/*
 *  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.plugins.odfweb.repository;

import java.util.Collection;
import java.util.List;
import java.util.Map;
import java.util.Map.Entry;
import java.util.Objects;
import java.util.Optional;
import java.util.stream.Collectors;

import org.apache.avalon.framework.service.ServiceException;
import org.apache.avalon.framework.service.ServiceManager;
import org.apache.avalon.framework.service.Serviceable;
import org.apache.commons.lang3.StringUtils;

import org.ametys.odf.program.Program;
import org.ametys.plugins.repository.AmetysObjectFactory;
import org.ametys.plugins.repository.AmetysObjectIterable;
import org.ametys.plugins.repository.AmetysObjectResolver;
import org.ametys.plugins.repository.AmetysRepositoryException;
import org.ametys.plugins.repository.CollectionIterable;
import org.ametys.plugins.repository.UnknownAmetysObjectException;
import org.ametys.plugins.repository.jcr.JCRAmetysObject;
import org.ametys.plugins.repository.virtual.VirtualAmetysObjectFactory;
import org.ametys.runtime.plugin.component.AbstractLogEnabled;
import org.ametys.web.repository.page.Page;

/**
 * {@link AmetysObjectFactory} handling {@link FirstLevelPage}.
 * This factory is referenced by an ODF root page.
 */
public class FirstLevelPageFactory extends AbstractLogEnabled implements VirtualAmetysObjectFactory<Page>, Serviceable
{
    private AmetysObjectResolver _resolver;
    private OdfPageHandler _odfPageHandler;
    private ODFPageCache _pageCache;
    
    @Override
    public void service(ServiceManager manager) throws ServiceException
    {
        _resolver = (AmetysObjectResolver) manager.lookup(AmetysObjectResolver.ROLE);
        _odfPageHandler = (OdfPageHandler) manager.lookup(OdfPageHandler.ROLE);
        _pageCache = (ODFPageCache) manager.lookup(ODFPageCache.ROLE);
    }
    
    @Override
    public String getScheme()
    {
        return "odfLevel1";
    }
    
    @Override
    public Page getAmetysObjectById(String id) throws AmetysRepositoryException
    {
        // E.g: odfLevel1://XA?rootId=xxx
        String childName = _extractChildName(id);
        Page rootPage = _extractRoot(id);
        
        return _findFirstLevelValueEntry(rootPage, childName)
            .map(entry -> _toFirstLevelPage(rootPage, entry))
            .orElseThrow(() -> 
                new UnknownAmetysObjectException("There's no virtual child page named " + childName + " for parent " + rootPage));
    }
    
    private Page _extractRoot(String id)
    {
        String rootId = StringUtils.substringAfter(id, "?rootId=");
        return _resolver.resolveById(rootId);
    }
    
    private String _extractChildName(String id)
    {
        String rawChildName = StringUtils.substringBetween(id, "://", "?");
        return _odfPageHandler.decodeLevelValue(rawChildName);
    }
    
    private Optional<Entry<String, String>> _findFirstLevelValueEntry(Page rootPage, String levelCode)
    {
        Map<String, String> firstLevelValues = _odfPageHandler.getLevel1Values(rootPage);
        return _findFirstLevelValueEntry(firstLevelValues, levelCode);
    }
    
    private Optional<Entry<String, String>> _findFirstLevelValueEntry(Map<String, String> firstLevelValues, String levelCode)
    {
        return firstLevelValues.entrySet().stream()
             // entry = (code, title)
            .filter(entry -> entry.getKey().equals(levelCode))
            .findFirst();
    }
    
    private FirstLevelPage _toFirstLevelPage(Page rootPage, Map.Entry<String, String> firstLevelValueEntry)
    {
        String childName = firstLevelValueEntry.getKey();
        String title = firstLevelValueEntry.getValue();
        return new FirstLevelPage(this, rootPage, childName, title, _odfPageHandler);
    }
    
    @Override
    public boolean hasAmetysObjectForId(String id) throws AmetysRepositoryException
    {
        // E.g: odfLevel1://XA?rootId=xxx
        String childName = _extractChildName(id);
        Page rootPage = _extractRoot(id);
        
        return _hasFirstLevelValue(rootPage, childName);
    }
    
    @Override
    public Page getChild(JCRAmetysObject parent, String childName)
    {
        if (!(parent instanceof Page))
        {
            throw new IllegalArgumentException("The holder of the ODF virtual pages should be a page.");
        }
        
        Page rootPage = (Page) parent;
        Map<String, String> firstLevelValues = _odfPageHandler.getLevel1Values(rootPage);
        
        // E.g: licence-lmd-XA
        
        int i = childName.lastIndexOf("-");
        String code = i != -1 ? _odfPageHandler.decodeLevelValue(childName.substring(i + 1)) : _odfPageHandler.decodeLevelValue(childName); // extract first level code
        String title = firstLevelValues.get(code);
        
        if (title != null)
        {
            return new FirstLevelPage(this, rootPage, code, title, _odfPageHandler);
        }
        
        throw new UnknownAmetysObjectException("There's no virtual child page named " + childName + " for parent " + parent);
    }
    
    @Override
    public AmetysObjectIterable<Page> getChildren(JCRAmetysObject parent)
    {
        if (!(parent instanceof Page))
        {
            throw new IllegalArgumentException("The holder of the ODF virtual pages should be a page.");
        }
        
        Page rootPage = (Page) parent;
        Map<String, String> firstLevelValues = _odfPageHandler.getLevel1Values(rootPage);
        Map<String, Map<String, Collection<Program>>> firstLevelCache = _pageCache.getProgramCache(rootPage, true);
        
        List<Page> children = firstLevelCache.keySet().stream()
            .map(firstLevelCode -> _findFirstLevelValueEntry(firstLevelValues, firstLevelCode).orElse(null))
            .filter(Objects::nonNull)
            .map(entry -> _toFirstLevelPage(rootPage, entry))
            .collect(Collectors.toList());

        return new CollectionIterable<>(children);
    }

    @Override
    public boolean hasChild(JCRAmetysObject parent, String childName)
    {
        if (!(parent instanceof Page))
        {
            throw new IllegalArgumentException("The holder of the ODF virtual pages should be a page.");
        }
        
        Page rootPage = (Page) parent;
        return _hasFirstLevelValue(rootPage, childName);
    }
    
    private boolean _hasFirstLevelValue(Page rootPage, String level1Code) throws AmetysRepositoryException
    {
        // FIXME should use page cache, because can return true when page does
        // not exist. Maybe done like this for performance reasons?
        Map<String, String> firstLevelValues = _odfPageHandler.getLevel1Values(rootPage);
        return firstLevelValues.containsKey(level1Code);
    }
    
    AmetysObjectResolver getResolver()
    {
        return _resolver;
    }
    
    ODFPageCache getODFPageCache()
    {
        return _pageCache;
    }
}