/*
 *  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.cms.content;

import java.io.IOException;
import java.io.InputStream;
import java.io.Serializable;
import java.util.Arrays;
import java.util.Iterator;
import java.util.List;
import java.util.Map;

import org.apache.avalon.framework.parameters.ParameterException;
import org.apache.avalon.framework.parameters.Parameters;
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.ProcessingException;
import org.apache.cocoon.caching.CacheableProcessingComponent;
import org.apache.cocoon.environment.ObjectModelHelper;
import org.apache.cocoon.environment.Request;
import org.apache.cocoon.environment.SourceResolver;
import org.apache.commons.lang.StringUtils;
import org.apache.excalibur.source.SourceValidity;
import org.apache.excalibur.source.impl.validity.TimeStampValidity;

import org.ametys.cms.repository.Content;
import org.ametys.core.util.URIUtils;
import org.ametys.core.util.cocoon.AbstractResourceReader;
import org.ametys.plugins.repository.AmetysObjectResolver;
import org.ametys.plugins.repository.metadata.BinaryMetadata;
import org.ametys.plugins.repository.metadata.CompositeMetadata;
import org.ametys.plugins.repository.metadata.CompositeMetadata.MetadataType;
import org.ametys.plugins.repository.metadata.MetadataAwareAmetysObject;
import org.ametys.plugins.repository.version.VersionableAmetysObject;

/**
 * Reader for binary or file metadata.
 */
public class FileReader extends AbstractResourceReader implements Serviceable, CacheableProcessingComponent
{
    /** The ametys object resolver. */
    protected AmetysObjectResolver _resolver;
    
    private MetadataAwareAmetysObject _ametysObject;
    private BinaryMetadata _binary;
    
    private String _path;
    
    @Override
    public void service(ServiceManager serviceManager) throws ServiceException
    {
        _resolver = (AmetysObjectResolver) serviceManager.lookup(AmetysObjectResolver.ROLE);
    }
    
    @Override
    public void doSetup(SourceResolver res, Map objModel, String src, Parameters par) throws ProcessingException, IOException
    {
        _ametysObject = getAmetysObject();
        
        CompositeMetadata metadata = _ametysObject.getMetadataHolder();
        
        try
        {
            _path = parameters.getParameter("path");
        }
        catch (ParameterException e)
        {
            throw new ProcessingException("The path parameter is mandatory for reading binary metadata.", e);
        }
        
        List<String> pathElements = Arrays.asList(_path.split("/"));
        
        Iterator<String> it = pathElements.iterator();
        
        while (it.hasNext())
        {
            String pathElement = it.next();
            
            if (it.hasNext())
            {
                // not the last segment : it is a composite
                metadata = metadata.getCompositeMetadata(URIUtils.decode(pathElement));
            }
            else
            {
                String metadataName = URIUtils.decode(pathElement);
                if (metadata.getType(metadataName) != MetadataType.BINARY)
                {
                    throw new UnsupportedOperationException("Only binary metadata are allowed");
                }
                
                _binary = metadata.getBinaryMetadata(metadataName);
            }
        }
    }

    /**
     * Get the ametys object.
     * @return the ametys object.
     * @throws ProcessingException if the information provided was insufficient to resolve an object.
     */
    protected MetadataAwareAmetysObject getAmetysObject() throws ProcessingException
    {
        MetadataAwareAmetysObject object = null;
        
        Request request = ObjectModelHelper.getRequest(objectModel);
        String objectPath = parameters.getParameter("objectPath", request.getParameter("objectPath"));
        String objectId = parameters.getParameter("objectId", request.getParameter("objectId"));
        // Legacy parameter name.
        if (StringUtils.isBlank(objectId))
        {
            objectId = parameters.getParameter("contentId", request.getParameter("contentId"));
        }
        
        if (StringUtils.isNotBlank(objectId))
        {
            object = _resolver.resolveById(objectId);
        }
        else if (StringUtils.isNotBlank(objectPath))
        {
            objectPath = objectPath.replaceAll("%3A", ":");
            object = _resolver.resolveByPath(objectPath);
        }
        else
        {
            object = (Content) request.getAttribute(Content.class.getName());
        }
        
        if (object == null)
        {
            throw new ProcessingException("The object ID parameter is mandatory for reading binary metadata.");
        }
        
        String revision = parameters.getParameter("contentVersion", null);
        if (StringUtils.isNotEmpty(revision) && object instanceof VersionableAmetysObject)
        {
            ((VersionableAmetysObject) object).switchToRevision(revision);
        }
        
        return object;
    }
    
    @Override
    protected InputStream getInputStream()
    {
        return _binary.getInputStream();
    }
    
    @Override
    protected String getFilename()
    {
        return _binary.getFilename();
    }
    
    @Override
    protected String getEncodedFilename()
    {
        return null;
    }
    
    @Override
    protected long getLength()
    {
        return _binary.getLength();
    }

    @Override
    public Serializable getKey()
    {
        return _ametysObject.getId() + ";" + _path + getKeySuffix();
    }

    @Override
    public SourceValidity getValidity()
    {
        return new TimeStampValidity(getLastModified());
    }
    
    @Override
    public long getLastModified()
    {
        if (_binary != null)
        {
            return _binary.getLastModified().getTime();
        }
        
        return super.getLastModified();
    }
    
    @Override
    public String getMimeType()
    {
        if (_binary != null)
        {
            return _binary.getMimeType();
        }

        return super.getMimeType();
    }

    @Override
    public void recycle()
    {
        super.recycle();
        
        _binary = null;
        _ametysObject = null;
    }
}