package com.jeeww.lucene.demo;

/*
 * Licensed to the Apache Software Foundation (ASF) under one or more contributor license agreements. See the NOTICE
 * file distributed with this work for additional information regarding copyright ownership. The ASF licenses this file
 * to You 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.
 */

import java.io.IOException;
import java.util.ArrayList;
import java.util.List;

import org.apache.lucene.analysis.core.WhitespaceAnalyzer;
import org.apache.lucene.document.Document;
import org.apache.lucene.facet.DrillDownQuery;
import org.apache.lucene.facet.FacetResult;
import org.apache.lucene.facet.Facets;
import org.apache.lucene.facet.FacetsCollector;
import org.apache.lucene.facet.FacetsConfig;
import org.apache.lucene.facet.taxonomy.FloatAssociationFacetField;
import org.apache.lucene.facet.taxonomy.IntAssociationFacetField;
import org.apache.lucene.facet.taxonomy.TaxonomyFacetSumFloatAssociations;
import org.apache.lucene.facet.taxonomy.TaxonomyFacetSumIntAssociations;
import org.apache.lucene.facet.taxonomy.TaxonomyReader;
import org.apache.lucene.facet.taxonomy.directory.DirectoryTaxonomyReader;
import org.apache.lucene.facet.taxonomy.directory.DirectoryTaxonomyWriter;
import org.apache.lucene.index.DirectoryReader;
import org.apache.lucene.index.IndexWriter;
import org.apache.lucene.index.IndexWriterConfig;
import org.apache.lucene.search.IndexSearcher;
import org.apache.lucene.search.MatchAllDocsQuery;
import org.apache.lucene.store.Directory;
import org.apache.lucene.store.RAMDirectory;

/** Shows example usage of category associations. */
public class AssociationsFacetsExample {

    private final Directory indexDir = new RAMDirectory();
    private final Directory taxoDir = new RAMDirectory();
    private final FacetsConfig config;

    /** Empty constructor */
    public AssociationsFacetsExample() {
        config = new FacetsConfig();
        config.setMultiValued("tags", true);
        config.setIndexFieldName("tags", "$tags");
        config.setMultiValued("genre", true);
        config.setIndexFieldName("genre", "$genre");
    }

    /** Build the example index. */
    private void index() throws IOException {
        IndexWriterConfig iwc = new IndexWriterConfig(FacetExamples.EXAMPLES_VER, new WhitespaceAnalyzer(
                FacetExamples.EXAMPLES_VER));
        IndexWriter indexWriter = new IndexWriter(indexDir, iwc);

        // Writes facet ords to a separate directory from the main index
        DirectoryTaxonomyWriter taxoWriter = new DirectoryTaxonomyWriter(taxoDir);

        Document doc = new Document();
        // 3 occurrences for tag 'lucene'
        doc.add(new IntAssociationFacetField(3, "tags", "lucene"));
        // 87% confidence level of genre 'computing'
        doc.add(new FloatAssociationFacetField(0.87f, "genre", "computing"));
        indexWriter.addDocument(config.build(taxoWriter, doc));

        doc = new Document();
        // 1 occurrence for tag 'lucene'
        doc.add(new IntAssociationFacetField(1, "tags", "lucene"));
        // 2 occurrence for tag 'solr'
        doc.add(new IntAssociationFacetField(2, "tags", "solr"));
        // 75% confidence level of genre 'computing'
        doc.add(new FloatAssociationFacetField(0.75f, "genre", "computing"));
        // 34% confidence level of genre 'software'
        doc.add(new FloatAssociationFacetField(0.34f, "genre", "software"));
        indexWriter.addDocument(config.build(taxoWriter, doc));

        indexWriter.close();
        taxoWriter.close();
    }

    /** User runs a query and aggregates facets by summing their association values. */
    private List<FacetResult> sumAssociations() throws IOException {
        DirectoryReader indexReader = DirectoryReader.open(indexDir);
        IndexSearcher searcher = new IndexSearcher(indexReader);
        TaxonomyReader taxoReader = new DirectoryTaxonomyReader(taxoDir);

        FacetsCollector fc = new FacetsCollector();

        // MatchAllDocsQuery is for "browsing" (counts facets
        // for all non-deleted docs in the index); normally
        // you'd use a "normal" query:
        FacetsCollector.search(searcher, new MatchAllDocsQuery(), 10, fc);

        Facets tags = new TaxonomyFacetSumIntAssociations("$tags", taxoReader, config, fc);
        Facets genre = new TaxonomyFacetSumFloatAssociations("$genre", taxoReader, config, fc);

        // Retrieve results
        List<FacetResult> results = new ArrayList<FacetResult>();
        results.add(tags.getTopChildren(10, "tags"));
        results.add(genre.getTopChildren(10, "genre"));

        indexReader.close();
        taxoReader.close();

        return results;
    }

    /** User drills down on 'tags/solr'. */
    private FacetResult drillDown() throws IOException {
        DirectoryReader indexReader = DirectoryReader.open(indexDir);
        IndexSearcher searcher = new IndexSearcher(indexReader);
        TaxonomyReader taxoReader = new DirectoryTaxonomyReader(taxoDir);

        // Passing no baseQuery means we drill down on all
        // documents ("browse only"):
        DrillDownQuery q = new DrillDownQuery(config);

        // Now user drills down on Publish Date/2010:
        q.add("tags", "solr");
        FacetsCollector fc = new FacetsCollector();
        FacetsCollector.search(searcher, q, 10, fc);

        // Retrieve results
        Facets facets = new TaxonomyFacetSumFloatAssociations("$genre", taxoReader, config, fc);
        FacetResult result = facets.getTopChildren(10, "genre");

        indexReader.close();
        taxoReader.close();

        return result;
    }

    /** Runs summing association example. */
    public List<FacetResult> runSumAssociations() throws IOException {
        index();
        return sumAssociations();
    }

    /** Runs the drill-down example. */
    public FacetResult runDrillDown() throws IOException {
        index();
        return drillDown();
    }

    /** Runs the sum int/float associations examples and prints the results. */
    public static void main(String[] args) throws Exception {
        System.out.println("Sum associations example:");
        System.out.println("-------------------------");
        List<FacetResult> results = new AssociationsFacetsExample().runSumAssociations();
        System.out.println("tags: " + results.get(0));
        System.out.println("genre: " + results.get(1));
    }
}
