/**
 * @file Special hotfix patch released by mystix on Ext development team
 * to fix known issues with the DateField class. Next release may see the
 * need to remove this.
 */

// private
Date.createParser = function(format) {
   var funcName = "parse" + Date.parseFunctions.count++;
   var regexNum = Date.parseRegexes.length;
   var currentGroup = 1;
   Date.parseFunctions[format] = funcName;

   var code = "Date." + funcName + " = function(input){\n"
   + "var y = -1, m = -1, d = -1, h = -1, i = -1, s = -1, ms = -1, o, z, u, v;\n"
   + "input = String(input);var d = new Date();\n"
   + "y = d.getFullYear();\n"
   + "m = d.getMonth();\n"
   + "d = d.getDate();\n"
   + "var results = input.match(Date.parseRegexes[" + regexNum + "]);\n"
   + "if (results && results.length > 0) {";
   var regex = "";

   var special = false;
   var ch = '';
   for (var i = 0; i < format.length; ++i) {
      ch = format.charAt(i);
      if (!special && ch == "\\") {
         special = true;
      }
      else if (special) {
         special = false;
         regex += String.escape(ch);
      }
      else {
         var obj = Date.formatCodeToRegex(ch, currentGroup);
         currentGroup += obj.g;
         regex += obj.s;
         if (obj.g && obj.c) {
            code += obj.c;
         }
      }
   }

   code += "if (u){\n"
   + "v = new Date(u * 1000);\n" // give top priority to UNIX time
   + "}else if (y >= 0 && m >= 0 && d > 0 && h >= 0 && i >= 0 && s >= 0 && ms >= 0){\n"
   + "v = new Date(y, m, d, h, i, s, ms);\n"
   + "}else if (y >= 0 && m >= 0 && d > 0 && h >= 0 && i >= 0 && s >= 0){\n"
   + "v = new Date(y, m, d, h, i, s);\n"
   + "}else if (y >= 0 && m >= 0 && d > 0 && h >= 0 && i >= 0){\n"
   + "v = new Date(y, m, d, h, i);\n"
   + "}else if (y >= 0 && m >= 0 && d > 0 && h >= 0){\n"
   + "v = new Date(y, m, d, h);\n"
   + "}else if (y >= 0 && m >= 0 && d > 0){\n"
   + "v = new Date(y, m, d);\n"
   + "}else if (y >= 0 && m >= 0){\n"
   + "v = new Date(y, m);\n"
   + "}else if (y >= 0){\n"
   + "v = new Date(y);\n"
   + "}\n}\nreturn (v && (z || o))?" // favour UTC offset over GMT offset
   +     " (Ext.type(z) == 'number' ? v.add(Date.SECOND, -v.getTimezoneOffset() * 60 - z) :" // reset to UTC, then add offset
   +         " v.add(Date.MINUTE, -v.getTimezoneOffset() + (sn == '+'? -1 : 1) * (hr * 60 + mn))) : v;\n" // reset to GMT, then add offset
   + "}";

   Date.parseRegexes[regexNum] = new RegExp("^" + regex + "$", "i");
   eval(code);
};

// private
Ext.apply(Date.parseCodes, {
   j: {
      g:1,
      c:"d = parseInt(results[{0}], 10);\n",
      s:"(\\d{1,2})" // day of month without leading zeroes (1 - 31)
   },
   M: function() {
      for (var a = [], i = 0; i < 12; a.push(Date.getShortMonthName(i)), ++i); // get localised short month names
      return Ext.applyIf({
         s:"(" + a.join("|") + ")"
      }, Date.formatCodeToRegex("F"));
   },
   n: {
      g:1,
      c:"m = parseInt(results[{0}], 10) - 1;\n",
      s:"(\\d{1,2})" // month number without leading zeros (1 - 12)
   },
   o: function() {
      return Date.formatCodeToRegex("Y");
   },
   g: function() {
      return Date.formatCodeToRegex("G");
   },
   h: function() {
      return Date.formatCodeToRegex("H");
   },
   P: {
      g:1,
      c:[
         "o = results[{0}];",
         "var sn = o.substring(0,1);", // get + / - sign
         "var hr = o.substring(1,3)*1 + Math.floor(o.substring(4,6) / 60);", // get hours (performs minutes-to-hour conversion also, just in case)
         "var mn = o.substring(4,6) % 60;", // get minutes
         "o = ((-12 <= (hr*60 + mn)/60) && ((hr*60 + mn)/60 <= 14))? (sn + String.leftPad(hr, 2, '0') + String.leftPad(mn, 2, '0')) : null;\n" // -12hrs <= GMT offset <= 14hrs
      ].join("\n"),
      s: "([+\-]\\d{2}:\\d{2})" // GMT offset in hrs and mins (with colon separator)
   }
});

// private
Date.formatCodeToRegex = function(character, currentGroup) {
   // Note: currentGroup - position in regex result array (see notes for Date.parseCodes above)
   var p = Date.parseCodes[character];

   if (p) {
      p = Ext.type(p) == 'function'? p() : p;
      Date.parseCodes[character] = p; // reassign function result to prevent repeated execution
   }

   return p? Ext.applyIf({
      c: p.c? String.format(p.c, currentGroup || "{0}") : p.c
   }, p) : {
      g:0,
      c:null,
      s:Ext.escapeRe(character) // treat unrecognised characters as literals
   }
};

Date.prototype.getGMTOffset = function(colon) {
   return (this.getTimezoneOffset() > 0 ? "-" : "+")
   + String.leftPad(Math.abs(Math.floor(this.getTimezoneOffset() / 60)), 2, "0")
   + (colon ? ":" : "")
   + String.leftPad(Math.abs(this.getTimezoneOffset() % 60), 2, "0");
};