var Contact = {

    Process: function() {
        if (Contact.IsEnquiry()) {
            var pagename = document.referrer.split('/').pop();
            var expression = (pagename.charAt(1) === 'c') ? Contact.CATEGORY_PRODUCT_FILE_NAME_EXPRESSION : Contact.PRODUCT_FILE_NAME_EXPRESSION;
            var parsedPageName = expression.exec(pagename);
            if (parsedPageName && parsedPageName.length === 3) {
                $('input[name=Subject]').val('RE: ' + parsedPageName[2].replace(/-/g, ' ') + ' (SKU: ' + Contact.ExtractSKU() + ')');
                return;
            }
        }
    },

    IsEnquiry: function() {
        var qs = new Querystring();
        return qs.get("source", "") === "enquiry";
    },
    
    ExtractSKU: function() {
        var qs = new Querystring();
        return qs.get("sku", "");
    },

    PRODUCT_FILE_NAME_EXPRESSION: /^p-(\d+)-(.+)\.aspx$/,

    CATEGORY_PRODUCT_FILE_NAME_EXPRESSION: /^pc-(\d+)-\d+-(.+)\.aspx$/

};

function Querystring(qs) { // optionally pass a querystring to parse
    this.params = {};

    if (qs == null) qs = location.search.substring(1, location.search.length);
    if (qs.length == 0) return;

    qs = qs.replace(/\+/g, ' ');
    var args = qs.split('&'); // parse out name/value pairs separated via &

    for (var i = 0; i < args.length; i++) {
        var pair = args[i].split('=');
        var name = decodeURIComponent(pair[0]);

        var value = (pair.length == 2)
			? decodeURIComponent(pair[1])
			: name;

        this.params[name] = value;
    }
}

Querystring.prototype.get = function(key, default_) {
    var value = this.params[key];
    return (value != null) ? value : default_;
}

Querystring.prototype.contains = function(key) {
    var value = this.params[key];
    return (value != null);
}

Contact.Process();