(function($) {

    /*
    Validation Singleton
    */
    var Validation = function() {

        var rules = {

            email: {
                check: function(value) {

                    if (value)
                        return testPattern(value, ".+@.+\..+");
                    return true;
                },
                msg: "Enter a valid e-mail address."
            },
            url: {

                check: function(value) {

                    if (value)
                        return testPattern(value, "https?://(.+\.)+.{2,4}(/.*)?");
                    return true;
                },
                msg: "Enter a valid URL."
            },
            required: {

                check: function(value) {

                    if (value)
                        return true;
                    else
                        return false;
                },
                msg: "This field is required."
            }
        }
        var testPattern = function(value, pattern) {

            var regExp = new RegExp("^" + pattern + "$", "");
            return regExp.test(value);
        }
        return {

            addRule: function(name, rule) {

                rules[name] = rule;
            },
            getRule: function(name) {

                return rules[name];
            }
        }
    }

    /* 
    Form factory 
    */
    var Form = function(form) {

        var fields = [];
        form.find("input[validation], textarea[validation]").each(function() {

            fields.push(new Field(this));
        });
        this.fields = fields;
    }
    Form.prototype = {
        validate: function() {

            for (field in this.fields) {

                this.fields[field].validate();
            }
        },
        isValid: function() {

            for (field in this.fields) {

                if (!this.fields[field].valid) {

                    this.fields[field].field.focus();
                    return false;
                }
            }
            return true;
        }
    }

    /* 
    Field factory 
    */
    var Field = function(field) {

        this.field = $(field);
        this.valid = false;
        this.attach("change");
    }
    Field.prototype = {

        attach: function(event) {

            var obj = this;
            if (event == "change") {
                obj.field.bind("change", function() {
                    return obj.validate();
                });
            }
            if (event == "keyup") {
                obj.field.bind("keyup", function(e) {
                    return obj.validate();
                });
            }
        },
        validate: function() {

            var obj = this,
                field = obj.field,
                errorClass = "errorlist",
                types = field.attr("validation").split(" "),
                container = field.parent(),
                errors = [];

            field.next(".errorlist").remove();
            for (var type in types) {
                var rule = $.Validation.getRule(types[type]);
                if (!rule.check(field.val())) {
                    container.addClass("error");
                    errors.push(rule.msg);
                }
            }
            if (errors.length) {
                obj.field.unbind("keyup")
                obj.attach("keyup");
                for (error in errors) {
                    $("#l" + $(obj.field).attr("id")).addClass("error");
                }
                $("#errormessage").show();
                obj.valid = false;
            }
            else {
                //container.removeClass("error");
                obj.valid = true;
            }
        }
    }

    /* 
    Validation extends jQuery prototype
    */
    $.extend($.fn, {

        validation: function() {

            var validator = new Form($(this));
            $.data($(this)[0], 'validator', validator);

            $(this).bind("submit", function(e) {
                validator.validate();
                if (!validator.isValid()) {
                    e.preventDefault();
                }
            });
        },
        validate: function() {

            var validator = $.data($(this)[0], 'validator');
            validator.validate();
            return validator.isValid();

        }
    });
    $.Validation = new Validation();
})(jQuery);