(function() {

  var bogus = [ "Dangerous comment" ];

  var warnings = [ [ "Expected '{'",
		     "Statement body should be inside '{ }' braces." ] ];

  var errors = [ "Missing semicolon", "Extra comma", "Missing property name",
	         "Unmatched ", " and instead saw", " is not defined",
	         "Unclosed string", "Stopping, unable to continue" ];

  function validator(options, text) {
    JSHINT(text, options);
    var errors = JSHINT.data().errors, result = [];
    if (errors) parseErrors(errors, result);
    return result;
  }

  CodeMirror.javascriptValidatorWithOptions = function(options) {
    return function(text) { return validator(options, text); };
  };

  CodeMirror.javascriptValidator = CodeMirror.javascriptValidatorWithOptions(null);

  function cleanup(error) {
    // All problems are warnings by default
    fixWith(error, warnings, "warning", true);
    fixWith(error, errors, "error");

    return isBogus(error) ? null : error;
  }

  function fixWith(error, fixes, severity, force) {
    var description, fix, find, replace, found;

    description = error.description;

    for ( var i = 0; i < fixes.length; i++) {
      fix = fixes[i];
      find = (typeof fix === "string" ? fix : fix[0]);
      replace = (typeof fix === "string" ? null : fix[1]);
      found = description.indexOf(find) !== -1;

      if (force || found) {
	error.severity = severity;
      }
      if (found && replace) {
	error.description = replace;
      }
    }
  }

  function isBogus(error) {
    var description = error.description;
    for ( var i = 0; i < bogus.length; i++) {
      if (description.indexOf(bogus[i]) !== -1) {
	return true;
      }
    }
    return false;
  }

  function parseErrors(errors, output) {
    for ( var i = 0; i < errors.length; i++) {
      var error = errors[i];
      if (error) {
	var linetabpositions, index;

	linetabpositions = [];

	// This next block is to fix a problem in jshint. Jshint
	// replaces
	// all tabs with spaces then performs some checks. The error
	// positions (character/space) are then reported incorrectly,
	// not taking the replacement step into account. Here we look
	// at the evidence line and try to adjust the character position
	// to the correct value.
	if (error.evidence) {
	  // Tab positions are computed once per line and cached
	  var tabpositions = linetabpositions[error.line];
	  if (!tabpositions) {
	    var evidence = error.evidence;
	    tabpositions = [];
	    // ugggh phantomjs does not like this
	    // forEachChar(evidence, function(item, index) {
	    Array.prototype.forEach.call(evidence, function(item,
							    index) {
	      if (item === '\t') {
		// First col is 1 (not 0) to match error
		// positions
		tabpositions.push(index + 1);
	      }
	    });
	    linetabpositions[error.line] = tabpositions;
	  }
	  if (tabpositions.length > 0) {
	    var pos = error.character;
	    tabpositions.forEach(function(tabposition) {
	      if (pos > tabposition) pos -= 1;
	    });
	    error.character = pos;
	  }
	}

	var start = error.character - 1, end = start + 1;
	if (error.evidence) {
	  index = error.evidence.substring(start).search(/.\b/);
	  if (index > -1) {
	    end += index;
	  }
	}

	// Convert to format expected by validation service
	error.description = error.reason;// + "(jshint)";
	error.start = error.character;
	error.end = end;
	error = cleanup(error);

	if (error)
          output.push({message: error.description,
                       severity: error.severity,
                       from: CodeMirror.Pos(error.line - 1, start),
                       to: CodeMirror.Pos(error.line - 1, end)});
      }
    }
  }
})();
