//Dstl (c) Crown Copyright 2017
package uk.gov.dstl.baleen.annotators.cleaners;

import java.util.List;

import org.apache.uima.analysis_engine.AnalysisEngineProcessException;
import org.apache.uima.fit.util.JCasUtil;
import org.apache.uima.jcas.JCas;

import com.google.common.collect.ImmutableSet;

import uk.gov.dstl.baleen.core.pipelines.orderers.AnalysisEngineAction;
import uk.gov.dstl.baleen.types.semantic.Location;
import uk.gov.dstl.baleen.uima.BaleenAnnotator;

/**
 * Tries to find instances where a single location may have been split into
 * several entities, and collapse them into a single entity.
 * 
 * Examples are:
 * <ul>
 * <li>The Iraq-Syria border</li>
 * <li>The city of Mosul</li>
 * </ul>
 */
public class CollapseLocations extends BaleenAnnotator{

	private static final String BORDER = "border";
	
	@Override
	protected void doProcess(JCas jCas) throws AnalysisEngineProcessException {
		collapseBorders(jCas);
		collapseOf(jCas);
	}
	
	private void collapseBorders(JCas jCas){
		for(Location l1 : JCasUtil.select(jCas, Location.class)){
			List<Location> followingLocs = JCasUtil.selectFollowing(jCas, Location.class, l1, 1);
			
			if(!followingLocs.isEmpty())
				checkBorders(jCas, l1, followingLocs.get(0));
		}
	}
	
	private void checkBorders(JCas jCas, Location l1, Location l2){
		String betweenText = jCas.getDocumentText().substring(l1.getEnd(), l2.getBegin());
		String followingText = jCas.getDocumentText().substring(l2.getEnd()).toLowerCase();
		if("-".equals(betweenText.trim())){
			Location l;
			if(l2.getCoveredText().toLowerCase().endsWith(BORDER)){
				l = new Location(jCas, l1.getBegin(), l2.getEnd());
			}else if(followingText.trim().startsWith(BORDER)){
				l = new Location(jCas, l1.getBegin(), l2.getEnd() + followingText.indexOf(BORDER) + BORDER.length());
			}else{
				return;
			}
			
			mergeWithNew(l, l1, l2);
		}
	}
	
	private void collapseOf(JCas jCas){
		for(Location l1 : JCasUtil.select(jCas, Location.class)){
			List<Location> followingLocs = JCasUtil.selectFollowing(jCas, Location.class, l1, 1);
			
			if(followingLocs.isEmpty())
				continue;
			
			Location l2 = followingLocs.get(0);
			
			String betweenText = jCas.getDocumentText().substring(l1.getEnd(), l2.getBegin());
			if("of".equals(betweenText.trim())){
				l2.setBegin(l1.getBegin());
				l2.setValue(l2.getCoveredText());
				mergeWithExisting(l2, l1);
			}
		}
	}

	@Override
	public AnalysisEngineAction getAction() {
		return new AnalysisEngineAction(ImmutableSet.of(Location.class), ImmutableSet.of(Location.class));
	}

}