REPLTextArea.java

/* 
 * License: source-license.txt
 * If this code is used independently, copy the license here.
 */

package wombat.gui.text;

import java.awt.Dimension;
import java.awt.Toolkit;
import java.awt.event.ActionEvent;
import java.awt.event.KeyEvent;
import java.awt.event.KeyListener;
import java.util.ArrayList;
import java.util.List;
import java.util.Stack;

import javax.swing.AbstractAction;
import javax.swing.KeyStroke;
import javax.swing.text.BadLocationException;

import wombat.gui.frames.MainFrame;
import wombat.util.Options;
import wombat.util.errors.ErrorManager;

/**
 * Special text area for running REPL text areas.
 * 
 * When you hit enter, run the command if it's at least possibly valid. 
 * 
 * Use Ctrl-Enter to override this check and guarantee it runs. 
 */
public class REPLTextArea extends SchemeTextArea {
	private static final long serialVersionUID = 8753865168892947915L;
	
	// Store previously entered commands.
	List<String> commandHistory;
	int currentCommand = 0;
	
	/**
	 * Create a new REPL area.
	 */
	public REPLTextArea() {
		super(false, false);
		
		commandHistory = new ArrayList<String>();
		setPreferredSize(new Dimension(100, 100));
		
		// Restore previously saved commands
		if (!Options.SavedHistory.isEmpty()) {
			for (String cmd : Options.SavedHistory.split("\\`\\|")) {
				commandHistory.add(cmd);
				currentCommand++;
			}
		}

		// When the user hits the 'ENTER' key, check for a complete command.
        code.getInputMap().put(
                KeyStroke.getKeyStroke("ENTER"),
                new AbstractAction() {
                    private static final long serialVersionUID = 723647997099071931L;

					public void actionPerformed(ActionEvent e) {
						if (MainFrame.Singleton().ToolBarStop.isEnabled()) return;
						
						checkRun();
                    }
                });
        
        // On CTRL-ENTER (command-ENTER on a mac).
        code.getInputMap().put(
        		KeyStroke.getKeyStroke(
                    KeyEvent.VK_ENTER,
                    Toolkit.getDefaultToolkit().getMenuShortcutKeyMask()
                ),
                new AbstractAction() {
                    private static final long serialVersionUID = 723647997099071931L;

					public void actionPerformed(ActionEvent e) {
						if (MainFrame.Singleton().ToolBarStop.isEnabled()) return;
						if (getText().trim().isEmpty()) return;
						
						commandHistory.add(getText());
			        	currentCommand = commandHistory.size();
			        	
						MainFrame.Singleton().doCommand(getText());
						setText("");
                    }
                });
        
        // When the user hits the up arrow, it they are on the first line, reload the previous command.
        // On the down arrow go to the next command.
        code.addKeyListener(new KeyListener() {
			public void keyPressed(KeyEvent event) {
				if (event.getKeyCode() == KeyEvent.VK_UP) {
					if (getText().lastIndexOf("\n", code.getCaretPosition() - 1) == -1) {
						if (currentCommand == commandHistory.size())
							commandHistory.add(getText());
						
						if (currentCommand == 0)
							return;
						
						currentCommand--;
						setText(commandHistory.get(currentCommand));
						code.setCaretPosition(code.getDocument().getLength());
						
						// Don't actually go up. That would be silly.
						event.consume();
					}
				}
				
				if (event.getKeyCode() == KeyEvent.VK_DOWN) {
					if (getText().indexOf("\n", code.getCaretPosition()) == -1) {
						if (currentCommand == commandHistory.size()) {
							setText(""); // Clear at the end
						} else if (currentCommand == commandHistory.size() - 1) {
							setText(commandHistory.remove(commandHistory.size() - 1));
						} else {
							currentCommand++;
							setText(commandHistory.get(currentCommand));
							code.setCaretPosition(code.getDocument().getLength());
							
							// Not really necessary because you won't be able to go down anyways, but gogoparallel.
							event.consume();
						}
					}
				}
			}

			@Override
			public void keyReleased(KeyEvent arg0) {}

			@Override
			public void keyTyped(KeyEvent arg0) {
				
			}
        });
	}
	
	/**
	 * Get up to max history items.
	 * @param max The most history items to return.
	 * @return A `| delimited history list.
	 */
	public String getHistory(int max) {
		try {
			int lo = Math.min(commandHistory.size() - 1, Math.max(0, currentCommand - max));
			int hi = Math.min(commandHistory.size() - 1, Math.max(0, currentCommand));
			
			if (lo == -1) {
				return "";
			}
			
			StringBuffer buf = new StringBuffer();
			for (int i = lo; i <= hi; i++) {
				buf.append(commandHistory.get(i));
				buf.append("`|");
			}
			if (lo != hi)
				return buf.substring(0, buf.length() - 2);
			else
				return "";
		} catch(Exception e) {
			ErrorManager.logError("Unable to load saved history: " + e.getMessage());
			e.printStackTrace();
			return "";
		}
	}

	/**
	 * Check if the command should run, run it if it should.
	 * 
	 * To run:
	 * - Last line
	 * - Brackets are matched
	 */
	protected void checkRun() {
		// The cursor should be on the last line and there should be at least some text. 
		if (!getText().trim().isEmpty() && getText().substring(code.getCaretPosition()).trim().isEmpty()) {
			
			// Check to see that we have a matched pair of brackets.
	        Stack<Character> brackets = new Stack<Character>();
	        char[] cs = getText().toCharArray();
	        char c;
	        for (int i = 0; i < cs.length; i++) {
	        	c = cs[i];
	        	
	        	// Skip character literals
	        	if (c == '#' && cs[i + 1] == '\\') {
	        		i += 2;
	        		continue;
	        	}
	        	
	        	// Skip strings
	        	if (c == '"') {
	        		int end = getText().indexOf('"', i + 1);
	        		i += (end - i);
	        	}
	        	
	            if (c == '(') brackets.push(')');
	            else if (c == '[') brackets.push(']');
	            else if (c == ')' || c == ']')
	                if (!brackets.empty() && brackets.peek() == c)
	                    brackets.pop();
	                else
	                    return;
	        }
	
	        // This means we matched them all.
	        if (brackets.empty()) {
	        	commandHistory.add(getText());
	        	currentCommand = commandHistory.size();
	        	
	            MainFrame.Singleton().doCommand(getText());
	            setText("");
	            return;
	        }
		}
        
        // Either we didn't match the brackets or we aren't on the last line. Insert the return normally.
        try {
            code.getDocument().insertString(code.getCaretPosition(), SchemeTextArea.NL, null);
        } catch (BadLocationException ble) {
            System.err.println("badwolf");
        }
        tab();
	}
}