Update src/main/java/dev/sillyangel/calc/utils.java

src/main/java/dev/sillyangel/calc/utils.java

@@ -1,6 +1,11 @@
-utils.java
 package dev.sillyangel.calc;
 
+import javax.swing.JOptionPane;
+import java.awt.datatransfer.Clipboard;
+import java.awt.datatransfer.DataFlavor;
+import java.awt.datatransfer.StringSelection;
+import java.awt.Toolkit;
+
 public class utils {
     // private double result;
     // private boolean resultVisible;
@@ -97,8 +102,89 @@ public class utils {
 		ci.operand1 = "";
 		ci.operand2 = "";
 
-		resultVisible = true;
+		ci.resultVisible = true;
-		display.setText(""+result);
+		ci.display.setText(""+ci.result);
-		saveToUndoStack(""+result);
+		saveToUndoStack(""+ci.result);
 	}
+
+    public void saveToUndoStack(String value) {
+		// Remove any states after current index (if user undid and then made a new action)
+		if (ci.undoIndex < ci.undoStack.size() - 1) {
+			ci.undoStack.subList(ci.undoIndex + 1, ci.undoStack.size()).clear();
+		}
+		ci.undoStack.add(value);
+		ci.undoIndex = ci.undoStack.size() - 1;
+	}
+    public void undoAction() {
+		if (ci.undoIndex > 0) {
+			ci.undoIndex--;
+			ci.display.setText(ci.undoStack.get(ci.undoIndex));
+		} else {
+			System.out.println("Nothing to undo");
+		}
+	}
+
+	public void redoAction() {
+		if (ci.undoIndex < ci.undoStack.size() - 1) {
+			ci.undoIndex++;
+			ci.display.setText(ci.undoStack.get(ci.undoIndex));
+		} else {
+			System.out.println("Nothing to redo");
+		}
+	}
+
+	// Clipboard operations
+	public void cutAction() {
+		copyAction();
+		ci.display.setText("");
+	}
+
+	public void copyAction() {
+		String text = ci.display.getText();
+		if (text != null && !text.isEmpty()) {
+			StringSelection selection = new StringSelection(text);
+			Clipboard clipboard = Toolkit.getDefaultToolkit().getSystemClipboard();
+			clipboard.setContents(selection, null);
+			System.out.println("Copied: " + text);
+		}
+	}
+
+	public void pasteAction() {
+		try {
+			Clipboard clipboard = Toolkit.getDefaultToolkit().getSystemClipboard();
+			String text = (String) clipboard.getData(DataFlavor.stringFlavor);
+			if (text != null && !text.isEmpty()) {
+				// Validate that pasted content is a valid number
+				try {
+					Double.parseDouble(text);
+					ci.display.setText(text);
+					saveToUndoStack(text);
+				} catch (NumberFormatException ex) {
+					JOptionPane.showMessageDialog(ci,
+							"Pasted content is not a valid number",
+							"Invalid Input", JOptionPane.ERROR_MESSAGE);
+				}
+			}
+		} catch (Exception ex) {
+			System.err.println("Error pasting: " + ex.getMessage());
+		}
+	}
+    public void processDigit(String actionCommand) {
+		if (ci.resultVisible) {
+			ci.display.setText("");
+			ci.resultVisible = false;
+		}
+		String newValue = ci.display.getText() + actionCommand;
+		ci.display.setText(newValue);
+		saveToUndoStack(newValue);
+	}
+	public void setOperator(String daop) {
+		ci.operand1 = ci.display.getText();
+		ci.operator = daop;
+		ci.display.setText("");
+	}
+    public void clearEntry() {
+		ci.display.setText("");
+	}
+
 }