/*
	Password Validator 0.1
	(c) 2007 Steven Levithan <stevenlevithan.com>
	MIT License
	
	Validation types supported
	
    *  Minimum and maximum length.
    * Minimum n lowercase characters (a\u2013z).
    * Minimum n uppercase characters (A\u2013Z).
    * Minimum n combined a\u2013z and A\u2013Z characters.
    * Minimum n numeric characters (0\u20139).
    * Minimum n special characters (characters other than a\u2013z, A\u2013Z, and 0\u20139).
    * Ban particular words (tested case-insensitively).
    * Ban n-length character sequences (e.g. "abc", "XYZ", or "789", with a sequence length of 3; does not apply to special characters).
    * Ban n-length qwerty character sequences (e.g. "qwerty" or "asdf", with a sequence length of 4; does not apply to special characters).
    * Ban sequential, identical characters (e.g. "aa" or "!!").
    * Use custom regular expressions (tested using RegExp.prototype.test) and functions (the password is provided as the first argument, and a Boolean value is expected in return).

*/

function validatePassword (pw, options) {
	// default options (allows any password)
	var o = {
		lower:    1,
		upper:    1,
		alpha:    1, /* lower + upper */
		numeric:  1,
		special:  1,
		length:   [10, 10],
		custom:   [ /* regexes and/or functions */ ],
		badWords: [],
		badSequenceLength: 0,
		noQwertySequences: false,
		noSequential:      false
	};

	for (var property in options)
		o[property] = options[property];

	var	re = {
			lower:   /[a-z]/g,
			upper:   /[A-Z]/g,
			alpha:   /[A-Z]/gi,
			numeric: /[0-9]/g,
			special: /[\W_]/g,
			custom: /[!@\u00A3$%^&*()_+]/g			
		},
		rule, i;

	// enforce min/max length
	if (pw.length < o.length[0] || pw.length > o.length[1])
		return false;

	// enforce lower/upper/alpha/numeric/special rules
	for (rule in re) {
		if ((pw.match(re[rule]) || []).length < o[rule])
			return false;
	}

	// enforce word ban (case insensitive)
	for (i = 0; i < o.badWords.length; i++) {
		if (pw.toLowerCase().indexOf(o.badWords[i].toLowerCase()) > -1)
			return false;
	}

	// enforce the no sequential, identical characters rule
	if (o.noSequential && /([\S\s])\1/.test(pw))
		return false;

	// enforce alphanumeric/qwerty sequence ban rules
	if (o.badSequenceLength) {
		var	lower   = "abcdefghijklmnopqrstuvwxyz",
			upper   = lower.toUpperCase(),
			numbers = "0123456789",
			qwerty  = "qwertyuiopasdfghjklzxcvbnm",
			start   = o.badSequenceLength - 1,
			seq     = "_" + pw.slice(0, start);
		for (i = start; i < pw.length; i++) {
			seq = seq.slice(1) + pw.charAt(i);
			if (
				lower.indexOf(seq)   > -1 ||
				upper.indexOf(seq)   > -1 ||
				numbers.indexOf(seq) > -1 ||
				(o.noQwertySequences && qwerty.indexOf(seq) > -1)
			) {
				return false;
			}
		}
	}

	// enforce custom regex/function rules
	for (i = 0; i < o.custom.length; i++) {
		rule = o.custom[i];
		if (rule instanceof RegExp) {
			if (!rule.test(pw))
				return false;
		} else if (rule instanceof Function) {
			if (!rule(pw))
				return false;
		}
	}

	// great success!
	return true;
}