subscribe_button = document.getElementById("subscribe");
if (subscribe_button.getAttribute('onclick')) {
    subscribe_button["href"] = "javascript:void(0)";
}

function subscribe(timeouts = 0) {
    subscribe_button = document.getElementById("subscribe");

    if (timeouts > 10) {
        console.log("Failed to subscribe.");
        return;
    }

    var url = "/subscription_ajax?action_create_subscription_to_channel=1&c=<%= ucid %>&referer=<%= env.get("current_page") %>";
    var xhr = new XMLHttpRequest();
    xhr.responseType = "json";
    xhr.timeout = 20000;
    xhr.open("GET", url, true);
    xhr.send();

    var fallback = subscribe_button.innerHTML;
    subscribe_button.onclick = unsubscribe;
    subscribe_button.innerHTML = '<b><%= translate(locale, "Unsubscribe").gsub("'", "\\'") %> | <%= sub_count_text %></b>'

    xhr.onreadystatechange = function() {
        if (xhr.readyState == 4) {
            if (xhr.status != 200) {
                subscribe_button.onclick = subscribe;
                subscribe_button.innerHTML = fallback;
            }
        }
    }

    xhr.ontimeout = function() {
        console.log("Subscribing timed out.");

        subscribe(timeouts + 1);
    };
}

function unsubscribe(timeouts = 0) {
    subscribe_button = document.getElementById("subscribe");

    if (timeouts > 10) {
        console.log("Failed to subscribe");
        return;
    }

    var url = "/subscription_ajax?action_remove_subscriptions=1&c=<%= ucid %>&referer=<%= env.get("current_page") %>";
    var xhr = new XMLHttpRequest();
    xhr.responseType = "json";
    xhr.timeout = 20000;
    xhr.open("GET", url, true);
    xhr.send();

    var fallback = subscribe_button.innerHTML;
    subscribe_button.onclick = subscribe;
    subscribe_button.innerHTML = '<b><%= translate(locale, "Subscribe").gsub("'", "\\'") %> | <%= sub_count_text %></b>'

    xhr.onreadystatechange = function() {
        if (xhr.readyState == 4) {
            if (xhr.status != 200) {
                subscribe_button.onclick = unsubscribe;
                subscribe_button.innerHTML = fallback;
            }
        }
    }

    xhr.ontimeout = function() {
        console.log("Unsubscribing timed out.");

        unsubscribe(timeouts + 1);
    };
}