/*
 *  ws_cobra_to_statsd.cpp
 *  Author: Benjamin Sergeant
 *  Copyright (c) 2019 Machine Zone, Inc. All rights reserved.
 */

#include <iostream>
#include <sstream>
#include <chrono>
#include <thread>
#include <atomic>
#include <vector>
#include <ixcobra/IXCobraConnection.h>

#include <statsd_client.h>
#include <spdlog/spdlog.h>

namespace ix
{
    // fields are command line argument that can be specified multiple times
    std::vector<std::string> parseFields(const std::string& fields)
    {
        std::vector<std::string> tokens;

        // Split by \n
        std::string token;
        std::stringstream tokenStream(fields);

        while (std::getline(tokenStream, token))
        {
            tokens.push_back(token);
        }

        return tokens;
    }

    //
    // Extract an attribute from a Json Value.
    // extractAttr("foo.bar", {"foo": {"bar": "baz"}}) => baz
    //
    std::string extractAttr(const std::string& attr,
                            const Json::Value& jsonValue)
    {
        // Split by .
        std::string token;
        std::stringstream tokenStream(attr);

        Json::Value val(jsonValue);

        while (std::getline(tokenStream, token, '.'))
        {
            val = val[token];
        }

        return val.asString();
    }

    int ws_cobra_to_statsd_main(const std::string& appkey,
                                const std::string& endpoint,
                                const std::string& rolename,
                                const std::string& rolesecret,
                                const std::string& channel,
                                const std::string& host,
                                int port,
                                const std::string& prefix,
                                const std::string& fields,
                                bool verbose)
    {
        ix::CobraConnection conn;
        conn.configure(appkey, endpoint,
                       rolename, rolesecret,
                       ix::WebSocketPerMessageDeflateOptions(true));
        conn.connect();

        auto tokens = parseFields(fields);

        // statsd client
        // test with netcat as a server: `nc -ul 8125`
        bool statsdBatch = true;
        statsd::StatsdClient statsdClient(host, port, prefix, statsdBatch);

        Json::FastWriter jsonWriter;
        uint64_t msgCount = 0;

        conn.setEventCallback(
            [&conn, &channel, &jsonWriter, &statsdClient, verbose, &tokens, &prefix, &msgCount]
            (ix::CobraConnectionEventType eventType,
             const std::string& errMsg,
             const ix::WebSocketHttpHeaders& headers,
             const std::string& subscriptionId)
            {
                if (eventType == ix::CobraConnection_EventType_Open)
                {
                    spdlog::info("Subscriber connected");

                    for (auto it : headers)
                    {
                        spdlog::info("{}: {}", it.first, it.second);
                    }
                }
                if (eventType == ix::CobraConnection_EventType_Closed)
                {
                    spdlog::info("Subscriber closed");
                }
                else if (eventType == ix::CobraConnection_EventType_Authenticated)
                {
                    spdlog::info("Subscriber authenticated");
                    conn.subscribe(channel,
                                   [&jsonWriter, &statsdClient,
                                    verbose, &tokens, &prefix, &msgCount]
                                   (const Json::Value& msg)
                                   {
                                       if (verbose)
                                       {
                                           spdlog::info(jsonWriter.write(msg));
                                       }

                                       std::string id;
                                       for (auto&& attr : tokens)
                                       {
                                           id += ".";
                                           id += extractAttr(attr, msg);
                                       }

                                       spdlog::info("{} {}{}", msgCount++, prefix, id);

                                       statsdClient.count(id, 1);
                                   });
                }
                else if (eventType == ix::CobraConnection_EventType_Subscribed)
                {
                    spdlog::info("Subscriber: subscribed to channel {}", subscriptionId);
                }
                else if (eventType == ix::CobraConnection_EventType_UnSubscribed)
                {
                    spdlog::info("Subscriber: unsubscribed from channel {}", subscriptionId);
                }
                else if (eventType == ix::CobraConnection_EventType_Error)
                {
                    spdlog::error("Subscriber: error {}", errMsg);
                }
            }
        );

        while (true)
        {
            std::chrono::duration<double, std::milli> duration(1000);
            std::this_thread::sleep_for(duration);
        }

        return 0;
    }
}