/**
 * This exception is thrown when parse errors are encountered.
 * You can explicitly create objects of this exception type by
 * calling the method generateParseException in the generated
 * parser.
 *
 * You can modify this class to customize your error reporting
 * mechanisms so long as you retain the public fields.
 */
public class ParseException extends Exception {

  /**
   * The version identifier for this Serializable class.
   * Increment only if the <i>serialized</i> form of the
   * class changes.
   */
  private static final long serialVersionUID = 1L;

  private static final String INDENT = "    ";
  
  /**
   * The end of line string (we do not use System.getProperty("") so that we are compatible with Android/GWT);
   */
  protected static String EOL = "\n";

  
  public ParseException(Token currentTokenVal,
          int[][] expectedTokenSequencesVal,
          String[] tokenImageVal
         )
	{
	  this (currentTokenVal, expectedTokenSequencesVal, tokenImageVal, null);
	}
  
  
  /**
   * This constructor is used by the method "generateParseException"
   * in the generated parser.  Calling this constructor generates
   * a new object of this type with the fields "currentToken",
   * "expectedTokenSequences", and "tokenImage" set.
   */
  public ParseException(Token currentTokenVal,
                        int[][] expectedTokenSequencesVal,
                        String[] tokenImageVal,
                        String lexicalStateName
                       )
  {
    super(initialise(currentTokenVal, expectedTokenSequencesVal, tokenImageVal, lexicalStateName));
    currentToken = currentTokenVal;
    expectedTokenSequences = expectedTokenSequencesVal;
    tokenImage = tokenImageVal;
  }

  /**
   * The following constructors are for use by you for whatever
   * purpose you can think of.  Constructing the exception in this
   * manner makes the exception behave in the normal way - i.e., as
   * documented in the class "Throwable".  The fields "errorToken",
   * "expectedTokenSequences", and "tokenImage" do not contain
   * relevant information.  The JavaCC generated code does not use
   * these constructors.
   */

  public ParseException() {
    super();
  }

  /** Constructor with message. */
  public ParseException(String message) {
    super(message);
  }


  /**
   * This is the last token that has been consumed successfully.  If
   * this object has been created due to a parse error, the token
   * followng this token will (therefore) be the first error token.
   */
  public Token currentToken;

  /**
   * Each entry in this array is an array of integers.  Each array
   * of integers represents a sequence of tokens (by their ordinal
   * values) that is expected at this point of the parse.
   */
  public int[][] expectedTokenSequences;

  /**
   * This is a reference to the "tokenImage" array of the generated
   * parser within which the parse error occurred.  This array is
   * defined in the generated ...Constants interface.
   */
  public String[] tokenImage;

  /**
   * It uses "currentToken" and "expectedTokenSequences" to generate a parse
   * error message and returns it.  If this object has been created
   * due to a parse error, and you do not catch it (it gets thrown
   * from the parser) the correct error message
   * gets displayed.
   */
  private static String initialise(Token currentToken,
                           int[][] expectedTokenSequences,
                           String[] tokenImage,
                           String lexicalStateName) {
	StringBuilder sb = new StringBuilder();
    StringBuffer expected = new StringBuffer();
    
    int maxSize = 0;
    java.util.TreeSet<String> sortedOptions = new java.util.TreeSet<String>();
    for (int i = 0; i < expectedTokenSequences.length; i++) {
      if (maxSize < expectedTokenSequences[i].length) {
        maxSize = expectedTokenSequences[i].length;
      }
      for (int j = 0; j < expectedTokenSequences[i].length; j++) {
    	  sortedOptions.add(tokenImage[expectedTokenSequences[i][j]]);
      }
    }
    
    for (String option : sortedOptions) {
        expected.append(INDENT).append(option).append(EOL);
      }
    
    sb.append("Encountered unexpected token:");
    
    Token tok = currentToken.next;
    for (int i = 0; i < maxSize; i++) {
      String tokenText = tok.image;
  	  String escapedTokenText = add_escapes(tokenText);
      if (i != 0) {
      	sb.append(" ");
      }
      if (tok.kind == 0) {
      	sb.append(tokenImage[0]);
        break;
      }
      sb.append(" \"");
	  sb.append(escapedTokenText);
      sb.append("\"");
      sb.append(" " + tokenImage[tok.kind]);
      tok = tok.next;
    }
#if KEEP_LINE_COLUMN
	sb.append(EOL).append(INDENT).append("at line " + currentToken.next.beginLine + ", column " + currentToken.next.beginColumn);
#fi
	sb.append(".").append(EOL);
    
    if (expectedTokenSequences.length == 0) {
        // Nothing to add here
    } else {
    	int numExpectedTokens = expectedTokenSequences.length;
    	sb.append(EOL).append("Was expecting"+ (numExpectedTokens == 1 ? ":" : " one of:") + EOL + EOL);
    	sb.append(expected.toString());
    }
    // 2013/07/30 --> Seems to be inaccurate as represents the readahead state, not the lexical state BEFORE the unknown token
//    if (lexicalStateName != null) {
//    	sb.append(EOL).append("** Lexical State : ").append(lexicalStateName).append(EOL).append(EOL);
//    }
    
    return sb.toString();
  }


  /**
   * Used to convert raw characters to their escaped version
   * when these raw version cannot be used as part of an ASCII
   * string literal.
   */
  static String add_escapes(String str) {
      StringBuffer retval = new StringBuffer();
      char ch;
      for (int i = 0; i < str.length(); i++) {
        switch (str.charAt(i))
        {
           case '\b':
              retval.append("\\b");
              continue;
           case '\t':
              retval.append("\\t");
              continue;
           case '\n':
              retval.append("\\n");
              continue;
           case '\f':
              retval.append("\\f");
              continue;
           case '\r':
              retval.append("\\r");
              continue;
           case '\"':
              retval.append("\\\"");
              continue;
           case '\'':
              retval.append("\\\'");
              continue;
           case '\\':
              retval.append("\\\\");
              continue;
           default:
              if ((ch = str.charAt(i)) < 0x20 || ch > 0x7e) {
                 String s = "0000" + Integer.toString(ch, 16);
                 retval.append("\\u" + s.substring(s.length() - 4, s.length()));
              } else {
                 retval.append(ch);
              }
              continue;
        }
      }
      return retval.toString();
   }

}
