/*******************************************************************************
 * Copyright (c) 2006 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/Oracle - initial API and implementation
 *    
 ********************************************************************************/

package org.eclipse.jst.jsf.designtime.internal.jsp;

import java.io.IOException;
import java.util.ArrayList;
import java.util.Collections;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.concurrent.locks.ReentrantLock;

import org.eclipse.core.resources.IFile;
import org.eclipse.core.resources.IProject;
import org.eclipse.core.runtime.CoreException;
import org.eclipse.core.runtime.IStatus;
import org.eclipse.core.runtime.Platform;
import org.eclipse.core.runtime.Status;
import org.eclipse.jst.jsf.common.JSFCommonPlugin;
import org.eclipse.jst.jsf.common.internal.resource.IResourceLifecycleListener;
import org.eclipse.jst.jsf.common.internal.resource.LifecycleListener;
import org.eclipse.jst.jsf.common.internal.resource.ResourceLifecycleEvent;
import org.eclipse.jst.jsf.common.internal.resource.ResourceLifecycleEvent.EventType;
import org.eclipse.jst.jsf.common.internal.resource.ResourceLifecycleEvent.ReasonType;
import org.eclipse.jst.jsf.common.metadata.Trait;
import org.eclipse.jst.jsf.common.metadata.internal.TraitValueHelper;
import org.eclipse.jst.jsf.common.metadata.query.ITaglibDomainMetaDataModelContext;
import org.eclipse.jst.jsf.common.metadata.query.TaglibDomainMetaDataQueryHelper;
import org.eclipse.jst.jsf.context.resolver.structureddocument.IStructuredDocumentContextResolverFactory;
import org.eclipse.jst.jsf.context.resolver.structureddocument.ITaglibContextResolver;
import org.eclipse.jst.jsf.context.structureddocument.IStructuredDocumentContext;
import org.eclipse.jst.jsf.context.structureddocument.IStructuredDocumentContextFactory;
import org.eclipse.jst.jsf.context.symbol.IComponentSymbol;
import org.eclipse.jst.jsf.context.symbol.ISymbol;
import org.eclipse.jst.jsf.context.symbol.SymbolFactory;
import org.eclipse.jst.jsf.context.symbol.source.AbstractContextSymbolFactory;
import org.eclipse.jst.jsf.context.symbol.source.ISymbolConstants;
import org.eclipse.jst.jsf.core.internal.JSFCorePlugin;
import org.eclipse.jst.jsf.designtime.DesignTimeApplicationManager;
import org.eclipse.jst.jsf.designtime.context.DTFacesContext;
import org.eclipse.wst.html.core.internal.document.DOMStyleModelImpl;
import org.eclipse.wst.sse.core.StructuredModelManager;
import org.eclipse.wst.sse.core.internal.provisional.IModelManager;
import org.eclipse.wst.sse.core.internal.provisional.IStructuredModel;
import org.eclipse.wst.xml.core.internal.provisional.document.IDOMDocument;
import org.eclipse.wst.xml.core.internal.provisional.document.IDOMModel;
import org.w3c.dom.Node;
import org.w3c.dom.NodeList;


/**
 * Processes a JSP model to determine information of interest about it such
 * as what tags are currently in use.  Listens to the model and updates it's 
 * information when the model changes.
 * 
 * @author cbateman
 *
 */
public class JSPModelProcessor
{
    private final static Map<IFile, JSPModelProcessor>  RESOURCE_MAP = 
        new HashMap<IFile, JSPModelProcessor>();
    private final static java.util.concurrent.locks.Lock CRITICAL_SECTION =
        new  ReentrantLock();
    private static LifecycleListener  LIFECYCLE_LISTENER;

    /**
     * @param file The file to get the model processor for  
     * @return the processor for a particular model, creating it if it does not
     *         already exist
     * @throws CoreException if an attempt to get the model associated with file
     *         fails due to reasons other than I/O problems
     */
    public static JSPModelProcessor get(IFile file) throws CoreException
    {
        CRITICAL_SECTION.lock();
        try
        {
            if (!file.isAccessible())
            {
                throw new CoreException(new Status(IStatus.ERROR, JSFCorePlugin.PLUGIN_ID, "File must be accessible")); //$NON-NLS-1$
            }

            JSPModelProcessor processor = RESOURCE_MAP.get(file);

            if (processor == null)
            {
                if (LIFECYCLE_LISTENER == null)
                {
                    LIFECYCLE_LISTENER = new LifecycleListener(file);
                }
                else
                {
                    LIFECYCLE_LISTENER.addResource(file);
                }

                processor = new JSPModelProcessor(file,LIFECYCLE_LISTENER);
                RESOURCE_MAP.put(file, processor);
            }

            return processor;
        }
        finally
        {
            CRITICAL_SECTION.unlock();
        }
    }

    /**
     * Disposes of the JSPModelProcessor associated with model
     * @param file the model processor to be disposed
     */
    private static void dispose(IFile file)
    {
        CRITICAL_SECTION.lock();
        try
        {
            JSPModelProcessor processor = RESOURCE_MAP.get(file);

            if (processor != null)
            {
                RESOURCE_MAP.remove(file);
                
                if (!processor.isDisposed())
                {
                    processor.dispose();
                    LIFECYCLE_LISTENER.removeResource(file);
                }
                
            }

            if (RESOURCE_MAP.size() == 0)
            {
                // if we no longer have any resources being tracked,
                // then dispose the lifecycle listener
                LIFECYCLE_LISTENER.dispose();
                LIFECYCLE_LISTENER = null;
            }
        }
        finally
        {
            CRITICAL_SECTION.unlock();
        }
    }

    private final IFile             _file;
    private LifecycleListener       _lifecycleListener;
    private IResourceLifecycleListener  _resListener;
    private boolean                 _isDisposed;
    private Map<Object, ISymbol>    _requestMap;
    private Map<Object, ISymbol>    _sessionMap;
    private Map<Object, ISymbol>    _applicationMap;
    private Map<Object, ISymbol>    _noneMap;
    private long                    _lastModificationStamp;

    // used to avoid infinite recursion in refresh.  Must never be null
    private final CountingMutex     _lastModificationStampMonitor = new CountingMutex();

    /**
     * Construct a new JSPModelProcessor for model
     * 
     * @param model
     */
    private JSPModelProcessor(final IFile  file, final LifecycleListener lifecycleListener)
    {
        //_model = getModelForFile(file);
        //_modelListener = new ModelListener();
        //_model.addModelLifecycleListener(_modelListener);
        _file = file;
        _lifecycleListener = lifecycleListener;
        _resListener = new IResourceLifecycleListener()
        {
            public EventResult acceptEvent(ResourceLifecycleEvent event)
            {
                final EventResult result = EventResult.getDefaultEventResult();

                // not interested
                if (!_file.equals(event.getAffectedResource()))
                {
                    return result; 
                }

                if (event.getEventType() == EventType.RESOURCE_INACCESSIBLE)
                {
                    dispose(_file);
                }
                else if (event.getEventType() == EventType.RESOURCE_CHANGED)
                {
                    // if the file has changed contents on disk, then
                    // invoke an unforced refresh of the JSP file
                    if (event.getReasonType() == ReasonType.RESOURCE_CHANGED_CONTENTS)
                    {
                        refresh(false);
                    }
                }

                return result;
            }
        };

        lifecycleListener.addListener(_resListener);
        
        // a negative value guarantees that refresh(false) will
        // force a refresh on the first run
        _lastModificationStamp = -1;
    }

    private DOMStyleModelImpl getModelForFile(final IFile file)
            throws CoreException, IOException
    {
        final IModelManager modelManager = 
            StructuredModelManager.getModelManager();

        IStructuredModel model = modelManager.getModelForRead(file);

        if (model instanceof DOMStyleModelImpl)
        {
            return (DOMStyleModelImpl) model;
        }
        else if (model != null)
        {
            // only release from read if we don't find a DOMModelForJSP
            // if the model is correct, it will be released in dispose
            model.releaseFromRead();
        }
        
        throw new CoreException
            (new Status(IStatus.ERROR
                        , "org.eclipse.blah" //$NON-NLS-1$
                        , 0
                        ,"model not of expected type" //$NON-NLS-1$
                        , new Throwable()));
    }

    private void dispose()
    {
        if (!_isDisposed)
        {
            // ensure the resource listener is disposed
            _lifecycleListener.removeListener(_resListener);
            _resListener = null;
            _lifecycleListener = null;

            if (_requestMap != null)
            {
                _requestMap.clear();
                _requestMap = null;
            }

            if (_sessionMap != null)
            {
                _sessionMap.clear();
                _sessionMap = null;
            }

            if (_applicationMap != null)
            {
                _applicationMap.clear();
                _applicationMap = null;
            }

            if (_noneMap != null)
            {
                _noneMap.clear();
                _noneMap = null;
            }

            // mark as disposed
            _isDisposed = true;
        }
    }

    /**
     * @return true if this model processor has been disposed.  Disposed
     * processors should not be used.
     */
    public boolean isDisposed()
    {
        return _isDisposed;
    }

    /**
     * If isModelDirty() returns true, then it means that a call
     * to refresh(false) will trigger a reprocess of the underlying document.
     *
     * @return true if the underlying JSP model is considered to be dirty
     */
    public boolean isModelDirty()
    {
        final long currentModificationStamp = _file.getModificationStamp();
        return _lastModificationStamp != currentModificationStamp;
    }
    
    /**
     * Updates the internal model
     * @param forceRefresh -- if true, always refreshes, if false,
     * then it only refreshes if the file's modification has changed
     * since the last refresh
     * @throws IllegalStateException if isDisposed() == true
     */
    public void refresh(final boolean forceRefresh)
    {
        if (isDisposed())
        {
            throw new IllegalStateException("Processor is disposed for file: "+_file.toString()); //$NON-NLS-1$
        }

        synchronized(_lastModificationStampMonitor)
        {
            if (_lastModificationStampMonitor.isSignalled())
            {
                // if this calls succeeds, then this thread has obtained the
                // lock already and has called through here before.  
                // return immediately to ensure that we don't recurse infinitely
                return;
            }

            DOMStyleModelImpl  model = null;
            try
            {
                _lastModificationStampMonitor.setSignalled(true);
                

                // only refresh if forced or if the underlying file has changed
                // since the last run
                if (forceRefresh
                        || isModelDirty())
                {
                    model = getModelForFile(_file);
                    refreshInternal(model);
                    _lastModificationStamp = _file.getModificationStamp();
                }
            }
            catch (CoreException e) {
               JSFCorePlugin.log(new RuntimeException(e), "Error refreshing internal model"); //$NON-NLS-1$
            } catch (IOException e) {
                JSFCorePlugin.log(new RuntimeException(e), "Error refreshing internal model"); //$NON-NLS-1$
            }
            // make sure that we unsignal the monitor before releasing the
            // mutex
            finally
            {
                if (model != null)
                {
                    model.releaseFromRead();
                }
                _lastModificationStampMonitor.setSignalled(false);
            }
        }
    }
    
    private void refreshInternal(DOMStyleModelImpl model)
    {
        final IStructuredDocumentContext context = 
            IStructuredDocumentContextFactory.INSTANCE.getContext(model.getStructuredDocument(), -1);
        final ITaglibContextResolver taglibResolver =
            IStructuredDocumentContextResolverFactory.INSTANCE.getTaglibContextResolver(context);
        IDOMDocument document = model.getDocument();
        getApplicationMap().clear();
        getRequestMap().clear();
        getSessionMap().clear();
        //long curTime = System.currentTimeMillis();
        recurseChildNodes(model, document.getChildNodes(), taglibResolver);
        //long netTime = System.currentTimeMillis() - curTime;
        //System.out.println("Net time to recurse document: "+netTime);
    }

    private void recurseChildNodes(final IDOMModel model,
                                   final NodeList nodes, 
                                    final ITaglibContextResolver taglibResolver)
    {
        for (int i = 0; i < nodes.getLength(); i++)
        {
            final Node child = nodes.item(i);
            
            // process attributes at this node before recursing
            processAttributes(model, child, taglibResolver);
            recurseChildNodes(model, child.getChildNodes(), taglibResolver);
        }
    }

    private void processAttributes(final IDOMModel model, final Node node, 
                                    final ITaglibContextResolver taglibResolver)
    {
        if (taglibResolver.hasTag(node))
        {
            final String uri =
                taglibResolver.getTagURIForNodeName(node);
            final String elementName = node.getLocalName();
            
            for (int i = 0; i < node.getAttributes().getLength(); i++)
            {
                final Node attribute = node.getAttributes().item(i);

                processSymbolContrib(model, uri, elementName, attribute);
                processSetsLocale(uri, elementName, attribute);
            }
        }
    }

    private void processSymbolContrib(final IDOMModel model, final String uri, final String elementName, Node attribute)
    {
        final SymbolContribAggregator  aggregator =
            SymbolContribAggregator.
               create(_file.getProject(), uri, elementName, attribute.getLocalName());
  
        if (aggregator != null)
        {    
            final AbstractContextSymbolFactory factory = aggregator.getFactory();
            final String symbolName = attribute.getNodeValue();

            if (factory != null)
            {
//                long curTime = System.currentTimeMillis();
                final IStructuredDocumentContext context = 
                    IStructuredDocumentContextFactory.INSTANCE.
                        getContext(model.getStructuredDocument(), 
                           attribute);

                if (factory.supports(context))
                {
                    final List problems = new ArrayList();
                    ISymbol symbol =
                        factory.create(symbolName, 
                                      ISymbolConstants.SYMBOL_SCOPE_REQUEST, //TODO:
                                      context,
                                      problems,
                                      // TODO: add meta-data for signature
                                      new AdditionalContextSymbolInfo(aggregator.getStaticType(), aggregator.getValueExpressionAttr()));
    
    //                long netTime = System.currentTimeMillis() - curTime;
    //                System.out.println("Time to process loadBundle: "+netTime);
    
                    if (symbol != null)
                    {
                        updateMap(symbol, aggregator.getScope());
                    }
                }
            }
            else
            {
                IComponentSymbol componentSymbol = 
                    SymbolFactory.eINSTANCE.createIComponentSymbol();
                componentSymbol.setName(symbolName);

                updateMap(componentSymbol, aggregator.getScope());
            }
        }
    }
    
    @SuppressWarnings("deprecation")
    private void processSetsLocale(final String uri, final String elementName, Node attribute)
    {
        LocaleSetAggregator  aggregator = LocaleSetAggregator.create(_file.getProject(), uri, elementName, attribute.getLocalName());

        if (aggregator != null)
        {
            DesignTimeApplicationManager  dtAppMgr =
                DesignTimeApplicationManager.getInstance(_file.getProject());

            if (dtAppMgr != null)
            {
                DTFacesContext facesContext = dtAppMgr.getFacesContext(_file);
                
                if (facesContext != null)
                {
                    facesContext.setLocaleString(attribute.getNodeValue());
                }
            }
        }
    }

   /**
     * @param scopeName - one of "request", "session" or "application"
     * @return an unmodifable map containing all known symbols for
     * that scope.  If scopeName is not found, returns the empty map.
     */
    public Map<Object, ISymbol> getMapForScope(String scopeName)
    {
        final Map<Object, ISymbol> map = getMapForScopeInternal(scopeName);
        
        if (map != null)
        {
            return Collections.unmodifiableMap(map);
        }

        return Collections.EMPTY_MAP;
    }

    private void updateMap(ISymbol symbol, String  scopeName)
    {
        final Map<Object, ISymbol> map = getMapForScopeInternal(scopeName);

        if (map != null)
        {
            map.put(symbol.getName(), symbol);
        }
        else
        {
            Platform.getLog(JSFCorePlugin.getDefault().getBundle()).log(new Status(IStatus.ERROR, JSFCorePlugin.PLUGIN_ID, 0, "Scope not found: "+scopeName, new Throwable())); //$NON-NLS-1$
        }
    }

    private Map<Object, ISymbol> getMapForScopeInternal(String scopeName)
    {
        if (ISymbolConstants.SYMBOL_SCOPE_REQUEST_STRING.equals(scopeName))
        {
            return getRequestMap();
        }
        else if (ISymbolConstants.SYMBOL_SCOPE_SESSION_STRING.equals(scopeName))
        {
            return getSessionMap();
        }
        else if (ISymbolConstants.SYMBOL_SCOPE_APPLICATION_STRING.equals(scopeName))
        {
            return getApplicationMap();
        }
        else if (ISymbolConstants.SYMBOL_SCOPE_NONE_STRING.equals(scopeName))
        {
            return getNoneMap();
        }
        
        Platform.getLog(JSFCorePlugin.getDefault().getBundle()).log(new Status(IStatus.ERROR, JSFCorePlugin.PLUGIN_ID, 0, "Scope not found: "+scopeName, new Throwable())); //$NON-NLS-1$
        return null;
    
    }
    
    private Map getRequestMap()
    {
        if (_requestMap == null)
        {
            _requestMap = new HashMap<Object, ISymbol>();
        }
        
        return _requestMap;
    }
    
    private Map<Object, ISymbol> getSessionMap()
    {
        if (_sessionMap == null)
        {
            _sessionMap = new HashMap<Object, ISymbol>();
        }
        
        return _sessionMap;
    }
    
    private Map<Object, ISymbol> getApplicationMap()
    {
        if (_applicationMap == null)
        {
            _applicationMap = new HashMap<Object, ISymbol>();
        }
        
        return _applicationMap;
    }
    
    private Map<Object, ISymbol> getNoneMap()
    {
        if (_noneMap == null)
        {
            _noneMap = new HashMap<Object, ISymbol>();
        }
        
        return _noneMap;
    }

    /**
     * Aggregates the sets-locale meta-data
     * 
     * @author cbateman
     */
    private static class LocaleSetAggregator
    {
        private final static String SETS_LOCALE = "sets-locale"; //$NON-NLS-1$
        
        static LocaleSetAggregator create(IProject project, 
                                              final String uri, 
                                              final String elementName, final String attributeName)
        {
            final ITaglibDomainMetaDataModelContext mdContext = TaglibDomainMetaDataQueryHelper.createMetaDataModelContext(project, uri);
            Trait trait = TaglibDomainMetaDataQueryHelper.getTrait(mdContext, elementName+"/"+attributeName, SETS_LOCALE); //$NON-NLS-1$

            if (TraitValueHelper.getValueAsBoolean(trait))
            {
                return new LocaleSetAggregator();
            }

            return null;
        }
    }
    
    /**
     * Aggregates all the symbol contributor meta-data into a single object
     * 
     * @author cbateman
     *
     */
    private static class SymbolContribAggregator
    {
        private final static String CONTRIBUTES_VALUE_BINDING = 
            "contributes-value-binding"; //$NON-NLS-1$
        private final static String VALUE_BINDING_SCOPE = "value-binding-scope"; //$NON-NLS-1$
        private final static String VALUE_BINDING_SYMBOL_FACTORY = 
            "value-binding-symbol-factory"; //$NON-NLS-1$
        private final static String STATIC_TYPE_KEY = "optional-value-binding-static-type"; //$NON-NLS-1$
        private final static String VALUEEXPRESSION_ATTR_NAME_KEY = "optional-value-binding-valueexpr-attr"; //$NON-NLS-1$
        
        /**
         * @param attributeName
         * @return a new instance only if attributeName is a symbol contributor
         */
        static SymbolContribAggregator create(final IProject project, 
                                              final String uri, 
                                              final String elementName, 
                                              final String attributeName)
        {
            final String entityKey = elementName+"/"+attributeName; //$NON-NLS-1$
            final ITaglibDomainMetaDataModelContext mdContext = TaglibDomainMetaDataQueryHelper.createMetaDataModelContext(project, uri);
            Trait trait = TaglibDomainMetaDataQueryHelper.getTrait(mdContext, entityKey, CONTRIBUTES_VALUE_BINDING);

            boolean contribsValueBindings = TraitValueHelper.getValueAsBoolean(trait);

            if (contribsValueBindings)
            {
                String scope = null;
                String symbolFactory = null;
                
                trait = TaglibDomainMetaDataQueryHelper.getTrait(mdContext, entityKey, VALUE_BINDING_SCOPE);
                scope = TraitValueHelper.getValueAsString(trait);

                if (scope != null && !scope.equals("")) //$NON-NLS-1$
                {
                    trait = TaglibDomainMetaDataQueryHelper.getTrait(mdContext, entityKey, VALUE_BINDING_SYMBOL_FACTORY);
                    symbolFactory = TraitValueHelper.getValueAsString(trait);
                }

                trait = TaglibDomainMetaDataQueryHelper.getTrait(mdContext, entityKey, STATIC_TYPE_KEY);

                String staticType = null;

                if (trait != null)
                {
                    staticType = TraitValueHelper.getValueAsString(trait);
                }

                trait = TaglibDomainMetaDataQueryHelper.getTrait(mdContext, entityKey, VALUEEXPRESSION_ATTR_NAME_KEY);

                String valueExprAttr = null;
                if (trait != null)
                {
                    valueExprAttr = TraitValueHelper.getValueAsString(trait);
                }

                return new SymbolContribAggregator(scope, symbolFactory, staticType, valueExprAttr);
            }

            return null;
        }

        private final Map<String, String>   _metadata = new HashMap<String, String>(4);

        SymbolContribAggregator(final String scope, final String factory, final String staticType, final String valueExprAttr)
        {
            _metadata.put("scope", scope); //$NON-NLS-1$
            _metadata.put("factory", factory); //$NON-NLS-1$
            _metadata.put("staticType", staticType); //$NON-NLS-1$
            _metadata.put("valueExprAttr", valueExprAttr); //$NON-NLS-1$
        }

        /**
         * @return the scope
         */
        public String getScope()
        {
            return _metadata.get("scope"); //$NON-NLS-1$
        }
        
        /**
         * @return the factory
         */
        public AbstractContextSymbolFactory getFactory()
        {
            return JSFCommonPlugin.getSymbolFactories().get(_metadata.get("factory")); //$NON-NLS-1$
        }
        
        public String getStaticType()
        {
            return _metadata.get("staticType"); //$NON-NLS-1$
        }
        
        public String getValueExpressionAttr()
        {
            return _metadata.get("valueExprAttr"); //$NON-NLS-1$
        }
    }

    private static class CountingMutex extends Object
    {
        private boolean _signalled = false;

        /**
         * @return true if the state of mutex is signalled
         */
        public synchronized boolean isSignalled() {
            return _signalled;
        }

        /**
         * @param signalled
         */
        public synchronized void setSignalled(boolean signalled) {
            this._signalled = signalled;
        }
    }
}