#include <chrono>
#include <system_error>
#include <string.h>
#include "timer.hpp"

namespace phosphor
{
namespace state
{
namespace manager
{
static std::chrono::microseconds getTime()
{
    using namespace std::chrono;
    auto usec = steady_clock::now().time_since_epoch();
    return duration_cast<microseconds>(usec);
}

int Timer::state(timer::Action value)
{
    action_ = value;
    return sd_event_source_set_enabled(eventSource_.get(), action_);
}

timer::Action Timer::getAction() const
{
    return action_;
}

std::chrono::microseconds Timer::getDuration() const
{
    return duration_;
}

Timer::Timer(EventPtr& event, std::function<void()> callback,
             std::chrono::microseconds usec, timer::Action action) :
    event_(event),
    callback_(callback), duration_(usec), action_(action)
{
    // Add infinite expiration time
    sd_event_source* sourcePtr = nullptr;

    auto r = sd_event_add_time(event_.get(), &sourcePtr,
                               CLOCK_MONOTONIC,            // Time base
                               (getTime() + usec).count(), // When to fire
                               0,              // Use default event accuracy
                               timeoutHandler, // Callback handler on timeout
                               this);          // User data

    if (r < 0)
    {
        throw std::system_error(r, std::generic_category(), strerror(-r));
    }

    eventSource_.reset(sourcePtr);
}

int Timer::timeoutHandler(sd_event_source* eventSrc, uint64_t usec,
                          void* userData)
{
    auto timer = static_cast<Timer*>(userData);

    if (timer->getAction() == timer::ON)
    {
        auto r = sd_event_source_set_time(
            eventSrc, (getTime() + timer->getDuration()).count());
        if (r < 0)
        {
            throw std::system_error(r, std::generic_category(), strerror(-r));
        }

        r = sd_event_source_set_enabled(eventSrc, timer::ON);
        if (r < 0)
        {
            throw std::system_error(r, std::generic_category(), strerror(-r));
        }
    }

    if (timer->callback_)
    {
        timer->callback_();
    }

    return 0;
}

} // namespace manager
} // namespace state
} // namespace phosphor