///////////////////////////////////////////////////////////////
// File Name: 	library.js
///////////////////////////////////////////////////////////////


///////////////////////////////////////////////////////////////
// Form Validation
// Author: 	David Hammond, based on Netscape library
// Description: General form validation functions
///////////////////////////////////////////////////////////////



///////////////////////////////////////////////////////////////
// VARIABLE DECLARATIONS
///////////////////////////////////////////////////////////////

// regualar expression definitions
var reWhitespace = /^\s+$/
var reEmail = /^.+\@.+\..+$/
var reInteger = /^\d+$/
var reFloat = /^((\d+(\.\d*)?)|((\d*\.)?\d+))$/

// prompts for "missing" information
var mPrefix = "You did not enter a value into the \""
var mSuffix = "\" field. This is a required field. Please enter it now."
var mPrefix2 = "You did not select a value for \""
var mSuffix2 = "\". This information is required. Please select a value now."

// prompts for "invalid" information
var iEmail = "We have detected an invalid email address. Please review the email address you've entered and try again."
var iZIPCode = "This field must be a 5 digit U.S. ZIP Code (like 94043). Please reenter it now."


///////////////////////////////////////////////////////////////
// BASIC DATA VALIDATION FUNCTIONS
///////////////////////////////////////////////////////////////

// Check whether string s is empty.
function isEmpty(s) {
	return ((s == null) || (s.length == 0))
}

// Returns true if string s is empty or
// whitespace characters only.
function isWhitespace (s) {
    return (isEmpty(s) || reWhitespace.test(s));
}

// isEmail (STRING s)
function isEmail (s) {
	return reEmail.test(s)
}

// general purpose function to see if a suspected numeric input
// is not empty and is a positive integer
function isNumber(s) {
	return reFloat.test(s)
}

// general purpose function to see if a suspected numeric input
// is not empty and is a positive integer
function isInteger(s) {
	return reInteger.test(s)
}

// isZIPCode (STRING s [, BOOLEAN emptyOK])
//
// isZIPCode returns true if string s is a valid
// U.S. ZIP code.  Must be 5 or 9 digits only.
//
// NOTE: Strip out any delimiters (spaces, hyphens, etc.)
// from string s before calling this function.
function isZIPCode (s) {
   return (isInteger(s) && s.length == 5)
}






///////////////////////////////////////////////////////////////
// FUNCTIONS TO PROMPT USER
///////////////////////////////////////////////////////////////

// Notify user that required field fieldObj is empty.
// String s describes expected contents of fieldObj.value.
// Put focus in fieldObj and return false.
function warnEmpty (fieldObj, s) {
	if (fieldObj.type != "hidden") {
		fieldObj.focus();
	}
    alert(mPrefix + s + mSuffix);
    return false
}

// Notify user that contents of field fieldObj are invalid.
// String s describes expected contents of fieldObj.value.
// Put select fieldObj, pu focus in it, and return false.
function warnInvalid (fieldObj, s) {
	if (fieldObj.type != "hidden") {
		fieldObj.focus();
	    if (fieldObj.type == "text") fieldObj.select()
	}
    alert(s)
    return false
}






///////////////////////////////////////////////////////////////
// FUNCTIONS TO INTERACTIVELY CHECK FIELD CONTENTS
///////////////////////////////////////////////////////////////

// checkText (TEXTFIELD fieldObj, STRING s)
//
// Check that string fieldObj.value is not all whitespace.
function checkText (fieldObj, s) {
	if (isWhitespace(fieldObj.value)) return warnEmpty (fieldObj, s);
    else return true;
}

// checkLength (TEXTAREA fieldObj, INT maxlength, STRING s)
//
// Check length of string fieldObj.value
function checkLength(fieldObj,maxLength,s) {
	if (fieldObj.value.length > maxLength) {
		return warnInvalid (fieldObj, "The value in the \"" + s + "\" field cannot have more than " + maxLength + " characters.\nIt currently has " + fieldObj.value.length + " characters");
	} else {
		return true;
	}
}


// checkChecked (RADIO|CHECKBOX fieldObj, STRING s)
//
// Check that at least one radio or checkbox is checked
function checkChecked (fieldObj, s) {
	if (fieldObj.length) {
		for (i=0; i < fieldObj.length; i++) {
			if (fieldObj[i].checked) return true;
		}
		fieldObj[0].focus();
	} else {
		if (fieldObj.checked) return true;
		fieldObj.focus();
	}
	alert(mPrefix2 + s + mSuffix2);
	return false;
}

// checkSelected (SELECT fieldObj, STRING s)
//
// Check that at least one option has been selected, and it has a value
function checkSelected (fieldObj, s) {
	for (i=0; i < fieldObj.length; i++) {
		if (fieldObj.options[i].selected && fieldObj.options[i].value.length > 0)	return true;
	}
	fieldObj.focus();
	alert(mPrefix2 + s + mSuffix2);
	return false;
}


// checkEmail (TEXTFIELD fieldObj)
//
// Check that string fieldObj.value is a valid Email.
// It is assumed that empty is okay. Run checkText first if this is required
function checkEmail (fieldObj) {
	if (fieldObj.value != "") {
		if (!isEmail(fieldObj.value)) return warnInvalid (fieldObj, iEmail);
	}
	return true;
}

// checkZIPCode (TEXTFIELD theField)
//
// Check that string theField.value is a valid ZIP code.
// It is assumed that empty is okay. Run checkText first if this is required
function checkZIPCode (theField) {
	if (isEmpty(theField.value)) {
		return true;
	} else {
		if (!isZIPCode(theField.value, false)) {
			return warnInvalid (theField, iZIPCode);
		} else {
			return true;
		}
    }
}


// checkNumber (TEXTFIELD fieldObj)
//
// Check that string fieldObj.value is a valid number.
// It is assumed that empty is okay. Run checkText first if this is required
function checkNumber(fieldObj, s) {
	// Strip legitimate characters that will cause SQL problems
	var value = fieldObj.value;
	value = value.replace(/[$,]/g,"");
	if (value == "") {
		fieldObj.value = value;
		return true;
	}
	if (!isNumber(value)) {
		return warnInvalid (fieldObj, "The value in field " + s + " must be a number.");
	} else {
		fieldObj.value = value;
		return true;
	}
}

// checkDate (TEXTFIELD fieldObj)
//
// This function accepts a string variable and verifies if it is a
// proper date or not. It validates format matching either
// mm-dd-yyyy or mm/dd/yyyy. Then it checks to make sure the month
// has the proper number of days, based on which month it is.
//
// It is assumed that empty is okay. Run checkText first if this is required
function checkDate(fieldObj, s) {
	dateStr = fieldObj.value;
	if (isEmpty(dateStr)) return true;

	var datePat = /^(\d{1,2})(\/|-)(\d{1,2})(\/|-)((\d{2}|\d{4}))$/;
	var matchArray = dateStr.match(datePat); // is the format ok?
	if (matchArray == null) {
		return warnInvalid (fieldObj,"Value in field " + s + " must be in the form of mm/dd/yyyy.");
	}
	month = matchArray[1]; // parse date into variables
	day = matchArray[3];
	year = matchArray[5];
	if (month < 1 || month > 12) { // check month range
		return warnInvalid (fieldObj,"Month must be between 1 and 12 for field " + s + ".");
	}
	if (day < 1 || day > 31) {
		return warnInvalid (fieldObj,"Day must be between 1 and 31 for field " + s + ".");
	}
	if ((month==4 || month==6 || month==9 || month==11) && day==31) {
		return warnInvalid (fieldObj,"Month "+month+" doesn't have 31 days for field " + s + ".")
	}
	if (month == 2) { // check for february 29th
		var isleap = (year % 4 == 0 && (year % 100 != 0 || year % 400 == 0));
		if (day > 29 || (day==29 && !isleap)) {
			return warnInvalid (fieldObj,"February " + year + " doesn't have " + day + " days for field " + s + ".");
		}
	}
	return true; // date is valid
}

// checkPhone (TEXTFIELD fieldObj)
//
// Check that string fieldObj.value is a valid phone number.
// It is assumed that empty is okay. Run checkText first if this is required
function checkPhone(fieldObj, s) {
	// Strip legitimate characters that will cause SQL problems
	var value = fieldObj.value;
	if (value == "") {
		return true;
	}
	value = value.replace(/\(/g,"");
	value = value.replace(/\)/g,"");
	value = value.replace(/[\s.x-]/g,"");
	if (!isNumber(value)) {
		return warnInvalid (fieldObj, "The value in field " + s + " must be a valid phone number.");
	}
	if (value.length < 10) {
		return warnInvalid (fieldObj, "The value in field " + s + " must be a valid phone number.");
	}
	return true;
}


///////////////////////////////////////////////////////////////
// OTHER UTILITY FUNCTIONS
///////////////////////////////////////////////////////////////


// Get value of checked radio button or checkbox if multiple are present
function getCheckedValue (fieldObj) {
	for (var i = 0; i < fieldObj.length; i++) {
		if (fieldObj[i].checked) { break }
    }
    return fieldObj[i].value
}

// Get value of selected option
function getSelectedValue (fieldObj) {
	for (var i = 0; i < fieldObj.length; i++) {
		if (fieldObj[i].selected) {
			return fieldObj[i].value
		}
    }
    return "";
}