/*******************************************************************************
 * Copyright (c) 2008 Oracle Corporation.
 * 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:
 *    Cameron Bateman - initial API and implementation
 *******************************************************************************/
package org.eclipse.jst.jsf.facelet.core.internal.cm.strategy;

import java.util.ArrayList;
import java.util.Collections;
import java.util.HashMap;
import java.util.Iterator;
import java.util.List;
import java.util.Map;
import java.util.concurrent.atomic.AtomicBoolean;

import org.eclipse.core.resources.IProject;
import org.eclipse.core.runtime.ISafeRunnable;
import org.eclipse.emf.edit.provider.ComposedAdapterFactory;
import org.eclipse.jface.util.SafeRunnable;
import org.eclipse.jst.jsf.common.dom.TagIdentifier;
import org.eclipse.jst.jsf.common.internal.managedobject.IManagedObject;
import org.eclipse.jst.jsf.common.internal.managedobject.ObjectManager.ManagedObjectException;
import org.eclipse.jst.jsf.common.internal.resource.ResourceSingletonObjectManager;
import org.eclipse.jst.jsf.facelet.core.internal.FaceletCorePlugin;
import org.eclipse.jst.jsf.facelet.core.internal.cm.AttributeCMAdapter;
import org.eclipse.jst.jsf.facelet.core.internal.cm.ExternalTagInfo;
import org.eclipse.jst.jsf.facelet.core.internal.cm.addtagmd.AddTagMDPackage;
import org.eclipse.jst.jsf.facelet.core.internal.cm.addtagmd.AttributeData;
import org.eclipse.jst.jsf.facelet.core.internal.cm.addtagmd.AttributeUsage;
import org.eclipse.jst.jsf.facelet.core.internal.cm.addtagmd.ElementData;
import org.eclipse.jst.jsf.facelet.core.internal.cm.addtagmd.provider.IResourceProvider;
import org.eclipse.jst.jsf.facelet.core.internal.util.TagMetadataLoader;
import org.eclipse.wst.xml.core.internal.contentmodel.CMAttributeDeclaration;
import org.eclipse.wst.xml.core.internal.contentmodel.CMNamedNodeMap;
import org.eclipse.wst.xml.core.internal.contentmodel.CMNode;

/**
 * An external meta-data strategy that uses the JSF meta-data framework.
 * 
 * @author cbateman
 * 
 */
public class MDExternalMetadataStrategy extends
        AbstractExternalMetadataStrategy implements IManagedObject
{
    private static MySingletonManager MANAGER = new MySingletonManager();

    /**
     * @param project
     * @return the instance of the strategy for project or
     */
    public static IExternalMetadataStrategy create(final IProject project)
    {
        try
        {
            return MANAGER.getInstance(project);
        }
        catch (final ManagedObjectException e)
        {
            FaceletCorePlugin.log(
                    "Getting managed instance of tag metadata strategy", e); //$NON-NLS-1$
        }
        return new NullExternalMetadataStrategy();
    }

    /**
     * The unique identifier for the strategy.
     */
    public final static String                   STRATEGY_ID = "org.eclipse.jst.jsf.facelet.core.internal.cm.strategy.MDExternalMetadataStrategy"; //$NON-NLS-1$

    //    private static final String     VAR         = "var";                                                  //$NON-NLS-1$
    //    private static final String     VALUE       = "value";                                                //$NON-NLS-1$
    //    private static final String     SRC         = "src";                                                  //$NON-NLS-1$
    //    private static final String     NAME        = "name";                                                 //$NON-NLS-1$
    //    private static final String     HOTKEY      = "hotkey";                                               //$NON-NLS-1$
    //    private static final String     TEMPLATE    = "template";                                             //$NON-NLS-1$
    //    private static final String     BINDING     = "binding";                                              //$NON-NLS-1$
    //    private static final String     ID          = "id";                                                   //$NON-NLS-1$

    private final IProject                       _project;
    private final TagMetadataLoader              _tagMetadataLoader;
    private final Map<String, MDExternalTagInfo> _cached;
    private final AtomicBoolean                  _isDisposed = new AtomicBoolean(
                                                                     false);

    /**
     * Default constructor
     * 
     * @param project
     */
    private MDExternalMetadataStrategy(final IProject project)
    {
        super(STRATEGY_ID, Messages.MDExternalMetadataStrategy_DisplayName);
        _project = project;
        _tagMetadataLoader = new TagMetadataLoader(_project);
        _cached = new HashMap<String, MDExternalTagInfo>();
    }

    public void checkpoint()
    {
        // do nothing
    }

    public void destroy()
    {
        // currently no persistent state, so just dispose
    }

    public void dispose()
    {
        if (_isDisposed.compareAndSet(false, true))
        {
            _cached.clear();
        }
    }

    /*
     * (non-Javadoc)
     * 
     * @see org.eclipse.jst.jsf.facelet.core.internal.cm.strategy.
     * AbstractExternalMetadataStrategy
     * #perform(org.eclipse.jst.jsf.common.dom.TagIdentifier)
     */
    @Override
    public ExternalTagInfo perform(final TagIdentifier input) throws Exception
    {
        MDExternalTagInfo tagInfo = _cached.get(input.getUri());

        if (tagInfo == null)
        {
            tagInfo = new MDExternalTagInfo(input.getUri(), _tagMetadataLoader);
            _cached.put(input.getUri(), tagInfo);
        }
        return tagInfo;
    }

    private static class MDExternalTagInfo extends ExternalTagInfo
    {
        private final String                            _uri;
        private final TagMetadataLoader                 _tagMetadataLoader;
        private final Map<String, InternalNamedNodeMap> _attributes;

        public MDExternalTagInfo(final String uri,
                final TagMetadataLoader tagMetadataLoader)
        {
            _uri = uri;
            _tagMetadataLoader = tagMetadataLoader;
            _attributes = new HashMap<String, InternalNamedNodeMap>();
        }

        @Override
        public CMNamedNodeMap getAttributes(final String tagName)
        {
            final InternalNamedNodeMap nodeMap = _attributes.get(tagName);
            final InternalNamedNodeMap[] innerClassNodeMap = new InternalNamedNodeMap[1];
            innerClassNodeMap[0] = nodeMap;

            if (nodeMap == null)
            {
                SafeRunnable.run(new ISafeRunnable()
                {
                    public void run()
                    {
                        final ElementData data = _tagMetadataLoader
                                .getElementData(_uri, tagName);

                        if (data != null)
                        {
                            innerClassNodeMap[0] = new InternalNamedNodeMap();

                            for (final AttributeData attribute : data
                                    .getAttributes())
                            {
                                innerClassNodeMap[0]
                                        .add(createAttribute(attribute));
                            }
                            _attributes.put(tagName, innerClassNodeMap[0]);
                        }
                        // no meta-data found for this tag, so mark as null
                        // instance so future calls don't bother a re-lookup.
                        else
                        {
                            _attributes.put(tagName,
                                    MDExternalMetadataStrategy.NULL_INSTANCE);
                        }
                    }

                    public void handleException(final Throwable exception)
                    {
                        FaceletCorePlugin.log(
                                "While loading attribute meta-data", exception); //$NON-NLS-1$
                    }
                });
            }

            // don't return the null map instance
            if (innerClassNodeMap[0] == MDExternalMetadataStrategy.NULL_INSTANCE)
            {
                return null;
            }
            return innerClassNodeMap[0];
        }

        @Override
        public Object getTagProperty(final String tagName, final String key)
        {
            final Object[] value = new Object[1];
            value[0] = null;

            SafeRunnable.run(new ISafeRunnable()
            {
                public void run()
                {
                    if ("description".equals(key)) //$NON-NLS-1$
                    {
                        value[0] = _tagMetadataLoader.getDescription(_uri,
                                tagName);
                    }
                }

                public void handleException(final Throwable exception)
                {
                    FaceletCorePlugin.log(
                            "While loading tag property meta-data", exception); //$NON-NLS-1$
                }
            });
            return value[0];
        }
    }

    private static class InternalNamedNodeMap implements CMNamedNodeMap
    {
        private final List<CMNode> _nodes = new ArrayList<CMNode>();

        public void add(final CMNode node)
        {
            _nodes.add(node);
        }

        public int getLength()
        {
            return _nodes.size();
        }

        public CMNode getNamedItem(final String name)
        {
            for (final CMNode foundNode : _nodes)
            {
                if (name.equals(foundNode.getNodeName()))
                {
                    return foundNode;
                }
            }
            return null;
        }

        public CMNode item(final int index)
        {
            if (index < _nodes.size())
            {
                return _nodes.get(index);
            }
            return null;
        }

        public Iterator<?> iterator()
        {
            return Collections.unmodifiableList(_nodes).iterator();
        }
    }

    private final static NullInternalNamedNodeMap NULL_INSTANCE = new NullInternalNamedNodeMap();

    private static class NullInternalNamedNodeMap extends InternalNamedNodeMap
    {

        @Override
        public void add(final CMNode node)
        {
            // do nothing
        }

        @Override
        public int getLength()
        {
            // always empty
            return 0;
        }

        @Override
        public CMNode getNamedItem(final String name)
        {
            return null;
        }

        @Override
        public CMNode item(final int index)
        {
            return null;
        }

        @Override
        public Iterator<?> iterator()
        {
            return Collections.EMPTY_LIST.iterator();
        }

    }

    // temporary: transfer out to metadata
    final static Map<String, InternalNamedNodeMap> _faceletData;

    static
    {
        // final String ID_DESCRIPTION =
        // Messages.MDExternalMetadataStrategy_ID_DESCRIPTION;
        // final String BINDING_DESCRIPTION =
        // Messages.MDExternalMetadataStrategy_BINDING_DESCRIPTION;
        // final String TEMPLATE_DESCRIPTION =
        // Messages.MDExternalMetadataStrategy_TEMPLATE_DESCRIPTION;
        // final String HOTKEY_DESCRIPTION =
        // Messages.MDExternalMetadataStrategy_HOTKEY_DESCRIPTION;
        // final String DEFINE_NAME_DESCRIPTION =
        // Messages.MDExternalMetadataStrategy_DEFINE_NAME_DESCRIPTION;
        // final String SRC_DESCRIPTION =
        // Messages.MDExternalMetadataStrategy_SRC_DESCRIPTION;
        // final String INSERT_NAME_DESCRIPTION =
        // Messages.MDExternalMetadataStrategy_INSERT_NAME_DESCRIPTION;
        // final String PARAM_NAME_DESCRIPTION =
        // Messages.MDExternalMetadataStrategy_PARAM_NAME_DESCRIPTION;
        // final String PARAM_VALUE_DESCRIPTION =
        // Messages.MDExternalMetadataStrategy_PARAM_VALUE_DESCRIPTION;
        // final String REPEAT_VAR_DESCRIPTION =
        // Messages.MDExternalMetadataStrategy_REPEAT_VAR_DESCRIPTION;
        // final String REPEAT_VALUE_DESCRIPTION =
        // Messages.MDExternalMetadataStrategy_REPEAT_VALUE_DESCRIPTION;

        final Map<String, InternalNamedNodeMap> map = new HashMap<String, InternalNamedNodeMap>();
        // component
        // InternalNamedNodeMap nodeMap = new InternalNamedNodeMap();
        // nodeMap.add(createAttribute(ID, CMAttributeDeclaration.OPTIONAL,
        // ID_DESCRIPTION));
        // nodeMap.add(createAttribute(BINDING, CMAttributeDeclaration.OPTIONAL,
        // BINDING_DESCRIPTION));
        // map.put(IFaceletTagConstants.TAG_COMPONENT, nodeMap);
        //
        // // composition
        // nodeMap = new InternalNamedNodeMap();
        // nodeMap.add(createAttribute(TEMPLATE,
        // CMAttributeDeclaration.OPTIONAL,
        // TEMPLATE_DESCRIPTION));
        // map.put(IFaceletTagConstants.TAG_COMPOSITION, nodeMap);

        // debug
        // nodeMap = new InternalNamedNodeMap();
        // nodeMap.add(createAttribute(HOTKEY, CMAttributeDeclaration.OPTIONAL,
        // HOTKEY_DESCRIPTION));
        // map.put(IFaceletTagConstants.TAG_DEBUG, nodeMap);

        // decorate
        // nodeMap = new InternalNamedNodeMap();
        // nodeMap.add(createAttribute(TEMPLATE,
        // CMAttributeDeclaration.REQUIRED,
        // TEMPLATE_DESCRIPTION));
        // map.put(IFaceletTagConstants.TAG_DECORATE, nodeMap);

        // define
        // nodeMap = new InternalNamedNodeMap();
        // nodeMap.add(createAttribute(NAME, CMAttributeDeclaration.REQUIRED,
        // DEFINE_NAME_DESCRIPTION));
        // map.put(IFaceletTagConstants.TAG_DEFINE, nodeMap);

        // fragment
        // nodeMap = new InternalNamedNodeMap();
        // nodeMap.add(createAttribute(ID, CMAttributeDeclaration.OPTIONAL,
        // ID_DESCRIPTION));
        // nodeMap.add(createAttribute(BINDING, CMAttributeDeclaration.OPTIONAL,
        // BINDING_DESCRIPTION));
        // map.put(IFaceletTagConstants.TAG_FRAGMENT, nodeMap);

        // include
        // nodeMap = new InternalNamedNodeMap();
        // nodeMap.add(createAttribute(SRC, CMAttributeDeclaration.REQUIRED,
        // SRC_DESCRIPTION));
        // map.put(IFaceletTagConstants.TAG_INCLUDE, nodeMap);

        // insert
        // nodeMap = new InternalNamedNodeMap();
        // nodeMap.add(createAttribute(NAME, CMAttributeDeclaration.OPTIONAL,
        // INSERT_NAME_DESCRIPTION));
        // map.put(IFaceletTagConstants.TAG_INSERT, nodeMap);

        // param
        // nodeMap = new InternalNamedNodeMap();
        // nodeMap.add(createAttribute(NAME, CMAttributeDeclaration.REQUIRED,
        // PARAM_NAME_DESCRIPTION));
        // nodeMap.add(createAttribute(VALUE, CMAttributeDeclaration.REQUIRED,
        // PARAM_VALUE_DESCRIPTION));
        // map.put(IFaceletTagConstants.TAG_PARAM, nodeMap);

        // remove
        // nodeMap = new InternalNamedNodeMap();
        // // no attributes
        // map.put(IFaceletTagConstants.TAG_PARAM, nodeMap);

        // repeat
        // nodeMap = new InternalNamedNodeMap();
        // nodeMap.add(createAttribute(VALUE, CMAttributeDeclaration.REQUIRED,
        // REPEAT_VALUE_DESCRIPTION));
        // nodeMap.add(createAttribute(VAR, CMAttributeDeclaration.REQUIRED,
        // REPEAT_VAR_DESCRIPTION));
        // map.put(IFaceletTagConstants.TAG_REPEAT, nodeMap);

        _faceletData = Collections.unmodifiableMap(map);
    }

    private static CMAttributeDeclaration createAttribute(
            final AttributeData attributeData)
    {
        final AttributeCMAdapter attribute = new AttributeCMAdapter(
                attributeData.getName(), convertUsageEnum(attributeData
                        .getUsage()));

        final ComposedAdapterFactory factory = new ComposedAdapterFactory(
                ComposedAdapterFactory.Descriptor.Registry.INSTANCE);

        final Object provider = factory.adapt(attributeData,
                IResourceProvider.class);

        // get the description from meta-data and feed through the provider
        // for possible translation
        String description = attributeData.getDescription();

        if (provider instanceof IResourceProvider)
        {
            final IResourceProvider resProvider = (IResourceProvider) provider;
            final String translated = resProvider.getTranslatedString(
                    attributeData, AddTagMDPackage.eINSTANCE
                            .getAttributeData_Description());
            description = translated != null ? translated : description;
        }

        attribute.setDescription(description);
        return attribute;
    }

    private static int convertUsageEnum(final AttributeUsage usage)
    {
        switch (usage)
        {
            case OPTIONAL:
                return CMAttributeDeclaration.OPTIONAL;
            case REQUIRED:
                return CMAttributeDeclaration.REQUIRED;
            case FIXED:
                return CMAttributeDeclaration.FIXED;
            case PROHIBITED:
                return CMAttributeDeclaration.PROHIBITED;
            default:
                return CMAttributeDeclaration.OPTIONAL;
        }
    }

    private static class MySingletonManager
            extends
            ResourceSingletonObjectManager<MDExternalMetadataStrategy, IProject>
    {

        @Override
        protected MDExternalMetadataStrategy createNewInstance(
                final IProject resource)
        {
            return new MDExternalMetadataStrategy(resource);
        }

    }
}