);

  if (   ((flags & Fd_Shell_Command::DONT_SHOW_TERMINAL) == 0)
      && (!shell_run_window->visible()))
  {
    show_terminal_window();
  }

  // Show the output window and clear things...
  if (flags & Fd_Shell_Command::CLEAR_TERMINAL)
    shell_run_terminal->printf("\033[2J\033[H");
  if (flags & Fd_Shell_Command::CLEAR_HISTORY)
    shell_run_terminal->printf("\033[3J");
  shell_run_terminal->scrollbar->value(0);
  shell_run_terminal->printf("\033[0;32m%s\033[0m\n", expanded_cmd.c_str());
  shell_run_window->label(expanded_cmd.c_str());

  if (s_proc.popen((char *)expanded_cmd.c_str()) == NULL) {
    shell_run_terminal->printf("\033[1;31mUnable to run shell command: %s\033[0m\n",
                               strerror(errno));
    shell_run_window->label("FLUID Shell");
    return;
  }
  shell_run_button->deactivate();

  // if the function below does not for some reason, we will check periodically
  // to see if the command is done
  Fl::add_timeout(0.25, shell_timer_cb);
  // this will tell us when the shell command is done
  Fl::add_fd(s_proc.get_fileno(), shell_pipe_cb);
}

/**
 Create an empty shell command structure.
 */
Fd_Shell_Command::Fd_Shell_Command()
: shortcut(0),
  storage(FD_STORE_USER),
  condition(0),
  flags(0),
  shell_menu_item_(NULL)
{
}

/**
 Copy the aspects of a shell command dataset into a new shell command.

 \param[in] rhs copy from this prototype
 */
Fd_Shell_Command::Fd_Shell_Command(const Fd_Shell_Command *rhs)
: name(rhs->name),
  label(rhs->label),
  shortcut(rhs->shortcut),
  storage(rhs->storage),
  condition(rhs->condition),
  condition_data(rhs->condition_data),
  command(rhs->command),
  flags(rhs->flags),
  shell_menu_item_(NULL)
{
}

/**
 Create a default storage for a shell command and how it is accessible in FLUID.

 \param[in] name is used as a stand-in for the command name and label
 */
Fd_Shell_Command::Fd_Shell_Command(const Fl_String &in_name)
: name(in_name),
  label(in_name),
  shortcut(0),
  storage(FD_STORE_USER),
  condition(Fd_Shell_Command::ALWAYS),
  command("echo \"Hello, FLUID!\""),
  flags(Fd_Shell_Command::SAVE_PROJECT|Fd_Shell_Command::SAVE_SOURCECODE),
  shell_menu_item_(NULL)
{
}

/**
 Create a storage for a shell command and how it is accessible in FLUID.

 \param[in] in_name name of this command in the command list in the settings panel
 \param[in] in_label label text in the main pulldown menu
 \param[in] in_shortcut a keyboard shortcut that will also appear in the main menu
 \param[in] in_storage storage location for this command
 \param[in] in_condition commands can be hidden for certain platforms by setting a condition
 \param[in] in_condition_data more details for future conditions, i.e. per user, per host, etc.
 \param[in] in_command the shell command that we want to run
 \param[in] in_flags some flags to tell FLUID to save the project, code, or strings before running the command
 */
Fd_Shell_Command::Fd_Shell_Command(const Fl_String &in_name,
                 const Fl_String &in_label,
                 Fl_Shortcut in_shortcut,
                 Fd_Tool_Store in_storage,
                 int in_condition,
                 const Fl_String &in_condition_data,
                 const Fl_String &in_command,
                 int in_flags)
: name(in_name),
  label(in_label),
  shortcut(in_shortcut),
  storage(in_storage),
  condition(in_condition),
  condition_data(in_condition_data),
  command(in_command),
  flags(in_flags),
  shell_menu_item_(NULL)
{
}

/**
 Run this command now.

 Will open the Shell Panel and execute the command if no other command is
 currently running.
 */
void Fd_Shell_Command::run() {
  if (!command.empty())
    run_shell_command(command, flags);
}

/**
 Update the shell submenu in main menu with the shortcut and a copy of the label.
 */
void Fd_Shell_Command::update_shell_menu() {
  if (shell_menu_item_) {
    const char *old_label = shell_menu_item_->label();  // can be NULL
    const char *new_label = label.c_str();              // never NULL
    if (!old_label || (old_label && strcmp(old_label, new_label))) {
      if (old_label) ::free((void*)old_label);
      shell_menu_item_->label(fl_strdup(new_label));
    }
    shell_menu_item_->shortcut(shortcut);
  }
}

/**
 Check if the set condition is met.

 \return true if this command appears in the main menu
 */
bool Fd_Shell_Command::is_active() {
  switch (condition) {
    case ALWAYS: return true;
    case NEVER: return false;
#ifdef _WIN32
    case MAC_ONLY: return false;
    case UX_ONLY: return false;
    case WIN_ONLY: return true;
    case MAC_AND_UX_ONLY: return false;
#elif defined(__APPLE__)
    case MAC_ONLY: return true;
    case UX_ONLY: return false;
    case WIN_ONLY: return false;
    case MAC_AND_UX_ONLY: return true;
#else
    case MAC_ONLY: return false;
    case UX_ONLY: return true;
    case WIN_ONLY: return false;
    case MAC_AND_UX_ONLY: return true;
#endif
    case USER_ONLY: return false; // TODO: get user name
    case HOST_ONLY: return false; // TODO: get host name
    case ENV_ONLY: {
      const char *value = fl_getenv(condition_data.c_str());
      if (value && *value) return true;
      return false;
    }
  }
  return false;
}

void Fd_Shell_Command::read(Fl_Preferences &prefs) {
  int tmp;
  preferences_get(prefs, "name", name, "<unnamed>");
  preferences_get(prefs, "label", label, "<no label>");
  prefs.get("shortcut", tmp, 0);
  shortcut = (Fl_Shortcut)tmp;
  prefs.get("storage", tmp, -1);
  if (tmp != -1) storage = (Fd_Tool_Store)tmp;
  prefs.get("condition", condition, ALWAYS);
  preferences_get(prefs, "condition_data", condition_data, "");
  preferences_get(prefs, "command", command, "");
  prefs.get("flags", flags, 0);
}

void Fd_Shell_Command::write(Fl_Preferences &prefs, bool save_location) {
  preferences_set(prefs, "name", name);
  preferences_set(prefs, "label", label);
  if (shortcut != 0) prefs.set("shortcut", (int)shortcut);
  if (save_location) prefs.set("storage", (int)storage);
  if (condition != ALWAYS) prefs.set("condition", condition);
  if (!condition_data.empty()) preferences_set(prefs, "condition_data", condition_data);
  if (!command.empty()) preferences_set(prefs, "command", command);
  if (flags != 0) prefs.set("flags", flags);
}

void Fd_Shell_Command::read(class Fd_Project_Reader *in) {
  const char *c = in->read_word(1);
  if (strcmp(c, "{")!=0) return; // expecting start of group
  storage = FD_STORE_PROJECT;
  for (;;) {
    c = in->read_word(1);
    if (strcmp(c, "}")==0) break; // end of command list
    else if (strcmp(c, "name")==0)
      name = in->read_word();
    else if (strcmp(c, "label")==0)
      label = in->read_word();
    else if (strcmp(c, "shortcut")==0)
      shortcut = in->read_int();
    else if (strcmp(c, "condition")==0)
      condition = in->read_int();
    else if (strcmp(c, "condition_data")==0)
      condition_data = in->read_word();
    else if (strcmp(c, "command")==0)
      command = in->read_word();
    else if (strcmp(c, "flags")==0)
      flags = in->read_int();
    else
      in->read_word(); // skip an unknown word
  }
}

void Fd_Shell_Command::write(class Fd_Project_Writer *out) {
  out->write_string("\n  command {");
  out->write_string("\n    name "); out->write_word(name.c_str());
  out->write_string("\n    label "); out->write_word(label.c_str());
  if (shortcut) out->write_string("\n    shortcut %d", shortcut);
  if (condition) out->write_string("\n    condition %d", condition);
  if (!condition_data.empty()) {
    out->write_string("\n    condition_data "); out->write_word(condition_data.c_str());
  }
  if (!command.empty()) {
    out->write_string("\n    command "); out->write_word(command.c_str());
  }
  if (flags) out->write_string("\n    flags %d", flags);
  out->write_string("\n  }");
}


/**
 Manage a list of shell commands and their parameters.
 */
Fd_Shell_Command_List::Fd_Shell_Command_List()
: list(NULL),
  list_size(0),
  list_capacity(0),
  shell_menu_(NULL)
{
}

/**
 Release all shell commands and destroy this class.
 */
Fd_Shell_Command_List::~Fd_Shell_Command_List() {
  clear();
}

/**
 Return the shell command at the given index.

 \param[in] index must be between 0 and list_size-1
 \return a pointer to the shell command data
 */
Fd_Shell_Command *Fd_Shell_Command_List::at(int index) const {
  return list[index];
}

/**
 Clear all shell commands.
 */
void Fd_Shell_Command_List::clear() {
  if (list) {
    for (int i=0; i<list_size; i++) {
      delete list[i];
    }
    ::free(list);
    list_size = 0;
    list_capacity = 0;
    list = 0;
  }
}

/**
 remove all shell commands of the given storage location from the list.
 */
void Fd_Shell_Command_List::clear(Fd_Tool_Store storage) {
  for (int i=list_size-1; i>=0; i--) {
    if (list[i]->storage == storage) {
      remove(i);
    }
  }
}

/**
 Read shell configuration from a preferences group.
 */
void Fd_Shell_Command_List::read(Fl_Preferences &prefs, Fd_Tool_Store storage) {
  // import the old shell commands from previous user settings
  if (&fluid_prefs == &prefs) {
    int version;
    prefs.get("shell_commands_version", version, 0);
    if (version == 0) {
      int save_fl, save_code, save_strings;
      Fd_Shell_Command *cmd = new Fd_Shell_Command();
      cmd->storage = FD_STORE_USER;
      cmd->name = "Sample Shell Command";
      cmd->label = "Sample Shell Command";
      cmd->shortcut = FL_ALT+'g';
      preferences_get(fluid_prefs, "shell_command", cmd->command, "echo \"Sample Shell Command\"");
      fluid_prefs.get("shell_savefl", save_fl, 1);
      fluid_prefs.get("shell_writecode", save_code, 1);
      fluid_prefs.get("shell_writemsgs", save_strings, 0);
      if (save_fl) cmd->flags |= Fd_Shell_Command::SAVE_PROJECT;
      if (save_code) cmd->flags |= Fd_Shell_Command::SAVE_SOURCECODE;
      if (save_strings) cmd->flags |= Fd_Shell_Command::SAVE_STRINGS;
      add(cmd);
    }
    version = 1;
    prefs.set("shell_commands_version", version);
  }
  Fl_Preferences shell_commands(prefs, "shell_commands");
  int n = shell_commands.groups();
  for (int i=0; i<n; i++) {
    Fl_Preferences cmd_prefs(shell_commands, Fl_Preferences::Name(i));
    Fd_Shell_Command *cmd = new Fd_Shell_Command();
    cmd->storage = FD_STORE_USER;
    cmd->read(cmd_prefs);
    add(cmd);
  }
}

/**
 Write shell configuration to a preferences group.
 */
void Fd_Shell_Command_List::write(Fl_Preferences &prefs, Fd_Tool_Store storage) {
  Fl_Preferences shell_commands(prefs, "shell_commands");
  shell_commands.delete_all_groups();
  int index = 0;
  for (int i=0; i<list_size; i++) {
    if (list[i]->storage == FD_STORE_USER) {
      Fl_Preferences cmd(shell_commands, Fl_Preferences::Name(index++));
      list[i]->write(cmd);
    }
  }
}

/**
 Read shell configuration from a project file.
 */
void Fd_Shell_Command_List::read(Fd_Project_Reader *in) {
  const char *c = in->read_word(1);
  if (strcmp(c, "{")!=0) return; // expecting start of group
  clear(FD_STORE_PROJECT);
  for (;;) {
    c = in->read_word(1);
    if (strcmp(c, "}")==0) break; // end of command list
    else if (strcmp(c, "command")==0) {
      Fd_Shell_Command *cmd = new Fd_Shell_Command();
      add(cmd);
      cmd->read(in);
    } else {
      in->read_word(); // skip an unknown group
    }
  }
}

/**
 Write shell configuration to a project file.
 */
void Fd_Shell_Command_List::write(Fd_Project_Writer *out) {
  int n_in_project_file = 0;
  for (int i=0; i<list_size; i++) {
    if (list[i]->storage == FD_STORE_PROJECT)
      n_in_project_file++;
  }
  if (n_in_project_file > 0) {
    out->write_string("\nshell_commands {");
    for (int i=0; i<list_size; i++) {
      if (list[i]->storage == FD_STORE_PROJECT)
        list[i]->write(out);
    }
    out->write_string("\n}");
  }
}

/**
 Add a previously created shell command to the end of the list.

 \param[in] cmd a pointer to the command that we want to add
 */
void Fd_Shell_Command_List::add(Fd_Shell_Command *cmd) {
  if (list_size == list_capacity) {
    list_capacity += 16;
    list = (Fd_Shell_Command**)::realloc(list, list_capacity * sizeof(Fd_Shell_Command*));
  }
  list[list_size++] = cmd;
}

/**
 Insert a newly created shell command at the given position in the list.

 \param[in] index must be between 0 and list_size-1
 \param[in] cmd a pointer to the command that we want to add
 */
void Fd_Shell_Command_List::insert(int index, Fd_Shell_Command *cmd) {
  if (list_size == list_capacity) {
    list_capacity += 16;
    list = (Fd_Shell_Command**)::realloc(list, list_capacity * sizeof(Fd_Shell_Command*));
  }
  ::memmove(list+index+1, list+index, (list_size-index)*sizeof(Fd_Shell_Command**));
  list_size++;
  list[index] = cmd;
}

/**
 Remove and delete the command at the given index.

 \param[in] index must be between 0 and list_size-1
 */
void Fd_Shell_Command_List::remove(int index) {
  delete list[index];
  list_size--;
  ::memmove(list+index, list+index+1, (list_size-index)*sizeof(Fd_Shell_Command**));
}

/**
 This is called whenever the user clicks a shell command menu in the main menu.

 \param[in] u cast tp long to get the index of the shell command
 */
void menu_shell_cmd_cb(Fl_Widget*, void *u) {
  long index = (long)(fl_intptr_t)u;
  g_shell_config->list[index]->run();
}

/**
 This is called when the user selects the menu to edit the shell commands.
 It pops up the setting panel at the shell settings tab.
 */
void menu_shell_customize_cb(Fl_Widget*, void*) {
  settings_window->show();
  w_settings_tabs->value(w_settings_shell_tab);
}

/**
 Rebuild the entire shell submenu from scratch and replace the old menu.
 */
void Fd_Shell_Command_List::rebuild_shell_menu() {
  static Fl_Menu_Item *shell_submenu = NULL;
  if (!shell_submenu)
    shell_submenu = (Fl_Menu_Item*)main_menubar->find_item(menu_marker);

  int i, j, num_active_items = 0;
  // count the active commands
  for (i=0; i<list_size; i++) {
    if (list[i]->is_active()) num_active_items++;
  }
  // allocate a menu item array
  Fl_Menu_Item *mi = (Fl_Menu_Item*)::calloc(num_active_items+2, sizeof(Fl_Menu_Item));
  // set the menu item pointer for all active commands
  for (i=j=0; i<list_size; i++) {
    Fd_Shell_Command *cmd = list[i];
    if (cmd->is_active()) {
      cmd->shell_menu_item_ = mi + j;
      mi[j].callback(menu_shell_cmd_cb);
      mi[j].argument(i);
      cmd->update_shell_menu();
      j++;
    }
  }
  if (j>0) mi[j-1].flags |= FL_MENU_DIVIDER;
  mi[j].label(fl_strdup("Customize..."));
  mi[j].shortcut(FL_ALT+'x');
  mi[j].callback(menu_shell_customize_cb);
  // replace the old menu array with the new one
  Fl_Menu_Item *mi_old = shell_menu_;
  shell_menu_ = mi;
  shell_submenu->user_data(shell_menu_);
  // free all resources from the old menu
  if (mi_old && (mi_old != default_menu)) {
    for (i=0; ; i++) {
      const char *label = mi_old[i].label();
      if (!label) break;
      ::free((void*)label);
    }
    ::free(mi_old);
  }
}

/**
 Tell the settings dialog to query this list and update its GUI elements.
 */
void Fd_Shell_Command_List::update_settings_dialog() {
  if (w_settings_shell_tab)
    w_settings_shell_tab->do_callback(w_settings_shell_tab, LOAD);
}

/**
 The default shell submenu in batch mode.
 */
Fl_Menu_Item Fd_Shell_Command_List::default_menu[] = {
  {   "Customize...", FL_ALT+'x', menu_shell_customize_cb },
  { NULL }
};

/**
 Used to find the shell submenu within the main menu tree.
 */
void Fd_Shell_Command_List::menu_marker(Fl_Widget*, void*) {
  // intentionally left empty
}

/**
 Export all selected shell commands to an external file.

 Verify that g_shell_config and w_settings_shell_list are not NULL. Open a
 file chooser and export all items that are selected in w_settings_shell_list
 into an external file.
 */
void Fd_Shell_Command_List::export_selected() {
  if (!g_shell_config || (g_shell_config->list_size == 0)) return;
  if (!w_settings_shell_list) return;

  Fl_Native_File_Chooser dialog;
  dialog.title("Export selected shell commands:");
  dialog.type(Fl_Native_File_Chooser::BROWSE_SAVE_FILE);
  dialog.filter("FLUID Files\t*.flcmd\n");
  dialog.directory(g_project.projectfile_path().c_str());
  dialog.preset_file((g_project.basename() + ".flcmd").c_str());
  if (dialog.show() != 0) return;

  Fl_Preferences file(dialog.filename(), "flcmd.fluid.fltk.org", NULL, (Fl_Preferences::Root)(Fl_Preferences::C_LOCALE|Fl_Preferences::CLEAR));
  Fl_Preferences shell_commands(file, "shell_commands");
  int i, index = 0, n = w_settings_shell_list->size();
  for (i = 0; i < n; i++) {
    if (w_settings_shell_list->selected(i+1)) {
      Fl_Preferences cmd(shell_commands, Fl_Preferences::Name(index++));
      g_shell_config->list[i]->write(cmd, true);
    }
  }
}

/**
 Import shell commands from an external file and add them to the list.

 Verify that g_shell_config and w_settings_shell_list are not NULL. Open a
 file chooser and import all items.
 */
void Fd_Shell_Command_List::import_from_file() {
  if (!g_shell_config || (g_shell_config->list_size == 0)) return;
  if (!w_settings_shell_list) return;

  Fl_Native_File_Chooser dialog;
  dialog.title("Import shell commands:");
  dialog.type(Fl_Native_File_Chooser::BROWSE_FILE);
  dialog.filter("FLUID Files\t*.flcmd\n");
  dialog.directory(g_project.projectfile_path().c_str());
  dialog.preset_file((g_project.basename() + ".flcmd").c_str());
  if (dialog.show() != 0) return;

  Fl_Preferences file(dialog.filename(), "flcmd.fluid.fltk.org", NULL, Fl_Preferences::C_LOCALE);
  Fl_Preferences shell_commands(file, "shell_commands");
  int i, n = shell_commands.groups();
  for (i = 0; i < n; i++) {
    Fl_Preferences cmd_prefs(shell_commands, Fl_Preferences::Name(i));
    Fd_Shell_Command *cmd = new Fd_Shell_Command();
    cmd->storage = FD_STORE_USER;
    cmd->read(cmd_prefs);
    g_shell_config->add(cmd);
  }
  w_settings_shell_list->do_callback(w_settings_shell_list, LOAD);
  w_settings_shell_cmd->do_callback(w_settings_shell_cmd, LOAD);
  w_settings_shell_toolbox->do_callback(w_settings_shell_toolbox, LOAD);
  g_shell_config->rebuild_shell_menu();
}

/**
 A pointer to the list of shell commands if we are not in batch mode.
 */
Fd_Shell_Command_List *g_shell_config = NULL;