#define _GNU_SOURCE
#include <unistd.h>
#include <pthread.h>
#include <stdio.h>
#include <sched.h>

#include <spa/ringbuffer.h>

#define ARRAY_SIZE 64
#define MAX_VALUE 0x10000

struct spa_ringbuffer rb;
uint8_t *data;

static int
fill_int_array (int *array, int start, int count)
{
  int i, j = start;
  for (i = 0; i < count; i++)
  {
    array[i] = j;
    j = (j + 1) % MAX_VALUE;
  }
  return j;
}

static int
cmp_array (int *array1, int *array2, int count)
{
  int i;
  for (i = 0; i < count; i++)
    if (array1[i] != array2[i])
    {
      printf("%d != %d at offset %d\n", array1[i], array2[i], i);
      return 0;
    }

  return 1;
}

static void *
reader_start (void * arg)
{
  int i = 0, a[ARRAY_SIZE], b[ARRAY_SIZE];
  unsigned long j = 0, nfailures = 0;

  printf("reader started on cpu: %d\n", sched_getcpu());

  i = fill_int_array (a, i, ARRAY_SIZE);

  while (1)
  {
    uint32_t index;

    if (spa_ringbuffer_get_read_index (&rb, &index) >= ARRAY_SIZE * sizeof (int))
    {
      spa_ringbuffer_read_data (&rb, data, index & rb.mask, b, ARRAY_SIZE * sizeof (int));

      if (!cmp_array (a, b, ARRAY_SIZE))
      {
        nfailures++;
        printf("failure in chunk %lu - probability: %lu/%lu = %.3f per million\n",
               j, nfailures, j, (float) nfailures / (j + 1) * 1000000);
        i = (b[0] + ARRAY_SIZE) % MAX_VALUE;
      }
      i = fill_int_array (a, i, ARRAY_SIZE);
      j++;

      spa_ringbuffer_read_update (&rb, index + ARRAY_SIZE * sizeof (int));
    }
  }

  return NULL;
}

static void *
writer_start (void * arg)
{
  int i = 0, a[ARRAY_SIZE];
  printf("writer started on cpu: %d\n", sched_getcpu());

  i = fill_int_array (a, i, ARRAY_SIZE);

  while (1)
  {
    uint32_t index;

    if (spa_ringbuffer_get_write_index (&rb, &index) >= ARRAY_SIZE * sizeof (int))
    {
      spa_ringbuffer_write_data (&rb, data, index & rb.mask, a, ARRAY_SIZE * sizeof (int));
      spa_ringbuffer_write_update (&rb, index + ARRAY_SIZE * sizeof (int));

      i = fill_int_array (a, i, ARRAY_SIZE);
    }
  }

  return NULL;
}

int main(int argc, char *argv[])
{
  int size;

  printf("starting ringbuffer stress test\n");

  sscanf(argv[1], "%d", &size);

  printf("buffer size (bytes): %d\n", size);
  printf("array size (bytes): %ld\n", sizeof(int) * ARRAY_SIZE);

  spa_ringbuffer_init (&rb, size);
  data = malloc (size);

  pthread_t reader_thread, writer_thread;
  pthread_create (&reader_thread, NULL, reader_start, NULL);
  pthread_create (&writer_thread, NULL, writer_start, NULL);

  while (1)
    sleep(1);

  return 0;
}