/*
 *  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.ArrayList;
import java.util.Collection;
import java.util.Collections;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.NoSuchElementException;
import java.util.Map.Entry;
import java.util.Objects;
import java.util.Optional;
import java.util.Set;
import java.util.stream.Collectors;

import org.ametys.cms.FilterNameHelper;
import org.ametys.odf.program.Program;
import org.ametys.plugins.explorer.resources.ResourceCollection;
import org.ametys.plugins.repository.AmetysObject;
import org.ametys.plugins.repository.AmetysObjectIterable;
import org.ametys.plugins.repository.AmetysObjectIterator;
import org.ametys.plugins.repository.AmetysRepositoryException;
import org.ametys.plugins.repository.CollectionIterable;
import org.ametys.plugins.repository.UnknownAmetysObjectException;
import org.ametys.plugins.repository.metadata.CompositeMetadata;
import org.ametys.web.repository.page.Page;
import org.ametys.web.repository.page.UnknownZoneException;
import org.ametys.web.repository.page.Zone;
import org.ametys.web.repository.site.Site;
import org.ametys.web.repository.sitemap.Sitemap;

/**
 * Page representing a first-level page.
 */
public class FirstLevelPage implements Page
{
    private FirstLevelPageFactory _factory;
    
    private Page _root;
    private String _name;
    private String _title;
    private OdfPageHandler _odfPageHandler;
    
    /**
     * Constructor.
     * @param factory the corresponding factory
     * @param root the odf root page.
     * @param name the page's name.
     * @param title the page's title.
     * @param odfPageHandler the ODF page handler.
     */
    public FirstLevelPage(FirstLevelPageFactory factory, Page root, String name, String title, OdfPageHandler odfPageHandler)
    {
        _factory = factory;
        _root = root;
        _name = name;
        _title = title;
        _odfPageHandler = odfPageHandler;
    }
    
    @Override
    public int getDepth() throws AmetysRepositoryException
    {
        return _root.getDepth() + 1;
    }

    @Override
    public Set<String> getReferers() throws AmetysRepositoryException
    {
        return null;
    }

    @Override
    public ResourceCollection getRootAttachments() throws AmetysRepositoryException
    {
        return null;
    }

    @Override
    public String getTemplate() throws AmetysRepositoryException
    {
        // TODO
        return "program-list";
    }

    @Override
    public String getTitle() throws AmetysRepositoryException
    {
        return _title;
    }
    
    @Override
    public String getLongTitle() throws AmetysRepositoryException
    {
        return _title;
    }

    @Override
    public PageType getType() throws AmetysRepositoryException
    {
        return PageType.CONTAINER;
    }

    @Override
    public String getURL() throws AmetysRepositoryException
    {
        throw new UnsupportedOperationException("getURL not supported on virtual odf pages");
    }

    @Override
    public LinkType getURLType() throws AmetysRepositoryException
    {
        throw new UnsupportedOperationException("getURLType not supported on virtual odf pages");
    }

    @Override
    public Zone getZone(String name) throws UnknownZoneException, AmetysRepositoryException
    {
        if (!"default".equals(name))
        {
            throw new IllegalArgumentException("Only the zone named 'default' is actually supported on virtual program pages.");
        }
        
        return new FirstLevelZone(this);
    }

    @Override
    public AmetysObjectIterable< ? extends Zone> getZones() throws AmetysRepositoryException
    {
        ArrayList<Zone> zones = new ArrayList<>();
        zones.add(new FirstLevelZone(this));
        return new CollectionIterable<>(zones);
    }

    @Override
    public boolean hasZone(String name) throws AmetysRepositoryException
    {
        return "default".equals(name);
    }
    
    @Override
    public AmetysObjectIterable<? extends Page> getChildrenPages() throws AmetysRepositoryException
    {
        Map<String, String> secondLevelValues = _odfPageHandler.getLevel2Values(_root);
        Map<String, Collection<Program>> secondLevelCache = Optional.ofNullable(_factory.getODFPageCache().getProgramCache(_root, true).get(_name)).orElseGet(HashMap::new);
        
        List<Page> children = secondLevelCache.keySet().stream()
            .map(secondLevelCode -> _findSecondLevelValueEntry(secondLevelValues, secondLevelCode).orElse(null))
            .filter(Objects::nonNull)
            .map(entry -> _toSecondLevelPage(entry))
            .collect(Collectors.toList());
            
        return new CollectionIterable<>(children); 
    }
    
    private Optional<Entry<String, String>> _findSecondLevelValueEntry(String levelCode)
    {
        Map<String, String> secondLevelValues = _odfPageHandler.getLevel2Values(_root);
        return _findSecondLevelValueEntry(secondLevelValues, levelCode);
    }
    
    private Optional<Entry<String, String>> _findSecondLevelValueEntry(Map<String, String> secondLevelValues, String levelCode)
    {
        return secondLevelValues.entrySet().stream()
             // entry = (code, title)
            .filter(entry -> entry.getKey().equals(levelCode))
            .findFirst();
    }
    
    private SecondLevelPage _toSecondLevelPage(Map.Entry<String, String> secondLevelValueEntry)
    {
        String childName = secondLevelValueEntry.getKey();
        String title = secondLevelValueEntry.getValue();
        
        return new SecondLevelPage(_factory.getResolver(), _factory.getODFPageCache(), _root, _name, childName, title, _odfPageHandler, this);
    }
    
    @Override
    public String getPathInSitemap() throws AmetysRepositoryException
    {
        return _root.getPathInSitemap() + "/" + getName();
    }

    @Override
    public Site getSite() throws AmetysRepositoryException
    {
        return _root.getSite();
    }

    @Override
    public String getSiteName() throws AmetysRepositoryException
    {
        return _root.getSiteName();
    }

    @Override
    public Sitemap getSitemap() throws AmetysRepositoryException
    {
        return _root.getSitemap();
    }

    @Override
    public String getSitemapName() throws AmetysRepositoryException
    {
        return _root.getSitemapName();
    }

    @SuppressWarnings("unchecked")
    @Override
    public <A extends AmetysObject> A getChild(String path) throws AmetysRepositoryException, UnknownAmetysObjectException
    {
        if (path.isEmpty())
        {
            throw new AmetysRepositoryException("path must be non empty");
        }
        
        int i = path.indexOf('/');
        
        String name = i == -1 ? path : path.substring(0, path.indexOf('/'));
        
        int index = name.lastIndexOf("-");
        String level2Code = index != -1 ? _odfPageHandler.decodeLevelValue(name.substring(index + 1)) : _odfPageHandler.decodeLevelValue(name);
        
        Page level2Page = _findSecondLevelValueEntry(level2Code)
                .map(this::_toSecondLevelPage)
                .orElseThrow(() -> 
                    new UnknownAmetysObjectException("There's no virtual child page at path " + path + " for page " + _name));
        
        if (i == -1)
        {
            return (A) level2Page;
        }
        else
        {
            return (A) level2Page.getChild(path.substring(i + 1));
        }
    }
    
    @SuppressWarnings("unchecked")
    @Override
    public AmetysObjectIterable<? extends Page> getChildren() throws AmetysRepositoryException
    {
        return getChildrenPages();
    }

    @Override
    public boolean hasChild(String childName) 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> secondLevelValues = _odfPageHandler.getLevel2Values(_root);
        return secondLevelValues.containsKey(childName);
    }
    
    @Override
    public String getId() throws AmetysRepositoryException
    {
        // E.g: odfLevel1://XA?rootId=...
        return "odfLevel1://" + _odfPageHandler.encodeLevelValue(_name) + "?rootId=" + _root.getId();
    }

    @Override
    public String getName() throws AmetysRepositoryException
    {
        // E.g: licence-lmd-XA
        return FilterNameHelper.filterName(_title) + "-" + _odfPageHandler.encodeLevelValue(_name);
    }
    
    @SuppressWarnings("unchecked")
    @Override
    public Page getParent() throws AmetysRepositoryException
    {
        return _root;
    }

    @Override
    public String getParentPath() throws AmetysRepositoryException
    {
        return _root.getPath();
    }

    @Override
    public String getPath() throws AmetysRepositoryException
    {
        return getParentPath() + "/" + getName();
    }

    @Override
    public CompositeMetadata getMetadataHolder()
    {
        return new StaticCompositeMetadata();
    }

    @Override
    public Set<String> getTags() throws AmetysRepositoryException
    {
        return Collections.emptySet();
    }
    
    @Override
    public boolean isVisible() throws AmetysRepositoryException
    {
        return true;
    }

    @Override
    public AmetysObjectIterable< ? extends Page> getChildrenPages(boolean includeInvisiblePages) throws AmetysRepositoryException
    {
        return getChildrenPages();
    }
    
    @Override
    public Page getChildPageAt(int index) throws UnknownAmetysObjectException, AmetysRepositoryException
    {
        if (index < 0)
        {
            throw new AmetysRepositoryException("Child page index cannot be negative");
        }
        
        AmetysObjectIterator<? extends Page> childPages = getChildrenPages().iterator();
        
        try
        {
            childPages.skip(index);
            return childPages.next();
        }
        catch (NoSuchElementException e)
        {
            throw new UnknownAmetysObjectException("There's no child page at index " + index + " for page " + this.getId());
        }
    }
}