/*
 * Copyright 2022 Rive
 */

#include "bench.hpp"

#include <chrono>
#include <string.h>

// Run a microbenchmark repeatedly for a few seconds and print the quickest
// time.
#ifdef __EMSCRIPTEN__
int rive_wasm_main(int argc, const char* const* argv)
#else
int main(int argc, const char** argv)
#endif
{
  using namespace std::chrono_literals;
  using clock = std::chrono::high_resolution_clock;

  // Default flags.
  clock::duration benchDuration = 5s;

  // Parse flags.
  const char* const* arg = argv + 1;
  const char* const* endarg = argv + argc;
  while (arg + 1 < endarg && *arg[0] == '-')
  {
    if (!strcmp(*arg, "--duration") || !strcmp(*arg, "-d"))
    {
      benchDuration = std::chrono::seconds(atoi(arg[1]));
    }
    arg += 2;
  }

  // Find the selected benchmark.
  Bench::BenchMap& registry = Bench::Registry();
  const char* benchName = arg < endarg ? *arg : "";
  auto benchIter = registry.find(benchName);
  if (benchIter == registry.end())
  {
    // Print out the usage unless they ran "bench list".
    if (arg >= endarg || !!strcmp(*arg, "list"))
    {
      fprintf(stderr, "Usage:\n\nbench [--duration <seconds>] <benchmark>\n\n");
      fprintf(stderr, "Benchmarks:\n\n");
      fflush(stderr);
    }
    // Print out the benchmarks.
    for (const auto& [name, constructor] : registry)
    {
      printf("%s ", name.c_str());
    }
    printf("\n");
    fflush(stdout);
    return 1;
  }

  // Run the benchmark.
  auto constructor = benchIter->second;
  std::unique_ptr<Bench> bench(constructor());
  bench->setup();

  clock::duration minTime = clock::duration::max();
  clock::time_point quitTime = clock::now() + benchDuration;
  clock::time_point start, end;
  do
  {
    bench->beforeRun();
    start = clock::now();
    bench->run();
    end = clock::now();
    minTime = std::min(end - start, minTime);
  } while (end < quitTime);

#ifdef DEBUG
  printf("<time hidden in debug builds> %s\n", benchName);
#else
  printf(
      "%.4gms %s\n",
      std::chrono::nanoseconds(minTime).count() * 1e-6,
      benchName);
#endif

  return 0;
}