/*******************************************************************************
 * Copyright (c) 2001, 2005 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
 *     Jens Lukowski/Innoopract - initial renaming/restructuring
 *     
 *******************************************************************************/
package org.eclipse.wst.sse.ui.internal.reconcile.validator;

import java.util.ArrayList;
import java.util.List;

import org.eclipse.core.runtime.IConfigurationElement;
import org.eclipse.core.runtime.IExtensionRegistry;
import org.eclipse.core.runtime.Platform;
import org.eclipse.wst.sse.ui.internal.Logger;
import org.eclipse.wst.sse.ui.internal.extension.RegistryReader;


/**
 * Based off of TransferBuilder. Reads the extension point for
 * <code>org.eclipse.wst.sse.ui.extensions.sourcevalidation</code>
 */
public class ValidatorBuilder extends RegistryReader {
    
	public static final String ATT_CLASS = "class"; //$NON-NLS-1$
	public static final String ATT_ID = "id"; //$NON-NLS-1$
	public static final String ATT_SCOPE = "scope"; //$NON-NLS-1$

	public static final ValidatorMetaData[] EMTPY_VMD_ARRAY = new ValidatorMetaData[0];

	// extension point ID
	public static final String PL_SOURCE_VALIDATION = "sourcevalidation"; //$NON-NLS-1$

	public static final String PLUGIN_ID = "org.eclipse.wst.sse.ui"; //$NON-NLS-1$
	public static final String TAG_CONTENT_TYPE_IDENTIFIER = "contentTypeIdentifier"; //$NON-NLS-1$
	public static final String TAG_PARTITION_TYPE = "partitionType"; //$NON-NLS-1$

	public static final String TAG_VALIDATOR = "validator"; //$NON-NLS-1$

	public static final String TRACE_FILTER = "reconcile_validator"; //$NON-NLS-1$

	public static final String TRUE = "true"; //$NON-NLS-1$
	private String fCurrentCTID;
	private ValidatorMetaData fCurrentVMD = null;
	private List fVmds = new ArrayList();
	protected String targetContributionTag;
	protected String targetID;

    private final String UNKNOWN = "???"; //$NON-NLS-1$
    
	/**
	 * Returns the name of the part ID attribute that is expected in the
	 * target extension.
	 * 
	 * @param element
	 * @return String
	 */
	protected String getID(IConfigurationElement element) {
		String value = element.getAttribute(ATT_ID);
		return value != null ? value : UNKNOWN; //$NON-NLS-1$
	}

	protected String getValidatorClass(IConfigurationElement element) {
		String value = element.getAttribute(ATT_CLASS);
		return value != null ? value : UNKNOWN; //$NON-NLS-1$
	}

	/**
	 * @param editorId
	 * @return Transfer[]
	 */
	public ValidatorMetaData[] getValidatorMetaData(String editorId) {
		readContributions(editorId, TAG_VALIDATOR, PL_SOURCE_VALIDATION);
		return (ValidatorMetaData[]) fVmds.toArray(new ValidatorMetaData[fVmds.size()]);
	}

	protected String getValidatorScope(IConfigurationElement element) {
		String value = element.getAttribute(ATT_SCOPE);
		return value != null ? value : UNKNOWN; //$NON-NLS-1$
	}

	/**
	 * Reads the contributions from the registry for the provided workbench
	 * part and the provided extension point ID.
	 * 
	 * @param id
	 * @param tag
	 * @param extensionPoint
	 */
	protected void readContributions(String id, String tag, String extensionPoint) {
		targetID = id;
		targetContributionTag = tag;
		IExtensionRegistry registry = Platform.getExtensionRegistry();
		readRegistry(registry, PLUGIN_ID, extensionPoint);
	}

	protected boolean readElement(IConfigurationElement element) {
		String tag = element.getName();
		//ie. targetContributionTag == validator
		if (tag.equals(targetContributionTag)) {
			String vId = getID(element);
			String vClass = getValidatorClass(element);
			String vScope = getValidatorScope(element);

			if (vId == null) {
				// This is not of interest to us - don't go deeper
				return true;
			}
			// start building a VMD
			fCurrentVMD = new ValidatorMetaData(element, vId, vClass, vScope);
			fVmds.add(fCurrentVMD);

			if (Logger.isTracing(ValidatorBuilder.TRACE_FILTER))
				System.out.println("added reconcile validator: " + vId + ":" + vClass + ":" + vScope); //$NON-NLS-1$ //$NON-NLS-2$ //$NON-NLS-3$
		} else if (tag.equals(TAG_CONTENT_TYPE_IDENTIFIER)) {
			// add to current VMD
			fCurrentCTID = getID(element);
			fCurrentVMD.addContentTypeId(fCurrentCTID);
		} else if (tag.equals(TAG_PARTITION_TYPE)) {
			// add to current VMD
			String partitionType = getID(element);
			fCurrentVMD.addParitionType(fCurrentCTID, partitionType);

			return true;
		} else {
			return false;
		}

		readElementChildren(element);
		return true;
	}
}