/**
 * 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.app.rest.repository;

import java.sql.SQLException;
import java.util.ArrayList;
import java.util.Iterator;
import java.util.List;
import javax.servlet.http.HttpServletRequest;

import org.apache.commons.lang3.StringUtils;
import org.dspace.app.rest.model.BrowseIndexRest;
import org.dspace.app.rest.model.ItemRest;
import org.dspace.app.rest.projection.Projection;
import org.dspace.app.rest.utils.ScopeResolver;
import org.dspace.browse.BrowseEngine;
import org.dspace.browse.BrowseException;
import org.dspace.browse.BrowseIndex;
import org.dspace.browse.BrowseInfo;
import org.dspace.browse.BrowserScope;
import org.dspace.content.Item;
import org.dspace.core.Context;
import org.dspace.discovery.IndexableObject;
import org.dspace.sort.SortException;
import org.dspace.sort.SortOption;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.data.domain.Page;
import org.springframework.data.domain.PageRequest;
import org.springframework.data.domain.Pageable;
import org.springframework.data.domain.Sort;
import org.springframework.data.domain.Sort.Order;
import org.springframework.stereotype.Component;

/**
 * This is the repository to retrieve the items associated with a specific
 * browse index or entries
 *
 * @author Andrea Bollini (andrea.bollini at 4science.it)
 */
@Component(BrowseIndexRest.CATEGORY + "." + BrowseIndexRest.NAME + "." + BrowseIndexRest.LINK_ITEMS)
public class BrowseItemLinkRepository extends AbstractDSpaceRestRepository
    implements LinkRestRepository {

    @Autowired
    ScopeResolver scopeResolver;

    public Page<ItemRest> listBrowseItems(HttpServletRequest request, String browseName, Pageable pageable,
                                          Projection projection)
        throws BrowseException, SQLException {
        //FIXME these should be bind automatically and available as method arguments
        String scope = null;
        String filterValue = null;
        String filterAuthority = null;
        String startsWith = null;

        if (request != null) {
            scope = request.getParameter("scope");
            filterValue = request.getParameter("filterValue");
            filterAuthority = request.getParameter("filterAuthority");
            startsWith = request.getParameter("startsWith");
        }
        Context context = obtainContext();
        BrowseEngine be = new BrowseEngine(context);
        BrowserScope bs = new BrowserScope(context);

        IndexableObject scopeObj = scopeResolver.resolveScope(context, scope);

        // process the input, performing some inline validation
        BrowseIndex bi = null;
        if (StringUtils.isNotEmpty(browseName)) {
            bi = BrowseIndex.getBrowseIndex(browseName);
        }
        if (bi == null) {
            throw new IllegalArgumentException("Unknown browse index");
        }
        if (!bi.isItemIndex() && (filterAuthority == null && filterValue == null)) {
            throw new IllegalStateException(
                "The requested browse doesn't provide direct access to items you must specify a filter");
        }

        if (!bi.isMetadataIndex() && (filterAuthority != null || filterValue != null)) {
            throw new IllegalStateException("The requested browse doesn't support filtering");
        }

        // set up a BrowseScope and start loading the values into it
        bs.setBrowseIndex(bi);
        Sort sort = null;
        if (pageable != null) {
            sort = pageable.getSort();
        }
        if (sort != null) {
            Iterator<Order> orders = sort.iterator();
            while (orders.hasNext()) {
                Order order = orders.next();
                bs.setOrder(order.getDirection().name());
                String sortBy;
                if (!StringUtils.equals("default", order.getProperty())) {
                    sortBy = order.getProperty();
                } else {
                    sortBy = bi.getDefaultOrder();
                }

                try {
                    SortOption so = SortOption.getSortOption(sortBy);
                    if (so != null) {
                        bs.setSortBy(so.getNumber());
                    }
                } catch (SortException e) {
                    throw new RuntimeException(e.getMessage(), e);
                }
            }
        }

        if (filterValue != null || filterAuthority != null) {
            bs.setFilterValue(filterValue);
            bs.setAuthorityValue(filterAuthority);
            bs.setBrowseLevel(1);
        }
        // bs.setFilterValueLang(valueLang);
        // bs.setJumpToItem(focus);
        // bs.setJumpToValue(valueFocus);
        // bs.setJumpToValueLang(valueFocusLang);
        bs.setStartsWith(startsWith);
        if (pageable != null) {
            bs.setOffset(Math.toIntExact(pageable.getOffset()));
            bs.setResultsPerPage(pageable.getPageSize());
        }

        if (scopeObj != null) {
            bs.setBrowseContainer(scopeObj);
        }

        // For second level browses on metadata indexes, we need to adjust the default sorting
        if (bi.isMetadataIndex() && bs.isSecondLevel() && bs.getSortBy() <= 0) {
            bs.setSortBy(1);
        }

        BrowseInfo binfo = be.browse(bs);

        Pageable pageResultInfo =
                PageRequest.of((binfo.getStart() - 1) / binfo.getResultsPerPage(), binfo.getResultsPerPage());
        List<Item> tmpResult = new ArrayList<>();
        for (Item bb : binfo.getBrowseItemResults()) {
            tmpResult.add(bb);
        }

        return converter.toRestPage(tmpResult, pageResultInfo, binfo.getTotal(), projection);
    }

    @Override
    public boolean isEmbeddableRelation(Object data, String name) {
        BrowseIndexRest bir = (BrowseIndexRest) data;
        if (bir.getBrowseType().equals(BrowseIndexRest.BROWSE_TYPE_FLAT) &&
                name.equals(BrowseIndexRest.LINK_ITEMS)) {
            return true;
        }
        return false;
    }
}
