Implement an advanced method of adding a user to chatterino.

You can now switch between multiple users in the settings dialog.
(Requires a restart for reconnecting etc)

src/util/urlfetch.hpp

@@ -1,5 +1,7 @@
 #pragma once
 
+#include "credentials.hpp"
+
 #include <QEventLoop>
 #include <QJsonArray>
 #include <QJsonDocument>
@@ -16,6 +18,67 @@
 namespace chatterino {
 namespace util {
 
+namespace twitch {
+
+static void get(QString url, std::function<void(QJsonObject &)> successCallback)
+{
+    auto manager = new QNetworkAccessManager();
+
+    QUrl requestUrl(url);
+    QNetworkRequest request(requestUrl);
+
+    request.setRawHeader("Client-ID", getDefaultClientID());
+    request.setRawHeader("Accept", "application/vnd.twitchtv.v5+json");
+
+    QNetworkReply *reply = manager->get(request);
+
+    QObject::connect(reply, &QNetworkReply::finished, [=] {
+        if (reply->error() == QNetworkReply::NetworkError::NoError) {
+            QByteArray data = reply->readAll();
+            QJsonDocument jsonDoc(QJsonDocument::fromJson(data));
+
+            if (!jsonDoc.isNull()) {
+                QJsonObject rootNode = jsonDoc.object();
+
+                successCallback(rootNode);
+            }
+        }
+
+        reply->deleteLater();
+        manager->deleteLater();
+    });
+}
+
+static void getUserID(QString username, std::function<void(QString)> successCallback)
+{
+    get("https://api.twitch.tv/kraken/users?login=" + username, [=](const QJsonObject &root) {
+        if (!root.value("users").isArray()) {
+            qDebug() << "API Error while getting user id, users is not an array";
+            return;
+        }
+
+        auto users = root.value("users").toArray();
+        if (users.size() != 1) {
+            qDebug() << "API Error while getting user id, users array size is not 1";
+            return;
+        }
+        if (!users[0].isObject()) {
+            qDebug() << "API Error while getting user id, first user is not an object";
+            return;
+        }
+        auto firstUser = users[0].toObject();
+        auto id = firstUser.value("_id");
+        if (!id.isString()) {
+            qDebug()
+                << "API Error: while getting user id, first user object `_id` key is not a string";
+            return;
+        }
+        successCallback(id.toString());
+    });
+}
+
+}  // namespace twitch
+
 static void urlFetch(const QString &url, std::function<void(QNetworkReply &)> successCallback,
                      QNetworkAccessManager *manager = nullptr)
 {