// Set a regular expression for the format and dividers.
var expressionToGetFormat = /[^A-Za-z0-9]/;
var expressionToGetDividers =  /[A-Za-z0-9]/;

function showCalendar(name, dateFormat) {
	var calendar = document.getElementById(name + "Calendar");
	if (calendar.style.visibility == "visible") {
	    // Hide calendar
		calendar.style.visibility = 'hidden';
	} else {
		// Show the calendar.
		calendar.style.visibility = "visible";
		var dateInput = document.getElementById(name +"DateInput");
		var date = parseDate(dateInput.value, dateFormat);
		// Set the month.
		var monthSelect = document.getElementById(name + "Month");
		monthSelect.value=date.getMonth();
		// Set the year.
		var yearSelect = document.getElementById(name + "Year");
		setYears(yearSelect, date.getFullYear());
		// Update the days.
		updateCalendar(name, dateFormat);
	}
}

function updateCalendar(name, dateFormat) {
	var dateInput = document.getElementById(name +"DateInput");
	var selectedDate = parseDate(dateInput.value, dateFormat);
	var monthSelect = document.getElementById(name + "Month");
	var month = monthSelect.value;
	var yearSelect = document.getElementById(name + "Year");
	var year = yearSelect.value;
	// Set the years in the year select.
	setYears(yearSelect, year);
	// Figure out the date that the first day of the week should start with.
	var date = new Date(year, month, 1);
	var dayOfWeek = date.getDay();
	if (dayOfWeek == 0) {
		dayOfWeek = 7;
	}
	date.setDate(date.getDate() - dayOfWeek);
	// Figure out the start of today so it can have a different style.
	var now = new Date();
	var today = new Date(now.getFullYear(), now.getMonth(), now.getDate());
	// Write each day of the month.
	for (row=1; row<=6; row++) {
		for (column=1; column<=7; column++) {
			var dateCell = document.getElementById(name + row + column);
			dateCell.innerHTML = date.getDate();
			dateCell.name = date.getTime();
			if (date.getMonth() != month) {
				dateCell.className = "outside";
			} else if (selectedDate != null && date.getTime() == selectedDate.getTime()) {
				dateCell.className = "selected";
			} else if (date.getTime() == today.getTime()) {
				dateCell.className = "today";
			} else if (date.getDay() == 0 || date.getDay() == 6) {
				dateCell.className = "weekend";
			} else {
				dateCell.className = "weekday";
			}
			date.setDate(date.getDate() + 1);
		}
	}
}

function setYears(yearSelect, selectedYear) {
	// Set the years in the years select.
	yearSelect.options.length = 0;
	for (i = 0; i < 11; i++) {
		var yearOption = selectedYear - 5 + i;
		yearSelect.options[i] = new Option(yearOption, yearOption);
		if (yearOption == selectedYear) {
			yearSelect.options[i].selected = "selected";
		}
	}
}

function setDateInput(dateCell, dateFormat) {
	// Set the date input to be the selected day of week.
	var name = dateCell.id.substring(0, dateCell.id.length - 2);
	var date = new Date(dateCell.name);
	var dateInput = document.getElementById(name + "DateInput");
	dateInput.value = getFormattedDateOnly(date, dateFormat);
	var calendar = document.getElementById(name + "Calendar");
	calendar.style.visibility = "hidden";
	setDateTimeInput(name);
}

function setDateTimeInput(name) {
	// Set the hidden date time input to be the combined date and time.
	var dateInput = document.getElementById(name + "DateInput");
	var timeInput = document.getElementById(name + "TimeInput");
	var dateTimeInput = document.getElementById(name + "DateTimeInput");
	dateTimeInput.value = dateInput.value + " " + timeInput.value;
}

function addTime(name, add, addUnit, dateFormat, timeFormat) {
	var dateInput = document.getElementById(name + "DateInput");
	var timeInput = document.getElementById(name + "TimeInput");
	var date = parseDateAndTime(dateInput.value, dateFormat, timeInput.value, timeFormat);
	if (addUnit == "h") {
		// Add the specified hours.
		date.setHours(date.getHours() + add);
	} else if (addUnit == "m") {
		if (add == 15) {
			// If the add is 15 minutes, round off to next 15 minutes.
			if (date.getMinutes() < 15) {
				date.setMinutes(15);
			} else if (date.getMinutes() < 30) {
				date.setMinutes(30);
			} else if (date.getMinutes() < 45) {
				date.setMinutes(45);
			} else {
				date.setMinutes(0);
				date.setHours(date.getHours() + 1);
			}
		} else if (add == 30) {
			// If the add is 30 minutes, round off to next 30 minutes.
			if (date.getMinutes() < 30) {
				date.setMinutes(30);
			} else {
				date.setMinutes(0);
				date.setHours(date.getHours() + 1);
			}
		} else {
			// Add the specified minutes.
			date.setMinutes(date.getMinutes() + add);
		}
	} else {
		alert("The addUnit '" + addUnit + "' is not valid. Use 'h' or 'm'.");
	}
	if (dateInput.value == "") {
		dateInput.value = getFormattedDateOnly(date, dateFormat);
	}
	timeInput.value = getFormattedTimeOnly(date, timeFormat);
	setDateTimeInput(name);
}

function parseDate(dateString, dateFormat) {
	var date = new Date();
	date.setHours(0);
	date.setMinutes(0);
	date.setSeconds(0);
	date.setMilliseconds(0);
	if (dateString == "") {
		return date;
	}
	// Split the date string and date format up into arrays based on the expressionToGetFormat.
	var splitDateString = dateString.split(expressionToGetFormat);
	var splitDateFormat = dateFormat.split(expressionToGetFormat);
	// Set the month, date, and year based on the split date string and date format arrays.
	for (i = 0; i < splitDateFormat.length; i++) {
		if (splitDateFormat[i].charAt(0) == 'm') {
			date.setMonth(splitDateString[i] - 1);
		} else if (splitDateFormat[i].charAt(0) == 'd') {
			date.setDate(splitDateString[i]);
		} else if (splitDateFormat[i].charAt(0) == 'y') {
			date.setYear(splitDateString[i]);
		} else {
			alert("The parameter '" + splitDateFormat[i] + "' is not valid for a date format.");
		}
	}
	return date;
}

function parseDateAndTime(dateString, dateFormat, timeString, timeFormat) {
	var date = parseDate(dateString, dateFormat);
	if (timeString == "") {
		return date;
	}
	// Split the time string and time format up into arrays based on the expressionToGetFormat.
	var splitTimeString = timeString.split(expressionToGetFormat);
	var splitTimeFormat = timeFormat.split(expressionToGetFormat);
	// Set the hours, minutes, seconds, and milliseconds based on the split time string and time format arrays.
	for (i = 0; i < splitTimeFormat.length; i++) {
		if (splitTimeFormat[i].charAt(0) == 'h') {
			var pmExpression = /pm|p\.m\./;
			date.setHours(splitTimeString[i]);
			if (pmExpression.test(timeString) && date.getHours() != 12) {
				// If 1pm or later, add 12 to hours.
				date.setHours(date.getHours() + 12);
			} else if (!pmExpression.test(timeString) && date.getHours() == 12) {
				// If midnight, subtract 12 from hours.
				date.setHours(date.getHours() - 12);
			}
		} else if (splitTimeFormat[i].charAt(0) == 'H') {
			date.setHours(splitTimeString[i]);
		} else if (splitTimeFormat[i].charAt(0) == 'm') {
			date.setMinutes(splitTimeString[i]);
		} else if (splitTimeFormat[i].charAt(0) == 's') {
			date.setSeconds(splitTimeString[i]);
		} else if (splitTimeFormat[i].charAt(0) == 'S') {
			date.setMilliseconds(splitTimeString[i]);
		} else {
			alert("The parameter '" + splitTimeFormat[i] + "' is not valid for a time format.");
		}

	}
	return date;
}

function getFormattedDateOnly(date, dateFormat) {
	// Split the date format up into arrays based on the expressionToGetFormat.
	var splitDateFormat = dateFormat.split(expressionToGetFormat);
	// Get the dividers.
	var dividers = dateFormat.split(expressionToGetDividers);
	// Set the hours, minutes, seconds, and milliseconds based on the split time string and time format arrays.
	var dateString = "";
	for (i = 0; i < splitDateFormat.length; i++) {
		if (splitDateFormat[i] == 'd') {
			dateString = dateString + date.getDate();
		} else if (splitDateFormat[i] == 'm') {
			dateString = dateString + (date.getMonth() + 1);
		} else if (splitDateFormat[i] == 'y') {
			dateString = dateString + date.getFullYear();
		} else if (splitDateFormat[i] == 'yyyy') {
			dateString = dateString + date.getFullYear();
		} else {
			alert("The parameter '" + splitDateFormat[i] + "' is not valid for a date format.");
		}
		// Add the divider. The regular expression on IE splits the string into just the dividers
		// but on Firefox and Safari, it includes an empty character in the first and last elements.
		if (dividers[0] == "") {
			if (i + 1 < dividers.length) {
				dateString = dateString + dividers[i+1];
			}
		} else {
			if (i < dividers.length) {
				dateString = dateString + dividers[i];
			}
		}
	}
	return dateString;
}

function getFormattedTimeOnly(date, timeFormat) {
	// Split the date format up into arrays based on the expressionToGetFormat.
	var splitTimeFormat = timeFormat.split(expressionToGetFormat);
	// Get the dividers.
	var dividers = timeFormat.split(expressionToGetDividers);
	// Set the hours, minutes, seconds, and milliseconds based on the split time string and time format arrays.
	var timeString = "";
	var ampm = "";
	for (i = 0; i < splitTimeFormat.length; i++) {
		if (splitTimeFormat[i] == 'h') {
			// Format hours with am and pm.
			if (date.getHours() == 0) {
				timeString = timeString + 12;
				ampm = " am";
			} else if (date.getHours() == 12) {
				timeString = timeString + 12;
				ampm = " pm";
			} else if (date.getHours() < 12) {
				timeString = timeString + date.getHours();
				ampm = " am";
			} else {
				timeString = timeString + (date.getHours() - 12);
				ampm = " pm"
			}
		} else if (splitTimeFormat[i] == 'H') {
			/// Format military time.
			timeString = timeString + date.getHours();
		} else if (splitTimeFormat[i] == 'm') {
			// Format minutes.
			if (date.getMinutes() < 10) {
				timeString = timeString + "0";
			}
			timeString = timeString + date.getMinutes();
		} else if (splitTimeFormat[i] == 's') {
			// Format seconds.
			if (date.getSeconds() < 10) {
				timeString = timeString + "0";
			}
			timeString = timeString + date.getSeconds();
		} else if (splitTimeFormat[i] == 'S') {
			// Format milliseconds.
			if (date.getMilliseconds() < 10) {
				timeString = timeString + "000";
			} else if (date.getMilliseconds() < 100) {
				timeString = timeString + "00";
			} else if (date.getMilliseconds() < 1000) {
				timeString = timeString + "0";
			}
			timeString = timeString + date.getMilliseconds();
		} else {
			alert("The parameter '" + splitTimeFormat[i] + "' is not valid for a time format.");
		}
		// Add the divider. The regular expression on IE splits the string into just the dividers
		// but on Firefox and Safari, it includes an empty character in the first and last elements.
		if (dividers[0] == "") {
			if (i + 1 < dividers.length) {
				timeString = timeString + dividers[i+1];
			}
		} else {
			if (i < dividers.length) {
				timeString = timeString + dividers[i];
			}
		}
	}
	timeString = timeString + ampm;
	return timeString;
}