#include <port/unistd.h>
#include <stdlib.h>
#include <fcntl.h>
#include <signal.h>
#include <time.h>
#include <iostream>
#include <fstream>
#include <iomanip>
#include <random>
#include <pcg_random.hpp>
#include <Poco/File.h>
#include <Poco/Util/Application.h>
#include <Common/Stopwatch.h>
#include <common/ThreadPool.h>
#include <AggregateFunctions/ReservoirSampler.h>
#include <AggregateFunctions/registerAggregateFunctions.h>
#include <boost/program_options.hpp>
#include <Common/ConcurrentBoundedQueue.h>
#include <Common/Exception.h>
#include <Common/randomSeed.h>
#include <Core/Types.h>
#include <IO/ReadBufferFromFileDescriptor.h>
#include <IO/WriteBufferFromFileDescriptor.h>
#include <IO/WriteBufferFromFile.h>
#include <IO/ReadHelpers.h>
#include <IO/WriteHelpers.h>
#include <IO/Operators.h>
#include <IO/ConnectionTimeouts.h>
#include <IO/UseSSL.h>
#include <DataStreams/RemoteBlockInputStream.h>
#include <Interpreters/Context.h>
#include <Client/Connection.h>
#include <Common/InterruptListener.h>


/** A tool for evaluating ClickHouse performance.
  * The tool emulates a case with fixed amount of simultaneously executing queries.
  */

namespace DB
{

namespace ErrorCodes
{
    extern const int POCO_EXCEPTION;
    extern const int STD_EXCEPTION;
    extern const int UNKNOWN_EXCEPTION;
    extern const int BAD_ARGUMENTS;
}

class Benchmark
{
public:
    Benchmark(unsigned concurrency_, double delay_,
            const String & host_, UInt16 port_, const String & default_database_,
            const String & user_, const String & password_, const String & stage,
            bool randomize_, size_t max_iterations_, double max_time_,
            const String & json_path_, const ConnectionTimeouts & timeouts, const Settings & settings_)
        :
        concurrency(concurrency_), delay(delay_), queue(concurrency),
        connections(concurrency, host_, port_, default_database_, user_, password_, timeouts),
        randomize(randomize_), max_iterations(max_iterations_), max_time(max_time_),
        json_path(json_path_), settings(settings_), global_context(Context::createGlobal()), pool(concurrency)
    {
        std::cerr << std::fixed << std::setprecision(3);

        /// This is needed to receive blocks with columns of AggregateFunction data type
        /// (example: when using stage = 'with_mergeable_state')
        registerAggregateFunctions();

        if (stage == "complete")
            query_processing_stage = QueryProcessingStage::Complete;
        else if (stage == "fetch_columns")
            query_processing_stage = QueryProcessingStage::FetchColumns;
        else if (stage == "with_mergeable_state")
            query_processing_stage = QueryProcessingStage::WithMergeableState;
        else
            throw Exception("Unknown query processing stage: " + stage, ErrorCodes::BAD_ARGUMENTS);

        if (!json_path.empty() && Poco::File(json_path).exists()) /// Clear file with previous results
        {
            Poco::File(json_path).remove();
        }

        readQueries();
        run();
    }

private:
    using Query = std::string;

    unsigned concurrency;
    double delay;

    using Queries = std::vector<Query>;
    Queries queries;

    using Queue = ConcurrentBoundedQueue<Query>;
    Queue queue;

    ConnectionPool connections;
    bool randomize;
    size_t max_iterations;
    double max_time;
    String json_path;
    Settings settings;
    Context global_context;
    QueryProcessingStage::Enum query_processing_stage;

    /// Don't execute new queries after timelimit or SIGINT or exception
    std::atomic<bool> shutdown{false};

    std::atomic<size_t> queries_executed{0};

    struct Stats
    {
        Stopwatch watch;
        std::atomic<size_t> queries{0};
        size_t read_rows = 0;
        size_t read_bytes = 0;
        size_t result_rows = 0;
        size_t result_bytes = 0;

        using Sampler = ReservoirSampler<double>;
        Sampler sampler {1 << 16};

        void add(double seconds, size_t read_rows_inc, size_t read_bytes_inc, size_t result_rows_inc, size_t result_bytes_inc)
        {
            ++queries;
            read_rows += read_rows_inc;
            read_bytes += read_bytes_inc;
            result_rows += result_rows_inc;
            result_bytes += result_bytes_inc;
            sampler.insert(seconds);
        }

        void clear()
        {
            watch.restart();
            queries = 0;
            read_rows = 0;
            read_bytes = 0;
            result_rows = 0;
            result_bytes = 0;
            sampler.clear();
        }
    };

    Stats info_per_interval;
    Stats info_total;
    Stopwatch delay_watch;

    std::mutex mutex;

    ThreadPool pool;


    void readQueries()
    {
        ReadBufferFromFileDescriptor in(STDIN_FILENO);

        while (!in.eof())
        {
            std::string query;
            readText(query, in);
            assertChar('\n', in);

            if (!query.empty())
                queries.emplace_back(query);
        }

        if (queries.empty())
            throw Exception("Empty list of queries.");

        std::cerr << "Loaded " << queries.size() << " queries.\n";
    }


    void printNumberOfQueriesExecuted(size_t num)
    {
        std::cerr << "\nQueries executed: " << num;
        if (queries.size() > 1)
            std::cerr << " (" << (num * 100.0 / queries.size()) << "%)";
        std::cerr << ".\n";
    }

    /// Try push new query and check cancellation conditions
    bool tryPushQueryInteractively(const String & query, InterruptListener & interrupt_listener)
    {
        bool inserted = false;

        while (!inserted)
        {
            inserted = queue.tryPush(query, 100);

            if (shutdown)
            {
                /// An exception occurred in a worker
                return false;
            }

            if (max_time > 0 && info_total.watch.elapsedSeconds() >= max_time)
            {
                std::cout << "Stopping launch of queries. Requested time limit is exhausted.\n";
                return false;
            }

            if (interrupt_listener.check())
            {
                std::cout << "Stopping launch of queries. SIGINT recieved.\n";
                return false;
            }

            if (delay > 0 && delay_watch.elapsedSeconds() > delay)
            {
                printNumberOfQueriesExecuted(info_total.queries);
                report(info_per_interval);
                delay_watch.restart();
            }
        };

        return true;
    }

    void run()
    {
        pcg64 generator(randomSeed());
        std::uniform_int_distribution<size_t> distribution(0, queries.size() - 1);

        for (size_t i = 0; i < concurrency; ++i)
            pool.schedule(std::bind(&Benchmark::thread, this, connections.get()));

        InterruptListener interrupt_listener;
        info_per_interval.watch.restart();
        delay_watch.restart();

        /// Push queries into queue
        for (size_t i = 0; !max_iterations || i < max_iterations; ++i)
        {
            size_t query_index = randomize ? distribution(generator) : i % queries.size();

            if (!tryPushQueryInteractively(queries[query_index], interrupt_listener))
            {
                shutdown = true;
                break;
            }
        }

        pool.wait();
        info_total.watch.stop();

        if (!json_path.empty())
            reportJSON(info_total, json_path);

        printNumberOfQueriesExecuted(info_total.queries);
        report(info_total);
    }


    void thread(ConnectionPool::Entry connection)
    {
        Query query;

        try
        {
            /// In these threads we do not accept INT signal.
            sigset_t sig_set;
            if (sigemptyset(&sig_set)
                || sigaddset(&sig_set, SIGINT)
                || pthread_sigmask(SIG_BLOCK, &sig_set, nullptr))
                throwFromErrno("Cannot block signal.", ErrorCodes::CANNOT_BLOCK_SIGNAL);

            while (true)
            {
                bool extracted = false;

                while (!extracted)
                {
                    extracted = queue.tryPop(query, 100);

                    if (shutdown || (max_iterations && queries_executed == max_iterations))
                        return;
                }

                execute(connection, query);
                ++queries_executed;
            }
        }
        catch (...)
        {
            shutdown = true;
            std::cerr << "An error occurred while processing query:\n" << query << "\n";
            throw;
        }
    }


    void execute(ConnectionPool::Entry & connection, Query & query)
    {
        Stopwatch watch;
        RemoteBlockInputStream stream(*connection, query, {}, global_context, &settings, nullptr, Tables(), query_processing_stage);

        Progress progress;
        stream.setProgressCallback([&progress](const Progress & value) { progress.incrementPiecewiseAtomically(value); });

        stream.readPrefix();
        while (Block block = stream.read())
            ;
        stream.readSuffix();

        const BlockStreamProfileInfo & info = stream.getProfileInfo();

        double seconds = watch.elapsedSeconds();

        std::lock_guard<std::mutex> lock(mutex);
        info_per_interval.add(seconds, progress.rows, progress.bytes, info.rows, info.bytes);
        info_total.add(seconds, progress.rows, progress.bytes, info.rows, info.bytes);
    }


    void report(Stats & info)
    {
        std::lock_guard<std::mutex> lock(mutex);

        /// Avoid zeros, nans or exceptions
        if (0 == info.queries)
            return;

        double seconds = info.watch.elapsedSeconds();

        std::cerr
            << "\n"
            << "QPS: " << (info.queries / seconds) << ", "
            << "RPS: " << (info.read_rows / seconds) << ", "
            << "MiB/s: " << (info.read_bytes / seconds / 1048576) << ", "
            << "result RPS: " << (info.result_rows / seconds) << ", "
            << "result MiB/s: " << (info.result_bytes / seconds / 1048576) << "."
            << "\n";

        auto print_percentile = [&](double percent)
        {
            std::cerr << percent << "%\t" << info.sampler.quantileInterpolated(percent / 100.0) << " sec." << std::endl;
        };

        for (int percent = 0; percent <= 90; percent += 10)
            print_percentile(percent);

        print_percentile(95);
        print_percentile(99);
        print_percentile(99.9);
        print_percentile(99.99);

        info.clear();
    }

    void reportJSON(Stats & info, const std::string & filename)
    {
        WriteBufferFromFile json_out(filename);

        std::lock_guard<std::mutex> lock(mutex);

        auto print_key_value = [&](auto key, auto value, bool with_comma = true)
        {
            json_out << double_quote << key << ": " << value << (with_comma ? ",\n" : "\n");
        };

        auto print_percentile = [&json_out, &info](auto percent, bool with_comma = true)
        {
            json_out << "\"" << percent << "\"" << ": " << info.sampler.quantileInterpolated(percent / 100.0) << (with_comma ? ",\n" : "\n");
        };

        json_out << "{\n";

        json_out << double_quote << "statistics" << ": {\n";

        double seconds = info.watch.elapsedSeconds();
        print_key_value("QPS", info.queries / seconds);
        print_key_value("RPS", info.read_rows / seconds);
        print_key_value("MiBPS", info.read_bytes / seconds);
        print_key_value("RPS_result", info.result_rows / seconds);
        print_key_value("MiBPS_result", info.result_bytes / seconds);
        print_key_value("num_queries", info.queries.load(), false);

        json_out << "},\n";

        json_out << double_quote << "query_time_percentiles" << ": {\n";

        for (int percent = 0; percent <= 90; percent += 10)
            print_percentile(percent);

        print_percentile(95);
        print_percentile(99);
        print_percentile(99.9);
        print_percentile(99.99, false);

        json_out << "}\n";

        json_out << "}\n";
    }

public:

    ~Benchmark()
    {
        shutdown = true;
    }
};

}


#ifndef __clang__
#pragma GCC optimize("-fno-var-tracking-assignments")
#endif

int mainEntryClickHouseBenchmark(int argc, char ** argv)
{
    using namespace DB;
    bool print_stacktrace = true;

    try
    {
        using boost::program_options::value;

        boost::program_options::options_description desc("Allowed options");
        desc.add_options()
            ("help",                                                            "produce help message")
            ("concurrency,c", value<unsigned>()->default_value(1),              "number of parallel queries")
            ("delay,d",       value<double>()->default_value(1),                "delay between intermediate reports in seconds (set 0 to disable reports)")
            ("stage",         value<std::string>()->default_value("complete"),  "request query processing up to specified stage")
            ("iterations,i",  value<size_t>()->default_value(0),                "amount of queries to be executed")
            ("timelimit,t",   value<double>()->default_value(0.),               "stop launch of queries after specified time limit")
            ("randomize,r",   value<bool>()->default_value(false),              "randomize order of execution")
            ("json",          value<std::string>()->default_value(""),          "write final report to specified file in JSON format")
            ("host,h",        value<std::string>()->default_value("localhost"), "")
            ("port",          value<UInt16>()->default_value(9000),             "")
            ("user",          value<std::string>()->default_value("default"),   "")
            ("password",      value<std::string>()->default_value(""),          "")
            ("database",      value<std::string>()->default_value("default"),   "")
            ("stacktrace",                                                      "print stack traces of exceptions")

        #define DECLARE_SETTING(TYPE, NAME, DEFAULT, DESCRIPTION) (#NAME, boost::program_options::value<std::string> (), DESCRIPTION)
            APPLY_FOR_SETTINGS(DECLARE_SETTING)
        #undef DECLARE_SETTING
        ;

        boost::program_options::variables_map options;
        boost::program_options::store(boost::program_options::parse_command_line(argc, argv, desc), options);

        if (options.count("help"))
        {
            std::cout << "Usage: " << argv[0] << " [options] < queries.txt\n";
            std::cout << desc << "\n";
            return 1;
        }

        print_stacktrace = options.count("stacktrace");

        /// Extract `settings` and `limits` from received `options`
        Settings settings;

        #define EXTRACT_SETTING(TYPE, NAME, DEFAULT, DESCRIPTION) \
        if (options.count(#NAME)) \
            settings.set(#NAME, options[#NAME].as<std::string>());
        APPLY_FOR_SETTINGS(EXTRACT_SETTING)
        #undef EXTRACT_SETTING

        UseSSL use_ssl;

        Benchmark benchmark(
            options["concurrency"].as<unsigned>(),
            options["delay"].as<double>(),
            options["host"].as<std::string>(),
            options["port"].as<UInt16>(),
            options["database"].as<std::string>(),
            options["user"].as<std::string>(),
            options["password"].as<std::string>(),
            options["stage"].as<std::string>(),
            options["randomize"].as<bool>(),
            options["iterations"].as<size_t>(),
            options["timelimit"].as<double>(),
            options["json"].as<std::string>(),
            ConnectionTimeouts::getTCPTimeoutsWithoutFailover(settings),
            settings);
    }
    catch (...)
    {
        std::cerr << getCurrentExceptionMessage(print_stacktrace, true) << std::endl;
        return getCurrentExceptionCode();
    }

    return 0;
}