/*
    * Copyright 2008, 2009, 2012 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 java.util.HashMap;
  import java.util.Map;
  
  import eu.simuline.octave.exception.OctaveParseException;
  import eu.simuline.octave.io.OctaveIO;
  import eu.simuline.octave.io.spi.OctaveDataReader;
  import eu.simuline.octave.type.OctaveCell;
  import eu.simuline.octave.type.OctaveObject;
  import eu.simuline.octave.type.OctaveStruct;
  
  import static eu.simuline.octave.io.impl.StructWriter.LENGTH;
  import static eu.simuline.octave.io.impl.StructWriter.NAME;
  import static eu.simuline.octave.io.impl.StructWriter.TYPE_CELL;
  
  /**
   * The reader for the octave type "struct" 
   * reading an {@link OctaveStruct} from a {@link BufferedReader}. 
   * Reads the format written by {@link StructWriter}
   */
  public final class StructReader extends OctaveDataReader {
      private static final String N_DIMS2 = "# ndims: 2";
      private static final String V_DIMS2 = " 1 1";
  
      private static final CellReaderder.html#CellReader">CellReader CELL_READER = new CellReader();
  
      @Override
      public String octaveType() {
          return "struct";
      }
  
      @Override
      @SuppressWarnings("PMD.NPathComplexity")
      public OctaveStruct read(final BufferedReader reader) {
          String line = OctaveIO.readerReadLine(reader);
          // In octave 3.6 dimension of the scalar is also written now 
  	// **** this i cannot see in Writer 
          if (line != null && line.startsWith("# ndims:")) {
              if (!N_DIMS2.equals(line)) {
                  throw new OctaveParseException
  		    ("JavaOctave does not support matrix structs, read '" + 
  		     line + "'");
              }
  
  	    // 1 1
              line = OctaveIO.readerReadLine(reader);
              if (!V_DIMS2.equals(line)) {
                  throw new OctaveParseException
  		    ("JavaOctave does not support matrix structs, read '" + 
  		     line + "'");
              }
              line = OctaveIO.readerReadLine(reader);
          }
  
          // # length: 4
  //        String line = OctaveIO.readerReadLine(reader);
          if (line == null || !line.startsWith(LENGTH)) {
              throw new OctaveParseException
  		("Expected <" + LENGTH + "> got <" + line + ">. ");
          }
          final int length = Integer.parseInt(line.substring(LENGTH.length()));
  	// only used during conversion
  
          final Map<String, OctaveObject> data = 
  	    new HashMap<String, OctaveObject>();
  
          for (int i = 0; i < length; i++) {
              // # name: elemmatrix
  	    // Work around differences in number of line feeds 
  	    // in octave 3.4 and 3.6: 
  	    // keep reading until line is non-empty
              do {
                  line = OctaveIO.readerReadLine(reader);
              } while ("".equals(line));
              if (!line.startsWith(NAME)) {
                  throw new OctaveParseException
  		    ("Expected <" + NAME + "> got <" + line + ">. ");
              }
              final String subname = line.substring(NAME.length());
  
  
  
 
             line = OctaveIO.readerReadLine(reader);
             if (!line.equals(TYPE_CELL)) {
                 throw new OctaveParseException
 		    ("Expected '" + TYPE_CELL + "' got '" + line + "'");
             }
 
             final OctaveCell cell = CELL_READER.read(reader);
             if (cell.getSize(1) != 1 || cell.getSize(2) != 1) {
                 throw new OctaveParseException
 		    ("JavaOctave does not support matrix structs, size="
 		     + cell.getSize(1) + " " + cell.getSize(2) + "...");
 	    }
 
             // data...
 	    final OctaveObject value = cell.get(1, 1);
 	    data.put(subname, value);
         } // for 
 
         return new OctaveStruct(data);
     }
 
 }