(function() {
    'use strict';
    var timeParsePatterns = [
        // 9
        {
            re: /^\d{1,2}$/i,
            handler: function(bits) {
                if (bits[0].length === 1) {
                    return '0' + bits[0] + ':00';
                } else {
                    return bits[0] + ':00';
                }
            }
        },
        // 13:00
        {
            re: /^\d{2}[:.]\d{2}$/i,
            handler: function(bits) {
                return bits[0].replace('.', ':');
            }
        },
        // 9:00
        {
            re: /^\d[:.]\d{2}$/i,
            handler: function(bits) {
                return '0' + bits[0].replace('.', ':');
            }
        },
        // 3 am / 3 a.m. / 3am
        {
            re: /^(\d+)\s*([ap])(?:.?m.?)?$/i,
            handler: function(bits) {
                var hour = parseInt(bits[1]);
                if (hour === 12) {
                    hour = 0;
                }
                if (bits[2].toLowerCase() === 'p') {
                    if (hour === 12) {
                        hour = 0;
                    }
                    return (hour + 12) + ':00';
                } else {
                    if (hour < 10) {
                        return '0' + hour + ':00';
                    } else {
                        return hour + ':00';
                    }
                }
            }
        },
        // 3.30 am / 3:15 a.m. / 3.00am
        {
            re: /^(\d+)[.:](\d{2})\s*([ap]).?m.?$/i,
            handler: function(bits) {
                var hour = parseInt(bits[1]);
                var mins = parseInt(bits[2]);
                if (mins < 10) {
                    mins = '0' + mins;
                }
                if (hour === 12) {
                    hour = 0;
                }
                if (bits[3].toLowerCase() === 'p') {
                    if (hour === 12) {
                        hour = 0;
                    }
                    return (hour + 12) + ':' + mins;
                } else {
                    if (hour < 10) {
                        return '0' + hour + ':' + mins;
                    } else {
                        return hour + ':' + mins;
                    }
                }
            }
        },
        // noon
        {
            re: /^no/i,
            handler: function(bits) {
                return '12:00';
            }
        },
        // midnight
        {
            re: /^mid/i,
            handler: function(bits) {
                return '00:00';
            }
        }
    ];

    function parseTimeString(s) {
        for (var i = 0; i < timeParsePatterns.length; i++) {
            var re = timeParsePatterns[i].re;
            var handler = timeParsePatterns[i].handler;
            var bits = re.exec(s);
            if (bits) {
                return handler(bits);
            }
        }
        return s;
    }

    window.parseTimeString = parseTimeString;
})();
