/**
 * The contents of this file are subject to the license and copyright
 * detailed in the LICENSE and NOTICE files at the root of the source
 * tree and available online at
 *
 * http://www.dspace.org/license/
 */
package org.dspace.sword2;


import org.apache.abdera.Abdera;
import org.apache.abdera.i18n.iri.IRI;
import org.apache.abdera.model.Entry;
import org.apache.abdera.model.Feed;
import org.dspace.content.Collection;
import org.dspace.content.DCValue;
import org.dspace.content.Item;
import org.dspace.content.ItemIterator;
import org.dspace.content.WorkspaceItem;
import org.dspace.core.ConfigurationManager;
import org.dspace.core.Context;
import org.dspace.eperson.EPerson;
import org.dspace.workflow.WorkflowItem;
import org.swordapp.server.AuthCredentials;
import org.swordapp.server.CollectionListManager;
import org.swordapp.server.SwordAuthException;
import org.swordapp.server.SwordConfiguration;
import org.swordapp.server.SwordError;
import org.swordapp.server.SwordServerException;

import java.sql.SQLException;
import java.util.ArrayList;
import java.util.List;

public class CollectionListManagerDSpace extends DSpaceSwordAPI implements CollectionListManager
{
	public Feed listCollectionContents(IRI colIRI, AuthCredentials authCredentials, SwordConfiguration swordConfig)
			throws SwordServerException, SwordError, SwordAuthException
	{
		SwordContext sc = null;
		try
		{
			SwordConfigurationDSpace config = (SwordConfigurationDSpace) swordConfig;
			sc = this.doAuth(authCredentials);
			Context context = sc.getContext();
			SwordUrlManager urlManager = config.getUrlManager(context, config);

			Collection collection = urlManager.getCollection(context, colIRI.toString());

			List<Item> items = this.listItems(sc, collection, swordConfig);
			Feed feed = this.itemListToFeed(sc, items, swordConfig);
			return feed;
		}
		catch (DSpaceSwordException e)
		{
			throw new SwordServerException(e);
		}
		finally
        {
            // this is a read operation only, so there's never any need to commit the context
            if (sc != null)
            {
                sc.abort();
            }
        }
	}

	private Feed itemListToFeed(SwordContext sc, List<Item> items, SwordConfiguration swordConfig)
			throws DSpaceSwordException
	{
		SwordConfigurationDSpace config = (SwordConfigurationDSpace) swordConfig;
		SwordUrlManager urlManager = config.getUrlManager(sc.getContext(), config);

		Abdera abdera = new Abdera();
        Feed feed = abdera.newFeed();

		for (Item item : items)
		{
			Entry entry = feed.addEntry();
			entry.setId(urlManager.getEditIRI(item).toString());
			String title = this.stringMetadata(item, ConfigurationManager.getProperty("swordv2-server", "title.field"));
			title = title == null? "Untitled" : title;
			entry.setTitle(title);
			entry.addLink(urlManager.getContentUrl(item).toString(), "edit-media");
		}

		return feed;
	}

	private List<Item> listItems(SwordContext sc, Collection collection, SwordConfiguration swordConfig)
			throws DSpaceSwordException
	{
		try
		{
			EPerson person = sc.getOnBehalfOf() != null ? sc.getOnBehalfOf() : sc.getAuthenticated();
			List<Item> collectionItems = new ArrayList<Item>();

			// first get the ones out of the archive
			ItemIterator items = Item.findBySubmitter(sc.getContext(), person);
			while(items.hasNext())
			{
				Item item = items.next();
				Collection[] cols = item.getCollections();
				for (Collection col : cols)
				{
					if (col.getID() == collection.getID())
					{
						collectionItems.add(item);
						break;
					}
				}
			}

			// now get the ones out of the workspace
			WorkspaceItem[] wsis = WorkspaceItem.findByEPerson(sc.getContext(), person);
			for (WorkspaceItem wsi : wsis)
			{
                Item item = wsi.getItem();

                // check for the wsi collection
                Collection wsCol = wsi.getCollection();
                if (wsCol.getID() == collection.getID())
                {
                    collectionItems.add(item);
                }

                // then see if there are any additional associated collections
				Collection[] cols = item.getCollections();
				for (Collection col : cols)
				{
					if (col.getID() == collection.getID())
					{
						collectionItems.add(item);
						break;
					}
				}
			}

			// finally get the ones out of the workflow
			WorkflowItem[] wfis = WorkflowItem.findByEPerson(sc.getContext(), person);
			for (WorkflowItem wfi : wfis)
			{
				Item item = wfi.getItem();

                // check for the wfi collection
                Collection wfCol = wfi.getCollection();
                if (wfCol.getID() == collection.getID())
                {
                    collectionItems.add(item);
                }

                // then see if there are any additional associated collections
				Collection[] cols = item.getCollections();
				for (Collection col : cols)
				{
					if (col.getID() == collection.getID())
					{
						collectionItems.add(item);
						break;
					}
				}
			}

			return collectionItems;
		}
		catch (SQLException e)
		{
			throw new DSpaceSwordException(e);
		}
	}

	private String stringMetadata(Item item, String field)
	{
		if (field == null)
		{
			return null;
		}

		DCValue[] dcvs = item.getMetadata(field);
		if (dcvs == null)
		{
			return null;
		}

		StringBuilder md = new StringBuilder();
		for (DCValue dcv : dcvs)
		{
			if (md.length() > 0)
			{
				md.append(", ");
			}
			md.append(dcv.value);
		}
		return md.toString();
	}
}