package org.eclipse.jst.jsf.facelet.core.internal.cm;

import java.util.HashMap;
import java.util.Map;

import org.eclipse.core.resources.IProject;
import org.eclipse.jst.jsf.common.runtime.internal.view.model.common.Namespace;
import org.eclipse.jst.jsf.designtime.internal.view.model.ITagRegistry;
import org.eclipse.jst.jsf.designtime.internal.view.model.TagRegistryFactory.TagRegistryFactoryException;
import org.eclipse.jst.jsf.facelet.core.internal.registry.FaceletRegistryManager.MyRegistryFactory;
import org.eclipse.jst.jsf.facelet.core.internal.util.ViewUtil;
import org.eclipse.jst.jsf.facelet.core.internal.util.ViewUtil.PrefixEntry;
import org.eclipse.jst.jsp.core.internal.contentmodel.tld.CMDocumentFactoryTLD;
import org.eclipse.jst.jsp.core.internal.contentmodel.tld.provisional.TLDDocument;
import org.eclipse.jst.jsp.core.taglib.ITaglibRecord;
import org.eclipse.jst.jsp.core.taglib.TaglibIndex;
import org.eclipse.wst.xml.core.internal.contentmodel.CMDocument;
import org.eclipse.wst.xml.core.internal.contentmodel.CMElementDeclaration;
import org.w3c.dom.Element;

/**
 * Creates CMDocument framework adaptation for Facelet features.
 * 
 * NOTE: this class currently caches state and is NOT THREADSAFE.  Share 
 * instances of this class between unowned classes at your own risk.
 * 
 * @author cbateman
 *
 */
public class FaceletDocumentFactory
{
    private final IProject                        _project;
    private final Map<String, NamespaceCMAdapter> _cmDocuments;
    private final Map<String, ExternalTagInfo>    _externalTagInfo;

    /**
     * @param project
     */
    public FaceletDocumentFactory(final IProject project)
    {
        _project = project;
        _cmDocuments = new HashMap<String, NamespaceCMAdapter>(8);
        _externalTagInfo = new HashMap<String, ExternalTagInfo>(8);
    }

    /**
     * @param uri
     * @param prefix
     * @return the CMDocument for the uri where prefix is used as its namespace
     * short-form (usually in the context of an XML document instance).
     */
    public CMDocument createCMDocumentForContext(final String uri,
            final String prefix)
    {
        final NamespaceCMAdapter cmDoc = getOrCreateCMDocument(_project, uri);

        if (cmDoc != null)
        {
            return new DocumentNamespaceCMAdapter(cmDoc, prefix);
        }
        return null;
    }

    /**
     * @param element
     * @return the CM model data for element or null if none.
     */
    public CMElementDeclaration createCMElementDeclaration(final Element element)
    {
        final String prefix = element.getPrefix();
        final Map<String, PrefixEntry> namespaces = ViewUtil
                .getDocumentNamespaces(element.getOwnerDocument());
        final PrefixEntry prefixEntry = namespaces.get(prefix);

        if (prefixEntry != null)
        {
            final CMDocument cmDoc = createCMDocumentForContext(prefixEntry
                    .getUri(), prefixEntry.getPrefix());

            if (cmDoc != null)
            {
                return (CMElementDeclaration) cmDoc.getElements().getNamedItem(
                        element.getLocalName());
            }
        }

        return null;
    }

    /**
     * @param ns
     * @return the externa tag info the namespace.  May return a previously
     * cached value. If there is no cached value, then creates it.
     */
    public ExternalTagInfo getOrCreateExtraTagInfo(final String ns)
    {
        ExternalTagInfo tagInfo = _externalTagInfo.get(ns);

        if (tagInfo == null)
        {
            tagInfo = createExternalTagInfo(ns);
            _externalTagInfo.put(ns, tagInfo);
        }
        return tagInfo;
    }

    /**
     * @return a new external tag info for this namespace
     */
    private ExternalTagInfo createExternalTagInfo(final String uri)
    {
        ExternalTagInfo tldTagInfo = new MetadataTagInfo(_project, uri);
        final ITaglibRecord[] tldrecs = TaglibIndex
                .getAvailableTaglibRecords(_project.getFullPath());
        FIND_TLDRECORD: for (final ITaglibRecord rec : tldrecs)
        {
            final String matchUri = rec.getDescriptor().getURI();
            if (uri.equals(matchUri))
            {
                final CMDocumentFactoryTLD factory = new CMDocumentFactoryTLD();
                tldTagInfo = new MetadataTagInfo(_project, (TLDDocument) factory
                        .createCMDocument(rec));
                break FIND_TLDRECORD;
            }
        }
        return tldTagInfo;
    }

    private NamespaceCMAdapter getOrCreateCMDocument(final IProject project,
            final String uri)
    {
        NamespaceCMAdapter adapter = _cmDocuments.get(uri);

        if (adapter == null)
        {
            final MyRegistryFactory factory = new MyRegistryFactory();

            ITagRegistry registry;
            try
            {
                registry = factory.createTagRegistry(project);
                final Namespace ns = registry.getTagLibrary(uri);

                if (ns != null)
                {
                    adapter = new NamespaceCMAdapter(ns, project);
                    _cmDocuments.put(uri, adapter);
                }
            }
            catch (final TagRegistryFactoryException e)
            {
                // fall-through
            }
        }
        return adapter;
    }

}