/*******************************************************************************
 * Copyright (c) 2003 IBM Corporation and others.
 * All rights reserved. This program and the accompanying materials 
 * are made available under the terms of the Common Public License v1.0
 * which accompanies this distribution, and is available at
 * http://www.eclipse.org/legal/cpl-v10.html
 * 
 * Contributors:
 *     IBM Corporation - initial API and implementation
 *******************************************************************************/
package org.eclipse.ui.internal.dialogs;

import java.io.PrintWriter;
import java.io.StringWriter;
import java.text.Collator;
import java.util.Arrays;
import java.util.Comparator;
import java.util.Date;
import java.util.Locale;

import org.eclipse.core.runtime.CoreException;
import org.eclipse.core.runtime.IConfigurationElement;
import org.eclipse.core.runtime.Platform;
import org.eclipse.jface.dialogs.Dialog;
import org.eclipse.jface.dialogs.IDialogConstants;
import org.eclipse.swt.SWT;
import org.eclipse.swt.layout.GridData;
import org.eclipse.swt.widgets.Composite;
import org.eclipse.swt.widgets.Control;
import org.eclipse.swt.widgets.Shell;
import org.eclipse.swt.widgets.Text;
import org.eclipse.ui.PlatformUI;
import org.eclipse.ui.about.ISystemSummarySection;
import org.eclipse.ui.help.WorkbenchHelp;
import org.eclipse.ui.internal.IHelpContextIds;
import org.eclipse.ui.internal.IWorkbenchConstants;
import org.eclipse.ui.internal.WorkbenchMessages;
import org.eclipse.ui.internal.WorkbenchPlugin;

/**
 * Displays system information about the eclipse application.  The content of
 * what is displayed is selectable through the
 * <code>org.eclipse.ui.systemSummaryExtensions</code> extension point.
 */
public final class AboutSystemDialog extends Dialog {
	
	public AboutSystemDialog(Shell parentShell) {
		super(parentShell);
		setShellStyle(SWT.DIALOG_TRIM | SWT.RESIZE | SWT.MAX | SWT.APPLICATION_MODAL);
	}

	/* (non-Javadoc)
	 * Method declared on Window.
	 */
	protected void configureShell(Shell newShell) {
		super.configureShell(newShell);
		newShell.setText(WorkbenchMessages.getString("SystemSummary.title")); //$NON-NLS-1$
		WorkbenchHelp.setHelp(newShell, IHelpContextIds.SYSTEM_SUMMARY_DIALOG);
	} 

	/* (non-Javadoc)
	 * Method declared on Dialog.
	 */
	protected void createButtonsForButtonBar(Composite parent) {
		createButton(parent, IDialogConstants.CLOSE_ID, IDialogConstants.CLOSE_LABEL, true);
	}

	/* (non-Javadoc)
	 * Method declared on Dialog.
	 */
	protected Control createDialogArea(Composite parent) {
		Composite outer = (Composite) super.createDialogArea(parent);

		Text text = new Text(outer, SWT.MULTI | SWT.BORDER | SWT.READ_ONLY | SWT.V_SCROLL | SWT.NO_FOCUS | SWT.H_SCROLL);
		text.setBackground(parent.getDisplay().getSystemColor(SWT.COLOR_LIST_BACKGROUND));
		GridData gridData =
			new GridData(GridData.HORIZONTAL_ALIGN_FILL | GridData.VERTICAL_ALIGN_FILL);
		gridData.grabExcessVerticalSpace = true;
		gridData.grabExcessHorizontalSpace = true;
		gridData.heightHint = convertVerticalDLUsToPixels(300);
		gridData.widthHint = convertHorizontalDLUsToPixels(400);
		text.setLayoutData(gridData);
		text.setText(getSystemSummary());
		return outer;
	}

	private String getSystemSummary() {
		StringWriter out = new StringWriter();
		PrintWriter writer = new PrintWriter(out);
		writer.println(WorkbenchMessages.format("SystemSummary.timeStamp", new Object[] {new Date()})); //$NON-NLS-1$

		appendExtensions(writer);
		writer.close();
		return out.toString();
	}

	/*
	 * Appends the contents of all extentions to the configurationLogSections
	 * extension point. 
	 */
	private void appendExtensions(PrintWriter writer) {
	    IConfigurationElement[] configElements = getSortedExtensions();
	    for(int i = 0; i < configElements.length; ++i ) {
	        IConfigurationElement element = configElements[i];

	        Object obj = null;
            try {
                obj = WorkbenchPlugin.createExtension(element,
                        IWorkbenchConstants.TAG_CLASS);
            } catch (CoreException e) {
    			WorkbenchPlugin.log(
                        "could not create class attribute for extension", //$NON-NLS-1$
                        e.getStatus());
            }

	        writer.println();
	        writer.println(WorkbenchMessages.format(
                    "SystemSummary.sectionTitle", //$NON-NLS-1$
                    new Object[] { element.getAttribute("sectionTitle")})); //$NON-NLS-1$

	        if(obj instanceof ISystemSummarySection) {
	            ISystemSummarySection logSection = (ISystemSummarySection)obj;
	            logSection.write(writer);
	        }
	        else
	            writer.println(WorkbenchMessages
                        .getString("SystemSummary.sectionError")); //$NON-NLS-1$
	    }
	}

	private IConfigurationElement[] getSortedExtensions() {
	    IConfigurationElement[] configElements = Platform
	    	.getExtensionRegistry().getConfigurationElementsFor(
                PlatformUI.PLUGIN_ID,
                IWorkbenchConstants.PL_SYSTEM_SUMMARY_SECTIONS);

        Arrays.sort(configElements, new Comparator() {
            Collator collator = Collator.getInstance(Locale.getDefault());
            public int compare(Object a, Object b) {
                IConfigurationElement element1 = (IConfigurationElement)a;
                IConfigurationElement element2 = (IConfigurationElement)b;

                String id1 = element1.getAttribute("id"); //$NON-NLS-1$
                String id2 = element2.getAttribute("id"); //$NON-NLS-1$

                if(id1 != null && id2 != null && !id1.equals(id2))
                    return collator.compare(id1, id2);

                String title1 = element1.getAttribute("sectionTitle"); //$NON-NLS-1$ 
                String title2 = element2.getAttribute("sectionTitle"); //$NON-NLS-1$

                if (title1 == null)
                    title1 = ""; //$NON-NLS-1$
                if (title2 == null)
                    title2 = ""; //$NON-NLS-1$

                return collator.compare(title1, title2);
            }
        });

        return configElements;
	}

	/* (non-Javadoc)
	 * @see org.eclipse.jface.dialogs.Dialog#buttonPressed(int)
	 */
	protected void buttonPressed(int buttonId) {
		if (buttonId == IDialogConstants.CLOSE_ID) {
			close();
		}
		super.buttonPressed(buttonId);
	}
}