// FormChek.js

// VARIABLE DECLARATIONS

var digits = "0123456789";
var lowercaseLetters = "abcdefghijklmnopqrstuvwxyzёйцукенгшщзхъфывапролджэячсмитьбю"
var uppercaseLetters = "ABCDEFGHIJKLMNOPQRSTUVWXYZЁЙЦУКЕНГШЩЗХЪФЫВАПРОЛДЖЭЯЧСМИТЬБЮ"

var whitespace = " \t\n\r";

var decimalPointDelimiter = "."

// CONSTANT STRING DECLARATIONS

var mPrefix = " Вы не заполнили "
var mSuffix = " . Это поле обязательно. Пожалуйста заполните."

var sUSLastName = "Фамилия"
var sUSFirstName = "Имя"
var sWorldLastName = "Фамилия"
var sWorldFirstName = "Имя"
var sEmail = "Email"
var sOtherInfo = "Дополнительная информация"

var iEmail = "В это поле надо ввести корректный  eMail (например wee@bar.com)."
var iDay = "В это поле надо ввести число от 1 до 31."
var iMonth = "В это поле надо ввести месяц от 1 до 12."
var iYear = "В это поле надо ввести год от 0 до 99."
var iHour = "В это поле надо ввести час от 0 до 23."
var iMinute = "В это поле надо ввести минуту от 0 до 59."
var iDatePrefix = ""
var iDateSuffix = ""

var pEntryPrompt = "Пожалуйста введите "
var pEmail = "корректный  eMail (например foo@bar.com)."
var pDay = "число от 1 до 31."
var pMonth = "ввести месяц от 1 до 12."
var pYear = "2 цифры года от 0 до 99."
var pHour = "число от 0 до 23."
var pMinute = "число от 1 до 59."

var defaultEmptyOK = false


function makeArray(n) {
//*** BUG: If I put this line in, I get two error messages:
//(1) Window.length can't be set by assignment
//(2) daysInMonth has no property indexed by 4
//If I leave it out, the code works fine.
//   this.length = n;
   for (var i = 1; i <= n; i++) {
      this[i] = 0
   } 
   return this
}

var daysInMonth = makeArray(12);
daysInMonth[1] = 31;
daysInMonth[2] = 29;   // must programmatically check this. There is a function DaysInFebruary
daysInMonth[3] = 31;
daysInMonth[4] = 30;
daysInMonth[5] = 31;
daysInMonth[6] = 30;
daysInMonth[7] = 31;
daysInMonth[8] = 31;
daysInMonth[9] = 30;
daysInMonth[10] = 31;
daysInMonth[11] = 30;
daysInMonth[12] = 31;

function isEmpty(s)
{   return ((s == null) || (s.length == 0))
}

function isWhitespace (s)
{   var i;
    if (isEmpty(s)) return true;
    for (i = 0; i < s.length; i++)
    {   // Check that current character isn't whitespace.
        var c = s.charAt(i);
        if (whitespace.indexOf(c) == -1) return false;
    }
    return true;
}


function stripCharsInBag (s, bag)
{   var i;
    var returnString = "";
    for (i = 0; i < s.length; i++)
    {   var c = s.charAt(i);
        if (bag.indexOf(c) == -1) returnString += c;
    }
    return returnString;
}

function stripWhitespace (s)
{   return stripCharsInBag (s, whitespace)
}

function charInString (c, s)
{   for (i = 0; i < s.length; i++)
    {   if (s.charAt(i) == c) return true;
    }
    return false
}

function stripInitialWhitespace (s)
{   var i = 0;
    while ((i < s.length) && charInString (s.charAt(i), whitespace))
       i++;
    return s.substring (i, s.length);
}

function isLetter (c)
{   return ( ((c >= "a") && (c <= "z")) || ((c >= "A") && (c <= "Z")) )
}

function isDigit (c)
{   return ((c >= "0") && (c <= "9"))
}

function isLetterOrDigit (c)
{   return (isLetter(c) || isDigit(c))
}

function isInteger (s)
{   var i;
    if (isEmpty(s)) 
       if (isInteger.arguments.length == 1) return defaultEmptyOK;
       else return (isInteger.arguments[1] == true);
    for (i = 0; i < s.length; i++)
    {   var c = s.charAt(i);
        if (!isDigit(c)) return false;
    }
    return true;
}

function isSignedInteger (s)

{   if (isEmpty(s)) 
       if (isSignedInteger.arguments.length == 1) return defaultEmptyOK;
       else return (isSignedInteger.arguments[1] == true);

    else {
        var startPos = 0;
        var secondArg = defaultEmptyOK;

        if (isSignedInteger.arguments.length > 1)
            secondArg = isSignedInteger.arguments[1];

        // skip leading + or -
        if ( (s.charAt(0) == "-") || (s.charAt(0) == "+") )
           startPos = 1;    
        return (isInteger(s.substring(startPos, s.length), secondArg))
    }
}

function isNonnegativeInteger (s)
{   var secondArg = defaultEmptyOK;

    if (isNonnegativeInteger.arguments.length > 1)
        secondArg = isNonnegativeInteger.arguments[1];
    return (isSignedInteger(s, secondArg)
         && ( (isEmpty(s) && secondArg)  || (parseInt (s) >= 0) ) );
}

function isAlphabetic (s)

{   var i;

    if (isEmpty(s)) 
       if (isAlphabetic.arguments.length == 1) return defaultEmptyOK;
       else return (isAlphabetic.arguments[1] == true);
    for (i = 0; i < s.length; i++)
    {   
        var c = s.charAt(i);
        if (!isLetter(c))
        return false;
    }
    return true;
}

function isAlphanumeric (s)

{   var i;

    if (isEmpty(s)) 
       if (isAlphanumeric.arguments.length == 1) return defaultEmptyOK;
       else return (isAlphanumeric.arguments[1] == true);
    for (i = 0; i < s.length; i++)
    {   
        var c = s.charAt(i);
        if (! (isLetter(c) || isDigit(c) ) )
        return false;
    }
    return true;
}

function isEmail (s)
{   if (isEmpty(s)) 
       if (isEmail.arguments.length == 1) return defaultEmptyOK;
       else return (isEmail.arguments[1] == true);
    if (isWhitespace(s)) return false;
    var i = 1;
    var sLength = s.length;
    while ((i < sLength) && (s.charAt(i) != "@"))
    { i++  }
    if ((i >= sLength) || (s.charAt(i) != "@")) return false;
    else i += 2;
    while ((i < sLength) && (s.charAt(i) != "."))
    { i++  }
    if ((i >= sLength - 1) || (s.charAt(i) != ".")) return false;
    else return true;
}

function isYear (s)
{   if (isEmpty(s)) 
       if (isYear.arguments.length == 1) return defaultEmptyOK;
       else return (isYear.arguments[1] == true);
    if (!isNonnegativeInteger(s)) return false;
    return ((s.length == 2) || (s.length == 4));
}

function isIntegerInRange (s, a, b)
{   if (isEmpty(s)) 
       if (isIntegerInRange.arguments.length == 1) return defaultEmptyOK;
       else return (isIntegerInRange.arguments[1] == true);
    if (!isInteger(s, false)) return false;
    var num = parseInt (s);
    return ((num >= a) && (num <= b));
}

function isMonth (s)
{   if (isEmpty(s)) 
       if (isMonth.arguments.length == 1) return defaultEmptyOK;
       else return (isMonth.arguments[1] == true);
    return isIntegerInRange (s, 1, 12);
}

function isDay (s)
{   if (isEmpty(s)) 
       if (isDay.arguments.length == 1) return defaultEmptyOK;
       else return (isDay.arguments[1] == true);   
    return isIntegerInRange (s, 1, 31);
}

function isHour (s)
{   if (isEmpty(s)) 
       if (isHour.arguments.length == 1) return defaultEmptyOK;
       else return (isHour.arguments[1] == true);   
    return isIntegerInRange (s, 0, 23);
}

function isMinute (s)
{   if (isEmpty(s)) 
       if (isMinute.arguments.length == 1) return defaultEmptyOK;
       else return (isMinute.arguments[1] == true);   
    return isIntegerInRange (s, 0, 59);
}

function daysInFebruary (year)
{   return (  ((year % 4 == 0) && ( (!(year % 100 == 0)) || (year % 400 == 0) ) ) ? 29 : 28 );
}

function isDate (year, month, day)
{   // catch invalid years (not 2- or 4-digit) and invalid months and days.
    if (! (isYear(year, false) && isMonth(month, false) && isDay(day, false))) return false;

    // Explicitly change type to integer to make code work in both
    // JavaScript 1.1 and JavaScript 1.2.
    var intYear = parseInt(year);
    var intMonth = parseInt(month);
    var intDay = parseInt(day);

    // catch invalid days, except for February
    if (intDay > daysInMonth[intMonth]) return false; 

    if ((intMonth == 2) && (intDay > daysInFebruary(intYear))) return false;

    return true;
}

/* FUNCTIONS TO NOTIFY USER OF INPUT REQUIREMENTS OR MISTAKES. */
function prompt (s)
{   window.status = s
}

function promptEntry (s)
{   window.status = pEntryPrompt + s
}

function warnEmpty (theField, s)
{   theField.focus()
    alert(mPrefix + s + mSuffix)
    return false
}

function warnInvalid (theField, s)
{   theField.focus()
    theField.select()
    alert(s)
    return false
}

/* FUNCTIONS TO INTERACTIVELY CHECK VARIOUS FIELDS. */

function checkString (theField, s, emptyOK)
{   if (checkString.arguments.length == 2) emptyOK = defaultEmptyOK;
    if ((emptyOK == true) && (isEmpty(theField.value))) return true;
    if (isWhitespace(theField.value)) 
       return warnEmpty (theField, s);
    else return true;
}

function checkEmail (theField, emptyOK)
{   if (checkEmail.arguments.length == 1) emptyOK = defaultEmptyOK;
    if ((emptyOK == true) && (isEmpty(theField.value))) return true;
    else if (!isEmail(theField.value, false)) 
       return warnInvalid (theField, iEmail);
    else return true;
}

function checkYear (theField, emptyOK)
{   if (checkYear.arguments.length == 1) emptyOK = defaultEmptyOK;
    if ((emptyOK == true) && (isEmpty(theField.value))) return true;
    if (!isYear(theField.value, false)) 
       return warnInvalid (theField, iYear);
    else return true;
}

function checkMonth (theField, emptyOK)
{   if (checkMonth.arguments.length == 1) emptyOK = defaultEmptyOK;
    if ((emptyOK == true) && (isEmpty(theField.value))) return true;
    if (!isMonth(theField.value, false)) 
       return warnInvalid (theField, iMonth);
    else return true;
}

function checkDay (theField, emptyOK)
{   if (checkDay.arguments.length == 1) emptyOK = defaultEmptyOK;
    if ((emptyOK == true) && (isEmpty(theField.value))) return true;
    if (!isDay(theField.value, false)) 
       return warnInvalid (theField, iDay);
    else return true;
}

function checkHour (theField, emptyOK)
{   if (checkHour.arguments.length == 1) emptyOK = defaultEmptyOK;
    if ((emptyOK == true) && (isEmpty(theField.value))) return true;
    if (!isHour(theField.value, false)) 
       return warnInvalid (theField, iHour);
    else return true;
}

function checkMinute (theField, emptyOK)
{   if (checkMinute.arguments.length == 1) emptyOK = defaultEmptyOK;
    if ((emptyOK == true) && (isEmpty(theField.value))) return true;
    if (!isMinute(theField.value, false)) 
       return warnInvalid (theField, iMinute);
    else return true;
}

function checkDate (yearField, monthField, dayField, labelString, OKtoOmitDay)
{   if (checkDate.arguments.length == 4) OKtoOmitDay = false;
    if (!isYear(yearField.value)) return warnInvalid (yearField, iYear);
    if (!isMonth(monthField.value)) return warnInvalid (monthField, iMonth);
    if ( (OKtoOmitDay == true) && isEmpty(dayField.value) ) return true;
    else if (!isDay(dayField.value)) 
       return warnInvalid (dayField, iDay);
    if (isDate (yearField.value, monthField.value, dayField.value))
       return true;
    alert (iDatePrefix + labelString + iDateSuffix)
    return false
}

function getRadioButtonValue (radio)
{   for (var i = 0; i < radio.length; i++)
    {   if (radio[i].checked) { break }
    }
    return radio[i].value
}