// This Source Code is in the Public Domain per: http://unlicense.org
package org.litesoft.GWT.client.widgets.nonpublic;

import org.litesoft.commonfoundation.base.*;

import com.google.gwt.dom.client.*;
import com.google.gwt.event.dom.client.*;
import com.google.gwt.user.client.*;
import com.google.gwt.user.client.ui.*;

public class TextBoxBaseChangeListenableHelper implements FocusHandler,
                                                          BlurHandler {
    private Timer mTimer = null;
    private String mText = "";
    private TextBoxBase mTextBoxBase;

    public TextBoxBaseChangeListenableHelper( TextBoxBase pTextBoxBase ) {
        mTextBoxBase = pTextBoxBase;
        pTextBoxBase.addFocusHandler( this );
        pTextBoxBase.addBlurHandler( this );
    }

    public void setText( String pText ) {
        mText = ConstrainTo.notNull( pText );
    }

    private void captureFieldValue() {
        mText = getCurrentText();
    }

    private boolean textBoxBaseTextChanged() {
        String value = getCurrentText();
        if ( !mText.equals( value ) ) {
            mText = value;
            return true;
        }
        return false;
    }

    private String getCurrentText() {
        return ConstrainTo.notNull( mTextBoxBase.getText() );
    }

    private void checkForChange() {
        if ( textBoxBaseTextChanged() ) {
            fireChangeListeners();
        }
    }

    @Override
    public void onBlur( BlurEvent event ) {
        if ( mWidgetIsFocused ) {
            mWidgetIsFocused = false;
            checkForChange();
            stopTimer();
        }
    }

    private boolean mWidgetIsFocused = false;

    @Override
    public void onFocus( FocusEvent event ) {
        mWidgetIsFocused = true;
        captureFieldValue();
        startTimer();
    }

    private void fireChangeListeners() {
        NativeEvent zEvent = Document.get().createChangeEvent();
        mTextBoxBase.getElement().dispatchEvent( zEvent );
    }

    public void onDetach() {
        stopTimer();
    }

    private void startTimer() {
        stopTimer();
        mTimer = new Timer() {
            @Override
            public void run() {
                checkForChange();
            }
        };

        mTimer.scheduleRepeating( 250 );
    }

    private void stopTimer() {
        if ( mTimer != null ) {
            mTimer.cancel();
            mTimer = null;
        }
    }
}