package net.mono_koubou.sample;

import java.io.IOException;

import org.apache.lucene.analysis.Analyzer;
import org.apache.lucene.analysis.cjk.CJKAnalyzer;
import org.apache.lucene.document.Document;
import org.apache.lucene.document.Field;
import org.apache.lucene.document.Field.Index;
import org.apache.lucene.document.Field.Store;
import org.apache.lucene.index.IndexReader;
import org.apache.lucene.index.IndexWriter;
import org.apache.lucene.index.Term;
import org.apache.lucene.search.FieldCache;
import org.apache.lucene.search.Hits;
import org.apache.lucene.search.IndexSearcher;
import org.apache.lucene.search.Query;
import org.apache.lucene.search.Searcher;
import org.apache.lucene.search.TermQuery;
import org.apache.lucene.search.function.CustomScoreQuery;
import org.apache.lucene.search.function.DocValues;
import org.apache.lucene.search.function.FloatFieldSource;
import org.apache.lucene.search.function.ValueSourceQuery;
import org.apache.lucene.store.Directory;
import org.apache.lucene.store.RAMDirectory;

/**
 * ValueSourceQueryのサンプルソース
 * 
 * library
 * 	lucene-core.jar
 * 	lucene-ja.jar
 * 	sen.jar
 * 	log4j.jar
 * 	commons-logging.jar
 * 
 */
public class ValueSourceQuerySample {

	public static void main(String[] args) throws Exception {
		ValueSourceQuerySample sample = new ValueSourceQuerySample();
		sample.makeIndex();
		sample.execute("すし",5,5,5);
	}

	
	private static final String[][] VALUES__ = {
									{"すし","1,7"},
									{"ラーメン","2,2"},
									{"すし","3,4"},
									{"ラーメン","4,7"},
									{"すし","5,2"},
									{"ラーメン","7,7"},
									{"ラーメン","8,3"},
									{"すし","9,1"},
									{"すし","9,5"},
									{"ラーメン","9,9"}};
	private static final String F_VALUE = "value";
	private static final String F_POS = "pos";
	
	private Analyzer analyzer_ = new CJKAnalyzer();
	private Directory dir_ = new RAMDirectory();

	/**
	 * INDEX作成
	 * @throws Exception
	 */
	public void makeIndex() throws Exception{
		IndexWriter writer = new IndexWriter( dir_, analyzer_ );
		try{
			for(int i=0;i<VALUES__.length;i++){
				Document doc = new Document();
				doc.add( new Field( F_VALUE, VALUES__[i][0], Store.YES, Index.UN_TOKENIZED ) );
				doc.add( new Field( F_POS, VALUES__[i][1], Store.YES, Index.UN_TOKENIZED ) );
				writer.addDocument( doc );
			}
		}finally{
			writer.close();
		}
	}
	
	/**
	 * 検索の実行
	 * @param value
	 * @param x
	 * @param y
	 * @param distance
	 * @throws Exception
	 */
	public void execute(String value,int x,int y,int distance) throws Exception{
		IndexSearcher searcher = new IndexSearcher( dir_ );
		try{
			_search(searcher,value,x,y,distance);
		}finally{
			searcher.close();
		}
	}

	private void _search(Searcher searcher,String value,int x,int y,int distance) throws Exception{
		
		Query tq = new TermQuery(new Term(F_VALUE,value));
		DistanceFunction func = new DistanceFunction(F_POS,x,y,distance);
		ValueSourceQuery vq = new ValueSourceQuery(func);
		Query query = new DistanceCustomScoreQuery(tq,vq);
//		System.out.println(query);
		Hits hits = searcher.search( query );
		
		int count = hits.length();
		for( int i = 0; i < count; i++ ){
			Document doc = hits.doc( i );
			float score = hits.score( i );
			System.out.println( score + " : " + doc.get( F_VALUE )+" / "+ doc.get( F_POS ));
//			Explanation exp = searcher.explain( query, id );
//			System.out.println( exp.toString() );
		}
	}

	/**
	 * CustomScoreQueryの動作確認用クラス
	 */
	public class DistanceCustomScoreQuery extends CustomScoreQuery {

		private static final long serialVersionUID = 1L;

		public DistanceCustomScoreQuery(Query arg0, ValueSourceQuery arg1) {
			super(arg0, arg1);
		}

		public DistanceCustomScoreQuery(Query arg0, ValueSourceQuery[] arg1) {
			super(arg0, arg1);
		}

		public DistanceCustomScoreQuery(Query arg0) {
			super(arg0);
		}

		@Override
		public float customScore(int doc, float subQueryScore, float valSrcScore) {
			// result = arg0 * arg1;
//			float result = super.customScore(doc, subQueryScore, valSrcScore);
//			System.out.println("doc:"+arg0+" / subQueryScore:"+arg1+" / valSrcScore:"+arg2 + " / result:"+result);
			return valSrcScore;
		}
		
		
	}

	/**
	 * 2点間の距離を求めるFunction
	 */
	public class DistanceFunction extends FloatFieldSource {
		
		private static final long serialVersionUID = 899237622894172602L;

		private final int x_;
		private final int y_;
		private final int d_;
		
		public DistanceFunction(String field,int x,int y,int d) {
			super(field);
			x_ = x;
			y_ = y;
			d_ = d;
		}
		public DocValues getCachedFieldValues (FieldCache cache, String field, IndexReader reader) throws IOException {
			String[] values = cache.getStrings(reader, field);
		    return new DistanceDocValues(values,d_,x_,y_);
		}

		/**
		 * 2点間の距離を求めるDocValues
		 */
		public class DistanceDocValues extends DocValues{
			private final String[] values_;
			private final int x_;
			private final int y_;
			private final int d_;
			public DistanceDocValues(String[] values,int d,int x,int y){
				super();
				values_ = values;
				x_ = x;
				y_ = y;
				d_ = d;
			}

			@Override
			public float floatVal(int doc) {
				float distance = 0f;
				try{
					String value = values_[doc];
					int px = Integer.parseInt(value.split(",")[0]);
					int py = Integer.parseInt(value.split(",")[1]);
					distance = (float)(Math.sqrt(Math.pow((px-x_),2)+Math.pow((py-y_),2)));
					distance = (float)d_ - distance;
					distance = distance>0f?distance:0f;
				}catch(Exception ex){
					ex.printStackTrace();
				}
				return distance;
			}

			@Override
			public String toString(int doc) {
				return super.toString();
			}
			
		}
		
	}
}