/*
 *  Copyright 2010 Anyware Services
 *
 *  Licensed under the Apache License, Version 2.0 (the "License");
 *  you may not use this file except in compliance with the License.
 *  You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 *  Unless required by applicable law or agreed to in writing, software
 *  distributed under the License is distributed on an "AS IS" BASIS,
 *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 *  See the License for the specific language governing permissions and
 *  limitations under the License.
 */
package org.ametys.web.repository.site;

import java.util.ArrayList;
import java.util.Collection;
import java.util.HashMap;
import java.util.HashSet;
import java.util.Iterator;
import java.util.Map;
import java.util.Set;

import javax.jcr.Repository;
import javax.jcr.RepositoryException;
import javax.jcr.Session;
import javax.jcr.observation.Event;
import javax.jcr.observation.ObservationManager;

import org.apache.avalon.framework.component.Component;
import org.apache.avalon.framework.context.Context;
import org.apache.avalon.framework.context.ContextException;
import org.apache.avalon.framework.context.Contextualizable;
import org.apache.avalon.framework.logger.AbstractLogEnabled;
import org.apache.avalon.framework.service.ServiceException;
import org.apache.avalon.framework.service.ServiceManager;
import org.apache.avalon.framework.service.Serviceable;
import org.apache.cocoon.components.ContextHelper;
import org.apache.cocoon.environment.Request;

import org.ametys.core.right.RightManager;
import org.ametys.core.user.CurrentUserProvider;
import org.ametys.core.user.UserIdentity;
import org.ametys.core.user.population.PopulationContextHelper;
import org.ametys.plugins.repository.AmetysObject;
import org.ametys.plugins.repository.AmetysObjectIterable;
import org.ametys.plugins.repository.AmetysObjectResolver;
import org.ametys.plugins.repository.AmetysRepositoryException;
import org.ametys.plugins.repository.ModifiableTraversableAmetysObject;
import org.ametys.plugins.repository.RepositoryConstants;
import org.ametys.plugins.repository.RepositoryIntegrityViolationException;
import org.ametys.plugins.repository.TraversableAmetysObject;
import org.ametys.plugins.repository.UnknownAmetysObjectException;
import org.ametys.plugins.repository.provider.AdminSessionProvider;
import org.ametys.plugins.repository.provider.WorkspaceSelector;
import org.ametys.web.live.LiveWorkspaceListener;
import org.ametys.web.repository.page.CopySiteComponent;
import org.ametys.web.synchronization.SynchronizeComponent;

/**
 * Helper component for managing sites.
 */
public class SiteManager extends AbstractLogEnabled implements Serviceable, Component, Contextualizable
{
    /** Avalon Role */
    public static final String ROLE = SiteManager.class.getName();
 
    /** Constant for storing the sites cache in request attribute. */
    public static final String SITES_KEY = SiteManager.class.getName();
    
    /** sites root's JCR node name */
    public static final String ROOT_SITES = RepositoryConstants.NAMESPACE_PREFIX_INTERNAL + ":sites";
    
    /** sites root's JCR path */
    public static final String ROOT_SITES_PATH = "/" + ROOT_SITES;
    
    private AmetysObjectResolver _resolver;
    private Repository _repository;
    private AdminSessionProvider _adminSessionProvider;
    private SynchronizeComponent _synchronizeComponent;
    private CopySiteComponent _copySiteComponent;
    private WorkspaceSelector _workspaceSelector;
    private RightManager _rightManager;
    private CurrentUserProvider _currentUserProvider;
    private PopulationContextHelper _populationContextHelper;
    
    private Context _context;


    
    @Override
    public void service(ServiceManager manager) throws ServiceException
    {
        _resolver = (AmetysObjectResolver) manager.lookup(AmetysObjectResolver.ROLE);
        _repository = (Repository) manager.lookup("javax.jcr.Repository");
        _adminSessionProvider = (AdminSessionProvider) manager.lookup(AdminSessionProvider.ROLE);
        _synchronizeComponent = (SynchronizeComponent) manager.lookup(SynchronizeComponent.ROLE);
        _copySiteComponent = (CopySiteComponent) manager.lookup(CopySiteComponent.ROLE);
        _workspaceSelector = (WorkspaceSelector) manager.lookup(WorkspaceSelector.ROLE);
        _rightManager = (RightManager) manager.lookup(RightManager.ROLE);
        _currentUserProvider = (CurrentUserProvider) manager.lookup(CurrentUserProvider.ROLE);
        _populationContextHelper = (PopulationContextHelper) manager.lookup(PopulationContextHelper.ROLE);
    }
    
    public void contextualize(Context context) throws ContextException
    {
        _context = context;
    }
    
    private Request _getRequest ()
    {
        try 
        {
            return (Request) _context.get(ContextHelper.CONTEXT_REQUEST_OBJECT);
        } 
        catch (ContextException ce)
        {
            getLogger().info("Unable to get the request", ce);
            return null;
        }
    }
    
    /**
     * Returns the sites names.
     * @return the sites names.
     */
    public Collection<String> getRootSiteNames()
    {
        TraversableAmetysObject root = _resolver.resolveByPath(ROOT_SITES_PATH);
        AmetysObjectIterable<AmetysObject> sites = root.getChildren();
        
        ArrayList<String> result = new ArrayList<>();
        
        for (AmetysObject object : sites)
        {
            result.add(object.getName());
        }
        
        return result;
    }
    
    /**
     * Returns the sites names.
     * @return the sites names.
     */
    public Collection<String> getSiteNames()
    {
        ArrayList<String> result = new ArrayList<>();
        AmetysObjectIterable<Site> sites = getSites();
        
        for (Site site : sites)
        {
            result.add(site.getName());
        }
        
        return result;
    }
    
    /**
     * Get the granted site names for the current user
     * @return The name of sites the current user can access
     */
    public Set<String> getGrantedSites()
    {
        return getGrantedSites(_currentUserProvider.getUser());
    }
    
    /**
     * Get the granted site names for user
     * @param user The user
     * @return The name of sites the user can access
     */
    public Set<String> getGrantedSites(UserIdentity user)
    {
        Set<String> grantedSiteNames = new HashSet<>();
        
        Request request = _getRequest();
        
        for (String siteName : getSiteNames())
        {
            if (_populationContextHelper.getUserPopulationsOnContext("/sites/" + siteName, false).contains(user.getPopulationId()))
            {
                try
                {
                    request.setAttribute("siteName", siteName); // Setting temporarily this attribute to check user rights on any object on this site
                    if (!_rightManager.getUserRights(user, "/cms").isEmpty())
                    {
                        grantedSiteNames.add(siteName);
                    }
                }
                finally
                {
                    request.setAttribute("siteName", null);
                }
            }
        }
        
        return grantedSiteNames;
    }
    
    /**
     * Determines if the user has granted access to the site 
     * @param user The user
     * @param siteName The site name
     * @return <code>true</code> if the user can access to the site
     */
    public boolean isGrantedSite (UserIdentity user, String siteName)
    {
        Object oldValue = null;
        
        Request request = _getRequest();
        try
        {
            oldValue = request.getAttribute("siteName");
            request.setAttribute("siteName", siteName); // Setting temporarily this attribute to check user rights on any object on this site
            return !_rightManager.getUserRights(user, "/cms").isEmpty();
        }
        finally
        {
            request.setAttribute("siteName", oldValue);
        }
    }
    
    /**
     * Returns the root for sites.
     * @return the root for sites.
     */
    public ModifiableTraversableAmetysObject getRoot()
    {
        return _resolver.resolveByPath(ROOT_SITES_PATH);
    }
    
    /**
     * Returns the root sites.
     * @return the root sites.
     */
    public AmetysObjectIterable<Site> getRootSites()
    {
        TraversableAmetysObject root = _resolver.resolveByPath(ROOT_SITES_PATH);
        return root.getChildren();
    }
    
    /**
     * Returns the all sites.
     * @return the all sites.
     */
    public AmetysObjectIterable<Site> getSites()
    {
        String jcrQuery = "//element(*, ametys:site)";
        return _resolver.query(jcrQuery);
    }
    
    /**
     * Creates a site with the given name.
     * @param siteName the site name.
     * @param parentId the id of the parent site. Can be null.
     * @return the newly created {@link Site}.
     * @throws RepositoryIntegrityViolationException if the named site already exists.
     */
    public Site createSite(String siteName, String parentId) throws RepositoryIntegrityViolationException
    {
        ModifiableTraversableAmetysObject root = null;
        if (parentId != null)
        {
            Site site = _resolver.resolveById(parentId);
            if (!site.hasChild(ROOT_SITES))
            {
                site.createChild(ROOT_SITES, "ametys:sites");
            }
            root = site.getChild(ROOT_SITES);
        }
        else
        {
            root = _resolver.resolveByPath(ROOT_SITES_PATH);
        }
        
        Site site = (Site) root.createChild(siteName, "ametys:site");
        try
        {
            String sitePath = site.getNode().getPath();
            
            // Create the resource explorer root.
            site.getNode().addNode(RepositoryConstants.NAMESPACE_PREFIX_INTERNAL + ":resources", "ametys:resources-collection");

            Session session = _adminSessionProvider.getAdminSession();
            ObservationManager manager = session.getWorkspace().getObservationManager();
            
            manager.addEventListener(new LiveWorkspaceListener(_repository, _synchronizeComponent, getLogger()), 
                                     Event.NODE_ADDED
                                     | Event.NODE_REMOVED
                                     | Event.NODE_MOVED
                                     | Event.PROPERTY_ADDED
                                     | Event.PROPERTY_CHANGED
                                     | Event.PROPERTY_REMOVED, 
                                     sitePath + "/ametys-internal:plugins", true, null, null, false);
            
            manager.addEventListener(new LiveWorkspaceListener(_repository, _synchronizeComponent, getLogger()), 
                                     Event.NODE_ADDED
                                     | Event.NODE_REMOVED
                                     | Event.NODE_MOVED
                                     | Event.PROPERTY_ADDED
                                     | Event.PROPERTY_CHANGED
                                     | Event.PROPERTY_REMOVED, 
                                     sitePath + "/ametys-internal:resources", true, null, null, false);
        }
        catch (RepositoryException ex)
        {
            throw new AmetysRepositoryException(ex);
        }
        
        return site;
    }
    
    /**
     * Creates a site with the given name.
     * @param siteName the site name.
     * @return the newly created {@link Site}.
     * @throws RepositoryIntegrityViolationException if the named site already exists.
     */
    public Site createSite(String siteName) throws RepositoryIntegrityViolationException
    {
        return createSite (siteName, null);
    }
    
    /**
     * Creates a site with the given name, from another site to copy 
     * @param site the site to be copied
     * @param siteName the site name
     * @return the newly created {@link Site}.
     * @throws RepositoryIntegrityViolationException if the named site already exists.
     */
    public Site copySite(Site site, String siteName) throws RepositoryIntegrityViolationException
    {
        return copySite(site, null, siteName);
    }
    
    /**
     * Creates a site with the given name, from another site to copy 
     * @param site the site to be copied
     * @param parentId the id of the parent site. Can be null.
     * @param siteName the site name
     * @return the newly created {@link Site}.
     * @throws RepositoryIntegrityViolationException if the named site already exists.
     */
    public Site copySite(Site site, String parentId, String siteName) throws RepositoryIntegrityViolationException
    {
        ModifiableTraversableAmetysObject root = null;
        if (parentId != null)
        {
            root = _resolver.resolveById(parentId);
        }
        else
        {
            root = _resolver.resolveByPath(ROOT_SITES_PATH);
        }
        
        Site cSite = site.copyTo(root, siteName);
        
        // Clear url and title
        cSite.removeValue("url");
        cSite.removeValue("title");
        
        // Change reference to ametys object, re-init contents workflow, update site name, ...
        _copySiteComponent.updateSiteAfterCopy(site, cSite);
        
        return cSite;
        
    }
    
    
    /**
     * Returns true if the given site exists.
     * @param siteName the site name.
     * @return true if the given site exists.
     */
    public boolean hasSite(String siteName)
    {
        if (siteName == null)
        {
            return false;
        }
        
        Request request = _getRequest();
        if (request == null)
        {
            // There is no request to store cache
            return _hasSite(siteName);
        }
        
        @SuppressWarnings("unchecked")
        Map<String, Site> sitesCache = (Map<String, Site>) request.getAttribute(SITES_KEY);
        if (sitesCache == null)
        {
            sitesCache = new HashMap<>();
            request.setAttribute(SITES_KEY, sitesCache);
        }
        
        // The site key in the cache is of the form "site/workspace".
        String siteKey = siteName + "/" + _workspaceSelector.getWorkspace();
        
        Site site = sitesCache.get(siteKey);
        if (site != null)
        {
            // Site is in cache
            return true;
        }
        
        site = _getSite(siteName);
        if (site != null)
        {
            // Store site in cache
            sitesCache.put(siteKey, site);
            return true;
        }
        
        return false;
    }
    
    private boolean _hasSite (String siteName)
    {
        String jcrQuery = "//element(" + siteName + ", ametys:site)";
        AmetysObjectIterable<Site> sites = _resolver.query(jcrQuery);
        
        return sites.iterator().hasNext();
    }
    
    /**
     * Returns the named {@link Site}.
     * @param siteName the site name.
     * @return the named {@link Site}.
     * @throws UnknownAmetysObjectException if the named site does not exist.
     */
    public Site getSite(String siteName) throws UnknownAmetysObjectException
    {
        Request request = _getRequest();
        if (request == null)
        {
            // There is no request to store cache
            return _getSite(siteName);
        }
        
        @SuppressWarnings("unchecked")
        Map<String, Site> sitesCache = (Map<String, Site>) request.getAttribute(SITES_KEY);
        if (sitesCache == null)
        {
            sitesCache = new HashMap<>();
            request.setAttribute(SITES_KEY, sitesCache);
        }
        
        // The site key in the cache is of the form "site/workspace".
        String siteKey = siteName + "/" + _workspaceSelector.getWorkspace();
        
        Site site = sitesCache.get(siteKey);
        if (site == null)
        {
            site = _getSite(siteName);
            if (site != null)
            {
                // Store site in cache
                sitesCache.put(siteKey, site);
            }
        }
        
        return site;
    }
    
    /**
     * Clear the site cache
     */
    public void clearCache ()
    {
        Request request = _getRequest();
        request.setAttribute(SITES_KEY, null);
    }
    
    private Site _getSite (String siteName) throws UnknownAmetysObjectException
    {
        String jcrQuery = "//element(" + siteName + ", ametys:site)";
        AmetysObjectIterable<Site> sites = _resolver.query(jcrQuery);
        Iterator<Site> it = sites.iterator();
        
        if (it.hasNext())
        {
            return it.next();
        }
        
        return null;
    }
}