/*
    * Copyright 2022 the original author or authors.
    *
    * Licensed 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.
   */
  
  package org.bremersee.geojson.converter.serialization;
  
  import static java.util.Collections.unmodifiableList;
  import static java.util.Objects.nonNull;
  
  import java.io.Serial;
  import java.io.Serializable;
  import java.math.BigDecimal;
  import java.math.RoundingMode;
  import java.text.NumberFormat;
  import java.util.ArrayList;
  import java.util.List;
  import java.util.Locale;
  import java.util.regex.Pattern;
  import org.locationtech.jts.geom.Coordinate;
  
  /**
   * The type Coordinate to list converter.
   *
   * @author Christian Bremer
   */
  class CoordinateToListConverter implements Serializable {
  
    @Serial
    private static final long serialVersionUID = 1L;
  
    private static final int MAXIMUM_INTEGER_DIGITS = 17;
  
    private static final int MAXIMUM_FRACTION_DIGITS = 9;
  
    private static final NumberFormat NUMBER_FORMAT = NumberFormat.getInstance(Locale.US);
  
    private static final NumberFormat TEST_NUMBER_FORMAT = NumberFormat.getInstance(Locale.US);
  
    static {
      NUMBER_FORMAT.setMaximumFractionDigits(MAXIMUM_FRACTION_DIGITS);
      NUMBER_FORMAT.setMaximumIntegerDigits(MAXIMUM_INTEGER_DIGITS);
      NUMBER_FORMAT.setRoundingMode(RoundingMode.HALF_UP);
      NUMBER_FORMAT.setGroupingUsed(false);
  
      TEST_NUMBER_FORMAT.setMaximumFractionDigits(MAXIMUM_FRACTION_DIGITS + 1);
      TEST_NUMBER_FORMAT.setMaximumIntegerDigits(MAXIMUM_INTEGER_DIGITS + 1);
      TEST_NUMBER_FORMAT.setRoundingMode(RoundingMode.HALF_UP);
      TEST_NUMBER_FORMAT.setGroupingUsed(false);
    }
  
    private final boolean useBigDecimal;
  
    /**
     * Instantiates a new Coordinate to list converter.
     *
     * @param useBigDecimal the use big decimal
     */
    CoordinateToListConverter(boolean useBigDecimal) {
      this.useBigDecimal = useBigDecimal;
    }
  
    /**
     * Convert list.
     *
     * @param source the source
     * @return the list
     */
    List<Number> convert(Coordinate source) {
      int size = nonNull(source) ? 2 : 0;
      List<Number> list = new ArrayList<>(size);
      if (size > 0) {
        Number x = round(source.getX());
        Number y = round(source.getY());
        if (nonNull(x) && nonNull(y)) {
          list.add(x);
          list.add(y);
        }
      }
      return unmodifiableList(list);
    }
  
    private Number round(double value) {
      if (Double.isNaN(value)) {
        return null;
      }
      if (formatValue(value)) {
        String strValue = NUMBER_FORMAT.format(value);
       return useBigDecimal ? new BigDecimal(strValue) : new BigDecimal(strValue).doubleValue();
     }
     return useBigDecimal ? BigDecimal.valueOf(value) : value;
   }
 
   private boolean formatValue(final double value) {
     String[] testValues = TEST_NUMBER_FORMAT.format(value).split(Pattern.quote("."));
     return testValues[0].length() > MAXIMUM_INTEGER_DIGITS
         || (testValues.length > 1 && testValues[1].length() > MAXIMUM_FRACTION_DIGITS);
   }
 
 }