var createXHR = function() {
    if('all' in document && !('atob' in window) && 'XDomainRequest' in window)
        return new XDomainRequest;

    if('XMLHttpRequest' in window)
        return new XMLHttpRequest;

    if('ActiveXObject' in window)
        try {
            return new ActiveXObject('Msxml2.XMLHTTP');
        } catch(e) {
            try {
                return new ActiveXObject('Microsoft.XMLHTTP');
            } catch(e) {}
        }

    throw 'no impl';
}

var getRemoteString = function(url, callback) {
    try {
        var xhr = createXHR();
        xhr.onload = function(ev) {
            callback({ success: true, info: ev, text: xhr.responseText });
        };
        xhr.onerror = function(ev) {
            callback({ success: false, info: ev });
        };
        xhr.open('GET', url);
        xhr.send();
    } catch(ex) {
        callback({ success: false, info: ex });
    }
};

var copyTextInElement = function(target, skipClipboardAPI) {
    if(!skipClipboardAPI && 'clipboard' in navigator) {
        // for some reason I'm supporting IE8 with this and it gets mad over the catch keyword...
        navigator.clipboard.writeText(target.textContent)['catch'](function(ex) {
            copyTextInElement(target, true);
        });
        return;
    }

    if('execCommand' in document) {
        if('createTextRange' in document.body) { // MSIE
            var range = document.body.createTextRange();
            range.moveToElementText(target);
            range.select();
        } else if('getSelection' in window) { // Mozilla
            var select = window.getSelection();
            var range = document.createRange();
            range.selectNodeContents(target);
            select.removeAllRanges();
            select.addRange(range);
        } else return;

        document.execCommand('copy');
        return;
    }
};

(function() {
    var fields = document.querySelectorAll('.js-address');

    for(var i = 0; i < fields.length; ++i)
        (function(field) {
            var valueField = field.querySelector('.js-address-value');
            if(valueField === null)
                return;

            var setValueField = function(text) {
                valueField['textContent' in valueField ? 'textContent' : 'innerText'] = text;
            };

            setValueField('loading...');

            var subdomain = field.getAttribute('data-subdomain');
            if(typeof subdomain !== 'string')
                return;

            var copyButton = field.querySelector('.js-address-copy');

            var host = location.host.split('.');
            host[0] = subdomain;

            var url = location.protocol + '//' + host.join('.') + '/';

            getRemoteString(url, function(info) {

                if(!info.success) {
                    setValueField('not available');
                    return;
                }

                setValueField(info.text);

                if(copyButton)
                    copyButton.onclick = function() { copyTextInElement(valueField); };
            });
        })(fields[i]);
})();