/*
 *  IXWebSocket.cpp
 *  Author: Benjamin Sergeant
 *  Copyright (c) 2017-2018 Machine Zone, Inc. All rights reserved.
 */

#include "IXWebSocket.h"

#include "IXExponentialBackoff.h"
#include "IXSetThreadName.h"
#include "IXUniquePtr.h"
#include "IXUtf8Validator.h"
#include "IXWebSocketHandshake.h"
#include <cassert>
#include <cmath>


namespace
{
    const std::string emptyMsg;
} // namespace


namespace ix
{
    OnTrafficTrackerCallback WebSocket::_onTrafficTrackerCallback = nullptr;
    const int WebSocket::kDefaultHandShakeTimeoutSecs(60);
    const int WebSocket::kDefaultPingIntervalSecs(-1);
    const bool WebSocket::kDefaultEnablePong(true);
    const uint32_t WebSocket::kDefaultMaxWaitBetweenReconnectionRetries(10 * 1000); // 10s
    const uint32_t WebSocket::kDefaultMinWaitBetweenReconnectionRetries(1);         // 1 ms

    WebSocket::WebSocket()
        : _onMessageCallback(OnMessageCallback())
        , _stop(false)
        , _automaticReconnection(true)
        , _maxWaitBetweenReconnectionRetries(kDefaultMaxWaitBetweenReconnectionRetries)
        , _minWaitBetweenReconnectionRetries(kDefaultMinWaitBetweenReconnectionRetries)
        , _handshakeTimeoutSecs(kDefaultHandShakeTimeoutSecs)
        , _enablePong(kDefaultEnablePong)
        , _pingIntervalSecs(kDefaultPingIntervalSecs)
    {
        _ws.setOnCloseCallback(
            [this](uint16_t code, const std::string& reason, size_t wireSize, bool remote) {
                _onMessageCallback(
                    ix::make_unique<WebSocketMessage>(WebSocketMessageType::Close,
                                                      emptyMsg,
                                                      wireSize,
                                                      WebSocketErrorInfo(),
                                                      WebSocketOpenInfo(),
                                                      WebSocketCloseInfo(code, reason, remote)));
            });
    }

    WebSocket::~WebSocket()
    {
        stop();
        _ws.setOnCloseCallback(nullptr);
    }

    void WebSocket::setUrl(const std::string& url)
    {
        std::lock_guard<std::mutex> lock(_configMutex);
        _url = url;
    }

    void WebSocket::setHandshakeTimeout(int handshakeTimeoutSecs)
    {
        _handshakeTimeoutSecs = handshakeTimeoutSecs;
    }

    void WebSocket::setExtraHeaders(const WebSocketHttpHeaders& headers)
    {
        std::lock_guard<std::mutex> lock(_configMutex);
        _extraHeaders = headers;
    }

    const std::string WebSocket::getUrl() const
    {
        std::lock_guard<std::mutex> lock(_configMutex);
        return _url;
    }

    void WebSocket::setPerMessageDeflateOptions(
        const WebSocketPerMessageDeflateOptions& perMessageDeflateOptions)
    {
        std::lock_guard<std::mutex> lock(_configMutex);
        _perMessageDeflateOptions = perMessageDeflateOptions;
    }

    void WebSocket::setTLSOptions(const SocketTLSOptions& socketTLSOptions)
    {
        std::lock_guard<std::mutex> lock(_configMutex);
        _socketTLSOptions = socketTLSOptions;
    }

    const WebSocketPerMessageDeflateOptions WebSocket::getPerMessageDeflateOptions() const
    {
        std::lock_guard<std::mutex> lock(_configMutex);
        return _perMessageDeflateOptions;
    }

    void WebSocket::setPingInterval(int pingIntervalSecs)
    {
        std::lock_guard<std::mutex> lock(_configMutex);
        _pingIntervalSecs = pingIntervalSecs;
    }

    int WebSocket::getPingInterval() const
    {
        std::lock_guard<std::mutex> lock(_configMutex);
        return _pingIntervalSecs;
    }

    void WebSocket::enablePong()
    {
        std::lock_guard<std::mutex> lock(_configMutex);
        _enablePong = true;
    }

    void WebSocket::disablePong()
    {
        std::lock_guard<std::mutex> lock(_configMutex);
        _enablePong = false;
    }

    void WebSocket::enablePerMessageDeflate()
    {
        std::lock_guard<std::mutex> lock(_configMutex);
        WebSocketPerMessageDeflateOptions perMessageDeflateOptions(true);
        _perMessageDeflateOptions = perMessageDeflateOptions;
    }

    void WebSocket::disablePerMessageDeflate()
    {
        std::lock_guard<std::mutex> lock(_configMutex);
        WebSocketPerMessageDeflateOptions perMessageDeflateOptions(false);
        _perMessageDeflateOptions = perMessageDeflateOptions;
    }

    void WebSocket::setMaxWaitBetweenReconnectionRetries(uint32_t maxWaitBetweenReconnectionRetries)
    {
        std::lock_guard<std::mutex> lock(_configMutex);
        _maxWaitBetweenReconnectionRetries = maxWaitBetweenReconnectionRetries;
    }

    void WebSocket::setMinWaitBetweenReconnectionRetries(uint32_t minWaitBetweenReconnectionRetries)
    {
        std::lock_guard<std::mutex> lock(_configMutex);
        _minWaitBetweenReconnectionRetries = minWaitBetweenReconnectionRetries;
    }

    uint32_t WebSocket::getMaxWaitBetweenReconnectionRetries() const
    {
        std::lock_guard<std::mutex> lock(_configMutex);
        return _maxWaitBetweenReconnectionRetries;
    }

    uint32_t WebSocket::getMinWaitBetweenReconnectionRetries() const
    {
        std::lock_guard<std::mutex> lock(_configMutex);
        return _minWaitBetweenReconnectionRetries;
    }

    void WebSocket::start()
    {
        if (_thread.joinable()) return; // we've already been started

        _thread = std::thread(&WebSocket::run, this);
    }

    void WebSocket::stop(uint16_t code, const std::string& reason)
    {
        close(code, reason);

        if (_thread.joinable())
        {
            // wait until working thread will exit
            // it will exit after close operation is finished
            _stop = true;
            _sleepCondition.notify_one();
            _thread.join();
            _stop = false;
        }
    }

    WebSocketInitResult WebSocket::connect(int timeoutSecs)
    {
        {
            std::lock_guard<std::mutex> lock(_configMutex);
            _ws.configure(
                _perMessageDeflateOptions, _socketTLSOptions, _enablePong, _pingIntervalSecs);
        }

        WebSocketHttpHeaders headers(_extraHeaders);
        std::string subProtocolsHeader;
        auto subProtocols = getSubProtocols();
        if (!subProtocols.empty())
        {
            //
            // Sub Protocol strings are comma separated.
            // Python code to do that is:
            // >>> ','.join(['json', 'msgpack'])
            // 'json,msgpack'
            //
            int i = 0;
            for (auto subProtocol : subProtocols)
            {
                if (i++ != 0)
                {
                    subProtocolsHeader += ",";
                }
                subProtocolsHeader += subProtocol;
            }
            headers["Sec-WebSocket-Protocol"] = subProtocolsHeader;
        }

        WebSocketInitResult status = _ws.connectToUrl(_url, headers, timeoutSecs);
        if (!status.success)
        {
            return status;
        }

        _onMessageCallback(ix::make_unique<WebSocketMessage>(
            WebSocketMessageType::Open,
            emptyMsg,
            0,
            WebSocketErrorInfo(),
            WebSocketOpenInfo(status.uri, status.headers, status.protocol),
            WebSocketCloseInfo()));

        if (_pingIntervalSecs > 0)
        {
            // Send a heart beat right away
            _ws.sendHeartBeat();
        }

        return status;
    }

    WebSocketInitResult WebSocket::connectToSocket(std::unique_ptr<Socket> socket,
                                                   int timeoutSecs,
                                                   bool enablePerMessageDeflate)
    {
        {
            std::lock_guard<std::mutex> lock(_configMutex);
            _ws.configure(
                _perMessageDeflateOptions, _socketTLSOptions, _enablePong, _pingIntervalSecs);
        }

        WebSocketInitResult status =
            _ws.connectToSocket(std::move(socket), timeoutSecs, enablePerMessageDeflate);
        if (!status.success)
        {
            return status;
        }

        _onMessageCallback(
            ix::make_unique<WebSocketMessage>(WebSocketMessageType::Open,
                                              emptyMsg,
                                              0,
                                              WebSocketErrorInfo(),
                                              WebSocketOpenInfo(status.uri, status.headers),
                                              WebSocketCloseInfo()));

        if (_pingIntervalSecs > 0)
        {
            // Send a heart beat right away
            _ws.sendHeartBeat();
        }

        return status;
    }

    bool WebSocket::isConnected() const
    {
        return getReadyState() == ReadyState::Open;
    }

    bool WebSocket::isClosing() const
    {
        return getReadyState() == ReadyState::Closing;
    }

    void WebSocket::close(uint16_t code, const std::string& reason)
    {
        _ws.close(code, reason);
    }

    void WebSocket::checkConnection(bool firstConnectionAttempt)
    {
        using millis = std::chrono::duration<double, std::milli>;

        uint32_t retries = 0;
        millis duration(0);

        // Try to connect perpertually
        while (true)
        {
            if (isConnected() || isClosing() || _stop)
            {
                break;
            }

            if (!firstConnectionAttempt && !_automaticReconnection)
            {
                // Do not attempt to reconnect
                break;
            }

            firstConnectionAttempt = false;

            // Only sleep if we are retrying
            if (duration.count() > 0)
            {
                std::unique_lock<std::mutex> lock(_sleepMutex);
                _sleepCondition.wait_for(lock, duration);
            }

            if (_stop)
            {
                break;
            }

            // Try to connect synchronously
            ix::WebSocketInitResult status = connect(_handshakeTimeoutSecs);

            if (!status.success)
            {
                WebSocketErrorInfo connectErr;

                if (_automaticReconnection)
                {
                    duration =
                        millis(calculateRetryWaitMilliseconds(retries++,
                                                              _maxWaitBetweenReconnectionRetries,
                                                              _minWaitBetweenReconnectionRetries));

                    connectErr.wait_time = duration.count();
                    connectErr.retries = retries;
                }

                connectErr.reason = status.errorStr;
                connectErr.http_status = status.http_status;

                _onMessageCallback(ix::make_unique<WebSocketMessage>(WebSocketMessageType::Error,
                                                                     emptyMsg,
                                                                     0,
                                                                     connectErr,
                                                                     WebSocketOpenInfo(),
                                                                     WebSocketCloseInfo()));
            }
        }
    }

    void WebSocket::run()
    {
        setThreadName(getUrl());

        bool firstConnectionAttempt = true;

        while (true)
        {
            // 1. Make sure we are always connected
            checkConnection(firstConnectionAttempt);

            firstConnectionAttempt = false;

            // if here we are closed then checkConnection was not able to connect
            if (getReadyState() == ReadyState::Closed)
            {
                break;
            }

            // We can avoid to poll if we want to stop and are not closing
            if (_stop && !isClosing()) break;

            // 2. Poll to see if there's any new data available
            WebSocketTransport::PollResult pollResult = _ws.poll();

            // 3. Dispatch the incoming messages
            _ws.dispatch(
                pollResult,
                [this](const std::string& msg,
                       size_t wireSize,
                       bool decompressionError,
                       WebSocketTransport::MessageKind messageKind) {
                    WebSocketMessageType webSocketMessageType{WebSocketMessageType::Error};
                    switch (messageKind)
                    {
                        case WebSocketTransport::MessageKind::MSG_TEXT:
                        case WebSocketTransport::MessageKind::MSG_BINARY:
                        {
                            webSocketMessageType = WebSocketMessageType::Message;
                        }
                        break;

                        case WebSocketTransport::MessageKind::PING:
                        {
                            webSocketMessageType = WebSocketMessageType::Ping;
                        }
                        break;

                        case WebSocketTransport::MessageKind::PONG:
                        {
                            webSocketMessageType = WebSocketMessageType::Pong;
                        }
                        break;

                        case WebSocketTransport::MessageKind::FRAGMENT:
                        {
                            webSocketMessageType = WebSocketMessageType::Fragment;
                        }
                        break;
                    }

                    WebSocketErrorInfo webSocketErrorInfo;
                    webSocketErrorInfo.decompressionError = decompressionError;

                    bool binary = messageKind == WebSocketTransport::MessageKind::MSG_BINARY;

                    _onMessageCallback(ix::make_unique<WebSocketMessage>(webSocketMessageType,
                                                                         msg,
                                                                         wireSize,
                                                                         webSocketErrorInfo,
                                                                         WebSocketOpenInfo(),
                                                                         WebSocketCloseInfo(),
                                                                         binary));

                    WebSocket::invokeTrafficTrackerCallback(wireSize, true);
                });
        }
    }

    void WebSocket::setOnMessageCallback(const OnMessageCallback& callback)
    {
        _onMessageCallback = callback;
    }

    bool WebSocket::isOnMessageCallbackRegistered() const
    {
        return _onMessageCallback != nullptr;
    }

    void WebSocket::setTrafficTrackerCallback(const OnTrafficTrackerCallback& callback)
    {
        _onTrafficTrackerCallback = callback;
    }

    void WebSocket::resetTrafficTrackerCallback()
    {
        setTrafficTrackerCallback(nullptr);
    }

    void WebSocket::invokeTrafficTrackerCallback(size_t size, bool incoming)
    {
        if (_onTrafficTrackerCallback)
        {
            _onTrafficTrackerCallback(size, incoming);
        }
    }

    WebSocketSendInfo WebSocket::send(const std::string& data,
                                      bool binary,
                                      const OnProgressCallback& onProgressCallback)
    {
        return (binary) ? sendBinary(data, onProgressCallback) : sendText(data, onProgressCallback);
    }

    WebSocketSendInfo WebSocket::sendBinary(const std::string& data,
                                            const OnProgressCallback& onProgressCallback)
    {
        return sendMessage(data, SendMessageKind::Binary, onProgressCallback);
    }

    WebSocketSendInfo WebSocket::sendBinary(const IXWebSocketSendData& data,
                                            const OnProgressCallback& onProgressCallback)
    {
        return sendMessage(data, SendMessageKind::Binary, onProgressCallback);
    }

    WebSocketSendInfo WebSocket::sendUtf8Text(const std::string& text,
                                              const OnProgressCallback& onProgressCallback)
    {
        return sendMessage(text, SendMessageKind::Text, onProgressCallback);
    }

    WebSocketSendInfo WebSocket::sendUtf8Text(const IXWebSocketSendData& text,
                                              const OnProgressCallback& onProgressCallback)
    {
        return sendMessage(text, SendMessageKind::Text, onProgressCallback);
    }

    WebSocketSendInfo WebSocket::sendText(const std::string& text,
                                          const OnProgressCallback& onProgressCallback)
    {
        if (!validateUtf8(text))
        {
            close(WebSocketCloseConstants::kInvalidFramePayloadData,
                  WebSocketCloseConstants::kInvalidFramePayloadDataMessage);
            return false;
        }
        return sendMessage(text, SendMessageKind::Text, onProgressCallback);
    }

    WebSocketSendInfo WebSocket::ping(const std::string& text)
    {
        // Standard limit ping message size
        constexpr size_t pingMaxPayloadSize = 125;
        if (text.size() > pingMaxPayloadSize) return WebSocketSendInfo(false);

        return sendMessage(text, SendMessageKind::Ping);
    }

    WebSocketSendInfo WebSocket::sendMessage(const IXWebSocketSendData& message,
                                             SendMessageKind sendMessageKind,
                                             const OnProgressCallback& onProgressCallback)
    {
        if (!isConnected()) return WebSocketSendInfo(false);

        //
        // It is OK to read and write on the same socket in 2 different threads.
        // https://stackoverflow.com/questions/1981372/are-parallel-calls-to-send-recv-on-the-same-socket-valid
        //
        // This makes it so that messages are sent right away, and we dont need
        // a timeout while we poll to keep wake ups to a minimum (which helps
        // with battery life), and use the system select call to notify us when
        // incoming messages are arriving / there's data to be received.
        //
        std::lock_guard<std::mutex> lock(_writeMutex);
        WebSocketSendInfo webSocketSendInfo;

        switch (sendMessageKind)
        {
            case SendMessageKind::Text:
            {
                webSocketSendInfo = _ws.sendText(message, onProgressCallback);
            }
            break;

            case SendMessageKind::Binary:
            {
                webSocketSendInfo = _ws.sendBinary(message, onProgressCallback);
            }
            break;

            case SendMessageKind::Ping:
            {
                webSocketSendInfo = _ws.sendPing(message);
            }
            break;
        }

        WebSocket::invokeTrafficTrackerCallback(webSocketSendInfo.wireSize, false);

        return webSocketSendInfo;
    }

    ReadyState WebSocket::getReadyState() const
    {
        switch (_ws.getReadyState())
        {
            case ix::WebSocketTransport::ReadyState::OPEN: return ReadyState::Open;
            case ix::WebSocketTransport::ReadyState::CONNECTING: return ReadyState::Connecting;
            case ix::WebSocketTransport::ReadyState::CLOSING: return ReadyState::Closing;
            case ix::WebSocketTransport::ReadyState::CLOSED: return ReadyState::Closed;
            default: return ReadyState::Closed;
        }
    }

    std::string WebSocket::readyStateToString(ReadyState readyState)
    {
        switch (readyState)
        {
            case ReadyState::Open: return "OPEN";
            case ReadyState::Connecting: return "CONNECTING";
            case ReadyState::Closing: return "CLOSING";
            case ReadyState::Closed: return "CLOSED";
            default: return "UNKNOWN";
        }
    }

    void WebSocket::enableAutomaticReconnection()
    {
        _automaticReconnection = true;
    }

    void WebSocket::disableAutomaticReconnection()
    {
        _automaticReconnection = false;
    }

    bool WebSocket::isAutomaticReconnectionEnabled() const
    {
        return _automaticReconnection;
    }

    size_t WebSocket::bufferedAmount() const
    {
        return _ws.bufferedAmount();
    }

    void WebSocket::addSubProtocol(const std::string& subProtocol)
    {
        std::lock_guard<std::mutex> lock(_configMutex);
        _subProtocols.push_back(subProtocol);
    }

    const std::vector<std::string>& WebSocket::getSubProtocols()
    {
        std::lock_guard<std::mutex> lock(_configMutex);
        return _subProtocols;
    }
} // namespace ix
