#include <test/unit_test/multi_runner.h>

#include <xrpl/beast/unit_test/amount.h>
#include <xrpl/beast/unit_test/suite_info.h>

#include <boost/container/static_vector.hpp>
#include <boost/interprocess/creation_tags.hpp>
#include <boost/interprocess/detail/os_file_functions.hpp>
#include <boost/interprocess/shared_memory_object.hpp>
#include <boost/lexical_cast.hpp>

#include <algorithm>
#include <cassert>
#include <chrono>
#include <cstddef>
#include <cstdlib>
#include <exception>
#include <iomanip>
#include <iostream>
#include <memory>
#include <mutex>
#include <sstream>
#include <string>
#include <thread>
#include <type_traits>
#include <utility>
#include <vector>

namespace xrpl {

namespace detail {

std::string
fmtdur(typename clock_type::duration const& d)
{
    using namespace std::chrono;
    auto const ms = duration_cast<milliseconds>(d);
    if (ms < seconds{1})
        return boost::lexical_cast<std::string>(ms.count()) + "ms";
    std::stringstream ss;
    ss << std::fixed << std::setprecision(1) << (ms.count() / 1000.) << "s";
    return ss.str();
}

//------------------------------------------------------------------------------

void
suite_results::add(case_results const& r)
{
    ++cases;
    total += r.total;
    failed += r.failed;
}

//------------------------------------------------------------------------------

void
results::add(suite_results const& r)
{
    ++suites;
    total += r.total;
    cases += r.cases;
    failed += r.failed;
    auto const elapsed = clock_type::now() - r.start;
    if (elapsed >= std::chrono::seconds{1})
    {
        auto const iter = std::lower_bound(
            top.begin(),
            top.end(),
            elapsed,
            [](run_time const& t1, typename clock_type::duration const& t2) {
                return t1.second > t2;
            });

        if (iter != top.end())
        {
            if (top.size() == max_top && iter == top.end() - 1)
            {
                // avoid invalidating the iterator
                *iter = run_time{static_string{static_string::string_view_type{r.name}}, elapsed};
            }
            else
            {
                if (top.size() == max_top)
                    top.resize(top.size() - 1);
                top.emplace(iter, static_string{static_string::string_view_type{r.name}}, elapsed);
            }
        }
        else if (top.size() < max_top)
        {
            top.emplace_back(static_string{static_string::string_view_type{r.name}}, elapsed);
        }
    }
}

void
results::merge(results const& r)
{
    suites += r.suites;
    total += r.total;
    cases += r.cases;
    failed += r.failed;

    // combine the two top collections
    boost::container::static_vector<run_time, 2 * max_top> top_result;
    top_result.resize(top.size() + r.top.size());
    std::merge(
        top.begin(),
        top.end(),
        r.top.begin(),
        r.top.end(),
        top_result.begin(),
        [](run_time const& t1, run_time const& t2) { return t1.second > t2.second; });

    if (top_result.size() > max_top)
        top_result.resize(max_top);

    top = top_result;
}

template <class S>
void
results::print(S& s)
{
    using namespace beast::unit_test;

    if (!top.empty())
    {
        s << "Longest suite times:\n";
        for (auto const& [name, dur] : top)
            s << std::setw(8) << fmtdur(dur) << " " << name << '\n';
    }

    auto const elapsed = clock_type::now() - start;
    s << fmtdur(elapsed) << ", " << amount{suites, "suite"} << ", " << amount{cases, "case"} << ", "
      << amount{total, "test"} << " total, " << amount{failed, "failure"} << std::endl;
}

//------------------------------------------------------------------------------

template <bool IsParent>
std::size_t
multi_runner_base<IsParent>::inner::checkout_job_index()
{
    return job_index_++;
}

template <bool IsParent>
std::size_t
multi_runner_base<IsParent>::inner::checkout_test_index()
{
    return test_index_++;
}

template <bool IsParent>
bool
multi_runner_base<IsParent>::inner::any_failed() const
{
    return any_failed_;
}

template <bool IsParent>
void
multi_runner_base<IsParent>::inner::any_failed(bool v)
{
    any_failed_ = any_failed_ || v;
}

template <bool IsParent>
std::size_t
multi_runner_base<IsParent>::inner::tests() const
{
    std::lock_guard const l{m_};
    return results_.total;
}

template <bool IsParent>
std::size_t
multi_runner_base<IsParent>::inner::suites() const
{
    std::lock_guard const l{m_};
    return results_.suites;
}

template <bool IsParent>
void
multi_runner_base<IsParent>::inner::inc_keep_alive_count()
{
    ++keep_alive_;
}

template <bool IsParent>
std::size_t
multi_runner_base<IsParent>::inner::get_keep_alive_count()
{
    return keep_alive_;
}

template <bool IsParent>
void
multi_runner_base<IsParent>::inner::add(results const& r)
{
    std::lock_guard const l{m_};
    results_.merge(r);
}

template <bool IsParent>
template <class S>
void
multi_runner_base<IsParent>::inner::print_results(S& s)
{
    std::lock_guard const l{m_};
    results_.print(s);
}

template <bool IsParent>
multi_runner_base<IsParent>::multi_runner_base()
{
    try
    {
        if (IsParent)
        {
            // cleanup any leftover state for any previous failed runs
            boost::interprocess::shared_memory_object::remove(shared_mem_name_);
            boost::interprocess::message_queue::remove(message_queue_name_);
        }

        shared_mem_ = boost::interprocess::shared_memory_object{
            std::conditional_t<
                IsParent,
                boost::interprocess::create_only_t,
                boost::interprocess::open_only_t>{},
            shared_mem_name_,
            boost::interprocess::read_write};

        if (IsParent)
        {
            shared_mem_.truncate(sizeof(inner));
            message_queue_ = std::make_unique<boost::interprocess::message_queue>(
                boost::interprocess::create_only,
                message_queue_name_,
                /*max messages*/ 16,
                /*max message size*/ 1 << 20);
        }
        else
        {
            message_queue_ = std::make_unique<boost::interprocess::message_queue>(
                boost::interprocess::open_only, message_queue_name_);
        }

        region_ = boost::interprocess::mapped_region{shared_mem_, boost::interprocess::read_write};
        if (IsParent)
        {
            inner_ = new (region_.get_address()) inner{};
        }
        else
        {
            inner_ = reinterpret_cast<inner*>(region_.get_address());
        }
    }
    catch (...)
    {
        if (IsParent)
        {
            boost::interprocess::shared_memory_object::remove(shared_mem_name_);
            boost::interprocess::message_queue::remove(message_queue_name_);
        }
        throw;
    }
}

template <bool IsParent>
multi_runner_base<IsParent>::~multi_runner_base()
{
    if (IsParent)
    {
        inner_->~inner();
        boost::interprocess::shared_memory_object::remove(shared_mem_name_);
        boost::interprocess::message_queue::remove(message_queue_name_);
    }
}

template <bool IsParent>
std::size_t
multi_runner_base<IsParent>::checkout_test_index()
{
    return inner_->checkout_test_index();
}

template <bool IsParent>
std::size_t
multi_runner_base<IsParent>::checkout_job_index()
{
    return inner_->checkout_job_index();
}

template <bool IsParent>
bool
multi_runner_base<IsParent>::any_failed() const
{
    return inner_->any_failed();
}

template <bool IsParent>
void
multi_runner_base<IsParent>::any_failed(bool v)
{
    return inner_->any_failed(v);
}

template <bool IsParent>
void
multi_runner_base<IsParent>::add(results const& r)
{
    inner_->add(r);
}

template <bool IsParent>
void
multi_runner_base<IsParent>::inc_keep_alive_count()
{
    inner_->inc_keep_alive_count();
}

template <bool IsParent>
std::size_t
multi_runner_base<IsParent>::get_keep_alive_count()
{
    return inner_->get_keep_alive_count();
}

template <bool IsParent>
template <class S>
void
multi_runner_base<IsParent>::print_results(S& s)
{
    inner_->print_results(s);
}

template <bool IsParent>
void
multi_runner_base<IsParent>::message_queue_send(MessageType mt, std::string const& s)
{
    // must use a mutex since the two "sends" must happen in order
    std::lock_guard const l{inner_->m_};
    message_queue_->send(&mt, sizeof(mt), /*priority*/ 0);
    message_queue_->send(s.c_str(), s.size(), /*priority*/ 0);
}

template <bool IsParent>
std::size_t
multi_runner_base<IsParent>::tests() const
{
    return inner_->tests();
}

template <bool IsParent>
std::size_t
multi_runner_base<IsParent>::suites() const
{
    return inner_->suites();
}

template <bool IsParent>
void
multi_runner_base<IsParent>::add_failures(std::size_t failures)
{
    results results;
    results.failed += failures;
    add(results);
    any_failed(failures != 0);
}

}  // namespace detail

namespace test {

//------------------------------------------------------------------------------

multi_runner_parent::multi_runner_parent() : os_(std::cout)
{
    message_queue_thread_ = std::thread([this] {
        std::vector<char> buf(1 << 20);
        while (this->continue_message_queue_ || this->message_queue_->get_num_msg())
        {
            // let children know the parent is still alive
            this->inc_keep_alive_count();
            if (!this->message_queue_->get_num_msg())
            {
                // If a child does not see the keep alive count incremented,
                // it will assume the parent has died. This sleep time needs
                // to be small enough so the child will see increments from
                // a live parent.
                std::this_thread::sleep_for(std::chrono::milliseconds(100));
                continue;
            }
            try
            {
                std::size_t recvd_size = 0;
                unsigned int priority = 0;
                this->message_queue_->receive(buf.data(), buf.size(), recvd_size, priority);
                if (!recvd_size)
                    continue;
                assert(recvd_size == 1);
                MessageType const mt{*reinterpret_cast<MessageType*>(buf.data())};

                this->message_queue_->receive(buf.data(), buf.size(), recvd_size, priority);
                if (recvd_size)
                {
                    std::string s{buf.data(), recvd_size};
                    switch (mt)
                    {
                        case MessageType::log:
                            this->os_ << s;
                            this->os_.flush();
                            break;
                        case MessageType::test_start:
                            running_suites_.insert(std::move(s));
                            break;
                        case MessageType::test_end:
                            running_suites_.erase(s);
                            break;
                        default:
                            assert(0);  // unknown message type
                    }
                }
            }
            catch (std::exception const& e)
            {
                std::cerr << "Error: " << e.what() << " reading unit test message queue.\n";
                return;
            }
            catch (...)
            {
                std::cerr << "Unknown error reading unit test message queue.\n";
                return;
            }
        }
    });
}

multi_runner_parent::~multi_runner_parent()
{
    using namespace beast::unit_test;

    continue_message_queue_ = false;
    message_queue_thread_.join();

    add_failures(running_suites_.size());

    print_results(os_);

    for (auto const& s : running_suites_)
    {
        os_ << "\nSuite: " << s << " failed to complete. The child process may have crashed.\n";
    }
}

bool
multi_runner_parent::any_failed() const
{
    return multi_runner_base<true>::any_failed();
}

std::size_t
multi_runner_parent::tests() const
{
    return multi_runner_base<true>::tests();
}

std::size_t
multi_runner_parent::suites() const
{
    return multi_runner_base<true>::suites();
}

void
multi_runner_parent::add_failures(std::size_t failures)
{
    multi_runner_base<true>::add_failures(failures);
}

//------------------------------------------------------------------------------

multi_runner_child::multi_runner_child(std::size_t num_jobs, bool quiet, bool print_log)
    : job_index_{checkout_job_index()}
    , num_jobs_{num_jobs}
    , quiet_{quiet}
    , print_log_{!quiet || print_log}
{
    if (num_jobs_ > 1)
    {
        keep_alive_thread_ = std::thread([this] {
            std::size_t last_count = get_keep_alive_count();
            while (this->continue_keep_alive_)
            {
                // Use a small sleep time so in the normal case the child
                // process may shutdown quickly. However, to protect against
                // false alarms, use a longer sleep time later on.
                std::this_thread::sleep_for(std::chrono::milliseconds(500));
                auto cur_count = this->get_keep_alive_count();
                if (cur_count == last_count)
                {
                    // longer sleep time to protect against false alarms
                    std::this_thread::sleep_for(std::chrono::seconds(2));
                    cur_count = this->get_keep_alive_count();
                    if (cur_count == last_count)
                    {
                        // assume parent process is no longer alive
                        std::cerr << "multi_runner_child " << job_index_
                                  << ": Assuming parent died, exiting.\n";
                        std::exit(EXIT_FAILURE);
                    }
                }
                last_count = cur_count;
            }
        });
    }
}

multi_runner_child::~multi_runner_child()
{
    if (num_jobs_ > 1)
    {
        continue_keep_alive_ = false;
        keep_alive_thread_.join();
    }

    add(results_);
}

std::size_t
multi_runner_child::tests() const
{
    return results_.total;
}

std::size_t
multi_runner_child::suites() const
{
    return results_.suites;
}

void
multi_runner_child::add_failures(std::size_t failures)
{
    results_.failed += failures;
    any_failed(failures != 0);
}

void
multi_runner_child::on_suite_begin(beast::unit_test::suite_info const& info)
{
    suite_results_ = detail::suite_results{info.full_name()};
    message_queue_send(MessageType::test_start, suite_results_.name);
}

void
multi_runner_child::on_suite_end()
{
    if (print_log_ || suite_results_.failed > 0)
    {
        std::stringstream s;
        if (num_jobs_ > 1)
            s << job_index_ << "> ";
        s << (suite_results_.failed > 0 ? "failed: " : "") << suite_results_.name << " had "
          << suite_results_.failed << " failures." << std::endl;
        message_queue_send(MessageType::log, s.str());
    }
    results_.add(suite_results_);
    message_queue_send(MessageType::test_end, suite_results_.name);
}

void
multi_runner_child::on_case_begin(std::string const& name)
{
    case_results_ = detail::case_results(name);

    if (quiet_)
        return;

    std::stringstream s;
    if (num_jobs_ > 1)
        s << job_index_ << "> ";
    s << suite_results_.name << (case_results_.name.empty() ? "" : (" " + case_results_.name))
      << '\n';
    message_queue_send(MessageType::log, s.str());
}

void
multi_runner_child::on_case_end()
{
    suite_results_.add(case_results_);
}

void
multi_runner_child::on_pass()
{
    ++case_results_.total;
}

void
multi_runner_child::on_fail(std::string const& reason)
{
    ++case_results_.failed;
    ++case_results_.total;
    std::stringstream s;
    if (num_jobs_ > 1)
        s << job_index_ << "> ";
    s << "#" << case_results_.total << " failed" << (reason.empty() ? "" : ": ") << reason << '\n';
    message_queue_send(MessageType::log, s.str());
}

void
multi_runner_child::on_log(std::string const& msg)
{
    if (!print_log_)
        return;

    std::stringstream s;
    if (num_jobs_ > 1)
        s << job_index_ << "> ";
    s << msg;
    message_queue_send(MessageType::log, s.str());
}

}  // namespace test

namespace detail {
template class multi_runner_base<true>;
template class multi_runner_base<false>;
}  // namespace detail

}  // namespace xrpl