/*******************************************************************************
 * Copyright (c) 2006, 2014 IBM Corporation and others.
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License v1.0
 * which accompanies this distribution, and is available at
 * http://www.eclipse.org/legal/epl-v10.html
 *
 * Contributors:
 *     IBM Corporation - initial API and implementation
 *     Wind Rvier Systems - added support for columns (bug 235646)
 *     Ralf M Petter <ralf.petter@gmail.com> - (bug 470536)
 *******************************************************************************/
package org.eclipse.debug.internal.ui.model.elements;

import org.eclipse.core.runtime.CoreException;
import org.eclipse.debug.core.model.IErrorReportingExpression;
import org.eclipse.debug.core.model.IExpression;
import org.eclipse.debug.core.model.IValue;
import org.eclipse.debug.core.model.IWatchExpression;
import org.eclipse.debug.internal.ui.DebugUIMessages;
import org.eclipse.debug.internal.ui.viewers.model.provisional.IPresentationContext;
import org.eclipse.debug.ui.IDebugUIConstants;
import org.eclipse.jface.viewers.TreePath;
import org.eclipse.swt.graphics.RGB;

/**
 * @since 3.3
 */
public class ExpressionLabelProvider extends VariableLabelProvider {

	/* (non-Javadoc)
	 * @see org.eclipse.debug.internal.ui.model.elements.VariableLabelProvider#getForeground(org.eclipse.jface.viewers.TreePath, org.eclipse.debug.internal.ui.viewers.model.provisional.IPresentationContext, java.lang.String)
	 */
	@Override
	protected RGB getForeground(TreePath elementPath, IPresentationContext presentationContext, String columnId) throws CoreException {
		Object element = elementPath.getLastSegment();
        if (element instanceof IErrorReportingExpression) {
            IErrorReportingExpression expression = (IErrorReportingExpression) element;
            if (expression.hasErrors()) {
                if (columnId == null || columnId.equals(IDebugUIConstants.COLUMN_ID_VARIABLE_VALUE)) {
                    return new RGB(255, 0, 0);
                }
            }
        }
		return super.getForeground(elementPath, presentationContext, columnId);
	}

   @Override
protected String getLabel(TreePath elementPath, IPresentationContext context, String columnId) throws CoreException {
       if (columnId == null) {
           return super.getLabel(elementPath, context, columnId);
       } else {
           IExpression expression = (IExpression) elementPath.getLastSegment();
           IValue value = expression.getValue();
           return getColumnText(expression, value, context, columnId);
       }
    }

    /**
     * Returns text for a specific columns for the expression/value.
     *
     * @param expression expression to retrieve text for
     * @param value the value associated with the variable
     * @param context presentation context specifying how to display the text
     * @param columnId the column to get the text for
     * @return the label text
     * @throws CoreException Error while retrieving data from model.
     *
     * @since 3.6
     */
    private String getColumnText(IExpression expression, IValue value, IPresentationContext context, String columnId) throws CoreException {
        if (IDebugUIConstants.COLUMN_ID_VARIABLE_NAME.equals(columnId)) {
            return getExpressionName(expression, context);
        } else if (IDebugUIConstants.COLUMN_ID_VARIABLE_VALUE.equals(columnId)) {
            return getExpressionValueText(expression, value, context);
        } else if (IDebugUIConstants.COLUMN_ID_VARIABLE_TYPE.equals(columnId) ||
        		IDebugUIConstants.COLUMN_ID_VARIABLE_VALUE_TYPE.equals(columnId))
        {
            if (value != null) {
                return getValueTypeName(null, value, context);
            }
        }
        return null;
    }

    /**
     * Returns the expression's text to show in the view's name column.
     *
     * @param expression expression to retrieve text for
     * @param context presentation context specifying how to display the text
     * @return Returns the expression's text to show in the view's name column.
     * @exception CoreException in an error occurs
     * @since 3.6
     */
    protected String getExpressionName(IExpression expression, IPresentationContext context) throws CoreException {
        if (expression instanceof IWatchExpression) {
            return getWatchExpressionName((IWatchExpression) expression, context);
        }
        return expression.getExpressionText();
    }

    /**
     * Returns the watch expression's text to show in the view's name column.
     *
     * @param expression the expression
     * @param context associated presentation context
     * @return Returns the watch expression's text to show in the view's name column.
     * @since 3.6
     */
    private String getWatchExpressionName(IWatchExpression expression, IPresentationContext context) {
        StringBuffer result= new StringBuffer();

        String snippet = expression.getExpressionText().trim();
        StringBuffer snippetBuffer = new StringBuffer();
		if (snippet.length() > 254) {
			snippetBuffer.append(snippet.substring(0, 127));
            snippetBuffer.append(DebugUIMessages.DefaultLabelProvider_0);
			snippetBuffer.append(snippet.substring(snippet.length() - 127));
        } else {
            snippetBuffer.append(snippet);
        }
        snippet = snippetBuffer.toString().replaceAll("[\n\r\t]+", " ");  //$NON-NLS-1$//$NON-NLS-2$

        result.append('"');
        result.append(snippet);
        result.append('"');

        return result.toString();
    }

    /**
     * Returns the expression's value, or a message to show in the value column,
     * if the value is not available.
     *
     * @param expression expression to retrieve text for
     * @param value the value associated with the variable
     * @param context presentation context specifying how to display the text
     * @return string representing the expression's value
     * @throws CoreException Error while retrieving data from model.
     *
     * @since 3.6
     */
    protected String getExpressionValueText(IExpression expression, IValue value, IPresentationContext context) throws CoreException {
        if (expression instanceof IWatchExpression) {
            IWatchExpression watchExpression = (IWatchExpression)expression;
            StringBuffer result = new StringBuffer();

			if (watchExpression.isPending() && value == null) {
                result.append(DebugUIMessages.DefaultLabelProvider_12);
            } else if (watchExpression.hasErrors()) {
                result.append(DebugUIMessages.DefaultLabelProvider_13);
            } else if (value != null) {
                result.append( getValueText(null, value, context) );
            }
            if (!watchExpression.isEnabled()) {
                result.append(DebugUIMessages.DefaultLabelProvider_15);
            }

            return result.toString();
        }

        if (value != null) {
            return getValueText(null, value, context);
        }
        return null;
    }

}