#include <util/logging/logger.hpp>
#include <util/time.hpp>
#include <util/thread/threadpool.h>
#include <util/thread/thread_pool.hpp>

#include <cstring>
#include <functional>
#include <queue>

struct llarp_threadpool *
llarp_init_threadpool(int workers, const char *name)
{
  if(workers <= 0)
    workers = 1;
  return new llarp_threadpool(workers, name);
}

void
llarp_threadpool_join(struct llarp_threadpool *pool)
{
  llarp::LogDebug("threadpool join");
  if(pool->impl)
    pool->impl->stop();
  pool->impl.reset();
}

void
llarp_threadpool_start(struct llarp_threadpool *pool)
{
  if(pool->impl)
    pool->impl->start();
}

void
llarp_threadpool_stop(struct llarp_threadpool *pool)
{
  llarp::LogDebug("threadpool stop");
  if(pool->impl)
    pool->impl->disable();
}

bool
llarp_threadpool_queue_job(struct llarp_threadpool *pool,
                           struct llarp_thread_job job)
{
  return llarp_threadpool_queue_job(pool, std::bind(job.work, job.user));
}

bool
llarp_threadpool_queue_job(struct llarp_threadpool *pool,
                           std::function< void(void) > func)
{
  return pool->impl && pool->impl->addJob(func);
}

void
llarp_threadpool_tick(struct llarp_threadpool *pool)
{
  if(pool->impl)
  {
    pool->impl->drain();
  }
}

void
llarp_free_threadpool(struct llarp_threadpool **pool)
{
  if(*pool)
  {
    delete *pool;
  }
  *pool = nullptr;
}

size_t
llarp_threadpool::size() const
{
  return impl ? impl->capacity() : 0;
}

size_t
llarp_threadpool::pendingJobs() const
{
  return impl ? impl->jobCount() : 0;
}

size_t
llarp_threadpool::numThreads() const
{
  return impl ? impl->activeThreadCount() : 0;
}

llarp_time_t
llarp_threadpool::GuessJobLatency(llarp_time_t granularity) const
{
  static const llarp_time_t minimum = llarp_time_t{10};
  granularity                       = std::max(granularity, minimum);
  const llarp_time_t _jobs          = llarp_time_t{pendingJobs()} * granularity;
  const llarp_time_t _capacity =
      std::max(llarp_time_t{size()} * granularity, granularity);
  const llarp_time_t _numthreads =
      std::max(llarp_time_t{numThreads()} * granularity, granularity);
  // divisor = log10(granularity)
  llarp_time_t divisor = 0;
  do
  {
    granularity /= 10;
    if(granularity > 0)
      divisor++;
  } while(granularity > 0);
  // granulairuty is minimum of 10 so log10(granulairuty) is never 0
  divisor *= divisor;
  // job lag is pending number of jobs divided by job queue length per thread
  // divided by log10(granularity) sqaured
  const llarp_time_t _queue_length = _capacity / _numthreads;
  return _jobs / _queue_length / divisor;
}