connect and heartbeat

discord/discord.cpp

@@ -0,0 +1,85 @@
+#include "discord.hpp"
+
+DiscordClient::DiscordClient() {}
+
+void DiscordClient::Start() {
+    if (m_client_connected)
+        throw std::runtime_error("attempt to start client twice consecutively");
+
+    m_client_connected = true;
+    m_websocket.StartConnection(DiscordGateway);
+    m_websocket.SetJSONCallback(std::bind(&DiscordClient::HandleGatewayMessage, this, std::placeholders::_1));
+}
+
+void DiscordClient::Stop() {
+    if (!m_client_connected) return;
+    m_heartbeat_waiter.kill();
+    m_heartbeat_thread.join();
+    m_client_connected = false;
+}
+
+bool DiscordClient::IsStarted() const {
+    return m_client_connected;
+}
+
+void DiscordClient::HandleGatewayMessage(nlohmann::json j) {
+    GatewayMessage m;
+    try {
+        m = j;
+    } catch (std::exception &e) {
+        printf("Error decoding JSON. Discarding message: %s\n", e.what());
+        return;
+    }
+
+    switch (m.Opcode) {
+        case GatewayOp::Hello: {
+            HelloMessageData d = m.Data;
+            m_heartbeat_msec = d.HeartbeatInterval;
+            m_heartbeat_thread = std::thread(std::bind(&DiscordClient::HeartbeatThread, this));
+        } break;
+        case GatewayOp::HeartbeatAck: {
+            m_heartbeat_acked = true;
+        } break;
+        default:
+            printf("Unknown opcode %d\n", m.Opcode);
+            break;
+    }
+}
+
+void DiscordClient::HeartbeatThread() {
+    while (m_client_connected) {
+        if (!m_heartbeat_acked) {
+            printf("wow! a heartbeat wasn't acked! how could this happen?");
+        }
+
+        m_heartbeat_acked = false;
+
+        HeartbeatMessage msg;
+        msg.Sequence = m_last_sequence;
+        nlohmann::json j = msg;
+        m_websocket.Send(j.dump());
+
+        if (!m_heartbeat_waiter.wait_for(std::chrono::milliseconds(m_heartbeat_msec)))
+            break;
+    }
+}
+
+void from_json(const nlohmann::json &j, GatewayMessage &m) {
+    j.at("op").get_to(m.Opcode);
+    m.Data = j.at("d");
+
+    if (j.contains("t") && !j.at("t").is_null())
+        j.at("t").get_to(m.Type);
+}
+
+void from_json(const nlohmann::json &j, HelloMessageData &m) {
+    j.at("heartbeat_interval").get_to(m.HeartbeatInterval);
+}
+
+void to_json(nlohmann::json &j, const HeartbeatMessage &m) {
+    j["op"] = GatewayOp::Heartbeat;
+    if (m.Sequence == -1)
+        j["d"] = nullptr;
+    else
+        j["d"] = m.Sequence;
+}