/*******************************************************************************
 * Copyright (c) 2010 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
 *******************************************************************************/
package org.eclipse.wst.sse.ui.preferences;

import java.util.ArrayList;
import java.util.HashSet;
import java.util.Iterator;
import java.util.List;
import java.util.Set;

import org.eclipse.jface.preference.IPreferenceStore;
import org.eclipse.wst.sse.ui.internal.contentassist.CompletionProposalCategory;

import com.ibm.icu.util.StringTokenizer;

/**
 * <p>Implements a completion proposal categories configuration
 * reader and writer using an {@link IPreferenceStore}</p>
 * 
 * <p>This class is meant to be subclasses by implementers of the
 * <code>org.eclipse.wst.sse.ui.completionProposalCategoriesConfiguration</code>
 * extension point as a convince rather then implementing
 * {@link ICompletionProposalCategoriesConfigurationReader} and
 * {@link ICompletionProposalCategoriesConfigurationWriter} from scratch.</p>
 */
public abstract class AbstractCompletionProposalCategoriesConfiguration
		implements ICompletionProposalCategoriesConfigurationReader,
		ICompletionProposalCategoriesConfigurationWriter {

	/** Separator used between preferences stored in the same key */
	private static final String PREFERENCE_CATEGORY_SEPERATOR = "\0"; //$NON-NLS-1$
	
	/**
	 * <p>{@link CompletionProposalCategory} IDs sorted by the order they should
	 * be listed on the default page if they are being displayed there</p>
	 * 
	 * <code>{@link List}<{@link String}></code>
	 * <ul><li><b>values:</b> {@link CompletionProposalCategory} IDs</li></ul>
	 */
	private List fDefaultPageSortOrder;
	
	/**
	 * <p>{@link CompletionProposalCategory} IDs sorted by the order they should
	 * be cycled through</p>
	 * 
	 * <code>{@link List}<{@link String}></code>
	 * <ul><li><b>values:</b> {@link CompletionProposalCategory} IDs</li></ul>
	 */
	private List fOwnPageSortOrder;
	
	/**
	 * <p>{@link CompletionProposalCategory} IDs that should not be displayed on
	 * their own page</p>
	 * 
	 * <code>{@link Set}<{@link String}></code>
	 * <ul><li><b>values:</b> {@link CompletionProposalCategory} IDs</li></ul>
	 */
	private Set fShouldNotDisplayOnOwnPage;
	
	/**
	 * <p>{@link CompletionProposalCategory} IDs that should not be displayed on
	 * on the default page</p>
	 * 
	 * <code>{@link Set}<{@link String}></code>
	 * <ul><li><b>values:</b> {@link CompletionProposalCategory} IDs</li></ul>
	 */
	private Set fShouldNotDisplayOnDefaultPage;
	
	/**
	 * <p>Create a new configuration by loading from the associated {@link IPreferenceStore}</p>
	 */
	public AbstractCompletionProposalCategoriesConfiguration() {
		this.fOwnPageSortOrder = new ArrayList();
		this.fDefaultPageSortOrder = new ArrayList();
		this.fShouldNotDisplayOnOwnPage = new HashSet();
		this.fShouldNotDisplayOnDefaultPage = new HashSet();
		
		this.loadUserConfiguration();
	}
	
	/**
	 * @return {@link IPreferenceStore} to read and write the configuration to and from
	 */
	protected abstract IPreferenceStore getPreferenceStore();
	
	/**
	 * @return Preference key to use in the {@link IPreferenceStore} for the category sort order
	 * when cycling through the pages
	 */
	protected abstract String getPageSortOrderPrefKey();
	
	/**
	 * @return Preference key to use in the {@link IPreferenceStore} for the category sort order
	 * on the default page
	 */
	protected abstract String getDefaultPageSortOrderPrefKey();
	
	/**
	 * @return Preference key to use in the {@link IPreferenceStore} for which
	 * categories not to display on their own page
	 */
	protected abstract String getShouldNotDisplayOnOwnPagePrefKey();
	
	/**
	 * @return Preference key to use in the {@link IPreferenceStore} for which
	 * categories not to display on the default page
	 */
	protected abstract String getShouldNotDisplayOnDefaultPagePrefKey();

	/**
	 * @see org.eclipse.wst.sse.ui.preferences.ICompletionProposalCategoriesConfigurationReader#getPageSortOrder(java.lang.String)
	 */
	public int getPageSortOrder(String categoryID) {
		int sortOrder = this.fOwnPageSortOrder.indexOf(categoryID);
		if(sortOrder == -1) {
			sortOrder = DEFAULT_SORT_ORDER;
		}
		
		return sortOrder;
	}
	
	/**
	 * @see org.eclipse.wst.sse.ui.preferences.ICompletionProposalCategoriesConfigurationReader#getDefaultPageSortOrder(java.lang.String)
	 */
	public int getDefaultPageSortOrder(String categoryID) {
		int sortOrder = this.fDefaultPageSortOrder.indexOf(categoryID);
		if(sortOrder == -1) {
			sortOrder = DEFAULT_SORT_ORDER;
		}
		
		return sortOrder;
	}

	/**
	 * @see org.eclipse.wst.sse.ui.preferences.ICompletionProposalCategoriesConfigurationReader#shouldDisplayOnDefaultPage(java.lang.String)
	 */
	public boolean shouldDisplayOnDefaultPage(String categoryID) {
		return !fShouldNotDisplayOnDefaultPage.contains(categoryID);
	}

	/**
	 * @see org.eclipse.wst.sse.ui.preferences.ICompletionProposalCategoriesConfigurationReader#shouldDisplayOnOwnPage(java.lang.String)
	 */
	public boolean shouldDisplayOnOwnPage(String categoryID) {
		return !this.fShouldNotDisplayOnOwnPage.contains(categoryID);
	}

	/**
	 * <p> Loads defaults from the associated {@link IPreferenceStore}</p>
	 * @see org.eclipse.wst.sse.ui.preferences.ICompletionProposalCategoriesConfigurationWriter#loadDefaults()
	 */
	public void loadDefaults() {
		this.loadDefaultPagePreference(true);
		this.loadPageSortOrder(true);
		this.loadDefaultPageSortOrder(true);
		this.loadShouldNotDisplayOnOwnPage(true);
	}

	/**
	 * <p>Saves to the associated {@link IPreferenceStore}</p>
	 * 
	 * @see org.eclipse.wst.sse.ui.preferences.ICompletionProposalCategoriesConfigurationWriter#saveConfiguration()
	 */
	public boolean saveConfiguration() {
		this.saveShouldDisplayOnDefaultPageConfiguration();
		this.saveShouldDisplayOnOwnPageConfiguration();
		this.saveDefaultPageSortOrderConfiguration();
		this.savePageSortOrderConfiguration();
		
		return true;
	}

	/**
	 * @see org.eclipse.wst.sse.ui.preferences.ICompletionProposalCategoriesConfigurationWriter#setShouldDisplayOnDefaultPage(java.lang.String, boolean)
	 */
	public void setShouldDisplayOnDefaultPage(String categoryID,
			boolean shouldDisplay) {
		
		if(shouldDisplay) {
			this.fShouldNotDisplayOnDefaultPage.remove(categoryID);
		} else {
			this.fShouldNotDisplayOnDefaultPage.add(categoryID);
		}
	}

	/**
	 * @see org.eclipse.wst.sse.ui.preferences.ICompletionProposalCategoriesConfigurationWriter#setShouldDisplayOnOwnPage(java.lang.String, boolean)
	 */
	public void setShouldDisplayOnOwnPage(String categoryID, boolean shouldDisplay) {
		
		if(shouldDisplay) {
			this.fShouldNotDisplayOnOwnPage.remove(categoryID);
		} else {
			this.fShouldNotDisplayOnOwnPage.add(categoryID);
		}
	}
	
	/**
	 * @see org.eclipse.wst.sse.ui.preferences.ICompletionProposalCategoriesConfigurationWriter#setPageOrder(java.util.List)
	 */
	public void setPageOrder(List order) {
		this.fOwnPageSortOrder = order;
	}
	
	/**
	 * @see org.eclipse.wst.sse.ui.preferences.ICompletionProposalCategoriesConfigurationWriter#setDefaultPageOrder(java.util.List)
	 */
	public void setDefaultPageOrder(List order) {
		this.fDefaultPageSortOrder = order;
	}

	/**
	 * <p>Loads the user configuration from the associated {@link IPreferenceStore}</p>
	 */
	private void loadUserConfiguration() {
		this.loadDefaultPagePreference(false);
		this.loadPageSortOrder(false);
		this.loadDefaultPageSortOrder(false);
		this.loadShouldNotDisplayOnOwnPage(false);
	}
	
	/**
	 * <p>Loads the user preferences for which categories to
	 * display on the default content assist page</p>
	 * 
	 * @param useDefaults if <code>true</code> then use the {@link IPreferenceStore} defaults,
	 * otherwise use the user specified preferences
	 */
	private void loadDefaultPagePreference(boolean useDefaults) {
		//clear the current display on default page configuration
		this.fShouldNotDisplayOnDefaultPage.clear();
		
		//parse either the default or user configuration preference
		String displayOnDefaultPage;
		if(useDefaults) {
			displayOnDefaultPage = getPreferenceStore().getDefaultString(getShouldNotDisplayOnDefaultPagePrefKey());
		} else {
			displayOnDefaultPage = getPreferenceStore().getString(getShouldNotDisplayOnDefaultPagePrefKey());
		}
		StringTokenizer defaultPageTokenizer = new StringTokenizer(displayOnDefaultPage, PREFERENCE_CATEGORY_SEPERATOR);
		while (defaultPageTokenizer.hasMoreTokens()) {
			fShouldNotDisplayOnDefaultPage.add(defaultPageTokenizer.nextToken());
		}
	}
	
	/**
	 * <p>Loads the user preferences for the sort order of the content assist pages</p>
	 * 
	 * @param useDefaults if <code>true</code> then use the {@link IPreferenceStore} defaults,
	 * otherwise use the user specified preferences
	 */
	private void loadPageSortOrder(boolean useDefaults){
		//clear the current sort order
		this.fOwnPageSortOrder.clear();
		
		//parse either the default or user configuration preference
		String sortOrder;
		if(useDefaults) {
			sortOrder = getPreferenceStore().getDefaultString(getPageSortOrderPrefKey());
		} else {
			sortOrder = getPreferenceStore().getString(getPageSortOrderPrefKey());
		}
		StringTokenizer tokenizer = new StringTokenizer(sortOrder, PREFERENCE_CATEGORY_SEPERATOR);
		while (tokenizer.hasMoreTokens()) {
			String categoryID = tokenizer.nextToken();
			this.fOwnPageSortOrder.add(categoryID);
		}
	}
	
	/**
	 * <p>Loads the user preferences for the sort order of the content assist pages</p>
	 * 
	 * @param useDefaults if <code>true</code> then use the {@link IPreferenceStore} defaults,
	 * otherwise use the user specified preferences
	 */
	private void loadDefaultPageSortOrder(boolean useDefaults){
		//clear the current sort order
		this.fDefaultPageSortOrder.clear();
		
		//parse either the default or user configuration preference
		String sortOrder;
		if(useDefaults) {
			sortOrder = getPreferenceStore().getDefaultString(getDefaultPageSortOrderPrefKey());
		} else {
			sortOrder = getPreferenceStore().getString(getDefaultPageSortOrderPrefKey());
		}
		StringTokenizer tokenizer = new StringTokenizer(sortOrder, PREFERENCE_CATEGORY_SEPERATOR);
		while (tokenizer.hasMoreTokens()) {
			String categoryID = tokenizer.nextToken();
			this.fDefaultPageSortOrder.add(categoryID);
		}
	}
	
	/**
	 * <p>Loads the user preferences for which categories should not be displayed on their own
	 * content assist page</p>
	 * 
	 * @param useDefaults if <code>true</code> then use the {@link IPreferenceStore} defaults,
	 * otherwise use the user specified preferences
	 */
	private void loadShouldNotDisplayOnOwnPage(boolean useDefaults){
		//clear the current sort order
		this.fShouldNotDisplayOnOwnPage.clear();
		
		//parse either the default or user configuration preference
		String preference;
		if(useDefaults) {
			preference = getPreferenceStore().getDefaultString(getShouldNotDisplayOnOwnPagePrefKey());
		} else {
			preference = getPreferenceStore().getString(getShouldNotDisplayOnOwnPagePrefKey());
		}
		StringTokenizer tokenizer = new StringTokenizer(preference, PREFERENCE_CATEGORY_SEPERATOR);
		while (tokenizer.hasMoreTokens()) {
			String categoryID = tokenizer.nextToken();
			this.fShouldNotDisplayOnOwnPage.add(categoryID);
		}
	}
	
	/**
	 * <p>Saves the user preferences for which categories to
	 * display on the default content assist page</p>
	 */
	private void saveShouldDisplayOnDefaultPageConfiguration() {
		//create the preference string
		StringBuffer defaultPageBuff = new StringBuffer();
		Iterator defaultPageIter = this.fShouldNotDisplayOnDefaultPage.iterator();
		while(defaultPageIter.hasNext()) {
			String categoryID = (String)defaultPageIter.next();
			defaultPageBuff.append(categoryID + PREFERENCE_CATEGORY_SEPERATOR);
		}
		
		//save the preference
		this.getPreferenceStore().setValue(this.getShouldNotDisplayOnDefaultPagePrefKey(), defaultPageBuff.toString());
	}
	
	/**
	 * <p>Saves the user preferences for the sort order of the content assist pages</p>
	 */
	private void savePageSortOrderConfiguration() {
		//create the preference string
		StringBuffer orderBuff = new StringBuffer();
		for(int i = 0; i < this.fOwnPageSortOrder.size(); ++i) {
			if(this.fOwnPageSortOrder.get(i) != null) {
				orderBuff.append(this.fOwnPageSortOrder.get(i) + PREFERENCE_CATEGORY_SEPERATOR);
			}
		}
		
		//save the preference
		this.getPreferenceStore().setValue(this.getPageSortOrderPrefKey(), orderBuff.toString());
	}
	
	/**
	 * <p>Saves the user preferences for the sort order of the categories on the default page</p>
	 */
	private void saveDefaultPageSortOrderConfiguration() {
		//create the preference string
		StringBuffer orderBuff = new StringBuffer();
		for(int i = 0; i < this.fDefaultPageSortOrder.size(); ++i) {
			if(this.fDefaultPageSortOrder.get(i) != null) {
				orderBuff.append(this.fDefaultPageSortOrder.get(i) + PREFERENCE_CATEGORY_SEPERATOR);
			}
		}
		
		//save the preference
		this.getPreferenceStore().setValue(this.getDefaultPageSortOrderPrefKey(), orderBuff.toString());
	}
	
	/**
	 * <p>Saves the user preferences for which categories should not be displayed on their own
	 * content assist page</p>
	 */
	private void saveShouldDisplayOnOwnPageConfiguration() {
		//create the preference string
		StringBuffer buff = new StringBuffer();
		Iterator iter = this.fShouldNotDisplayOnOwnPage.iterator();
		while(iter.hasNext()) {
			String categoryID = (String)iter.next();
			buff.append(categoryID + PREFERENCE_CATEGORY_SEPERATOR);
		}
		
		//save the preference
		this.getPreferenceStore().setValue(this.getShouldNotDisplayOnOwnPagePrefKey(), buff.toString());
	}
}