: QMainWindow(parent), isDarkTheme(true), isModified(false)

{

themeManager = new ThemeManager();

compileProcess = new QProcess(this);

setupUI();

setupMenuBar();

setupToolBar();

setupStatusBar();

setupOutputPanel();

loadSettings();

applyTheme();

autoSaveTimer = new QTimer(this);

connect(autoSaveTimer, &QTimer::timeout, this, [this]() {

CodeEditor *ed = currentEditor();

if (ed && !ed->filePath.isEmpty() && ed->document()->isModified()) {

saveFile();

statusLabel->setText("Auto Saved");

}

});

autoSaveTimer->start(30000);

connect(compileProcess, &QProcess::readyReadStandardOutput, this, [this]() {

outputPanel->appendPlainText(compileProcess->readAllStandardOutput());

});

connect(compileProcess, &QProcess::readyReadStandardError, this, [this]() {

outputPanel->appendPlainText(compileProcess->readAllStandardError());

});

setWindowTitle("Code Editor");

resize(1200, 750);

tabWidget = new QTabWidget(this);

tabWidget->setTabsClosable(true);

tabWidget->setMovable(true);

connect(tabWidget, &QTabWidget::tabCloseRequested, this, &Editor::closeTab);

setCentralWidget(tabWidget);

newTab();

CodeEditor *ed = new CodeEditor(this);

connect(ed->document(), &QTextDocument::modificationChanged,

this, &Editor::documentModified);

connect(ed, &CodeEditor::cursorPositionChanged,

this, &Editor::updateStatusBar);

int idx = tabWidget->addTab(ed, "Untitled");

tabWidget->setCurrentIndex(idx);

CodeEditor *ed = qobject_cast<CodeEditor*>(tabWidget->widget(index));

if (ed && ed->document()->isModified()) {

auto btn = QMessageBox::warning(this, "Unsaved Changes",

"Save before closing this tab?",

QMessageBox::Save | QMessageBox::Discard | QMessageBox::Cancel);

if (btn == QMessageBox::Cancel) return;

if (btn == QMessageBox::Save) {

tabWidget->setCurrentIndex(index);

saveFile();

}

}

tabWidget->removeTab(index);

if (tabWidget->count() == 0) newTab();

outputDock = new QDockWidget("Output", this);

outputPanel = new QPlainTextEdit(outputDock);

outputPanel->setReadOnly(true);

outputPanel->setMaximumHeight(180);

QFont f("Cascadia Code", 11);

f.setStyleHint(QFont::Monospace);

outputPanel->setFont(f);

outputDock->setWidget(outputPanel);

outputDock->setAllowedAreas(Qt::BottomDockWidgetArea);

addDockWidget(Qt::BottomDockWidgetArea, outputDock);

outputDock->hide();

QMenu *fileMenu = menuBar()->addMenu("&File");

fileMenu->addAction("New Tab", this, &Editor::newTab, QKeySequence::New);

fileMenu->addAction("Open...", this, &Editor::openFile, QKeySequence::Open);

fileMenu->addSeparator();

fileMenu->addAction("Save", this, &Editor::saveFile, QKeySequence::Save);

fileMenu->addAction("Save As...",this, &Editor::saveFileAs, QKeySequence::SaveAs);

fileMenu->addSeparator();

fileMenu->addAction("Exit", this, &QWidget::close, QKeySequence::Quit);

QMenu *editMenu = menuBar()->addMenu("&Edit");

editMenu->addAction("Undo", this, [this](){ if(currentEditor()) currentEditor()->undo(); }, QKeySequence::Undo);

editMenu->addAction("Redo", this, [this](){ if(currentEditor()) currentEditor()->redo(); }, QKeySequence::Redo);

editMenu->addSeparator();

editMenu->addAction("Cut", this, [this](){ if(currentEditor()) currentEditor()->cut(); }, QKeySequence::Cut);

editMenu->addAction("Copy", this, [this](){ if(currentEditor()) currentEditor()->copy(); }, QKeySequence::Copy);

editMenu->addAction("Paste", this, [this](){ if(currentEditor()) currentEditor()->paste(); },QKeySequence::Paste);

editMenu->addSeparator();

editMenu->addAction("Find & Replace...", this, &Editor::showFindReplace, QKeySequence::Find);

QMenu *viewMenu = menuBar()->addMenu("&View");

viewMenu->addAction("Toggle Dark/Light Theme", this, &Editor::toggleTheme,

QKeySequence(Qt::CTRL | Qt::Key_T));

viewMenu->addAction("Change Font...", this, &Editor::changeFont);

viewMenu->addAction("Toggle Output Panel", this, [this](){

outputDock->setVisible(!outputDock->isVisible());

});

QMenu *runMenu = menuBar()->addMenu("&Run");

runMenu->addAction("▶ Run Code", this, &Editor::runCode, QKeySequence(Qt::CTRL | Qt::Key_R));

toolBar = addToolBar("Main Toolbar");

toolBar->setMovable(false);

toolBar->addAction("New", this, &Editor::newTab);

toolBar->addAction("Open", this, &Editor::openFile);

toolBar->addAction("Save", this, &Editor::saveFile);

toolBar->addSeparator();

toolBar->addAction("Find", this, &Editor::showFindReplace);

toolBar->addSeparator();

toolBar->addAction("▶ Run", this, &Editor::runCode);

toolBar->addSeparator();

toolBar->addAction("Theme", this, &Editor::toggleTheme);

toolBar->addSeparator();

toolBar->addWidget(new QLabel(" Size: "));

fontSizeBox = new QComboBox(this);

for (int sz : {10,11,12,13,14,16,18,20,24,28,32})

fontSizeBox->addItem(QString::number(sz), sz);

fontSizeBox->setCurrentText("14");

connect(fontSizeBox, QOverload<int>::of(&QComboBox::currentIndexChanged),

[this](int idx){ changeFontSize(fontSizeBox->itemData(idx).toInt()); });

toolBar->addWidget(fontSizeBox);

statusLabel = new QLabel("Ready");

lineColLabel = new QLabel("Ln 1, Col 1");

fileLabel = new QLabel("Untitled");

statusBar()->addWidget(statusLabel, 1);

statusBar()->addPermanentWidget(fileLabel);

statusBar()->addPermanentWidget(lineColLabel);

CodeEditor *ed = currentEditor();

if (!ed) return;

// Save first

if (ed->document()->isModified() || ed->filePath.isEmpty()) {

if (!saveFile()) return;

}

QString filePath = ed->filePath;

if (!filePath.endsWith(".cpp") && !filePath.endsWith(".c")) {

outputPanel->setPlainText("⚠ Only C/C++ files can be compiled.");

outputDock->show();

return;

}

outputDock->show();

outputPanel->clear();

outputPanel->appendPlainText("▶ Compiling: " + filePath + "\n");

QString outFile = QFileInfo(filePath).absolutePath() + "/" +

QFileInfo(filePath).baseName();

#ifdef Q_OS_WIN

outFile += ".exe";

#endif

QStringList args = { filePath, "-o", outFile, "-std=c++17", "-Wall" };

compileProcess->disconnect();

connect(compileProcess,

QOverload<int, QProcess::ExitStatus>::of(&QProcess::finished),

this, [this, outFile](int code, QProcess::ExitStatus) {

if (code == 0) {

outputPanel->appendPlainText("\n✅ Compiled! Running...\n─────────────────");

QProcess *run = new QProcess(this);

run->setProcessChannelMode(QProcess::MergedChannels);

connect(run, &QProcess::readyRead, this, [this, run](){

outputPanel->appendPlainText(run->readAll());

});

connect(run, QOverload<int,QProcess::ExitStatus>::of(&QProcess::finished),

this, [this](int exitCode, QProcess::ExitStatus){

outputPanel->appendPlainText(

QString("\n─────────────────\n✔ Exited with code %1").arg(exitCode));

});

run->start(outFile, {});

} else {

outputPanel->appendPlainText("\n❌ Compilation failed.");

}

});

connect(compileProcess, &QProcess::readyReadStandardError, this, [this](){

outputPanel->appendPlainText(compileProcess->readAllStandardError());

});

compileProcess->start("g++", args);

QString path = QFileDialog::getOpenFileName(this, "Open File", {},

"C++ Files (*.cpp *.h *.hpp *.c);;All Files (*)");

if (path.isEmpty()) return;

QFile f(path);

if (!f.open(QIODevice::ReadOnly | QIODevice::Text)) {

QMessageBox::warning(this, "Error", "Cannot open:\n" + path);

return;

}

QTextStream in(&f);

newTab();

CodeEditor *ed = currentEditor();

ed->setPlainText(in.readAll());

ed->filePath = path;

ed->document()->setModified(false);

tabWidget->setTabText(tabWidget->currentIndex(), QFileInfo(path).fileName());

setCurrentFile(path);

CodeEditor *ed = currentEditor();

if (!ed) return false;

if (ed->filePath.isEmpty()) return saveFileAs();

QFile f(ed->filePath);

if (!f.open(QIODevice::WriteOnly | QIODevice::Text)) {

QMessageBox::warning(this, "Error", "Cannot save:\n" + ed->filePath);

return false;

}

QTextStream out(&f);

out << ed->toPlainText();

ed->document()->setModified(false);

statusLabel->setText("Saved.");

return true;

QString path = QFileDialog::getSaveFileName(this, "Save As", {},

"C++ Files (*.cpp *.h *.hpp);;All Files (*)");

if (path.isEmpty()) return false;

CodeEditor *ed = currentEditor();

if (!ed) return false;

ed->filePath = path;

tabWidget->setTabText(tabWidget->currentIndex(), QFileInfo(path).fileName());

setCurrentFile(path);

return saveFile();

CodeEditor *ed = currentEditor();

if (!ed || !ed->document()->isModified()) return true;

auto btn = QMessageBox::warning(this, "Unsaved Changes",

"Document modified. Save?",

QMessageBox::Save | QMessageBox::Discard | QMessageBox::Cancel);

if (btn == QMessageBox::Save) return saveFile();

if (btn == QMessageBox::Cancel) return false;

return true;

currentFile = path;

QString shown = path.isEmpty() ? "Untitled" : QFileInfo(path).fileName();

setWindowTitle(shown + " - Code Editor");

fileLabel->setText(shown);

Theme theme = isDarkTheme ? themeManager->darkTheme() : themeManager->lightTheme();

QString sheet = isDarkTheme ? themeManager->darkStyleSheet() : themeManager->lightStyleSheet();

setStyleSheet(sheet);

// Output panel style

QString outBg = theme.windowBg.name(), outFg = theme.foreground.name();

outputPanel->setStyleSheet(QString(

"QPlainTextEdit{background:%1;color:%2;font-family:'Cascadia Code',monospace;font-size:12px;border:none;}"

).arg(outBg, outFg));

// Apply to all tabs

for (int i = 0; i < tabWidget->count(); ++i) {

CodeEditor *ed = qobject_cast<CodeEditor*>(tabWidget->widget(i));

if (ed) ed->applyTheme(theme);

}

statusLabel->setText(isDarkTheme ? "Dark theme" : "Light theme");

CodeEditor *ed = currentEditor();

if (!ed) return;

// Wrap CodeEditor in a QTextEdit-compatible way via a helper

// Since FindReplaceDialog expects QTextEdit, we use a workaround

auto *dlg = new QDialog(this);

dlg->setWindowTitle("Find & Replace");

dlg->setMinimumWidth(400);

dlg->setStyleSheet(styleSheet());

auto *layout = new QGridLayout(dlg);

auto *findEdit = new QLineEdit(dlg);

auto *replaceEdit = new QLineEdit(dlg);

auto *caseCb = new QCheckBox("Case sensitive", dlg);

auto *wholeCb = new QCheckBox("Whole word", dlg);

auto *statusLbl = new QLabel("", dlg);

layout->addWidget(new QLabel("Find:"), 0, 0);

layout->addWidget(findEdit, 0, 1, 1, 2);

layout->addWidget(new QLabel("Replace:"), 1, 0);

layout->addWidget(replaceEdit, 1, 1, 1, 2);

layout->addWidget(caseCb, 2, 0);

layout->addWidget(wholeCb, 2, 1);

auto *btnPrev = new QPushButton("Prev", dlg);

auto *btnNext = new QPushButton("Next", dlg);

auto *btnReplace = new QPushButton("Replace", dlg);

auto *btnAll = new QPushButton("Replace All", dlg);

auto *btnClose = new QPushButton("Close", dlg);

layout->addWidget(btnPrev, 3, 0);

layout->addWidget(btnNext, 3, 1);

layout->addWidget(btnReplace, 3, 2);

layout->addWidget(btnAll, 4, 0);

layout->addWidget(btnClose, 4, 2);

layout->addWidget(statusLbl, 5, 0, 1, 3);

auto getFlags = [&](bool backward = false) {

QTextDocument::FindFlags f;

if (backward) f |= QTextDocument::FindBackward;

if (caseCb->isChecked()) f |= QTextDocument::FindCaseSensitively;

if (wholeCb->isChecked()) f |= QTextDocument::FindWholeWords;

return f;

};

connect(btnNext, &QPushButton::clicked, dlg, [&, ed](){

bool found = ed->find(findEdit->text(), getFlags());

statusLbl->setText(found ? "" : "Not found.");

});

connect(btnPrev, &QPushButton::clicked, dlg, [&, ed](){

bool found = ed->find(findEdit->text(), getFlags(true));

statusLbl->setText(found ? "" : "Not found.");

});

connect(btnReplace, &QPushButton::clicked, dlg, [&, ed](){

QTextCursor c = ed->textCursor();

if (c.hasSelection()) c.insertText(replaceEdit->text());

ed->find(findEdit->text(), getFlags());

});

connect(btnAll, &QPushButton::clicked, dlg, [&, ed](){

QTextCursor c = ed->textCursor();

c.movePosition(QTextCursor::Start);

ed->setTextCursor(c);

int count = 0;

while (ed->find(findEdit->text(), getFlags())) {

ed->textCursor().insertText(replaceEdit->text());

++count;

}

statusLbl->setText(count > 0 ?

QString("Replaced %1 occurrence(s).").arg(count) : "Not found.");

});

connect(btnClose, &QPushButton::clicked, dlg, &QDialog::close);

connect(findEdit, &QLineEdit::returnPressed, btnNext, &QPushButton::click);

dlg->show();

CodeEditor *ed = currentEditor();

if (!ed) return;

bool ok;

QFont f = QFontDialog::getFont(&ok, ed->font(), this, "Choose Font");

if (ok) ed->setFont(f);

for (int i = 0; i < tabWidget->count(); ++i) {

CodeEditor *ed = qobject_cast<CodeEditor*>(tabWidget->widget(i));

if (ed) {

QFont f = ed->font();

f.setPointSize(size);

ed->setFont(f);

}

}

CodeEditor *ed = currentEditor();

if (!ed) return;

QTextCursor c = ed->textCursor();

lineColLabel->setText(QString("Ln %1, Col %2")

.arg(c.blockNumber() + 1).arg(c.columnNumber() + 1));

CodeEditor *ed = currentEditor();

if (!ed) return;

bool mod = ed->document()->isModified();

QString title = windowTitle();

if (mod && !title.startsWith("*")) setWindowTitle("*" + title);

if (!mod && title.startsWith("*")) setWindowTitle(title.mid(1));

QSettings s("CodeEditor", "Settings");

isDarkTheme = s.value("darkTheme", true).toBool();

resize(s.value("size", QSize(1200, 750)).toSize());

move(s.value("pos", QPoint(100, 100)).toPoint());

applyTheme();

QSettings s("CodeEditor", "Settings");

s.setValue("darkTheme", isDarkTheme);

s.setValue("size", size());

s.setValue("pos", pos());