void DeleteLine::undo(EditorModel& model){
// Handling deletion of line if cursor is not in the first line
if(lineNumber != firstLine){
model.insertString(lineNumber, oldString);
model.incrementLineCount();
// If previous line was at the end of the text
if(lineNumber == model.lineCount()){
model.incrementCursorLine();
}
}
// Handling deletion of first line of text
else{
// If first line contained either empty string or was not the last line of text
if (oldString == emptyString || lineCount != 1){
model.incrementLineCount();
model.insertString(lineNumber, oldString);
}
// Initializes first line of text if it was the only line left
else{
model.setLineString(lineNumber, oldString);
}
}
// Fix cursor positioning
model.setCursorColumn(cursorPos);
}
void DeleteLine::execute(EditorModel& model){
// Obtain previous values of pre-deletion for line
oldString = model.line(model.cursorLine());
lineNumber = model.cursorLine();
cursorPos = model.cursorColumn();
lineCount = model.lineCount();
// Throw error if text is empty
if (lineNumber == firstLine && model.line(lineNumber) == emptyString && model.lineCount() == 1){
model.setErrorMessage( deleteLineError.getReason() );
throw deleteLineError;
}
// Empty the first line if that is the only line in the text (there should be at least one line in the text)
if (model.lineCount() == firstLine){
model.setLineString(firstLine, emptyString);
model.setCursorColumn(1);
}
// Delete the line and move the curser up if you are at the end of the page
else{
// Set boolean variables for cursor line placement
const bool atBeginningOfPage = model.cursorAtBeginningOfPage();
const bool atEndOfPage = model.cursorAtEndOfPage();
const bool previousColumnPlacementTooFar = model.cursorColumn() > model.line(model.cursorLine()).length();
// Only initialize this boolean if you are not at the end of the page
const bool nextColumnPlacementTooFar = !atEndOfPage ? model.cursorColumn() > model.line(model.cursorLine()+1).length() : false;
// Deletes current line from text
model.deleteLine(model.cursorLine());
// Move cursor up if at the end of the page
if (atEndOfPage){
CursorUp c;
c.execute(model);
}
// Fix cursor column placement if cursor is at the beginning of text,
else if (atBeginningOfPage && previousColumnPlacementTooFar){
model.setCursorColumn(model.line(model.cursorLine()).length()+1);
}
else if (nextColumnPlacementTooFar){
model.setCursorColumn(model.line(model.cursorLine()).length()+1);
}
// Decrement the current line count
model.decrementLineCount();
}
}