mainwindow.cpp

/*
 *   Program                :     Rich Text Editor using QWidgets
 *   Author                 :     Vishnu Kiran (CS18B067)
 *   Date of Completion     :     29/04/2020
 *   Description            :     This program creates a rich text editor with basic functionalities using QWidgets Application
 *                                of Qt. It uses the QTextEdit inbuilt class which is used for all the text operations. The UI
 *                                has been created using QtDesigner tool which enabled addition of menu bars and toolbars with
 *                                available features. QTextEdit class provides inbuilt scrollbar facility which has been utilised.
 *                                Qt Resource System(.qrc in Resources directory) has been used to manage the resources for the project(images for icons etc.)
 *                                Qt Project File(.pro) contains infomation required by qmake to build application.
 *                                qmake tool is used for building application across different platforms.
 *
 *
*/

/* Contents of project:
 *           Text_Editor_Widget.pro  -      Qt Project File for building of application
 *           Headers
 *                  mainwindow.h     -      Header file for mainwindow in our UI
 *                  TextEdit.h       -      Definition of TextEdit class which is the central Widget
 *           Forms(Sources)
 *                  main.cpp         -      Contains main program
 *                  mainwindow.cpp   -      Contains functionalities of mainwindow
 *           Resources
 *                  Resources.qrc    -      Resource file containing icons used
*/




#include "mainwindow.h"
#include "ui_mainwindow.h"
#include "TextEdit.h"
#include <QInputDialog>
#include <QLineEdit>
#include <iostream>
#include <QListWidget>
#include <QKeyEvent>
#include <QScrollBar>
#include <QStringListModel>


using namespace std;

/*
 * Constructor for TextEdit
*/
TextEdit::TextEdit(QWidget *parent)
    : QTextEdit(parent)
{

}

/*
 * Destructor for TextEdit
*/
TextEdit::~TextEdit()
{
}

/*
 * Used to set up a completer
*/
void TextEdit::completeword(QCompleter *completer)
{
    if (word)
        word->disconnect(this);  //Disconnect the signal from the slot

    word = completer;

    if (!word)
        return;

    word->setWidget(this); //Completer acts on this widget
    word->setCompletionMode(QCompleter::PopupCompletion);  // A pop menu printing options is displayed
    word->setCaseSensitivity(Qt::CaseInsensitive); // Make word matching case insensitive

    // Connect activated signal with insertword slot.Activated signal is sent when an item in the popup() is selected by the user

    QObject::connect(word, QOverload<const QString &>::of(&QCompleter::activated),this, &TextEdit::insertword);
}

/*
 * Return the QCompleter
*/
QCompleter *TextEdit::completer() const
{
    return word;
}

/*
 * Inserts word selected by user into the current cursor position. It is trigerred when selects a word from the popup options
*/
void TextEdit::insertword(const QString &completion)
{
    QTextCursor ins = textCursor();
    int diff = completion.length() - word->completionPrefix().length();
    ins.movePosition(QTextCursor::Left);
    ins.movePosition(QTextCursor::EndOfWord);
    ins.insertText(completion.right(diff)); //Insert the rest of strin(completion) into TextEdit
    setTextCursor(ins); //Cursor is set at the end of word
}

/*
 * Select the word under the cursor and returns it
*/
QString TextEdit::currText() const
{
    QTextCursor ins = textCursor();
    ins.select(QTextCursor::WordUnderCursor);
    return ins.selectedText();
}

/*
 * Handle keyboard focus events
*/
void TextEdit::focusInEvent(QFocusEvent *e)
{
    if (word)
        word->setWidget(this);
    QTextEdit::focusInEvent(e);
}

/*
 * Ignore certain key events to let completer handle them
 */
void TextEdit::keyPressEvent(QKeyEvent *e)
{
    if (word && word->popup()->isVisible()) {
        // Completer forward keys to widget
       switch (e->key())
       {
            case Qt::Key_Enter:
            case Qt::Key_Return:
            case Qt::Key_Escape:
            case Qt::Key_Tab:
            case Qt::Key_Backtab:
                e->ignore();
                return; // Completer default behavior
            default:
                break;
       }
    }

    //Completer should not respond to certain modifiers and shortcuts

    const bool togg = (e->modifiers().testFlag(Qt::ControlModifier) && e->key() == Qt::Key_E); // CTRL+E shorcut
    if (!word || !togg)
        QTextEdit::keyPressEvent(e);
    const bool ok1 = e->modifiers().testFlag(Qt::ControlModifier) || e->modifiers().testFlag(Qt::ShiftModifier);
    if (!word || (ok1 && e->text().isEmpty()))
           return;

     static QString end_word("~!@#$%^&*()_+{}|:\"<>?,./;'[]\\-="); // end of word
     const bool ok2 = (e->modifiers() != Qt::NoModifier) && !ok1;
     QString comp_word = currText();

     if (!togg && (ok2 || e->text().isEmpty()|| comp_word.length() < 3 || end_word.contains(e->text().right(1))))
     {
           word->popup()->hide();
           return;
     }

       if (comp_word != word->completionPrefix())
       {
           word->setCompletionPrefix(comp_word);
           word->popup()->setCurrentIndex(word->completionModel()->index(0, 0));
       }

       QRect curr_cursor = cursorRect();
       curr_cursor.setWidth(word->popup()->sizeHintForColumn(0)
                   + word->popup()->verticalScrollBar()->sizeHint().width());
       word->complete(curr_cursor);
   }

/*
 * Mainwindow constructor
 */
MainWindow::MainWindow(QWidget *parent):QMainWindow(parent),ui(new Ui::MainWindow)
{
    ui->setupUi(this);
    completingTextEdit = new TextEdit; //Set up TextEdit block

    //Set up QCompleter

    completer = new QCompleter(this);
    completer->setModel(modelFromFile(":/icons/wordlist.txt"));
    completer->setModelSorting(QCompleter::CaseInsensitivelySortedModel);
    completer->setCaseSensitivity(Qt::CaseInsensitive);
    completer->setWrapAround(false);
    completingTextEdit->completeword(completer);
    this->setCentralWidget(completingTextEdit);
     completingTextEdit->setFontWeight(QFont::Thin);
}

/*
 * Extract contents of wordlist.txt as a StringList
*/

QAbstractItemModel *MainWindow::modelFromFile(const QString& fileName)
{
    QFile file(fileName);
    if (!file.open(QFile::ReadOnly))
        return new QStringListModel(completer);

#ifndef QT_NO_CURSOR
    QGuiApplication::setOverrideCursor(QCursor(Qt::WaitCursor));
#endif
    QStringList words;

    while (!file.atEnd()) {
        QByteArray line = file.readLine();
        if (!line.isEmpty())
            words << QString::fromUtf8(line.trimmed());
    }

#ifndef QT_NO_CURSOR
    QGuiApplication::restoreOverrideCursor();
#endif
    return new QStringListModel(words, completer);
}

/*
 * Mainwindow destructor
*/
MainWindow::~MainWindow()
{
    delete ui;
}

/*
 *  This function is called when New File button is pressed/selected in toolbar
*/
void MainWindow::on_actionNew_triggered()
{
    lastsaved="";
    QString current=completingTextEdit->toPlainText();
    if(current!=lastsaved) // Check if current file is saved
    {
        // Check if user wants to save the current file or discard it

        QMessageBox modified;
        modified.setText("Do you want to save this document?");
        modified.setStandardButtons(QMessageBox::Save |  QMessageBox::Discard | QMessageBox::Cancel);
        modified.setDefaultButton(QMessageBox::Save);
        int ret = modified.exec(); // ret returns the value of Standard Button pressed
        if(ret==0x00000800)
        {
            MainWindow::on_actionSave_triggered();
        }
        else if(ret==0x00800000)
        {
            currentfile.clear();
            completingTextEdit->setText(QString());
            setWindowTitle("Untitled");
        }
      }
    else
    {
        currentfile.clear();
        completingTextEdit->setText(QString());
        setWindowTitle("Untitled"); // A New File is named Untitled by default
    }

}

/*
 *This function is called if open file button is pressed
*/
void MainWindow::on_actionOpen_triggered()
{
    QString current=completingTextEdit->toPlainText();
    if(current!=lastsaved) //Check current file is saved
    {
        QMessageBox modified;
        modified.setText("Do you want to save this document?");
        modified.setStandardButtons(QMessageBox::Save |  QMessageBox::Discard | QMessageBox::Cancel);
        modified.setDefaultButton(QMessageBox::Save);
        int ret = modified.exec(); // ret returns the value of Standard Button pressed
        if(ret==0x00000800)
        {
            MainWindow::on_actionSave_triggered();return;
        }
        else if(ret==0x00400000)
        {
            return;
         }
     }
        QString openfile = QFileDialog::getOpenFileName(this, "Open file"); //Get name of file to open
        QFile file(openfile);
        currentfile = openfile;
        if (!file.open(QIODevice::ReadOnly | QFile::Text)) {
            QMessageBox::warning(this, "Warning", "Unable to open file: " + file.errorString());
            return;
        }
        setWindowTitle(openfile);
        QTextStream in(&file);
        QString text = in.readAll();
        completingTextEdit->setText(text); //Get contents of file into TextEdit window
        file.close();
}

/*
 * This function is called when save button is pressed
*/
void MainWindow::on_actionSave_triggered()
{
        QString fileName = QFileDialog::getSaveFileName(this, "Save as"); //Get file name to save as
        QFile file(fileName);

        //Check if file could be opened

        if (!file.open(QFile::WriteOnly | QFile::Text)) {
            QMessageBox::warning(this, "Warning", "Cannot save file: " + file.errorString());
            return;
        }


        currentfile = fileName;
        setWindowTitle(fileName);
        QTextStream out(&file);
        QString text = completingTextEdit->toPlainText();
        out << text; //Write contents in QTextEdit into the file
        lastsaved=text;
        file.close();
}

/*
 *Used to cut text and save in clipboard
*/
void MainWindow::on_actionCut_triggered()
{
    completingTextEdit->cut();
}

/*
 *Copy text and save in clipboard
*/
void MainWindow::on_actionCopy_triggered()
{
    completingTextEdit->copy();
}

/*
 * Paste text at the current cursor position
*/
void MainWindow::on_actionPaste_triggered()
{
   completingTextEdit->paste();
}

/*
 * Undo the last action
*/
void MainWindow::on_actionUndo_triggered()
{
    completingTextEdit->undo();
}

/*
 * Redo the last action
*/
void MainWindow::on_actionRedo_triggered()
{
    completingTextEdit->redo();
}

/*
 * Used to exit the application
*/
void MainWindow::on_actionExit_triggered() {
    QString current=completingTextEdit->toPlainText();
    if(current!=lastsaved) //Check if file has been saved
      {

        QMessageBox modified;
        modified.setText("The document has been modified");
        modified.setStandardButtons(QMessageBox::Save |  QMessageBox::Discard | QMessageBox::Cancel);
        modified.setDefaultButton(QMessageBox::Save);
        int ret = modified.exec(); // ret returns the value of Standard Button pressed
        if(ret==0x00000800)
           {
            MainWindow::on_actionSave_triggered(); //Call Save function if user wants to save the file before quitting
        }
        else if(ret==0x00800000)
        {
            QApplication::quit();
       }
      }
    else
    {
          QApplication::quit();
    }
}

/*
 *Turns normal characters into bold font and vice versa
*/
void MainWindow::on_actionBold_triggered()
{
    if(completingTextEdit->fontWeight()!=QFont::Bold)
    completingTextEdit->setFontWeight(QFont::Bold);
    else
    completingTextEdit->setFontWeight(QFont::Thin);
}

/*
 *  Underlines text not underline and vice-versa
*/
void MainWindow::on_actionUnderline_triggered()
{
    //fontUnderline returns true if the last character in selected string is underlined

    if(completingTextEdit->fontUnderline())
    completingTextEdit->setFontUnderline(false);
    else
    completingTextEdit->setFontUnderline(true);
}

/*
 * Turns non italised text into italics and vice-versa
*/
void MainWindow::on_actionItalics_triggered()
{
    //fontItalic returns true if the last character in selected string is italicised
    if(completingTextEdit->fontItalic())
    completingTextEdit->setFontItalic(false);
    else
    completingTextEdit->setFontItalic(true);
}

/*
 *  Opens a inputdialog to change font size of selected text
*/
void MainWindow::on_actionFont_size_triggered()
{
    bool ok;
    Qt::WindowFlags a;

    //Opens a InputDialog where font size is to be entered

    qreal i = QInputDialog::getDouble(this, tr("Font Size "),tr("Enter Font Size: "), completingTextEdit->fontPointSize(), 0, 1638, 4, &ok,a,1);
    if(ok)
    completingTextEdit->setFontPointSize(i);

}
// 0 is minimum font point size and 1638 is maximum font point size with step size=1, decimal places=4

/*
 * Used to change font color
*/
void MainWindow::on_actionFont_Color_triggered()
{
    //Define some standard colours to be used

    QColor red(255,0,0);
    QColor green(0,255,0);
    QColor blue(0,0,255);
    QColor orange(255,165,0);
    QColor violet(238,130,238);
    QColor black(0,0,0);
    QColor white(255,255,255);
    QColor yellow(255,255,0);
    bool ok1,ok2,ok3,ok;
    QStringList colors;
    colors<< tr("Red") << tr("Green") << tr("Blue") << tr("Orange")<<tr("Violet")<<tr("Black")<<tr("White")<<tr("Yellow")<<tr("Custom Color");

    // A Menu dialog box with standard colors is displayed and can be chosen from

    QString item = QInputDialog::getItem(this, tr("Text Color"),tr("Select Color: "), colors, 0, false, &ok);
    string c=item.toStdString();
        if(c=="Red")
        completingTextEdit->setTextColor(red);
        else if(c=="Green")
        completingTextEdit->setTextColor(green);
        else if(c=="Blue")
        completingTextEdit->setTextColor(blue);
        else if(c=="Orange")
        completingTextEdit->setTextColor(orange);
        else if(c=="Violet")
        completingTextEdit->setTextColor(violet);
        else if(c=="Black")
        completingTextEdit->setTextColor(black);
        else if(c=="White")
        completingTextEdit->setTextColor(white);
        else if(c=="Yellow")
        completingTextEdit->setTextColor(yellow);
        else if(c=="Custom Color")
        {
            // Enables creating custom colors from RGB values. Popups dialogs for the same

            int x=QInputDialog::getInt(this,tr("Font Color"),tr("Enter R Value: "),completingTextEdit->textColor().red(),0,255,1,&ok1);
            int y=QInputDialog::getInt(this,tr("Font Color"),tr("Enter G Value: "),completingTextEdit->textColor().green(),0,255,1,&ok2);
            int z=QInputDialog::getInt(this,tr("Font Color"),tr("Enter B Value: "),completingTextEdit->textColor().blue(),0,255,1,&ok3);
            if(ok1&&ok2&&ok3)
            {
                QColor a(x,y,z);
                completingTextEdit->setTextColor(a);
            }
        }
}

/*
 * Finds occurences of an input string from current cursor position till the end of document
*/
void MainWindow::on_actionFind_triggered()
{
    bool ok,found;
    QTextCursor original=completingTextEdit->textCursor(); //Save current cursor position to be restored after string search is done
    QStringList act;QString item;string c;
    act<<tr("Find Next")<<tr("Close");

    // Dialogbox to input string to be searched

    QString p = QInputDialog::getText(this, tr("String Search"),tr("Enter String to Search:"), QLineEdit::Normal,QDir::home().dirName(), &ok);
    if(ok)
    {
        found=completingTextEdit->find(p);
        if(found)
        {
            // Lets user continue search or stop search

            item=QInputDialog::getItem(this, tr("Find"),tr("Continue Search: "), act, 0, false, &ok);
            c=item.toStdString();
        }
        else
        {
            // No string match found

            QMessageBox findend;
            findend.setText("No matching string found");
            findend.exec();
            c="Close";
        }

        //Continues search

        while(c=="Find Next")
        {
            found=completingTextEdit->find(p);
            if(found)
            {
            item=QInputDialog::getItem(this, tr("Find"),tr("Continue Search: "), act, 0, false, &ok);
            c=item.toStdString();
            }
            else
            {
                QMessageBox findend;
                findend.setText("No matching string found");
                findend.exec();
                c="Close";
            }

         }
    }
    completingTextEdit->setTextCursor(original);
}

/*
 * Provides text replacement locally and globally
*/
void MainWindow::on_actionFind_Replace_triggered()
{

    bool ok,found,ok1,ok2;
    QTextCharFormat form;
    QTextCursor original=completingTextEdit->textCursor();
    QStringList act,repl;QString item,replaceoption;string c,d;

    //Declaration of lists for user options

    act<<tr("Find Next")<<tr("Close");
    repl<<tr("Replace all future occurences")<<tr("Replace current occurence")<<tr("Cancel");

    //String to be searched

    QString p = QInputDialog::getText(this, tr("String Search"),tr("Enter String to Search:"), QLineEdit::Normal,QDir::home().dirName(), &ok1);

    if(ok1)
    {
        //String to be replaced with

        QString q = QInputDialog::getText(this, tr("String Replace"),tr("Enter String to Replace:"), QLineEdit::Normal,QDir::home().dirName(), &ok2);
        if(ok2)
        {
            found=completingTextEdit->find(p);

            if(found)
            {
                replaceoption=QInputDialog::getItem(this, tr("Replace String"),tr("Replace Option: "), repl, 0, false, &ok);
                d=replaceoption.toStdString();
            }
            else
            {
                QMessageBox findend;
                findend.setText("No matching string found");
                findend.exec();
                c="Close";
            }
            while(d=="Replace current occurence"||d=="Replace all future occurences")
            {
                if(d=="Replace all future occurences")
                {
                    QString str;
                    while(found==true) // Replacement occurs as long as a new occurence is found
                    {

                        QTextCursor orign=completingTextEdit->textCursor();QString str;
                        QTextCursor *c = new QTextCursor(orign);

                        // Select the current occurence of the string and remove it

                        form=c->charFormat(); //Store formatting of the last character in string
                        c->movePosition(QTextCursor::NextCharacter,QTextCursor::KeepAnchor,p.size());                        
                        str=c->selectedText();
                        c->removeSelectedText();                        

                        str.replace(str.indexOf(p), p.size(), q); //Replace first occurence of string to be searched for by string to be replaced.
                        orign.setCharFormat(form); //Restore formatting

                        orign.insertText(str); //Insert the modified text at the current position
                        completingTextEdit->setTextCursor(orign);
                        found=completingTextEdit->find(p);
                    }
                    return;
                }
                else if(d=="Replace current occurence")
                {
                    QTextCursor orign=completingTextEdit->textCursor();QString str;
                    QTextCursor *c = new QTextCursor(orign);
                    c->movePosition(QTextCursor::NextCharacter,QTextCursor::KeepAnchor,p.size());
                    str=c->selectedText();
                    c->removeSelectedText();
                    str.replace(str.indexOf(p), p.size(), q);
                    orign.insertText(str);
                    completingTextEdit->setTextCursor(orign);
                    found=completingTextEdit->find(p);
                }
                if(found)
                {
                    replaceoption=QInputDialog::getItem(this, tr("Replace String"),tr("Replace Option: "), repl, 0, false, &ok);
                    d=replaceoption.toStdString();
                }
                else
                {
                    QMessageBox findend;
                    findend.setText("No matching string found");
                    findend.exec();
                    d="Close";
                }

             }
        }
        completingTextEdit->setTextCursor(original);
   }
}
//Note that string formatting may not be reflected properly in text to be replaced in certain cases.

/*
 * Position cursor based on line number
*/
 void MainWindow::on_actionCursor_Line_Number_triggered()
{
    bool ok;

    // Dialog box to enter line number to be moved to

    int x=QInputDialog::getInt(this,tr("Cursor Positioning"),tr("Enter Line Number: "),completingTextEdit->textCursor().blockNumber(),1,completingTextEdit->toPlainText().split("\n" ).size(),1,&ok);
    if(ok)
    {
        completingTextEdit->moveCursor(QTextCursor::Start);
        for(int i=1;i<x;i++)
        completingTextEdit->moveCursor(QTextCursor::Down);
    }
    // Maximum Line Number allowed is the number of lines in the document
}