Added tooltip to links via BTTV API.

src/providers/bttv/BttvTooltip.cpp

@@ -0,0 +1,39 @@
+#include "providers/bttv/BttvTooltip.hpp"
+
+#include "common/Common.hpp"
+#include "common/NetworkRequest.hpp"
+
+#include <QString>
+
+namespace chatterino {
+
+void BttvTooltip::getUrlTooltip(const QString url,
+                           std::function<void(QString)> successCallback)
+{
+    QString requestUrl("https://api.betterttv.net/2/link_resolver/" + 
+        QUrl::toPercentEncoding(url, "", "/:"));
+
+    NetworkRequest request(requestUrl);
+    request.setCaller(QThread::currentThread());
+    request.setTimeout(30000);
+    request.onSuccess([successCallback](auto result) mutable -> Outcome {
+        auto root = result.parseJson();
+        /* When tooltip is not a string, in this case, 
+        onError runs before onSuccess, 
+        so there is no point in doing "if" condition. */
+        auto tooltip = root.value("tooltip").toString();
+        successCallback(QUrl::fromPercentEncoding(tooltip.toUtf8()));
+
+        return Success;
+    });
+
+    request.onError([successCallback](auto result) {
+        successCallback("No link info found");
+
+        return true;
+    });
+
+    request.execute();
+}
+
+}  // namespace chatterino

src/providers/bttv/BttvTooltip.hpp

@@ -0,0 +1,17 @@
+#pragma once
+
+#include <QString>
+#include <functional>
+
+namespace chatterino {
+
+class BttvTooltip
+{
+public:
+    static void getUrlTooltip(const QString url,
+                           std::function<void(QString)> callback);
+
+private:
+};
+
+}  // namespace chatterino