/*******************************************************************************
 * Copyright (c) 2001, 2008 Oracle 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:
 *     Oracle Corporation - initial API and implementation
 *******************************************************************************/
package org.eclipse.jst.jsf.designtime.internal.view.model.jsp.registry;

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

import org.eclipse.jface.preference.IPreferenceStore;
import org.eclipse.jst.jsf.common.internal.policy.OrderedListProvider;
import org.eclipse.jst.jsf.common.internal.policy.OrderedListProvider.OrderableObject;
import org.eclipse.jst.jsf.designtime.internal.view.model.jsp.DefaultJSPTagResolver;
import org.eclipse.jst.jsf.designtime.internal.view.model.jsp.TagIntrospectingStrategy;
import org.eclipse.jst.jsf.designtime.internal.view.model.jsp.persistence.PersistedDataTagStrategy;

/**
 * Preferences model for the TLD registry
 * 
 * @author cbateman
 * 
 */
public class TLDRegistryPreferences
{
    private final IPreferenceStore             _prefStore;

    private final static String                KEY_STRATEGY_ID_ORDER = "org.eclipse.jst.jsf.designtime.jsp.registry.StrategyIDOrder";

    private final static List<OrderableObject> DEFAULT_STRATEGY_ORDER;

    static
    {
        final List<OrderableObject> list = new ArrayList<OrderableObject>();
        list.add(new OrderableObject(new StrategyIdentifier(PersistedDataTagStrategy.DISPLAY_NAME,
                PersistedDataTagStrategy.ID), true));
        list.add(new OrderableObject(new StrategyIdentifier(DefaultJSPTagResolver.DISPLAY_NAME,
                DefaultJSPTagResolver.ID), true));
        list.add(new OrderableObject(new StrategyIdentifier(TagIntrospectingStrategy.DISPLAY_NAME,
                TagIntrospectingStrategy.ID), true));
        // list.add(UnresolvedJSPTagResolvingStrategy.ID);
        DEFAULT_STRATEGY_ORDER = Collections.unmodifiableList(list);
    }

    private List<OrderableObject>              _ids;
    private List<OrderableObject>              _originalIds;

    /**
     * Constructor
     * 
     * @param prefStore
     */
    public TLDRegistryPreferences(final IPreferenceStore prefStore)
    {
        _prefStore = prefStore;
        _ids = new ArrayList<OrderableObject>();
    }

    /**
     * IPreferenceStore The default preference loader
     */
    public void load()
    {
        load(_prefStore);
    }

    /**
     * @return the ordered list provider for the strategy id ordering
     */
    public OrderedListProvider getOrderedListProvider()
    {
        return new MyOrderedListProvider();
    }

    /**
     * @return the strategy id ordering
     */
    public List<OrderableObject> getStrategyIdOrdering()
    {
        return _ids;
    }

    /**
     * @param ids
     */
    public void setStrategyIdOrdering(final List<OrderableObject> ids)
    {
        _ids = ids;
    }

    /**
     * @return the list of strategy ids in the order they should be consulted
     */
    public List<String> getEnabledIds()
    {
        final List<String> strategies = new ArrayList<String>();

        for (final OrderableObject id : _ids)
        {
            if (id.isEnabled())
            {
                StrategyIdentifier strategyId = (StrategyIdentifier) id.getObject();
                strategies.add(strategyId.getId());
            }
        }
        return strategies;
    }

    /**
     * Loads preferences from prefStore
     * 
     * @param prefStore
     */
    private void load(final IPreferenceStore prefStore)
    {
        if (!prefStore.contains(KEY_STRATEGY_ID_ORDER))
        {
            prefStore.setDefault(KEY_STRATEGY_ID_ORDER,
                    serialize(DEFAULT_STRATEGY_ORDER));
        }
        List<OrderableObject> ids = deserialize(prefStore
                .getString(KEY_STRATEGY_ID_ORDER));
        if (ids == null)
        {
            ids = deserialize(serialize(DEFAULT_STRATEGY_ORDER));
        }
        _ids = ids;
        final List<OrderableObject> originalList = new ArrayList<OrderableObject>();
        for (final OrderableObject id : _ids)
        {
            final OrderableObject copy = id.clone();
            originalList.add(copy);
        }
        _originalIds = Collections.unmodifiableList(originalList);
    }

    private String serialize(final List<OrderableObject> ids)
    {
        final StringBuffer buffer = new StringBuffer();

        for (final OrderableObject id : ids)
        {
            StrategyIdentifier strategyId = (StrategyIdentifier) id.getObject();
            buffer.append(strategyId.getDisplayName());
            buffer.append(",");
            buffer.append(strategyId.getId());
            buffer.append(",");
            buffer.append(id.isEnabled());
            buffer.append(",");
        }
        return buffer.toString();
    }

    private List<OrderableObject> deserialize(final String serializedList)
    {
        final List<OrderableObject> list = new ArrayList<OrderableObject>();
        final String[] ids = serializedList.split(",");
        if ((ids.length % 3) != 0)
        {
            return new ArrayList<OrderableObject>();
        }

        for (int i = 0; i < ids.length; i += 3)
        {
            final String displayName = ids[i];
            String id = ids[i + 1];
            final String enabled = ids[i + 2];

            // fix old id for meta-data resolver
            if ("org.eclipse.jst.jsf.THISISTEMPORARY".equals(id))
            {
                id = DefaultJSPTagResolver.ID;
            }

            final StrategyIdentifier strategyIdentifier = new StrategyIdentifier(
                    displayName, id);
            list.add(new OrderableObject(strategyIdentifier
                    , Boolean.valueOf(enabled).booleanValue()));
        }
        return list;
    }

    /**
     * Commits but does not store the preferences
     * 
     * @param prefStore
     */
    public void commit(final IPreferenceStore prefStore)
    {
        prefStore.setValue(KEY_STRATEGY_ID_ORDER,
                serialize(getStrategyIdOrdering()));
    }

    /**
     * Reverts the model to it's defaults. Does not commit to pref store.
     */
    public void setDefaults()
    {
         setStrategyIdOrdering(new ArrayList<OrderableObject>(
                DEFAULT_STRATEGY_ORDER));
    }

    /**
     * @return true if this preference object's properties have
     * changed since load() was last called.
     */
    public boolean isDirty()
    {
        // dirty if the current list is not equal to the original list
        // generated at load time.
        return !(_ids.equals(_originalIds));
    }

    /**
     * Used as the model for sorting and enabling strategy identifiers.
     * 
     */
    public static class StrategyIdentifier
    {
        private final String _id;
        private final String _displayName;

        StrategyIdentifier(final String displayName, final String id)
        {
            _displayName = displayName;
            _id = id;
        }

        /**
         * @return the id
         */
        public String getId()
        {
            return _id;
        }

        /**
         * @return the display name for the strategy
         */
        public String getDisplayName()
        {
            return _displayName;
        }

        @Override
        public boolean equals(Object obj)
        {
            if (obj instanceof StrategyIdentifier)
            {
                return _id.equals(((StrategyIdentifier)obj)._id);
            }
            return false;
        }

        @Override
        public int hashCode()
        {
            return _id.hashCode();
        }
    }

    private class MyOrderedListProvider extends OrderedListProvider
    {
        @Override
        protected List<OrderableObject> createAndPopulateOrderedObjects()
        {
            return _ids;
        }
    }

}