/*
    * Copyright 2010 Ange Optimization ApS
    *
    * 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 eu.simuline.octave.io.impl;
  
  import java.io.BufferedReader;
  
  import eu.simuline.octave.exception.OctaveParseException;
  
  import eu.simuline.octave.io.OctaveIO;
  
  import eu.simuline.octave.io.spi.OctaveDataReader;
  import eu.simuline.octave.type.OctaveSparseBoolean;
  import eu.simuline.octave.util.StringUtil;
  
  /**
   * The reader for the octave type "sparse bool matrix" 
   * reading an {@link OctaveSparseBoolean} from a {@link BufferedReader}. 
   *
   * <pre>
   * # name: x
   * # type: sparse bool matrix
   * # nnz: 1
   * # rows: 1
   * # columns: 1
   * 1 1 1
   * </pre>
   */
  public final class SparseBooleanReader extends OctaveDataReader {
  
      @Override
      public String octaveType() {
          return "sparse bool matrix";
      }
  
      /**
       * @throws OctaveParseException
       */
      @Override
      @SuppressWarnings("checkstyle:magicnumber")
      // 3 is clear from SparseBooleanWriter 
      // **** seems buggy: headline "# type: sparse bool matrix\n" not read. 
      public OctaveSparseBoolean read(final BufferedReader reader) {
          final int nnz     = parseHeader("# nnz: ", 
  					OctaveIO.readerReadLine(reader));
          final int rows    = parseHeader("# rows: ", 
  					OctaveIO.readerReadLine(reader));
          final int columns = parseHeader("# columns: ", 
  					OctaveIO.readerReadLine(reader));
  
          final OctaveSparseBoolean sparse = 
  	    new OctaveSparseBoolean(rows, columns, nnz);
          for (int n = 0; n < nnz; ++n) {
              final String line = OctaveIO.readerReadLine(reader);
              final String[] split = line.split(" ");
              if (split.length != 3) { // NOPMD 
                  throw new OctaveParseException("split.length != 3");
              }
              try {
                  final int row       = Integer.parseInt(split[0]);
                  final int column    = Integer.parseInt(split[1]);
                  final boolean value = StringUtil.parseBoolean(split[2]);
                  sparse.set(value, row, column);
              } catch (final NumberFormatException e) {
                  throw new OctaveParseException(e);
              }
          }
  
          return sparse;
      }
  
      private int parseHeader(final String prefix, final String line) {
          if (line == null || !line.startsWith(prefix)) {
              throw new OctaveParseException
  		("Expected a line that should start with '" + prefix + 
  		 "', got '" + line + "'");
          }
          try {
              return Integer.parseInt(line.substring(prefix.length()));
          } catch (final NumberFormatException e) {
              throw new OctaveParseException(e);
          }
      }
  
  }