dateParsers.js

var vic = require('./vic').vic;
var singular = require('./singularValidators');
var DateRange = require('./DateRange');
var Date = require('./Date');
var NativeDate = Date.NativeDate;

// Regexes adaped/used in the regexBuilder (r)
// Flag hard-set to 'i';
var YEAR = /(\d{2,4})/;
var MONTH = /(\d{1,2})/;
var DAY = /(\d{1,2}\s*(?:[a-z]{2}(?![a-z]))?)/;
var WORD = /\b([A-Z]+)/;
var DASH = /(-|–)/;
var SEP = /(,|\.|\/|\||-|–)/; // i.e. Date Numerical separators
var COMMA = /(;|,|\s+)/;
var TIME = /(\d{1,2}(?:[:,.-]\d{1,2})?\s*(?:AM|PM)?)/;

function isValidDay(oneBasedDay, zeroBasedMonth, year) {
	// If Day is > than next month's zeroth day (i.e. its previous months last)
	// then we can say it is invalid
	return oneBasedDay > 0 && oneBasedDay <= new NativeDate(year, zeroBasedMonth + 1, 0).getDate();
}

function r() { // regex builder
	// NOTE: This will discard flags of the regexes:
	var r = '';
	for (var i = 0, l = arguments.length; i < l; ++i) {
		var a = arguments[i];
		r += (a instanceof RegExp ? a.source : a);
		// Separate each component by optional whitespace characters:
		r += '\\s*';
	}
	return RegExp(r, 'i');
}

/**
 * All parsers for Dates and Date Ranges
 */
module.exports = [

	/**********
	 * RANGES *
	 **********/

	// * 01 January - Tue 31 December 2013
	vic(r(DAY, WORD, DASH, WORD, DAY, WORD, YEAR), {
		1: singular.day,
		2: singular.monthName,
		5: singular.day,
		6: singular.monthName,
		7: singular.year
	}, function(startDay, startMonth, _a, _b, endDay, endMonth, year) {

		if (
			(startMonth > endMonth) ||
			(startMonth === endMonth && startDay >= endDay)
		) {
			return false;
		}

		if (!isValidDay(startDay, startMonth, year) || !isValidDay(endDay, endMonth, year)) {
			return false;
		}

		return new DateRange(
			new Date(year, startMonth, startDay),
			new Date(year, endMonth, endDay)
		);
	}),

	// 20 April, 2013 - 12:00 to 18:00
	vic(r(DAY, WORD, COMMA, YEAR, DASH, TIME, /(to)/, TIME), {
		1: singular.day,
		2: singular.monthName,
		4: singular.year,
		6: singular.time,
		8: singular.time
	}, function(day, month, _a, year, _b, startTime, _c, endTime) {

		if (
			startTime.h > endTime.h ||
			(startTime.h === endTime.h && startTime.m > endTime.m)
		) {
			return false;
		}

		if (!isValidDay(day, month, year)) {
			return false;
		}

		return new DateRange(
			new Date(year, month, day, startTime.h, startTime.m, startTime.s),
			new Date(year, month, day, endTime.h, endTime.m, endTime.s)
		);
	}),

	// 27 February 2012 – 19 May 2013
	vic(r(DAY, WORD, YEAR, DASH, DAY, WORD, YEAR), {
		1: singular.day,
		2: singular.monthName,
		3: singular.year,
		5: singular.day,
		6: singular.monthName,
		7: singular.year
	}, function(startDay, startMonth, startYear, _dash, endDay, endMonth, endYear) {

		if (
			startYear > endYear ||
			(startYear === endYear && startMonth >= endMonth) ||
			(startYear === endYear && startMonth === endMonth && startDay >= endDay)
		) {
			return false;
		}

		if (!isValidDay(startDay, startMonth, startYear) || !isValidDay(endDay, endMonth, endYear)) {
			return false;
		}

		return new DateRange(
			new Date(startYear, startMonth, startDay),
			new Date(endYear, endMonth, endDay)
		);
	}),

	// 27 February – 19 May 2013
	vic(r(DAY, WORD, DASH, DAY, WORD, YEAR), {
		1: singular.day,
		2: singular.monthName,
		4: singular.day,
		5: singular.monthName,
		6: singular.year
	}, function(startDay, startMonth, _dash, endDay, endMonth, year) {

		if (startMonth > endMonth || (startMonth === endMonth && startDay >= endDay)) {
			return false;
		}

		if (!isValidDay(startDay, startMonth, year) || !isValidDay(endDay, endMonth, year)) {
			return false;
		}

		return new DateRange(
			new Date(year, startMonth, startDay),
			new Date(year, endMonth, endDay)
		);
	}),

	// 01 - 02 April 2013
	vic(r(DAY, DASH, DAY, WORD, YEAR), {
		1: singular.day,
		3: singular.day,
		4: singular.monthName,
		5: singular.year
	}, function(startDay, _dash, endDay, month, year) {

		if (startDay >= endDay) {
			return false;
		}

		if (!isValidDay(startDay, month, year) || !isValidDay(endDay, month, year)) {
			return false;
		}

		return new DateRange(
			new Date(year, month, startDay),
			new Date(year, month, endDay)
		);
	}),

	/*************
	 * SINGLULAR *
	 *************/

	 // 13 April 2013, 12:00 PM 
	 vic(r(DAY, WORD, YEAR, COMMA, TIME), {
		1: singular.day,
		2: singular.monthName,
		3: singular.year,
		5: singular.time
	 }, function(day, month, year, _c, time) {

		if (!isValidDay(day, month, year)) {
			return false;
		}

		var d = new Date(year, month, day, time.h, time.m, time.s);

		d.setIsSpecificTime(true);

		return d;
	 }),

	 // 20:00 19/04/13
	 vic(r(TIME, DAY, SEP, MONTH, SEP, YEAR), {
		1: singular.time,
		2: singular.day,
		4: singular.month,
		6: singular.year
	 }, function(time, day, _a, month, _b, year) {

		if (!isValidDay(day, month, year)) {
			return false;
		}

		var d = new Date(year, month, day, time.h, time.m, time.s);

		d.setIsSpecificTime(true);

		return d;
	}),

	 // 13 April 2013
	 vic(r(DAY, WORD, YEAR), {
		1: singular.day,
		2: singular.monthName,
		3: singular.year
	 }, function(day, month, year) {

		if (!isValidDay(day, month, year)) {
			return false;
		}

		return new Date(year, month, day);
	 })

];