Ensure live status requests are always batched (#4713)

src/controllers/twitch/LiveController.hpp

@@ -0,0 +1,89 @@
+#pragma once
+
+#include "common/Singleton.hpp"
+#include "util/QStringHash.hpp"
+
+#include <QString>
+#include <QTimer>
+
+#include <chrono>
+#include <memory>
+#include <mutex>
+#include <optional>
+#include <shared_mutex>
+#include <unordered_map>
+#include <unordered_set>
+
+namespace chatterino {
+
+class TwitchChannel;
+
+class ITwitchLiveController
+{
+public:
+    virtual ~ITwitchLiveController() = default;
+
+    virtual void add(const std::shared_ptr<TwitchChannel> &newChannel) = 0;
+};
+
+class TwitchLiveController : public ITwitchLiveController, public Singleton
+{
+public:
+    // Controls how often all channels have their stream status refreshed
+    static constexpr std::chrono::seconds REFRESH_INTERVAL{30};
+
+    // Controls how quickly new channels have their stream status loaded
+    static constexpr std::chrono::seconds IMMEDIATE_REQUEST_INTERVAL{1};
+
+    /**
+     * How many channels to include in a single request
+     *
+     * Should not be more than 100
+     **/
+    static constexpr int BATCH_SIZE{100};
+
+    TwitchLiveController();
+
+    // Add a Twitch channel to be queried for live status
+    // A request is made within a few seconds if this is the first time this channel is added
+    void add(const std::shared_ptr<TwitchChannel> &newChannel) override;
+
+private:
+    /**
+     * Run batched Helix Channels & Stream requests for channels
+     *
+     * If a list of channel IDs is passed to request, we only make a request for those channels
+     *
+     * If no list of channels is passed to request (the default behaviour), we make requests for all channels
+     * in the `channels` map.
+     **/
+    void request(std::optional<QStringList> optChannelIDs = std::nullopt);
+
+    /**
+     * List of channel IDs pointing to their Twitch Channel
+     *
+     * These channels will have their stream status updated every REFRESH_INTERVAL seconds
+     **/
+    std::unordered_map<QString, std::weak_ptr<TwitchChannel>> channels;
+    std::shared_mutex channelsMutex;
+
+    /**
+     * List of channels that need an immediate live status update
+     *
+     * These channels will have their stream status updated after at most IMMEDIATE_REQUEST_INTERVAL seconds
+     **/
+    std::unordered_set<QString> immediateRequests;
+    std::mutex immediateRequestsMutex;
+
+    /**
+     * Timer responsible for refreshing `channels`
+     **/
+    QTimer refreshTimer;
+
+    /**
+     * Timer responsible for refreshing `immediateRequests`
+     **/
+    QTimer immediateRequestTimer;
+};
+
+}  // namespace chatterino