/**
* Converts an xs:date or xs:dateTime formatted string into the local timezone
* and outputs a human-readable form of this date or date/time.
*
* @param {string} gCalTime is the xs:date or xs:dateTime formatted string
* @return {string} is the human-readable date or date/time string
*/
function formatGCalDateTime(gCalTime) {
    // text for regex matches
    var remtxt = gCalTime;

    function consume(retxt) {
        var match = remtxt.match(new RegExp('^' + retxt));
        if (match) {
            remtxt = remtxt.substring(match[0].length);
            return match[0];
        }
        return '';
    }

    // minutes of correction between gCalTime and GMT
    var totalCorrMins = 0;

    var year = consume('\\d{4}');
    consume('-?');
    var month = consume('\\d{2}');
    consume('-?');
    var dateMonth = consume('\\d{2}');
    var timeOrNot = consume('T');

    // if a DATE-TIME was matched in the regex 
    if (timeOrNot == 'T') {
        var hours = consume('\\d{2}');
        consume(':?');
        var mins = consume('\\d{2}');
        consume('(:\\d{2})?(\\.\\d{3})?');
        var zuluOrNot = consume('Z');

        // if time from server is not already in GMT, calculate offset
        if (zuluOrNot != 'Z') {
            var corrPlusMinus = consume('[\\+\\-]');
            if (corrPlusMinus != '') {
                var corrHours = consume('\\d{2}');
                consume(':?');
                var corrMins = consume('\\d{2}');
                totalCorrMins = (corrPlusMinus == '-' ? 1 : -1) *
            (Number(corrHours) * 60 +
	    (corrMins == '' ? 0 : Number(corrMins)));
            }
        }

        // get time since epoch and apply correction, if necessary
        // relies upon Date object to convert the GMT time to the local
        // timezone
        var originalDateEpoch = Date.UTC(year, month - 1, dateMonth, hours, mins);
        var gmtDateEpoch = originalDateEpoch + totalCorrMins * 1000 * 60;
        var ld = new Date(gmtDateEpoch);

        // date is originally in YYYY-MM-DD format
        // time is originally in a 24-hour format
        // this converts it to MM/DD hh:mm (AM|PM) 
        dateString = (ld.getMonth() + 1) + '/' + ld.getDate() + ' ' +
        ((ld.getHours() > 12) ? (ld.getHours() - 12) : (ld.getHours() === 0 ? 12 :
	ld.getHours())) + ':' + ((ld.getMinutes() < 10) ? ('0' +
	ld.getMinutes()) : (ld.getMinutes())) + ' ' +
	((ld.getHours() >= 12) ? 'PM' : 'AM');
    } else {
        // if only a DATE was matched
        dateString = parseInt(month, 10) + '/' + parseInt(dateMonth, 10);
    }
    return dateString;
}

function formatGCalTime(gCalTime) {
    // text for regex matches
    var remtxt = gCalTime;

    function consume(retxt) {
        var match = remtxt.match(new RegExp('^' + retxt));
        if (match) {
            remtxt = remtxt.substring(match[0].length);
            return match[0];
        }
        return '';
    }

    // minutes of correction between gCalTime and GMT
    var totalCorrMins = 0;

    var year = consume('\\d{4}');
    consume('-?');
    var month = consume('\\d{2}');
    consume('-?');
    var dateMonth = consume('\\d{2}');
    var timeOrNot = consume('T');

    // if a DATE-TIME was matched in the regex 
    if (timeOrNot == 'T') {
        var hours = consume('\\d{2}');
        consume(':?');
        var mins = consume('\\d{2}');
        consume('(:\\d{2})?(\\.\\d{3})?');
        var zuluOrNot = consume('Z');

        // if time from server is not already in GMT, calculate offset
        if (zuluOrNot != 'Z') {
            var corrPlusMinus = consume('[\\+\\-]');
            if (corrPlusMinus != '') {
                var corrHours = consume('\\d{2}');
                consume(':?');
                var corrMins = consume('\\d{2}');
                totalCorrMins = (corrPlusMinus == '-' ? 1 : -1) *
            (Number(corrHours) * 60 +
	    (corrMins == '' ? 0 : Number(corrMins)));
            }
        }

        // get time since epoch and apply correction, if necessary
        // relies upon Date object to convert the GMT time to the local
        // timezone
        var originalDateEpoch = Date.UTC(year, month - 1, dateMonth, hours, mins);
        var gmtDateEpoch = originalDateEpoch + totalCorrMins * 1000 * 60;
        var ld = new Date(gmtDateEpoch);

        // date is originally in YYYY-MM-DD format
        // time is originally in a 24-hour format
        // this converts it to MM/DD hh:mm (AM|PM) 
        dateString = ((ld.getHours() > 12) ? (ld.getHours() - 12) : (ld.getHours() === 0 ? 12 :
	ld.getHours())) + ':' + ((ld.getMinutes() < 10) ? ('0' +
	ld.getMinutes()) : (ld.getMinutes())) + ' ' +
	((ld.getHours() >= 12) ? 'PM' : 'AM');
    } else {
        // if only a DATE was matched
        dateString = "";
    }
    return dateString;
}