/**
    * Copyright 2014 The Kuali Foundation Licensed under the
    * Educational Community 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.osedu.org/licenses/ECL-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.
   *
   * Created by Charles on 8/4/2014
   */
  package org.kuali.student.poc.jsonparser.consumer;
  
  import org.kuali.student.poc.jsonparser.producer.BaseProducer;
  import org.kuali.student.poc.jsonparser.tokenizer.token.BaseToken;
  import org.kuali.student.poc.jsonparser.tokenizer.token.NumberToken;
  
  import java.text.ParseException;
  
  /**
   * Tokenizes a JSON number
   *
   * @author Kuali Student Team
   */
  public class NumberConsumer implements BaseConsumer {
      @Override
      public BaseToken consume(BaseProducer producer) throws ParseException {
          if (!producer.hasNext()) {
              return null;
          }
          char ch = producer.peek();
          StringBuilder buf = new StringBuilder();
          int dotCount = 0;
          int i = 0;
          while (ch == '-' || Character.isDigit(ch) || ch == '.') {
              if (ch == '-' && i > 0) {
                  String err = "Error at row = " + producer.getRow() + " col = " + producer.getColumn();
                  throw new ParseException(err, producer.getColumn());
              }
              if (ch == '.') {
                  dotCount++;
                  if (dotCount > 1) {
                      String err = "Error at row = " + producer.getRow() + " col = " + producer.getColumn();
                      throw new ParseException(err, producer.getColumn());
                  }
              }
              buf.append(ch);
              producer.consume();
              ch = producer.peek();
              i++;
          }
          String numStr = buf.toString();
          NumberToken numberToken = new NumberToken(numStr);
          return numberToken;
      }
  }