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*/

package com.google.refine.model.recon;

import java.io.IOException;
import java.io.StringWriter;
import java.util.ArrayList;
import java.util.Collections;
import java.util.Comparator;
import java.util.HashMap;
import java.util.HashSet;
import java.util.List;
import java.util.Map;
import java.util.Optional;
import java.util.Set;

import com.fasterxml.jackson.annotation.JsonCreator;
import com.fasterxml.jackson.annotation.JsonIgnore;
import com.fasterxml.jackson.annotation.JsonInclude;
import com.fasterxml.jackson.annotation.JsonInclude.Include;
import com.fasterxml.jackson.annotation.JsonProperty;
import com.fasterxml.jackson.annotation.JsonSetter;
import com.fasterxml.jackson.annotation.Nulls;
import com.fasterxml.jackson.core.JsonProcessingException;
import com.fasterxml.jackson.core.type.TypeReference;
import com.fasterxml.jackson.databind.node.ArrayNode;
import com.fasterxml.jackson.databind.node.ObjectNode;
import org.apache.commons.lang3.StringUtils;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import com.google.refine.expr.ExpressionUtils;
import com.google.refine.model.Cell;
import com.google.refine.model.Project;
import com.google.refine.model.Recon;
import com.google.refine.model.Recon.Judgment;
import com.google.refine.model.ReconCandidate;
import com.google.refine.model.ReconType;
import com.google.refine.model.RecordModel.RowDependency;
import com.google.refine.model.Row;
import com.google.refine.util.HttpClient;
import com.google.refine.util.ParsingUtilities;

public class StandardReconConfig extends ReconConfig {

    final static Logger logger = LoggerFactory.getLogger("refine-standard-recon");

    private static final String DEFAULT_SCHEMA_SPACE = "http://localhost/schema";
    private static final String DEFAULT_IDENTIFIER_SPACE = "http://localhost/identifier";
    private static final int DEFAULT_BATCH_SIZE = 10;

    static public class ColumnDetail {

        @JsonProperty("column")
        final public String columnName;
        @JsonProperty("propertyName")
        final public String propertyName;
        @JsonProperty("propertyID")
        final public String propertyID;

        /**
         * Unfortunately the format of ColumnDetail is inconsistent in the UI and the backend so we need to support two
         * deserialization formats. See the tests for that.
         *
         * FIXME: Clean this up the next time we make breaking changes
         */
        @JsonCreator
        public ColumnDetail(
                @JsonProperty("column") String columnName,
                @JsonProperty("propertyName") String propertyName,
                @JsonProperty("propertyID") String propertyID,
                @JsonProperty("property") ReconType property) {
            this.columnName = columnName;
            this.propertyName = property == null ? propertyName : property.name;
            this.propertyID = property == null ? propertyID : property.id;
        }

        @Override
        public String toString() {
            try {
                return ParsingUtilities.mapper.writeValueAsString(this);
            } catch (JsonProcessingException e) {
                return super.toString();
            }
        }
    }

    static public StandardReconConfig reconstruct(String json) throws IOException {
        return ParsingUtilities.mapper.readValue(json, StandardReconConfig.class);
    }

    static protected class StandardReconJob extends ReconJob {

        String text;
        String code;

        @Override
        public int getKey() {
            return code.hashCode();
        }

        @Override
        public String toString() {
            return code;
        }
    }

    @JsonProperty("service")
    final public String service;
    @JsonProperty("identifierSpace")
    final public String identifierSpace;
    @JsonProperty("schemaSpace")
    final public String schemaSpace;

    @JsonIgnore
    final public String typeID;
    @JsonIgnore
    final public String typeName;
    @JsonProperty("autoMatch")
    final public boolean autoMatch;
    @JsonInclude(Include.NON_EMPTY)
    @JsonSetter(nulls = Nulls.SKIP)
    @JsonProperty("batchSize")
    final public Optional<Integer> batchSize;
    @JsonProperty("columnDetails")
    final public List<ColumnDetail> columnDetails;
    @JsonProperty("limit")
    final private int limit;

    // initialized lazily
    private HttpClient httpClient = null;

    @JsonCreator
    public StandardReconConfig(
            @JsonProperty("service") String service,
            @JsonProperty("identifierSpace") String identifierSpace,
            @JsonProperty("schemaSpace") String schemaSpace,
            @JsonProperty("type") ReconType type,
            @JsonProperty("autoMatch") boolean autoMatch,
            @JsonProperty("batchSize") Optional<Integer> batchSize,
            @JsonProperty("columnDetails") List<ColumnDetail> columnDetails,
            @JsonProperty("limit") int limit) {
        this(service, identifierSpace, schemaSpace,
                type != null ? type.id : null,
                type != null ? type.name : null,
                autoMatch, batchSize, columnDetails, limit);
    }

    public StandardReconConfig(
            String service,
            String identifierSpace,
            String schemaSpace,
            ReconType type,
            boolean autoMatch,
            List<ColumnDetail> columnDetails,
            int limit) {
        this(service, identifierSpace, schemaSpace,
                type != null ? type.id : null,
                type != null ? type.name : null,
                autoMatch, columnDetails, limit);
    }

    /**
     * Recently added by mistake, so slated for removal quickly after a short deprecation period.
     * 
     * @since 3.8.0
     * @deprecated for 3.8.3
     */
    @Deprecated(since = "3.8.3")
    public StandardReconConfig(
            String service,
            String identifierSpace,
            String schemaSpace,
            ReconType type,
            boolean autoMatch,
            int batchSize,
            List<ColumnDetail> columnDetails,
            int limit) {
        this(service, identifierSpace, schemaSpace,
                type != null ? type.id : null,
                type != null ? type.name : null,
                autoMatch, Optional.of(batchSize), columnDetails, limit);
    }

    public StandardReconConfig(
            String service,
            String identifierSpace,
            String schemaSpace,
            String typeID,
            String typeName,
            boolean autoMatch,
            List<ColumnDetail> columnDetails) {
        this(service, identifierSpace, schemaSpace, typeID, typeName, autoMatch, Optional.empty(), columnDetails, 0);
    }

    /**
     * Recently added by mistake, so slated for removal quickly after a short deprecation period.
     * 
     * @since 3.8.0
     * @deprecated for 3.8.3
     */
    @Deprecated(since = "3.8.3")
    public StandardReconConfig(
            String service,
            String identifierSpace,
            String schemaSpace,
            String typeID,
            String typeName,
            boolean autoMatch,
            int batchSize,
            List<ColumnDetail> columnDetails) {
        this(service, identifierSpace, schemaSpace, typeID, typeName, autoMatch, Optional.of(batchSize), columnDetails, 0);
    }

    /**
     * @param service
     * @param identifierSpace
     * @param schemaSpace
     * @param typeID
     * @param typeName
     * @param autoMatch
     * @param columnDetails
     * @param limit
     *            maximum number of results to return (0 = default)
     */
    public StandardReconConfig(
            String service,
            String identifierSpace,
            String schemaSpace,
            String typeID,
            String typeName,
            boolean autoMatch,
            List<ColumnDetail> columnDetails,
            int limit) {
        this(service, identifierSpace, schemaSpace, typeID, typeName, autoMatch, Optional.empty(), columnDetails, limit);
    }

    /**
     * @param service
     * @param identifierSpace
     * @param schemaSpace
     * @param typeID
     * @param typeName
     * @param autoMatch
     * @param columnDetails
     * @param limit
     *            maximum number of results to return (0 = default)
     */
    public StandardReconConfig(
            String service,
            String identifierSpace,
            String schemaSpace,
            String typeID,
            String typeName,
            boolean autoMatch,
            Optional<Integer> batchSize,
            List<ColumnDetail> columnDetails,
            int limit) {
        this.service = service;
        this.identifierSpace = identifierSpace != null ? identifierSpace : DEFAULT_IDENTIFIER_SPACE;
        this.schemaSpace = schemaSpace != null ? schemaSpace : DEFAULT_SCHEMA_SPACE;

        this.typeID = typeID;
        this.typeName = typeName;
        this.autoMatch = autoMatch;
        this.batchSize = batchSize;
        this.columnDetails = columnDetails;
        this.limit = limit;
    }

    @JsonProperty("type")
    @JsonInclude(Include.NON_NULL)
    public ReconType getReconType() {
        if (typeID != null) {
            return new ReconType(typeID, typeName);
        }
        return null;
    }

    @Deprecated
    @Override
    @JsonIgnore
    public int getBatchSize() {
        return DEFAULT_BATCH_SIZE;
    }

    @Override
    @JsonIgnore
    public int getBatchSize(int rowCount) {
        if (batchSize.isEmpty()) {
            return DEFAULT_BATCH_SIZE;
        }
        return Math.min(Math.max(rowCount / DEFAULT_BATCH_SIZE, DEFAULT_BATCH_SIZE), batchSize.get());
    }

    @Override
    public String getBriefDescription(Project project, String columnName) {
        return "Reconcile cells in column " + columnName + " to type " + typeID;
    }

    public ReconJob createSimpleJob(String query) {
        /*
         * Same as createJob, but for simpler queries without any properties. This is much easier to generate as there
         * is no need for a Project, Row and Cell: this means the job can be created outside the usual context of
         * reconciliation (e.g. in an importer).
         */
        StandardReconJob job = new StandardReconJob();
        try {
            String queryJson = ParsingUtilities.defaultWriter.writeValueAsString(
                    Collections.singletonMap("query", query));
            job.text = query;
            job.code = queryJson;
            return job;
        } catch (JsonProcessingException e) {
            e.printStackTrace();
            return null;
        }
    }

    protected static class QueryProperty {

        @JsonProperty("pid")
        String pid;
        @JsonProperty("v")
        Object v;

        protected QueryProperty(
                String pid,
                Object v) {
            this.pid = pid;
            this.v = v;
        }

        @Override
        public String toString() {
            try {
                return ParsingUtilities.mapper.writeValueAsString(this);
            } catch (JsonProcessingException e) {
                return super.toString();
            }
        }
    }

    protected static class ReconQuery {

        @JsonProperty("query")
        protected String query;

        @JsonProperty("type")
        @JsonInclude(Include.NON_NULL)
        protected String typeID;

        @JsonProperty("type_strict")
        @JsonInclude(Include.NON_NULL)
        public String isTypeStrict() {
            if (typeID != null) {
                return "should";
            }
            return null;
        }

        @JsonProperty("properties")
        @JsonInclude(Include.NON_EMPTY)
        protected List<QueryProperty> properties;

        // Only send limit if it's non-default (default = 0) to preserve backward
        // compatibility with services which might choke on this (pre-2013)
        @JsonProperty("limit")
        @JsonInclude(Include.NON_DEFAULT)
        protected int limit;

        public ReconQuery() {
            super();
            this.query = "";
            this.typeID = null;
            this.properties = null;
            this.limit = 0;
        }

        @JsonCreator
        public ReconQuery(
                String query,
                String typeID,
                List<QueryProperty> properties,
                int limit) {
            this.query = query;
            this.typeID = typeID;
            this.properties = properties;
            this.limit = limit;
        }

        @Override
        public String toString() {
            try {
                return ParsingUtilities.mapper.writeValueAsString(this);
            } catch (JsonProcessingException e) {
                return super.toString();
            }
        }
    }

    public static class ReconResult {

        @JsonProperty("name")
        public String name;
        @JsonProperty("id")
        public String id;
        @JsonProperty("type")
        public List<ReconType> types = Collections.emptyList();
        @JsonProperty("score")
        public double score;
        @JsonProperty("match")
        public boolean match = false;
        // TODO: Do we have a way of testing this for compatibility? Hopefully clients ignore unknown fields
        @JsonInclude(Include.NON_NULL)
        @JsonProperty("error")
        public ReconCandidate error = null;

        @JsonIgnore
        public ReconCandidate toCandidate() {
            String[] bareTypes = new String[types.size()];
            for (int i = 0; i != types.size(); i++) {
                bareTypes[i] = types.get(i).id;
            }
            ReconCandidate result = new ReconCandidate(id, name, bareTypes, score);

            return result;
        }

        @Override
        public String toString() {
            try {
                return ParsingUtilities.mapper.writeValueAsString(this);
            } catch (JsonProcessingException e) {
                return super.toString();
            }
        }
    }

    @Override
    public ReconJob createJob(Project project, int rowIndex, Row row,
            String columnName, Cell cell) {

        StandardReconJob job = new StandardReconJob();

        List<QueryProperty> properties = new ArrayList<>();

        for (ColumnDetail c : columnDetails) {
            int detailCellIndex = project.columnModel.getColumnByName(c.columnName).getCellIndex();

            Cell cell2 = row.getCell(detailCellIndex);
            if (cell2 == null || !ExpressionUtils.isNonBlankData(cell2.value)) {
                int cellIndex = project.columnModel.getColumnByName(columnName).getCellIndex();

                RowDependency rd = project.recordModel.getRowDependency(rowIndex);
                if (rd != null && rd.cellDependencies != null) {
                    int contextRowIndex = rd.cellDependencies[cellIndex].rowIndex;
                    if (contextRowIndex >= 0 && contextRowIndex < project.rows.size()) {
                        Row row2 = project.rows.get(contextRowIndex);

                        cell2 = row2.getCell(detailCellIndex);
                    }
                }
            }

            if (cell2 != null && ExpressionUtils.isNonBlankData(cell2.value)) {
                Object v = null;
                if (cell2.recon != null && cell2.recon.match != null) {
                    Map<String, String> recon = new HashMap<>();
                    recon.put("id", cell2.recon.match.id);
                    recon.put("name", cell2.recon.match.name);
                    v = recon;
                } else {
                    v = cell2.value;
                }
                properties.add(new QueryProperty(c.propertyID, v));
            }

        }

        ReconQuery query = new ReconQuery(cell.value.toString(), typeID, properties, limit);

        job.text = cell.value.toString();
        try {
            job.code = ParsingUtilities.defaultWriter.writeValueAsString(query);
        } catch (JsonProcessingException e) {
            // FIXME: This error will get lost
            e.printStackTrace();
            return null; // TODO: Throw exception instead?
        }
        return job;
    }

    private HttpClient getHttpClient() {
        if (httpClient == null) {
            httpClient = new HttpClient();
        }
        return httpClient;
    }

    private String postQueries(String url, String queriesString) throws IOException {
        return getHttpClient().postNameValue(url, "queries", queriesString);
    }

    @Override
    public List<Recon> batchRecon(List<ReconJob> jobs, long historyEntryID) {
        List<Recon> recons = new ArrayList<Recon>(jobs.size());

        StringWriter stringWriter = new StringWriter();

        stringWriter.write("{");
        for (int i = 0; i < jobs.size(); i++) {
            StandardReconJob job = (StandardReconJob) jobs.get(i);
            if (i > 0) {
                stringWriter.write(",");
            }
            stringWriter.write("\"q" + i + "\":");
            stringWriter.write(job.code);
        }
        stringWriter.write("}");
        String queriesString = stringWriter.toString();

        String responseString = "";
        ObjectNode o = null;
        try {

            responseString = postQueries(service, queriesString);
            o = ParsingUtilities.mapper.readValue(responseString, ObjectNode.class);
        } catch (IOException e) {
            Recon recon = new Recon(historyEntryID, identifierSpace, schemaSpace);
            recon.error = e.getMessage();
            recon.judgment = Judgment.Error;
            recons.add(recon);
        }

        if (o == null) { // utility method returns null instead of throwing
            Recon recon = new Recon(historyEntryID, identifierSpace, schemaSpace);
            recon.error = "The reconciliation service returned an invalid response";
            recon.judgment = Judgment.Error;
            recons.add(recon);

        } else {
            for (int i = 0; i < jobs.size(); i++) {
                StandardReconJob job = (StandardReconJob) jobs.get(i);
                Recon recon = null;

                String text = job.text;
                String key = "q" + i;
                if (o.has(key) && o.get(key) instanceof ObjectNode) {
                    ObjectNode o2 = (ObjectNode) o.get(key);
                    if (o2.has("result") && o2.get("result") instanceof ArrayNode) {
                        ArrayNode results = (ArrayNode) o2.get("result");

                        recon = createReconServiceResults(text, results, historyEntryID);
                    } else {
                        recon = new Recon(historyEntryID, identifierSpace, schemaSpace);
                        recon.error = "The service returned a JSON response without \"result\" field for query " + key;
                        recon.judgment = Judgment.Error;

                    }
                } else {
                    recon = new Recon(historyEntryID, identifierSpace, schemaSpace);
                    recon.error = "The service returned a JSON response without \"" + key + "\" field ";
                    recon.judgment = Judgment.Error;
                }

                if (recon != null) {
                    recon.service = service;
                }
                recons.add(recon);
            }

        }

        while (recons.size() < jobs.size()) {
            Recon recon = new Recon(historyEntryID, identifierSpace, schemaSpace);
            // TODO: Needs i18n
            recon.error = "No. of recon objects was less than no. of jobs";
            recon.judgment = Judgment.Error;
            recons.add(recon);
        }

        return recons;
    }

    @Override
    public Recon createNewRecon(long historyEntryID) {
        Recon recon = new Recon(historyEntryID, identifierSpace, schemaSpace);
        recon.service = service;
        return recon;
    }

    protected Recon createReconServiceResults(String text, ArrayNode resultsList, long historyEntryID) {
        Recon recon = new Recon(historyEntryID, identifierSpace, schemaSpace);
        List<ReconResult> results = ParsingUtilities.mapper.convertValue(resultsList, new TypeReference<List<ReconResult>>() {
        });

        // Sort results by decreasing score
        results.sort(new Comparator<ReconResult>() {

            @Override
            public int compare(ReconResult a, ReconResult b) {
                return Double.compare(b.score, a.score);
            }
        });

        int length = results.size();
        for (int i = 0; i < length; i++) {
            ReconResult result = results.get(i);

            ReconCandidate candidate = result.toCandidate();

            if (autoMatch && i == 0 && result.match) {
                recon.match = candidate;
                recon.matchRank = 0;
                recon.judgment = Judgment.Matched;
                recon.judgmentAction = "auto";
            }

            recon.addCandidate(candidate);
        }

        computeFeatures(recon, text);
        return recon;
    }

    /**
     * Recomputes the features associated with this reconciliation object (only if we have at least one candidate).
     * 
     * @param text
     *            the cell value to compare the reconciliation data to
     */
    public void computeFeatures(Recon recon, String text) {
        if (recon.candidates != null && !recon.candidates.isEmpty() && text != null) {
            ReconCandidate candidate = recon.candidates.get(0);

            if (candidate.name != null) {
                recon.setFeature(Recon.Feature_nameMatch, text.equalsIgnoreCase(candidate.name));
                recon.setFeature(Recon.Feature_nameLevenshtein,
                        // TODO: Probably want diacritic folding as well as case folding here for i18n
                        StringUtils.getLevenshteinDistance(StringUtils.lowerCase(text), StringUtils.lowerCase(candidate.name)));
                recon.setFeature(Recon.Feature_nameWordDistance, wordDistance(text, candidate.name));
            }
            recon.setFeature(Recon.Feature_typeMatch, false);
            if (this.typeID != null) {
                for (String typeID : candidate.types) {
                    if (this.typeID.equals(typeID)) {
                        recon.setFeature(Recon.Feature_typeMatch, true);
                        break;
                    }
                }
            }
        } else {
            recon.features = new Object[Recon.Feature_max];
        }
    }

    static protected double wordDistance(String s1, String s2) {
        Set<String> words1 = breakWords(s1);
        Set<String> words2 = breakWords(s2);
        return words1.size() >= words2.size() ? wordDistance(words1, words2) : wordDistance(words2, words1);
    }

    static protected double wordDistance(Set<String> longWords, Set<String> shortWords) {
        if (longWords.size() == 0) {
            return 0.0;
        }

        double common = 0;
        for (String word : shortWords) {
            if (longWords.contains(word)) {
                common++;
            }
        }
        return common / longWords.size();
    }

    static final protected Set<String> s_stopWords = new HashSet<String>();
    static {
        // FIXME: This is English specific - needs i18n
        s_stopWords.add("the");
        s_stopWords.add("a");
        s_stopWords.add("and");
        s_stopWords.add("of");
        s_stopWords.add("on");
        s_stopWords.add("in");
        s_stopWords.add("at");
        s_stopWords.add("by");
    }

    static protected Set<String> breakWords(String s) {
        // TODO: This needs i18n
        String[] words = s.toLowerCase().split("\\s+");

        Set<String> set = new HashSet<String>(words.length);
        for (String word : words) {
            if (!s_stopWords.contains(word)) {
                set.add(word);
            }
        }
        return set;
    }

    @Override
    public String getMode() {
        return "standard-service";
    }
}
