var transmit = (function () {

var exports = {};

var socket;
if (page_params.use_websockets) {
    socket = new Socket("/sockjs");
}
// For debugging.  The socket will eventually move out of this file anyway.
exports._socket = socket;

function send_message_socket(request, success, error) {
    request.socket_user_agent = navigator.userAgent;
    socket.send(request, success, function (type, resp) {
        var err_msg = "Error sending message";
        if (type === 'response') {
            err_msg += ": " + resp.msg;
        }
        error(err_msg);
    });
}

function send_message_ajax(request, success, error) {
    channel.post({
        url: '/json/messages',
        data: request,
        success: success,
        error: function (xhr, error_type) {
            if (error_type !== 'timeout' && reload.is_pending()) {
                // The error might be due to the server changing
                reload.initiate({immediate: true,
                                 save_pointer: true,
                                 save_narrow: true,
                                 save_compose: true,
                                 send_after_reload: true});
                return;
            }

            var response = channel.xhr_error_message("Error sending message", xhr);
            error(response);
        },
    });
}

exports.send_message = function (request, on_success, error) {
    function success(data) {
        // Call back to our callers to do things like closing the compose
        // box and turning off spinners and reifying locally echoed messages.
        on_success(data);

        // Once everything is done, get ready to report times to the server.
        sent_messages.report_server_ack(request.local_id);
    }

    if (page_params.use_websockets) {
        send_message_socket(request, success, error);
    } else {
        send_message_ajax(request, success, error);
    }
};

return exports;
}());

if (typeof module !== 'undefined') {
    module.exports = transmit;
}