/* 'Magic' date parsing, by Simon Willison (6th October 2003)
   http://simon.incutio.com/archive/2003/10/06/betterDateInput
*/

/* Finds the index of the first occurence of item in the array, or -1 if not found */
Array.prototype.indexOf = function(item) {
    for (var i = 0; i < this.length; i++) {
        if (this[i] == item) {
            return i;
        }
    }
    return -1;
};
/* Returns an array of items judged 'true' by the passed in test function */
Array.prototype.filter = function(test) {
    var matches = [];
    for (var i = 0; i < this.length; i++) {
        if (test(this[i])) {
            matches[matches.length] = this[i];
        }
    }
    return matches;
};

var monthNames = "January February March April May June July August September October November December".split(" ");
var weekdayNames = "Sunday Monday Tuesday Wednesday Thursday Friday Saturday".split(" ");

/* Takes a string, returns the index of the month matching that string, throws
   an error if 0 or more than 1 matches
*/
function parseMonth(month) {
    var matches = monthNames.filter(function(item) { 
        return new RegExp("^" + month, "i").test(item);
    });
    if (matches.length == 0) {
        throw new Error("Invalid month string");
    }
    if (matches.length > 1) {
        throw new Error("Ambiguous month");
    }
    return monthNames.indexOf(matches[0]);
}
/* Same as parseMonth but for days of the week */
function parseWeekday(weekday) {
    var matches = weekdayNames.filter(function(item) {
        return new RegExp("^" + weekday, "i").test(item);
    });
    if (matches.length == 0) {
        throw new Error("Invalid day string");
    }
    if (matches.length > 1) {
        throw new Error("Ambiguous weekday");
    }
    return weekdayNames.indexOf(matches[0]);
}

/* Array of objects, each has 're', a regular expression and 'handler', a 
   function for creating a date from something that matches the regular 
   expression. Handlers may throw errors if string is unparseable. 
*/
var dateParsePatterns = [
    // mm/dd/yyyy (American style)
    {   re: /(\d{1,2})\/(\d{1,2})\/(\d{4})/,
        handler: function(bits) {
            var d = new Date();
            d.setYear(bits[3]);
            d.setMonth(parseInt(bits[1], 10) - 1); // Because months indexed from 0
            d.setDate(parseInt(bits[2], 10));
            
            return d;
        }
    },
    // mm/dd/yyyy (American style)
    {   re: /(\d{1,2})\\(\d{1,2})\\(\d{4})/,
        handler: function(bits) {
            var d = new Date();
            d.setYear(bits[3]);
            d.setMonth(parseInt(bits[1], 10) - 1); // Because months indexed from 0
            d.setDate(parseInt(bits[2], 10));
            
            return d;
        }
    },
    // mm-dd-yyyy (American style)
    {   re: /(\d{1,2})-(\d{1,2})-(\d{4})/,
        handler: function(bits) {
            var d = new Date();
            d.setYear(bits[3]);
            d.setMonth(parseInt(bits[1], 10) - 1); // Because months indexed from 0
            d.setDate(parseInt(bits[2], 10));
            
            return d;
        }
    },
    // mm/dd/yy (American style)
    {   re: /(\d{1,2})\/(\d{1,2})\/(\d{2})/,
        handler: function(bits) {
            var d = new Date();
            d.setYear('20' + bits[3]);
             d.setMonth(parseInt(bits[1], 10) - 1); // Because months indexed from 0
            d.setDate(parseInt(bits[2], 10));
           
            return d;
        }
    },
     // mm\dd\yy (American style)
    {   re: /(\d{1,2})\\(\d{1,2})\\(\d{2})/,
        handler: function(bits) {
            var d = new Date();
            d.setYear('20' + bits[3]);
             d.setMonth(parseInt(bits[1], 10) - 1); // Because months indexed from 0
            d.setDate(parseInt(bits[2], 10));
           
            return d;
        }
    },
     // mmddyy (American style)
    {   re: /^(\d{2})(\d{2})(\d{2})$/,
        handler: function(bits) {
            var d = new Date();
            d.setYear('20' + bits[3]);
            d.setMonth(parseInt(bits[1], 10) - 1); // Because months indexed from 0
            d.setDate(parseInt(bits[2], 10));           
            return d;
        }
    },  
      // mmddyyyy (American style)
    {   re: /^(\d{2})(\d{2})20(\d{2})$/,
        handler: function(bits) {
            var d = new Date();
            d.setYear('20' + bits[3]);
            d.setMonth(parseInt(bits[1], 10) - 1); // Because months indexed from 0
            d.setDate(parseInt(bits[2], 10));           
            return d;
        }
    },  
    // mm-dd-yy (American style)
    {   re: /(\d{1,2})-(\d{1,2})-(\d{2})/,
        handler: function(bits) {
            var d = new Date();
            d.setYear('20' + bits[3]);
            d.setMonth(parseInt(bits[1], 10) - 1); // Because months indexed from 0
            d.setDate(parseInt(bits[2], 10));
            
            return d;
        }
    },       
    // yyyy-mm-dd (ISO style)
    {   re: /(\d{4})-(\d{1,2})-(\d{1,2})/,
        handler: function(bits) {
            var d = new Date();
            d.setYear(parseInt(bits[1]));
            d.setDate(parseInt(bits[3], 10));
            d.setMonth(parseInt(bits[2], 10) - 1);
            return d;
        }
    },
    // yyyymmdd (ISO style)
    {   re: /^20(\d{2})(\d{2})(\d{2})$/,
        handler: function(bits) {
            var d = new Date();
            d.setYear(parseInt('20' + bits[1]));
            d.setDate(parseInt(bits[3], 10));
            d.setMonth(parseInt(bits[2], 10) - 1);
            
            return d;
        }
    },
];

function parseDateString(s) {
    for (var i = 0; i < dateParsePatterns.length; i++) {
        var re = dateParsePatterns[i].re;
        var handler = dateParsePatterns[i].handler;
        var bits = re.exec(s);
        if (bits) {
            return handler(bits);
        }
    }
    throw new Error("Invalid date string");
}

function magicDate(input) {
    var messagespan = input.id + 'Msg';
    
    try {
        var d = parseDateString(input.value);
        
        input.value = (d.getMonth() + 1) + '/' + d.getDate() + '/' + d.getFullYear();
        input.className = '';
        
        // Human readable date
        document.getElementById(messagespan).firstChild.nodeValue = d.toDateString();
        document.getElementById(messagespan).className = 'normal';
        
        return true;
    }
    catch (e) {
        input.className = 'error';
        
        var message = e.message;
        
        // Fix for IE6 bug
        if (message.indexOf('is null or not an object') > -1) {
            message = 'Invalid date string';
        }
        
        document.getElementById(messagespan).firstChild.nodeValue = message;
        document.getElementById(messagespan).className = 'error';
        
        
        document.getElementById('ctl00_cphLeftContent_ReservationWidget_CheckRatesLinkButton').disabled=true;
        document.getElementById('ctl00_cphLeftContent_ReservationWidget_CheckRatesLinkButton').style.filter='alpha(opacity=25)'
        document.getElementById('ctl00_cphLeftContent_ReservationWidget_ViewRateCalendarLinkButton').style.filter='alpha(opacity=25)' 
        document.getElementById('ctl00_cphLeftContent_ReservationWidget_CheckRatesLinkButton').style.opacity=25
        document.getElementById('ctl00_cphLeftContent_ReservationWidget_ViewRateCalendarLinkButton').style.opacity=25
        document.getElementById('ctl00_cphLeftContent_ReservationWidget_ViewRateCalendarLinkButton').disabled=true; 
                
        
        return false;
    }
}