/***************************************************************************

  PMsgBox.cpp

  Author: Andreas Suter
  e-mail: andreas.suter@psi.ch

***************************************************************************/

/***************************************************************************
 *   Copyright (C) 2007-2025 by Andreas Suter                              *
 *   andreas.suter@psi.ch                                                  *
 *                                                                         *
 *   This program 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 2 of the License, or     *
 *   (at your option) any later version.                                   *
 *                                                                         *
 *   This program 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 this program; if not, write to the                         *
 *   Free Software Foundation, Inc.,                                       *
 *   59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.             *
 ***************************************************************************/

#include "PMsgBox.h"

//--------------------------------------------------------------------------
// Constructor
//--------------------------------------------------------------------------
/**
 * \brief Constructor that creates and displays the message box GUI.
 *
 * This constructor performs the following steps:
 * 1. Creates a scrollable list box widget
 * 2. Parses the error message string by splitting at newline characters
 * 3. Populates the list box with individual message lines
 * 4. Creates an Exit button with callback to DoExit()
 * 5. Configures layout and displays the window
 *
 * The message parsing algorithm:
 * - Adds an initial empty line
 * - Splits the input string at each '\n' character
 * - Each substring becomes a separate list box entry
 * - Handles multi-line messages gracefully
 *
 * GUI Layout:
 * - List box: 600x200 pixels, expandable, with 5-pixel margins
 * - Button frame: Fixed width (150px), contains Exit button
 * - Window title: "Error Message"
 *
 * \param errMsg Multi-line error message string with '\n' separators
 * \param p Parent window pointer (typically gClient->GetRoot())
 * \param w Initial window width in pixels
 * \param h Initial window height in pixels
 *
 * \note The window is automatically mapped (displayed) after construction
 * \note The list box ID is set to 89 (ROOT widget identifier)
 */
PMsgBox::PMsgBox(const std::string errMsg, const TGWindow *p, UInt_t w, UInt_t h) : TGMainFrame(p, w, h)
{
   fListBox = new TGListBox(this, 89);

   // feed list box with errMsg
   size_t start = 0;
   size_t end = errMsg.find("\n");
   unsigned int i=1;
   std::string tok{""};
   fListBox->AddEntry(tok.c_str(), i++);
   while (end != std::string::npos) {
     tok = errMsg.substr(start, end - start);
     start = end + 1;
     end = errMsg.find("\n", start);
     fListBox->AddEntry(tok.c_str(), i++);
   }

   fListBox->Resize(600, 200);
   AddFrame(fListBox, new TGLayoutHints(kLHintsTop | kLHintsLeft | kLHintsExpandX | kLHintsExpandY, 5, 5, 5, 5));

   // Create a horizontal frame containing button(s)
   TGHorizontalFrame *hframe = new TGHorizontalFrame(this, 150, 20, kFixedWidth);
   TGTextButton *exit = new TGTextButton(hframe, "&Exit ");
   exit->Connect("Pressed()", "PMsgBox", this, "DoExit()");
   hframe->AddFrame(exit, new TGLayoutHints(kLHintsExpandX, 5, 5, 3, 4));
   AddFrame(hframe, new TGLayoutHints(kLHintsExpandX, 2, 2, 5, 1));

   // Set a name to the main frame
   SetWindowName("Error Message");
   MapSubwindows();

   // Initialize the layout algorithm via Resize()
   Resize(GetDefaultSize());

   // Map main frame
   MapWindow();
}

//--------------------------------------------------------------------------
// Destructor
//--------------------------------------------------------------------------
/**
 * \brief Destructor that cleans up the message box resources.
 *
 * The ROOT framework automatically handles cleanup of GUI components
 * (list box, buttons, frames) through the TGMainFrame destructor chain,
 * so no explicit cleanup is required here.
 *
 * \note GUI widgets are managed by ROOT and are automatically deleted
 *       when the main frame is destroyed
 */
PMsgBox::~PMsgBox()
{
  // nothing to be done here - ROOT handles GUI cleanup automatically
}

//--------------------------------------------------------------------------
// DoExit
//--------------------------------------------------------------------------
/**
 * \brief Exit button callback that terminates the application.
 *
 * This method is invoked when the user clicks the Exit button.
 * It terminates the entire ROOT application with exit code 0,
 * which causes a clean shutdown of the program.
 *
 * The method is connected to the Exit button's "Pressed()" signal
 * in the constructor via ROOT's signal/slot mechanism:
 * \code
 * exit->Connect("Pressed()", "PMsgBox", this, "DoExit()");
 * \endcode
 *
 * \note This terminates the entire application, not just the message box window
 * \note Exit code 0 indicates successful termination
 *
 * \see gApplication for ROOT's global application object
 */
void PMsgBox::DoExit()
{
   gApplication->Terminate(0);
}