package eu.dnetlib.featureextraction;

import com.google.common.collect.Lists;
import com.jayway.jsonpath.JsonPath;
import net.minidev.json.JSONArray;
import org.apache.commons.lang3.StringUtils;
import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.fs.FSDataOutputStream;
import org.apache.hadoop.fs.FileSystem;
import org.apache.hadoop.fs.Path;
import org.apache.spark.api.java.JavaRDD;
import org.apache.spark.sql.Dataset;
import org.apache.spark.sql.Row;
import org.apache.spark.sql.RowFactory;
import org.apache.spark.sql.SQLContext;
import org.apache.spark.sql.types.DataTypes;
import org.apache.spark.sql.types.Metadata;
import org.apache.spark.sql.types.StructField;
import org.apache.spark.sql.types.StructType;
import com.ibm.icu.text.Transliterator;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.Serializable;
import java.math.BigDecimal;
import java.text.Normalizer;
import java.util.List;
import java.util.regex.Matcher;
import java.util.regex.Pattern;
import java.util.stream.Collectors;

public class Utilities implements Serializable {

    public static String DATA_ID_FIELD = "$.id";
    private static final String aliases_from = "⁰¹²³⁴⁵⁶⁷⁸⁹⁺⁻⁼⁽⁾ⁿ₀₁₂₃₄₅₆₇₈₉₊₋₌₍₎àáâäæãåāèéêëēėęəîïíīįìôöòóœøōõûüùúūßśšłžźżçćčñń";
    private static final String aliases_to = "0123456789+-=()n0123456789+-=()aaaaaaaaeeeeeeeeiiiiiioooooooouuuuussslzzzcccnn";

    static StructType inputSchema = new StructType(new StructField[]{
            new StructField("id", DataTypes.StringType, false, Metadata.empty()),
            new StructField("sentence", DataTypes.StringType, false, Metadata.empty())
    });

    /**
     * Returns a view of the dataset including the id and the chosen field.
     *
     * @param sqlContext: the spark sql context
     * @param jsonRDD: the input dataset
     * @param inputFieldJPath: the input field jpath
     * @return the view of the dataset with normalized data of the inputField (id, inputField)
      */
    public static Dataset<Row> prepareDataset(SQLContext sqlContext, JavaRDD<String> jsonRDD, String inputFieldJPath) {

        JavaRDD<Row> rowRDD = jsonRDD
                .map(json ->
                        RowFactory.create(getJPathString(DATA_ID_FIELD, json), Utilities.normalize(getJPathString(inputFieldJPath, json))));
        return sqlContext.createDataFrame(rowRDD, inputSchema);
    }

    //returns the string value of the jpath in the given input json
    public static String getJPathString(final String jsonPath, final String inputJson) {
        try {
            Object o = JsonPath.read(inputJson, jsonPath);
            if (o instanceof String)
                return (String)o;
            if (o instanceof JSONArray && ((JSONArray)o).size()>0)
                return (String)((JSONArray)o).get(0);
            return "";
        }
        catch (Exception e) {
            return "";
        }
    }

    public static double[] getJPathArray(final String jsonPath, final String inputJson) {
        try {
            Object o = JsonPath.read(inputJson, jsonPath);
            if (o instanceof double[])
                return (double[]) o;
            if (o instanceof JSONArray) {
                Object[] objects = ((JSONArray) o).toArray();
                double[] array = new double[objects.length];
                for (int i = 0; i < objects.length; i++) {
                    if (objects[i] instanceof BigDecimal)
                        array[i] = ((BigDecimal)objects[i]).doubleValue();
                    else
                        array[i] = (double) objects[i];
                }
                return array;
            }
            return new double[0];
        }
        catch (Exception e) {
            e.printStackTrace();
            return new double[0];
        }
    }

//    public static String normalize(final String s) {
//        return Normalizer.normalize(s, Normalizer.Form.NFD)
//                .replaceAll("[^\\w\\s-]", "") // Remove all non-word, non-space or non-dash characters
//                .replace('-', ' ') // Replace dashes with spaces
//                .trim()  // trim leading/trailing whitespace (including what used to be leading/trailing dashes)
//                .toLowerCase(); // Lowercase the final results
//    }

    public static void writeLinesToHDFSFile(List<String> lines, String filePath) throws IOException {
        Configuration conf = new Configuration();

        FileSystem fs = FileSystem.get(conf);
        fs.delete(new Path(filePath), true);

        try {
            fs = FileSystem.get(conf);

            Path outFile = new Path(filePath);
            // Verification
            if (fs.exists(outFile)) {
                System.out.println("Output file already exists");
                throw new IOException("Output file already exists");
            }

            // Create file to write
            FSDataOutputStream out = fs.create(outFile);
            try{
                for (String line: lines) {
                    out.writeBytes(line + "\n");
                }
            }
            finally {
                out.close();
            }
        } catch (IOException e) {
            e.printStackTrace();
        }
    }

    public static String unicodeNormalization(final String s) {

        Matcher m = Pattern.compile("\\\\u(\\p{XDigit}{4})").matcher(s);
        StringBuffer buf = new StringBuffer(s.length());
        while (m.find()) {
            String ch = String.valueOf((char) Integer.parseInt(m.group(1), 16));
            m.appendReplacement(buf, Matcher.quoteReplacement(ch));
        }
        m.appendTail(buf);
        return buf.toString();
    }


    public static String normalize(final String s) {
        return  fixAliases(Normalizer.normalize(unicodeNormalization(s), Normalizer.Form.NFD))
                // do not compact the regexes in a single expression, would cause StackOverflowError in case of large input strings
                .replaceAll("[^ \\w]+", "")
                .replaceAll("(\\p{InCombiningDiacriticalMarks})+", "")
                .replaceAll("(\\p{Punct})+", " ")
                .replaceAll("(\\d)+", " ")
                .replaceAll("(\\n)+", " ")
                .toLowerCase()
                .trim();
    }

    protected static String fixAliases(final String s) {
        final StringBuilder sb = new StringBuilder();
        for (final char ch : Lists.charactersOf(s)) {
            final int i = StringUtils.indexOf(aliases_from, ch);
            sb.append(i >= 0 ? aliases_to.charAt(i) : ch);
        }
        return sb.toString();
    }
}