/*******************************************************************************
 * Copyright (c) 2015-2018 Skymind, Inc.
 *
 * This program and the accompanying materials are made available under the
 * terms of the Apache License, Version 2.0 which is available at
 * https://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.
 *
 * SPDX-License-Identifier: Apache-2.0
 ******************************************************************************/

package org.deeplearning4j.models.sequencevectors;

import lombok.Data;
import lombok.Getter;
import lombok.Setter;
import lombok.val;
import org.datavec.api.records.reader.impl.csv.CSVRecordReader;
import org.datavec.api.split.FileSplit;
import org.deeplearning4j.BaseDL4JTest;
import org.nd4j.linalg.io.ClassPathResource;
import org.datavec.api.writable.Writable;
import org.deeplearning4j.models.embeddings.WeightLookupTable;
import org.deeplearning4j.models.embeddings.inmemory.InMemoryLookupTable;
import org.deeplearning4j.models.embeddings.learning.impl.elements.GloVe;
import org.deeplearning4j.models.embeddings.learning.impl.elements.SkipGram;
import org.deeplearning4j.models.embeddings.loader.VectorsConfiguration;
import org.deeplearning4j.models.embeddings.loader.WordVectorSerializer;
import org.deeplearning4j.models.embeddings.reader.impl.FlatModelUtils;
import org.deeplearning4j.models.sequencevectors.graph.enums.NoEdgeHandling;
import org.deeplearning4j.models.sequencevectors.graph.enums.PopularityMode;
import org.deeplearning4j.models.sequencevectors.graph.enums.SpreadSpectrum;
import org.deeplearning4j.models.sequencevectors.graph.enums.WalkDirection;
import org.deeplearning4j.models.sequencevectors.graph.primitives.Graph;
import org.deeplearning4j.models.sequencevectors.graph.primitives.Vertex;
import org.deeplearning4j.models.sequencevectors.graph.walkers.GraphWalker;
import org.deeplearning4j.models.sequencevectors.graph.walkers.impl.PopularityWalker;
import org.deeplearning4j.models.sequencevectors.interfaces.SequenceElementFactory;
import org.deeplearning4j.models.sequencevectors.iterators.AbstractSequenceIterator;
import org.deeplearning4j.models.sequencevectors.sequence.SequenceElement;
import org.deeplearning4j.models.sequencevectors.serialization.AbstractElementFactory;
import org.deeplearning4j.models.sequencevectors.transformers.impl.GraphTransformer;
import org.deeplearning4j.models.sequencevectors.transformers.impl.SentenceTransformer;
import org.deeplearning4j.models.word2vec.VocabWord;
import org.deeplearning4j.models.word2vec.wordstore.VocabConstructor;
import org.deeplearning4j.models.word2vec.wordstore.inmemory.AbstractCache;
import org.deeplearning4j.text.sentenceiterator.BasicLineIterator;
import org.deeplearning4j.text.tokenization.tokenizer.preprocessor.CommonPreprocessor;
import org.deeplearning4j.text.tokenization.tokenizerfactory.DefaultTokenizerFactory;
import org.deeplearning4j.text.tokenization.tokenizerfactory.TokenizerFactory;
import org.junit.Before;
import org.junit.Ignore;
import org.junit.Test;
import org.nd4j.linalg.factory.Nd4j;
import org.nd4j.linalg.heartbeat.Heartbeat;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

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

import static org.junit.Assert.*;

/**
 *
 * @author raver119@gmail.com
 */
@Ignore
public class SequenceVectorsTest extends BaseDL4JTest {

    protected static final Logger logger = LoggerFactory.getLogger(SequenceVectorsTest.class);

    @Before
    public void setUp() throws Exception {

    }

    @Test
    public void testAbstractW2VModel() throws Exception {
        ClassPathResource resource = new ClassPathResource("big/raw_sentences.txt");
        File file = resource.getFile();

        logger.info("dtype: {}", Nd4j.dataType());

        AbstractCache<VocabWord> vocabCache = new AbstractCache.Builder<VocabWord>().build();

        /*
            First we build line iterator
         */
        BasicLineIterator underlyingIterator = new BasicLineIterator(file);


        /*
            Now we need the way to convert lines into Sequences of VocabWords.
            In this example that's SentenceTransformer
         */
        TokenizerFactory t = new DefaultTokenizerFactory();
        t.setTokenPreProcessor(new CommonPreprocessor());

        SentenceTransformer transformer =
                        new SentenceTransformer.Builder().iterator(underlyingIterator).tokenizerFactory(t).build();


        /*
            And we pack that transformer into AbstractSequenceIterator
         */
        AbstractSequenceIterator<VocabWord> sequenceIterator =
                        new AbstractSequenceIterator.Builder<>(transformer).build();


        /*
            Now we should build vocabulary out of sequence iterator.
            We can skip this phase, and just set SequenceVectors.resetModel(TRUE), and vocabulary will be mastered internally
        */
        VocabConstructor<VocabWord> constructor = new VocabConstructor.Builder<VocabWord>()
                        .addSource(sequenceIterator, 5).setTargetVocabCache(vocabCache).build();

        constructor.buildJointVocabulary(false, true);

        assertEquals(242, vocabCache.numWords());

        assertEquals(634303, vocabCache.totalWordOccurrences());

        VocabWord wordz = vocabCache.wordFor("day");

        logger.info("Wordz: " + wordz);

        /*
            Time to build WeightLookupTable instance for our new model
        */

        WeightLookupTable<VocabWord> lookupTable = new InMemoryLookupTable.Builder<VocabWord>().lr(0.025)
                        .vectorLength(150).useAdaGrad(false).cache(vocabCache).build();

        /*
            reset model is viable only if you're setting SequenceVectors.resetModel() to false
            if set to True - it will be called internally
        */
        lookupTable.resetWeights(true);

        /*
            Now we can build SequenceVectors model, that suits our needs
         */
        SequenceVectors<VocabWord> vectors = new SequenceVectors.Builder<VocabWord>(new VectorsConfiguration())
                        // minimum number of occurencies for each element in training corpus. All elements below this value will be ignored
                        // Please note: this value has effect only if resetModel() set to TRUE, for internal model building. Otherwise it'll be ignored, and actual vocabulary content will be used
                        .minWordFrequency(5)

                        // WeightLookupTable
                        .lookupTable(lookupTable)

                        // abstract iterator that covers training corpus
                        .iterate(sequenceIterator)

                        // vocabulary built prior to modelling
                        .vocabCache(vocabCache)

                        // we might want to set layer size here. otherwise it'll be derived from lookupTable
                        //.layerSize(150)

                        // batchSize is the number of sequences being processed by 1 thread at once
                        // this value actually matters if you have iterations > 1
                        .batchSize(250)

                        // number of iterations over batch
                        .iterations(1)

                        // number of iterations over whole training corpus
                        .epochs(1)

                        // if set to true, vocabulary will be built from scratches internally
                        // otherwise externally provided vocab will be used
                        .resetModel(false)


                        /*
                            These two methods define our training goals. At least one goal should be set to TRUE.
                         */
                        .trainElementsRepresentation(true).trainSequencesRepresentation(false)

                        .build();

        /*
            Now, after all options are set, we just call fit()
         */
        logger.info("Starting training...");

        vectors.fit();

        logger.info("Model saved...");

        /*
            As soon as fit() exits, model considered built, and we can test it.
            Please note: all similarity context is handled via SequenceElement's labels, so if you're using SequenceVectors to build models for complex
            objects/relations please take care of Labels uniqueness and meaning for yourself.
         */
        double sim = vectors.similarity("day", "night");
        logger.info("Day/night similarity: " + sim);
        assertTrue(sim > 0.6d);

        Collection<String> labels = vectors.wordsNearest("day", 10);
        logger.info("Nearest labels to 'day': " + labels);

        SequenceElementFactory<VocabWord> factory = new AbstractElementFactory<VocabWord>(VocabWord.class);
        WordVectorSerializer.writeSequenceVectors(vectors, factory, "seqvec.mod");

        SequenceVectors<VocabWord> model = WordVectorSerializer.readSequenceVectors(factory, new File("seqvec.mod"));
        sim = model.similarity("day", "night");
        logger.info("day/night similarity: " + sim);
    }

    @Test
    public void testInternalVocabConstruction() throws Exception {
        ClassPathResource resource = new ClassPathResource("big/raw_sentences.txt");
        File file = resource.getFile();

        BasicLineIterator underlyingIterator = new BasicLineIterator(file);

        TokenizerFactory t = new DefaultTokenizerFactory();
        t.setTokenPreProcessor(new CommonPreprocessor());

        SentenceTransformer transformer =
                        new SentenceTransformer.Builder().iterator(underlyingIterator).tokenizerFactory(t).build();

        AbstractSequenceIterator<VocabWord> sequenceIterator =
                        new AbstractSequenceIterator.Builder<>(transformer).build();

        SequenceVectors<VocabWord> vectors = new SequenceVectors.Builder<VocabWord>(new VectorsConfiguration())
                        .minWordFrequency(5).iterate(sequenceIterator).batchSize(250).iterations(1).epochs(1)
                        .resetModel(false).trainElementsRepresentation(true).build();


        logger.info("Fitting model...");

        vectors.fit();

        logger.info("Model ready...");

        double sim = vectors.similarity("day", "night");
        logger.info("Day/night similarity: " + sim);
        assertTrue(sim > 0.6d);

        Collection<String> labels = vectors.wordsNearest("day", 10);
        logger.info("Nearest labels to 'day': " + labels);
    }

    @Test
    public void testElementsLearningAlgo1() throws Exception {
        SequenceVectors<VocabWord> vectors = new SequenceVectors.Builder<VocabWord>(new VectorsConfiguration())
                        .minWordFrequency(5).batchSize(250).iterations(1)
                        .elementsLearningAlgorithm(
                                        "org.deeplearning4j.models.embeddings.learning.impl.elements.SkipGram")
                        .epochs(1).resetModel(false).trainElementsRepresentation(true).build();
    }

    @Test
    public void testSequenceLearningAlgo1() throws Exception {
        SequenceVectors<VocabWord> vectors =
                        new SequenceVectors.Builder<VocabWord>(new VectorsConfiguration()).minWordFrequency(5)
                                        .batchSize(250).iterations(1)
                                        .sequenceLearningAlgorithm(
                                                        "org.deeplearning4j.models.embeddings.learning.impl.sequence.DBOW")
                                        .epochs(1).resetModel(false).trainElementsRepresentation(false).build();
    }

    @Ignore
    @Test
    public void testGlove1() throws Exception {
        logger.info("Max available memory: " + Runtime.getRuntime().maxMemory());
        ClassPathResource resource = new ClassPathResource("big/raw_sentences.txt");
        File file = resource.getFile();

        BasicLineIterator underlyingIterator = new BasicLineIterator(file);

        TokenizerFactory t = new DefaultTokenizerFactory();
        t.setTokenPreProcessor(new CommonPreprocessor());

        SentenceTransformer transformer =
                        new SentenceTransformer.Builder().iterator(underlyingIterator).tokenizerFactory(t).build();

        AbstractSequenceIterator<VocabWord> sequenceIterator =
                        new AbstractSequenceIterator.Builder<>(transformer).build();

        VectorsConfiguration configuration = new VectorsConfiguration();
        configuration.setWindow(5);
        configuration.setLearningRate(0.06);
        configuration.setLayersSize(100);


        SequenceVectors<VocabWord> vectors = new SequenceVectors.Builder<VocabWord>(configuration)
                        .iterate(sequenceIterator).iterations(1).epochs(45)
                        .elementsLearningAlgorithm(new GloVe.Builder<VocabWord>().shuffle(true).symmetric(true)
                                        .learningRate(0.05).alpha(0.75).xMax(100.0).build())
                        .resetModel(true).trainElementsRepresentation(true).trainSequencesRepresentation(false).build();

        vectors.fit();

        double sim = vectors.similarity("day", "night");
        logger.info("Day/night similarity: " + sim);


        sim = vectors.similarity("day", "another");
        logger.info("Day/another similarity: " + sim);

        sim = vectors.similarity("night", "year");
        logger.info("Night/year similarity: " + sim);

        sim = vectors.similarity("night", "me");
        logger.info("Night/me similarity: " + sim);

        sim = vectors.similarity("day", "know");
        logger.info("Day/know similarity: " + sim);

        sim = vectors.similarity("best", "police");
        logger.info("Best/police similarity: " + sim);

        Collection<String> labels = vectors.wordsNearest("day", 10);
        logger.info("Nearest labels to 'day': " + labels);


        sim = vectors.similarity("day", "night");
        assertTrue(sim > 0.6d);
    }

    @Test
    @Ignore
    public void testDeepWalk() throws Exception {
        Heartbeat.getInstance().disableHeartbeat();

        AbstractCache<Blogger> vocabCache = new AbstractCache.Builder<Blogger>().build();

        Graph<Blogger, Double> graph = buildGraph();


        GraphWalker<Blogger> walker = new PopularityWalker.Builder<>(graph)
                        .setNoEdgeHandling(NoEdgeHandling.RESTART_ON_DISCONNECTED).setWalkLength(40)
                        .setWalkDirection(WalkDirection.FORWARD_UNIQUE).setRestartProbability(0.05)
                        .setPopularitySpread(10).setPopularityMode(PopularityMode.MAXIMUM)
                        .setSpreadSpectrum(SpreadSpectrum.PROPORTIONAL).build();

        /*
        GraphWalker<Blogger> walker = new RandomWalker.Builder<Blogger>(graph)
                .setNoEdgeHandling(NoEdgeHandling.RESTART_ON_DISCONNECTED)
                .setWalkLength(40)
                .setWalkDirection(WalkDirection.RANDOM)
                .setRestartProbability(0.05)
                .build();
        */

        GraphTransformer<Blogger> graphTransformer = new GraphTransformer.Builder<>(graph).setGraphWalker(walker)
                        .shuffleOnReset(true).setVocabCache(vocabCache).build();

        Blogger blogger = graph.getVertex(0).getValue();
        assertEquals(119, blogger.getElementFrequency(), 0.001);

        logger.info("Blogger: " + blogger);


        AbstractSequenceIterator<Blogger> sequenceIterator =
                        new AbstractSequenceIterator.Builder<>(graphTransformer).build();

        WeightLookupTable<Blogger> lookupTable = new InMemoryLookupTable.Builder<Blogger>().lr(0.025).vectorLength(150)
                        .useAdaGrad(false).cache(vocabCache).seed(42).build();


        lookupTable.resetWeights(true);

        SequenceVectors<Blogger> vectors = new SequenceVectors.Builder<Blogger>(new VectorsConfiguration())
                        // WeightLookupTable
                        .lookupTable(lookupTable)

                        // abstract iterator that covers training corpus
                        .iterate(sequenceIterator)

                        // vocabulary built prior to modelling
                        .vocabCache(vocabCache)

                        // batchSize is the number of sequences being processed by 1 thread at once
                        // this value actually matters if you have iterations > 1
                        .batchSize(1000)

                        // number of iterations over batch
                        .iterations(1)

                        // number of iterations over whole training corpus
                        .epochs(10)

                        // if set to true, vocabulary will be built from scratches internally
                        // otherwise externally provided vocab will be used
                        .resetModel(false)

                        /*
                            These two methods define our training goals. At least one goal should be set to TRUE.
                         */
                        .trainElementsRepresentation(true).trainSequencesRepresentation(false)

                        /*
                            Specifies elements learning algorithms. SkipGram, for example.
                         */
                        .elementsLearningAlgorithm(new SkipGram<Blogger>())


                        .learningRate(0.025)

                        .layerSize(150)

                        .sampling(0)

                        .negativeSample(0)

                        .windowSize(4)

                        .workers(6)

                        .seed(42)

                        .build();

        vectors.fit();

        vectors.setModelUtils(new FlatModelUtils());

        //     logger.info("12: " + Arrays.toString(vectors.getWordVector("12")));

        double sim = vectors.similarity("12", "72");
        Collection<String> list = vectors.wordsNearest("12", 20);
        logger.info("12->72: " + sim);
        printWords("12", list, vectors);

        assertTrue(sim > 0.10);
        assertFalse(Double.isNaN(sim));
    }


    private List<Blogger> getBloggersFromGraph(Graph<Blogger, Double> graph) {
        List<Blogger> result = new ArrayList<>();

        List<Vertex<Blogger>> bloggers = graph.getVertices(0, graph.numVertices() - 1);
        for (Vertex<Blogger> vertex : bloggers) {
            result.add(vertex.getValue());
        }

        return result;
    }

    private static Graph<Blogger, Double> buildGraph() throws IOException, InterruptedException {
        File nodes = new File("/ext/Temp/BlogCatalog/nodes.csv");

        CSVRecordReader reader = new CSVRecordReader(0, ',');
        reader.initialize(new FileSplit(nodes));

        List<Blogger> bloggers = new ArrayList<>();
        int cnt = 0;
        while (reader.hasNext()) {
            List<Writable> lines = new ArrayList<>(reader.next());
            Blogger blogger = new Blogger(lines.get(0).toInt());
            bloggers.add(blogger);
            cnt++;
        }

        reader.close();

        Graph<Blogger, Double> graph = new Graph<>(bloggers, true);

        // load edges
        File edges = new File("/ext/Temp/BlogCatalog/edges.csv");

        reader = new CSVRecordReader(0, ',');
        reader.initialize(new FileSplit(edges));

        while (reader.hasNext()) {
            List<Writable> lines = new ArrayList<>(reader.next());
            int from = lines.get(0).toInt();
            int to = lines.get(1).toInt();

            graph.addEdge(from - 1, to - 1, 1.0, false);
        }

        logger.info("Connected on 0: [" + graph.getConnectedVertices(0).size() + "]");
        logger.info("Connected on 1: [" + graph.getConnectedVertices(1).size() + "]");
        logger.info("Connected on 3: [" + graph.getConnectedVertices(3).size() + "]");
        assertEquals(119, graph.getConnectedVertices(0).size());
        assertEquals(9, graph.getConnectedVertices(1).size());
        assertEquals(6, graph.getConnectedVertices(3).size());

        return graph;
    }

    @Data
    private static class Blogger extends SequenceElement {
        @Getter
        @Setter
        private int id;

        public Blogger() {
            super();
        }

        public Blogger(int id) {
            super();
            this.id = id;
        }

        /**
         * This method should return string representation of this SequenceElement, so it can be used for
         *
         * @return
         */
        @Override
        public String getLabel() {
            return String.valueOf(id);
        }

        /**
         * @return
         */
        @Override
        public String toJSON() {
            return null;
        }

        @Override
        public String toString() {
            return "VocabWord{" + "wordFrequency=" + this.elementFrequency + ", index=" + index + ", codes=" + codes
                            + ", word='" + String.valueOf(id) + '\'' + ", points=" + points + ", codeLength="
                            + codeLength + '}';
        }
    }

    private static void printWords(String target, Collection<String> list, SequenceVectors vec) {
        System.out.println("Words close to [" + target + "]: ");
        for (String word : list) {
            double sim = vec.similarity(target, word);
            System.out.print("'" + word + "': [" + sim + "], ");
        }
        System.out.print("\n");
    }
}
