text: /*
      Date format with slash "/" (also "-" and ".") between numbers
      - Tuesday 11/3/2015 
      - 11/3/2015
      - 11/3
  
      By default the paser us "middle-endien" format (US English),
      then fallback to little-endian if failed.
      - 11/3/2015 = November 3rd, 2015
      - 23/4/2015 = April 23th, 2015
  
      If "littleEndian" config is set, the parser will try the little-endian first. 
      - 11/3/2015 = March 11th, 2015
  */
  var moment = require('moment');
  var Parser = require('../parser').Parser;
  var ParsedResult = require('../../result').ParsedResult;
  
  var PATTERN = new RegExp('(\\W|^)' +
      '(?:' +
          '(?:on\\s*?)?' +
          '((?:sun|mon|tues?|wed(?:nes)?|thu(?:rs?)?|fri|sat(?:ur)?)(?:day)?)' +
          '\\s*\\,?\\s*' +
      ')?' +
      '([0-3]{0,1}[0-9]{1})[\\/\\.\\-]([0-3]{0,1}[0-9]{1})' +
      '(?:' +
          '[\\/\\.\\-]' +
          '([0-9]{4}\s*\,?\s*|[0-9]{2}\s*\,?\s*)' +
      ')?' +
      '(\\W|$)', 'i');
  
  var DAYS_OFFSET = { 'sunday': 0, 'sun': 0, 'monday': 1, 'mon': 1,'tuesday': 2, 'wednesday': 3, 'wed': 3,
      'thursday': 4, 'thur': 4,'friday': 5, 'fri': 5,'saturday': 6, 'sat': 6,}
  
  
  var OPENNING_GROUP = 1;
  var ENDING_GROUP = 6;
  
  var WEEKDAY_GROUP = 2;
  
  
  var FIRST_NUMBERS_GROUP = 3;
  var SECOND_NUMBERS_GROUP = 4;
  
  var YEAR_GROUP = 5;
  
  exports.Parser = function ENSlashDateFormatParser(config) {
      Parser.apply(this, arguments);
      config = config || {};
      var littleEndian  = config.littleEndian;
      var MONTH_GROUP = littleEndian ? SECOND_NUMBERS_GROUP : FIRST_NUMBERS_GROUP;
      var DAY_GROUP = littleEndian ? FIRST_NUMBERS_GROUP : SECOND_NUMBERS_GROUP;
  
      this.pattern = function () { return PATTERN; };
      this.extract = function(text, ref, match, opt){
  
          if(match[OPENNING_GROUP] == '/' || match[ENDING_GROUP] == '/') {
              // Long skip, if there is some overlapping like:
              // XX[/YY/ZZ]
              // [XX/YY/]ZZ
              match.index += match[0].length
              return;
          }
  
          var index = match.index + match[OPENNING_GROUP].length;
          var text = match[0].substr(match[OPENNING_GROUP].length, match[0].length - match[ENDING_GROUP].length);
  
  
          var result = new ParsedResult({
              text: text,
              index: index,
              ref: ref,
          });
  
          if(text.match(/^\d\.\d$/)) return;
          if(text.match(/^\d\.\d{1,2}\.\d{1,2}$/)) return;
  
          // MM/dd -> OK
          // MM.dd -> NG
          if(!match[YEAR_GROUP] && match[0].indexOf('/') < 0) return;
  
          var date = null;
          var year = match[YEAR_GROUP] || moment(ref).year() + '';
          var month = match[MONTH_GROUP];
          var day   = match[DAY_GROUP];
  
          month = parseInt(month);
          day  = parseInt(day);
          year = parseInt(year);
  
          if(month < 1 || month > 12) {
              if(month > 12) {
                  // dd/mm/yyyy date format if day looks like a month, and month
                  // looks like a day.
                  if (day >= 1 && day <= 12 && month >= 13 && month <= 31) {
                      // unambiguous
                      var tday = month;
                      month = day;
                      day = tday;
                  }
                  else {
                      // both month and day are <= 12
                      return null;
                  }
              }
          }
          if(day < 1 || day > 31) return null;
  
          if(year < 100){
              if (year > 50) {
                  year = year + 1900;
              } else {
                  year = year + 2000;
              }
          }
  
          result.start.assign('day', day);
          result.start.assign('month', month);
          if (match[YEAR_GROUP]) {
              result.start.assign('year', year);
          } else {
              result.start.imply('year', year);
          }
  
          //Day of week
          if(match[WEEKDAY_GROUP]) {
              result.start.assign('weekday', DAYS_OFFSET[match[WEEKDAY_GROUP].toLowerCase()]);
          }
  
          result.tags['ENSlashDateFormatParser'] = true;
          return result;
      };
  };
  