/**
 * Copyright 2013 Facebook, Inc.
 *
 * 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.
 */


var docblockRe = /^\s*(\/\*\*(.|\r?\n)*?\*\/)/;

var ltrimRe = /^\s*/;
/**
 * @param {String} contents
 * @return {String}
 */
function extract(contents) {
  var match = contents.match(docblockRe);
  if (match) {
    return match[0].replace(ltrimRe, '') || '';
  }
  return '';
}


var commentStartRe = /^\/\*\*?/;
var commentEndRe = /\*\/$/;
var wsRe = /[\t ]+/g;
var stringStartRe = /(\r?\n|^) *\*/g;
var multilineRe = /(?:^|\r?\n) *(@[^\r\n]*?) *\r?\n *([^@\r\n\s][^@\r\n]+?) *\r?\n/g;
var propertyRe = /(?:^|\r?\n) *@(\S+) *([^\r\n]*)/g;

/**
 * @param {String} contents
 * @return {Array}
 */
function parse(docblock) {
  docblock = docblock
    .replace(commentStartRe, '')
    .replace(commentEndRe, '')
    .replace(wsRe, ' ')
    .replace(stringStartRe, '$1');

  // Normalize multi-line directives
  var prev = '';
  while (prev != docblock) {
    prev = docblock;
    docblock = docblock.replace(multilineRe, "\n$1 $2\n");
  }
  docblock = docblock.trim();

  var result = [];
  var match;
  while (match = propertyRe.exec(docblock)) {
    result.push([match[1], match[2]]);
  }

  return result;
}

/**
 * Same as parse but returns an object of prop: value instead of array of paris
 * If a property appers more than once the last one will be returned
 *
 * @param {String} contents
 * @return {Object}
 */
function parseAsObject(docblock) {
  var pairs = parse(docblock);
  var result = {};
  for (var i = 0; i < pairs.length; i++) {
    result[pairs[i][0]] = pairs[i][1];
  }
  return result;
}


exports.extract = extract;
exports.parse = parse;
exports.parseAsObject = parseAsObject;