/* Copyright 2002-2025 CS GROUP
    * Licensed to CS GROUP (CS) under one or more
    * contributor license agreements.  See the NOTICE file distributed with
    * this work for additional information regarding copyright ownership.
    * CS 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.
   */
  package org.orekit.forces.gravity.potential;
  
  import java.io.BufferedReader;
  import java.io.IOException;
  import java.io.InputStream;
  import java.io.InputStreamReader;
  import java.nio.charset.StandardCharsets;
  import java.util.Collections;
  import java.util.HashMap;
  import java.util.Map;
  import java.util.regex.Matcher;
  import java.util.regex.Pattern;
  
  import org.hipparchus.util.FastMath;
  import org.orekit.data.DataLoader;
  import org.orekit.errors.OrekitException;
  import org.orekit.errors.OrekitMessages;
  
  /**
   * Parser for tides astronomical amplitude H<sub>f</sub>.
   * @author Luc Maisonobe
   * @since 6.1
   */
  public class AstronomicalAmplitudeReader implements DataLoader {
  
      /** Pattern for optional fields (either nothing or non-space characters). */
      private static final String  OPTIONAL_FIELD_PATTERN = "\\S*";
  
      /** Pattern for fields with Doodson number. */
      private static final String  DOODSON_TYPE_PATTERN = "\\p{Digit}{2,3}[.,]\\p{Digit}{3}";
  
      /** Pattern for fields with real type. */
      private static final String  REAL_TYPE_PATTERN =
              "[-+]?(?:(?:\\p{Digit}+(?:\\.\\p{Digit}*)?)|(?:\\.\\p{Digit}+))(?:[eE][-+]?\\p{Digit}+)?";
  
      /** Pattern for regular data. */
      private static final Pattern PATTERN = Pattern.compile("[.,]");
  
      /** Regular expression for supported files names. */
      private final String supportedNames;
  
      /** Pattern for regular data lines. */
      private final Pattern regularLinePattern;
  
      /** Doodson number column. */
      private final int columnDoodson;
  
      /** H<sub>f</sub> column. */
      private final int columnHf;
  
      /** Scaling factor for astronomical amplitude. */
      private final double scale;
  
      /** Amplitudes map. */
      private final Map<Integer, Double> amplitudesMap;
  
      /** Simple constructor.
       * @param supportedNames regular expression for supported files names
       * @param columns number of columns
       * @param columnDoodson Doodson number column (counting from 1)
       * @param columnHf H<sub>f</sub> column (counting from 1)
       * @param scale scaling factor for astronomical amplitude
       */
      public AstronomicalAmplitudeReader(final String supportedNames, final int columns,
                                         final int columnDoodson, final int columnHf,
                                         final double scale) {
  
          // build the pattern for the regular data lines
          final StringBuilder builder = new StringBuilder("^\\p{Space}*");
          for (int i = 1; i <= columns; ++i) {
              builder.append("(");
              if (i == columnDoodson) {
                  builder.append(DOODSON_TYPE_PATTERN);
              } else if (i == columnHf) {
                  builder.append(REAL_TYPE_PATTERN);
              } else {
                  builder.append(OPTIONAL_FIELD_PATTERN);
              }
              builder.append(")");
              builder.append(i < FastMath.max(columnDoodson, columnHf) ? "\\p{Space}+" : "\\p{Space}*");
          }
          builder.append('$');
          this.regularLinePattern = Pattern.compile(builder.toString());
 
         this.supportedNames = supportedNames;
         this.columnDoodson  = columnDoodson;
         this.columnHf       = columnHf;
         this.scale          = scale;
 
         this.amplitudesMap  = new HashMap<>();
 
     }
 
     /** Get the regular expression for supported files names.
      * @return regular expression for supported files names
      */
     public String getSupportedNames() {
         return supportedNames;
     }
 
     /** {@inheritDoc} */
     @Override
     public boolean stillAcceptsData() {
         return amplitudesMap.isEmpty();
     }
 
     /** {@inheritDoc} */
     @Override
     public void loadData(final InputStream input, final String name)
         throws IOException {
 
         int lineNumber = 0;
         String line = null;
         // parse the file
         try (BufferedReader r = new BufferedReader(new InputStreamReader(input, StandardCharsets.UTF_8))) {
 
             for (line = r.readLine(); line != null; line = r.readLine()) {
                 ++lineNumber;
 
                 // replace unicode minus sign ('−') by regular hyphen ('-') for parsing
                 // such unicode characters occur in tables that are copy-pasted from PDF files
                 line = line.replace('\u2212', '-');
 
                 final Matcher regularMatcher = regularLinePattern.matcher(line);
                 if (regularMatcher.matches()) {
                     // we have found a regular data line
                     final int    doodson = Integer.parseInt(PATTERN.matcher(regularMatcher.group(columnDoodson)).replaceAll(""));
                     final double hf      = scale * Double.parseDouble(regularMatcher.group(columnHf));
                     amplitudesMap.put(doodson, hf);
                 }
             }
 
         } catch (NumberFormatException nfe) {
             throw new OrekitException(OrekitMessages.UNABLE_TO_PARSE_LINE_IN_FILE,
                                       lineNumber, name, line);
         }
 
         if (amplitudesMap.isEmpty()) {
             throw new OrekitException(OrekitMessages.NOT_A_SUPPORTED_IERS_DATA_FILE, name);
         }
 
     }
 
     /** Get astronomical amplitudes map.
      * @return an unmodifiable map containing astronomical amplitudes H<sub>f</sub>
      * from a Doodson number key
      */
     public Map<Integer, Double> getAstronomicalAmplitudesMap() {
         return Collections.unmodifiableMap(amplitudesMap);
     }
 
 }