package arcommon.ui.component;

import java.awt.Color;

import javax.swing.JComponent;
import javax.swing.JTextArea;
import javax.swing.event.CaretListener;
import javax.swing.text.BadLocationException;
import javax.swing.text.Caret;
import javax.swing.text.DefaultCaret;

import arcommon.StringUtil;
import arcommon.ui.other.MyUndoManager;

/**
 * A {@link javax.swing.JTextArea} with undo in a {@link javax.swing.JScrollPane}.
 * <br>
 * Undo is cleared (by default) when {@link #setText(String)} is called.<br>
 * Note: Uses {@link javax.swing.text.DefaultCaret#NEVER_UPDATE} instead of the default {@link javax.swing.text.DefaultCaret#UPDATE_WHEN_ON_EDT} when {@link #setText(String)} is called.
 */
public class MyJTextArea extends AbstractDelegatingJScrollPane {
    
    private static final long serialVersionUID = 7195806586966402037L;
    
    // This class is a hack to make super.getRowHeight() visible.
    private class JTextAreaHack extends JTextArea {
        private static final long serialVersionUID = -434197405913512358L;

        public int getRowHeight() {
            return super.getRowHeight();
        }
    }
    
    private MyUndoManager myUndoManager;
    private JTextAreaHack textArea;
    private boolean moveCaretInitial;
    
    public MyJTextArea() {
        textArea = new JTextAreaHack();
        
        moveCaretInitial = true;
        
        initActionMap();
        
        setViewportView(textArea);
                
        myUndoManager = MyUndoManager.addUndoToTextComponent(textArea);
    }
    
    public void addCaretListener(CaretListener caretListener) {
        textArea.addCaretListener(caretListener);
    }
    
    public void setCaret(Caret caret) {
        textArea.setCaret(caret);
    }
    
    public void setCaretPosition(int position) {
        textArea.setCaretPosition(position);
    }
    
    public int getCaretPosition() {
        return textArea.getCaretPosition();
    }
    
    /**
     * See {@link #setText(String, boolean, boolean)} for details
     */
    public void setText(String text) {
        setText(text, true, moveCaretInitial);
    }
    
    /**
     * Sets the text of the text field without moving the caret.
     * <br>
     * If {@code discardsAllEdits} is true the undo history is removed.<br>
     * if {@code moveCaretInitial} is true the caret to it's initial position (0).<br>
     * See {@link arcommon.ui.component.MyJTextField#setText(String, boolean, boolean)} for at very similar method.
     */
    public void setText(String text, boolean discardsAllEdits, boolean pmoveCaretInitial) {
        // Code copied from https://stackoverflow.com/questions/1627028/how-to-set-auto-scrolling-of-jtextarea-in-java-gui
        // and modified a lot
        if (!StringUtil.stringEquals(text, getText())) {
            DefaultCaret caret = (DefaultCaret)textArea.getCaret();
            int updatePolicy = caret.getUpdatePolicy();
            // Set UpdatePolicy to DefaultCaret.NEVER_UPDATE to avoid that the caret is moved to end of the text area when setText() is used.
            caret.setUpdatePolicy(DefaultCaret.NEVER_UPDATE);
            
            int oldCaretPosition = getCaretPosition();
            myUndoManager.nextUndoIsDouble();
            textArea.setText(text);
            int newCaretPosition = getCaretPosition();
            if (oldCaretPosition != newCaretPosition) {
                if (text == null) {
                    oldCaretPosition = 0;
                } else if (oldCaretPosition > text.length()) {
                    oldCaretPosition = text.length();
                }
                // Move the caret position to the position that the documentation states that is it should be in.
                setCaretPosition(oldCaretPosition);
            }
            
            caret.setUpdatePolicy(updatePolicy); // Set UpdatePolicy back
        }
        
        if (pmoveCaretInitial) {
            setCaretPosition(0);
            moveCaretInitial = false;
        }
        
        if (discardsAllEdits) {
            myUndoManager.discardAllEdits();
        }
    }
    
    public String getText() {
        return textArea.getText();
    }
    
    public String getText(int offset, int length) {
        try {
            return textArea.getText(offset, length);
        } catch (BadLocationException e) {
            throw new RuntimeException(e);
        }
    }
    
    public void setEditable(boolean editable) {
        textArea.setEditable(editable);
    }
    
    public boolean getLineWrap() {
        return textArea.getLineWrap();
    }
    
    public void setLineWrap(boolean wrap) {
        textArea.setLineWrap(wrap);
    }
    
    public boolean getWrapStyleWord() {
        return textArea.getWrapStyleWord();
    }
    
    public void setWrapStyleWord(boolean word) {
        textArea.setWrapStyleWord(word);
    }
    
    public void setDisabledTextColor(Color color) {
        textArea.setDisabledTextColor(color);
    }
    
    public String getSelectedText() {
        return textArea.getSelectedText();
    }
    
    public void select(int selectionStart, int selectionEnd) {
        textArea.select(selectionStart, selectionEnd);
    }
    
    public int getSelectionStart() {
        return textArea.getSelectionStart();
    }

    public int getSelectionEnd() {
        return textArea.getSelectionEnd();
    }
    
    public int getRowHeight() {
        return textArea.getRowHeight();
    }
    
    public int getLineOfOffset(int offset) {
        try {
            return textArea.getLineOfOffset(offset);
        } catch (BadLocationException e) {
            throw new RuntimeException(e);
        }
    }
    
    public int getLineCount() {
        return textArea.getLineCount();
    }

    public int getLineStartOffset(int line) {
        try {
            return textArea.getLineStartOffset(line);
        } catch (BadLocationException e) {
            throw new RuntimeException(e);
        }
    }
    
    public int getLineEndOffset(int line) {
        try {
            return textArea.getLineEndOffset(line);
        } catch (BadLocationException e) {
            throw new RuntimeException(e);
        }
    }
    
    public int getTabSize() {
        return textArea.getTabSize();
    }
    
    public void setTabSize(int size) {
        textArea.setTabSize(size);
    }
    
    @Override
    protected JComponent getDelegatingJComponent() {
        return textArea;
    }
}