WebSocketClient.hpp

/*
	MIT License

	DiscordCoreAPI, A bot library for Discord, written in C++, and featuring explicit multithreading through the usage of custom, asynchronous C++ CoRoutines.

	Copyright 2022, 2023 Chris M. (RealTimeChris)

	Permission is hereby granted, free of charge, to any person obtaining a copy
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	in the Software without restriction, including without limitation the rights
	to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
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	The above copyright notice and this permission notice shall be included in all
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	THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
	IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
	FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
	AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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	OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
	SOFTWARE.
*/
/// WebsocketClient.hpp - Header for the webSocket related classes and
/// structs. may 13, 2021 Chris M.
/// https://discordcoreapi.com
/// \file WebsocketClient.hpp
#pragma once

#include <discordcoreapi/Utilities/AudioDecoder.hpp>
#include <discordcoreapi/FoundationEntities.hpp>
#include <discordcoreapi/Utilities/EventEntities.hpp>
#include <discordcoreapi/Utilities/TCPConnection.hpp>
#include <discordcoreapi/Utilities/Etf.hpp>
#include <thread>

namespace discord_core_api {

	namespace discord_core_internal {

		constexpr uint16_t webSocketMaxPayloadLengthLarge{ 65535u };
		constexpr uint8_t webSocketPayloadLengthMagicLarge{ 126u };
		constexpr uint8_t webSocketPayloadLengthMagicHuge{ 127u };
		constexpr uint8_t maxHeaderSize{ sizeof(uint64_t) + 2u };
		constexpr uint8_t webSocketMaxPayloadLengthSmall{ 125u };
		constexpr uint8_t webSocketMaskBit{ (1u << 7u) };

		enum class websocket_op_code : uint8_t { Op_Continuation = 0x00, Op_Text = 0x01, Op_Binary = 0x02, Op_Close = 0x08, Op_Ping = 0x09, Op_Pong = 0x0a };

		/// @brief Websocket close codes.
		class websocket_close {
		  public:
			/// @brief Websocket close codes.
			enum class websocket_close_code : uint16_t {
				Unset				  = 0,///< Unset.
				Normal_Close		  = 1000,///< Normal close.
				Unknown_Error		  = 4000,///< We're not sure what went wrong. try reconnecting?
				Unknown_Opcode		  = 4001,///< You sent an invalid gateway opcode or an invalid payload for an opcode. don't do that!
				Decode_Error		  = 4002,///< You sent an invalid payload to us. don't do that!
				Not_Authenticated	  = 4003,///< You sent us a payload prior to identifying.
				Authentication_Failed = 4004,///< The account token sent with your identify payload is incorrect.
				Already_Authenticated = 4005,///< You sent more than one identify payload. don't do that!
				Invalid_Seq			  = 4007,///<	the sequence sent when resuming the session was invalid. reconnect and start a new session.
				Rate_Limited		  = 4008,///< Woah nelly! you're sending payloads to us too quickly. slow it down! you will be disconnected on receiving this.
				Session_Timed		  = 4009,///< Your session timed out. reconnect and start a new one.
				Invalid_Shard		  = 4010,///< You sent us an invalid shard when identifying.
				Sharding_Required	  = 4011,///< The session would have handled too many guilds - you are required to shard your connection in order to connect.
				Invalid_API_Version	  = 4012,///< You sent an invalid version for the gateway.
				Invalid_Intent		  = 4013,///< You sent an invalid intent for a gateway intent. you may have incorrectly calculated the bitwise value.
				Disallowed_Intent	  = 4014,///< You sent a disallowed intent for a gateway intent. you may have tried to specify an intent that you have not enabled.
			};

			DCA_INLINE static unordered_map<websocket_close_code, jsonifier::string> outputErrorValues{ {
																										websocket_close_code::Unknown_Error,
																										"we're not sure what went wrong.",
																									},
				{ websocket_close_code::Unknown_Opcode, "you sent an invalid gateway opcode or an invalid payload for an opcode. don't do that!" },
				{ websocket_close_code::Decode_Error, "you sent an invalid payload to discord. don't do that!" },
				{ websocket_close_code::Not_Authenticated, "you sent us a payload prior to identifying." },
				{ websocket_close_code::Authentication_Failed, "The account token sent with your identify payload is incorrect." },
				{ websocket_close_code::Already_Authenticated, "you sent more than one identify payload. don't do that!" },
				{ websocket_close_code::Invalid_Seq, "The sequence sent when resuming the session was invalid. reconnect and start a new session." },
				{ websocket_close_code::Rate_Limited, "woah nelly! you're sending payloads to us too quickly. slow it down! you will be disconnected on receiving this." },
				{ websocket_close_code::Session_Timed, "your session timed out. reconnect and start a new one." },
				{ websocket_close_code::Invalid_Shard, "you sent us an invalid shard when identifying." },
				{ websocket_close_code::Sharding_Required, "The session would have handled too many guilds - you are required to shard your connection in order to connect." },
				{ websocket_close_code::Invalid_API_Version, "you sent an invalid version for the gateway." },
				{ websocket_close_code::Invalid_Intent, "you sent an invalid intent for a gateway intent. you may have incorrectly calculated the bitwise value." },
				{ websocket_close_code::Disallowed_Intent,
					"you sent a disallowed intent for a gateway intent. you may have tried to specify an intent that you have not enabled or are not "
					"approved for." } };

			websocket_close_code value{};

			DCA_INLINE websocket_close& operator=(uint16_t valueNew) {
				value = static_cast<websocket_close_code>(valueNew);
				return *this;
			};

			DCA_INLINE websocket_close(uint16_t valueNew) {
				*this = valueNew;
			};

			DCA_INLINE operator jsonifier::string_view() {
				return websocket_close::outputErrorValues[static_cast<websocket_close_code>(value)];
			}
		};

		class DiscordCoreAPI_Dll event_converter {
		  public:
			event_converter(const jsonifier::string& eventNew);

			operator uint64_t();

		  protected:
			jsonifier::string_view eventValue{};
		};

		/// @brief For the opcodes that could be sent/received via discord's websockets.
		enum class websocket_op_codes {
			dispatch			  = 0,///< An event was dispatched.
			heartbeat			  = 1,///< Fired periodically by the client to keep the connection alive.
			identify			  = 2,///< Starts a new session during the initial handshake.
			Presence_Update		  = 3,///< Update the client's presence.
			Voice_State_Update	  = 4,///< Used to join/leave or move between voice channels.
			resume				  = 6,///< Resume a previous session that was disconnected.
			reconnect			  = 7,///< You should attempt to reconnect and resume immediately.
			Request_Guild_Members = 8,///< Request information about offline guild members in a large guild.
			Invalid_Session		  = 9,/// the session has been invalidated. you should reconnect and identify/resume accordingly.
			hello				  = 10,///< Sent immediately after connecting, contains the heartbeat_interval to use.
			Heartbeat_ACK		  = 11,///<sent in response to receiving a heartbeat to acknowledge that it has been received.
		};

		class websocket_core;

		class DiscordCoreAPI_Dll websocket_tcpconnection : public tcp_connection<websocket_tcpconnection> {
		  public:
			friend class websocket_core;

			DCA_INLINE websocket_tcpconnection() = default;

			DCA_INLINE websocket_tcpconnection& operator=(websocket_tcpconnection&& other) = default;
			DCA_INLINE websocket_tcpconnection(websocket_tcpconnection&& other)			   = default;

			websocket_tcpconnection(const jsonifier::string& baseUrlNew, uint16_t portNew, websocket_core* ptrNew);

			void handleBuffer() override;

		  protected:
			websocket_core* ptr{};
		};

		enum class websocket_type { normal = 0, voice = 1 };

		enum class websocket_state { connecting = 0, upgrading = 1, Collecting_Hello = 2, Sending_Identify = 3, authenticated = 4, disconnected = 5 };

		class DiscordCoreAPI_Dll websocket_core {
		  public:
			friend class discord_core_api::voice_connection;
			friend class websocket_tcpconnection;

			DCA_INLINE websocket_core() = default;

			websocket_core& operator=(websocket_core&& data) noexcept;
			websocket_core(websocket_core&& data) noexcept;

			websocket_core(config_manager* configManagerNew, websocket_type typeOfWebSocketNew);

			template<typename value_type> void createHeader(jsonifier::string_base<value_type>& outBuffer, websocket_op_code opCode) {
				int64_t originalSize{ static_cast<int64_t>(outBuffer.size()) };
				outBuffer.insert(outBuffer.begin(), static_cast<value_type>(static_cast<uint8_t>(opCode) | webSocketMaskBit));

				int64_t indexCount{};
				if (originalSize <= webSocketMaxPayloadLengthSmall) {
					outBuffer.insert(outBuffer.begin() + 1, static_cast<value_type>(originalSize));
					indexCount = 0;
				} else if (originalSize <= webSocketMaxPayloadLengthLarge) {
					outBuffer.insert(outBuffer.begin() + 1, static_cast<value_type>(webSocketPayloadLengthMagicLarge));
					indexCount = 2;
				} else {
					outBuffer.insert(outBuffer.begin() + 1, static_cast<value_type>(webSocketPayloadLengthMagicHuge));
					indexCount = 8;
				}
				for (int64_t x = indexCount - 1; x >= 0; x--) {
					outBuffer.insert(outBuffer.begin() + 1 + indexCount - x, static_cast<value_type>(originalSize >> (x * 8)));
				}

				outBuffer.at(1) |= webSocketMaskBit;
				outBuffer.insert(outBuffer.begin() + 2 + indexCount, 0);
				outBuffer.insert(outBuffer.begin() + 3 + indexCount, 0);
				outBuffer.insert(outBuffer.begin() + 4 + indexCount, 0);
				outBuffer.insert(outBuffer.begin() + 5 + indexCount, 0);
			}

			bool connect(const jsonifier::string& baseUrlNew, jsonifier::string_view relativePath, const uint16_t portNew);

			virtual bool onMessageReceived(jsonifier::string_view_base<uint8_t> message) = 0;

			bool sendMessage(jsonifier::string_base<uint8_t>& dataToSend, bool priority);

			bool checkForAndSendHeartBeat(bool = false);

			void parseConnectionHeaders();

			virtual void onClosed() = 0;

			bool areWeConnected();

			bool parseMessage();

			void disconnect();

			virtual ~websocket_core() = default;

		  protected:
			stop_watch<milliseconds> heartBeatStopWatch{ 20000ms };
			jsonifier::string_base<uint8_t> currentMessage{};
			std::atomic<websocket_state> currentState{};
			bool haveWeReceivedHeartbeatAck{ true };
			std::atomic_bool areWeCollectingData{};
			websocket_tcpconnection tcpConnection{};
			uint32_t maxReconnectTries{ 10 };
			uint32_t currentReconnectTries{};
			std::array<uint64_t, 2> shard{};
			config_manager* configManager{};
			uint32_t lastNumberReceived{};
			websocket_op_code dataOpCode{};
			std::mutex accessMutex{};
			bool areWeHeartBeating{};
			websocket_type wsType{};
			bool areWeResuming{};
		};

		/// @brief A websocket client, for communication via a tcp-connection.
		class DiscordCoreAPI_Dll websocket_client : public websocket_core {
		  public:
			friend struct discord_core_api::on_voice_server_update_data;
			friend struct discord_core_api::on_voice_state_update_data;
			friend class tcp_connection<websocket_tcpconnection>;
			friend class discord_core_api::discord_core_client;
			friend class discord_core_api::voice_connection;
			friend class discord_core_api::bot_user;
			friend class base_socket_agent;
			friend class sound_cloud_api;
			friend class websocket_core;
			friend class you_tube_api;

			DCA_INLINE websocket_client() = default;

			DCA_INLINE websocket_client& operator=(websocket_client&&) = default;
			DCA_INLINE websocket_client(websocket_client&&)			   = default;

			websocket_client(uint64_t currentShardNew, std::atomic_bool* doWeQuitNew);

			void getVoiceConnectionData(const voice_connect_init_data& doWeCollect);

			bool onMessageReceived(jsonifier::string_view_base<uint8_t> message) override;

			void disconnect();

			void onClosed() override;

			virtual ~websocket_client();

		  protected:
			unordered_map<uint64_t, unbounded_message_block<voice_connection_data>*> voiceConnectionDataBufferMap{};
			voice_connection_data voiceConnectionData{};
			jsonifier::string resumeUrl{};
			jsonifier::string sessionId{};
			std::atomic_bool* doWeQuit{};
			bool serverUpdateCollected{};
			bool stateUpdateCollected{};
			snowflake userId{};
		};

		class DiscordCoreAPI_Dll base_socket_agent {
		  public:
			friend class discord_core_api::discord_core_client;
			friend class discord_core_api::bot_user;

			base_socket_agent(std::atomic_bool* doWeQuitNew);

			void connect(websocket_client& value);

			~base_socket_agent();

		  protected:
			unordered_map<uint64_t, websocket_client> shardMap{};
			std::deque<connection_package> connections{};
			std::atomic_bool* doWeQuit{};
			std::jthread taskThread{};

			void run(std::stop_token);
		};

	}// namespace
}