package gui.interfaces;

import javax.swing.text.AbstractDocument;
import javax.swing.text.AttributeSet;
import javax.swing.text.BadLocationException;
import javax.swing.text.PlainDocument;

/**
 * Taken from: http://www.java2s.com/Tutorials/Java/Swing/JTextField/Set_max_length_for_JTextField_in_Java.htm
 */
public class BoundedPlainDocument extends PlainDocument {
    public BoundedPlainDocument() {
        // Default constructor - must use setMaxLength later
        this.maxLength = 0;
    }

    public BoundedPlainDocument(int maxLength) {
        this.maxLength = maxLength;
    }

    public BoundedPlainDocument(AbstractDocument.Content content, int maxLength) {
        super(content);
        if (content.length() > maxLength) {
            throw new IllegalArgumentException(
                    "Initial content larger than maximum size");
        }
        this.maxLength = maxLength;
    }

    public void setMaxLength(int maxLength) {
        if (getLength() > maxLength) {
            throw new IllegalArgumentException(
                    "Current content larger than new maximum size");
        }

        this.maxLength = maxLength;
    }

    public int getMaxLength() {
        return maxLength;
    }

    public void insertString(int offset, String str, AttributeSet a)
            throws BadLocationException {
        if (str == null) {
            return;
        }

        // Note: be careful here - the content always has a
        // trailing newline, which should not be counted!
        int capacity = maxLength + 1 - getContent().length();
        if (capacity >= str.length()) {
            // It all fits
            super.insertString(offset, str, a);
        } else {
            // It doesn't all fit. Add as much as we can.
            if (capacity > 0) {
                super.insertString(offset, str.substring(0, capacity), a);
            }

            // Finally, signal an error.
            if (errorListener != null) {
                errorListener.insertFailed(this, offset, str, a);
            }
        }
    }

    public void addInsertErrorListener(InsertErrorListener l) {
        if (errorListener == null) {
            errorListener = l;
            return;
        }
        throw new IllegalArgumentException("InsertErrorListener already registered");
    }

    public void removeInsertErrorListener(InsertErrorListener l) {
        if (errorListener == l) {
            errorListener = null;
        }
    }

    public interface InsertErrorListener {
        public abstract void insertFailed(BoundedPlainDocument doc, int offset,
                                          String str, AttributeSet a);
    }

    protected InsertErrorListener errorListener; // Unicast listener

    protected int maxLength;
}