/*
  Copyright 2011-2021 David Robillard <d@drobilla.net>

  Permission to use, copy, modify, and/or distribute this software for any
  purpose with or without fee is hereby granted, provided that the above
  copyright notice and this permission notice appear in all copies.

  THIS SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
  WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
  MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
  ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
  WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
  ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
  OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
*/

#undef NDEBUG

#include "failing_allocator.h"

#include "zix/allocator.h"
#include "zix/attributes.h"
#include "zix/ring.h"
#include "zix/thread.h"

#include <assert.h>
#include <limits.h>
#include <stdbool.h>
#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>

#define MSG_SIZE 20u

static ZixRing* ring       = 0;
static unsigned n_writes   = 0;
static bool     read_error = false;

static int
gen_msg(int* const msg, int start)
{
  for (unsigned i = 0u; i < MSG_SIZE; ++i) {
    msg[i] = start;
    start  = (start + 1) % INT_MAX;
  }
  return start;
}

static int
cmp_msg(const int* const msg1, const int* const msg2)
{
  for (unsigned i = 0u; i < MSG_SIZE; ++i) {
    assert(msg1[i] == msg2[i]);
  }

  return 1;
}

static void*
reader(void* ZIX_UNUSED(arg))
{
  printf("Reader starting\n");

  int      ref_msg[MSG_SIZE];  // Reference generated for comparison
  int      read_msg[MSG_SIZE]; // Read from ring
  unsigned count = 0;
  int      start = gen_msg(ref_msg, 0);
  for (unsigned i = 0; i < n_writes; ++i) {
    if (zix_ring_read_space(ring) >= MSG_SIZE * sizeof(int)) {
      if (zix_ring_read(ring, read_msg, MSG_SIZE * sizeof(int))) {
        assert(cmp_msg(ref_msg, read_msg));
        start = gen_msg(ref_msg, start);
        ++count;
      }
    }
  }

  printf("Reader finished\n");
  return NULL;
}

static void*
writer(void* ZIX_UNUSED(arg))
{
  printf("Writer starting\n");

  int write_msg[MSG_SIZE]; // Written to ring
  int start = gen_msg(write_msg, 0);
  for (unsigned i = 0; i < n_writes; ++i) {
    if (zix_ring_write_space(ring) >= MSG_SIZE * sizeof(int)) {
      if (zix_ring_write(ring, write_msg, MSG_SIZE * sizeof(int))) {
        start = gen_msg(write_msg, start);
      }
    }
  }

  printf("Writer finished\n");
  return NULL;
}

static int
test_ring(const unsigned size)
{
  zix_ring_free(NULL);

  printf("Testing %u writes of %u ints to a %u int ring...\n",
         n_writes,
         MSG_SIZE,
         size);

  ring = zix_ring_new(NULL, size);
  assert(ring);
  assert(zix_ring_read_space(ring) == 0);
  assert(zix_ring_write_space(ring) == zix_ring_capacity(ring));

  zix_ring_mlock(ring);

  ZixThread reader_thread; // NOLINT
  assert(!zix_thread_create(&reader_thread, MSG_SIZE * 4, reader, NULL));

  ZixThread writer_thread; // NOLINT
  assert(!zix_thread_create(&writer_thread, MSG_SIZE * 4, writer, NULL));

  zix_thread_join(reader_thread, NULL);
  zix_thread_join(writer_thread, NULL);

  assert(!read_error);
  assert(ring);
  zix_ring_reset(ring);
  assert(zix_ring_read_space(ring) == 0);
  assert(zix_ring_write_space(ring) == zix_ring_capacity(ring));

  zix_ring_write(ring, "a", 1);
  zix_ring_write(ring, "b", 1);

  char     buf = 0;
  uint32_t n   = zix_ring_peek(ring, &buf, 1);
  assert(n == 1);
  assert(buf == 'a');

  n = zix_ring_skip(ring, 1);
  assert(n == 1);

  assert(zix_ring_read_space(ring) == 1);

  n = zix_ring_read(ring, &buf, 1);
  assert(n == 1);
  assert(buf == 'b');

  assert(zix_ring_read_space(ring) == 0);

  n = zix_ring_peek(ring, &buf, 1);
  assert(n == 0);

  n = zix_ring_read(ring, &buf, 1);
  assert(n == 0);

  n = zix_ring_skip(ring, 1);
  assert(n == 0);

  char* big_buf = (char*)calloc(size, 1);
  n             = zix_ring_write(ring, big_buf, size - 1);
  assert(n == (uint32_t)size - 1);

  n = zix_ring_write(ring, big_buf, size);
  assert(n == 0);

  free(big_buf);
  zix_ring_free(ring);
  return 0;
}

static void
test_failed_alloc(void)
{
  ZixFailingAllocatorState state     = {0u, SIZE_MAX};
  ZixAllocator             allocator = zix_failing_allocator(&state);

  // Successfully allocate a ring to count the number of allocations
  ring = zix_ring_new(&allocator, 512);
  assert(ring);

  // Test that each allocation failing is handled gracefully
  const size_t n_new_allocs = state.n_allocations;
  for (size_t i = 0u; i < n_new_allocs; ++i) {
    state.n_remaining = i;
    assert(!zix_ring_new(&allocator, 512));
  }

  zix_ring_free(ring);
}

int
main(int argc, char** argv)
{
  if (argc > 1 && argv[1][0] == '-') {
    printf("Usage: %s SIZE N_WRITES\n", argv[0]);
    return 1;
  }

  const unsigned size =
    (argc > 1) ? (unsigned)strtoul(argv[1], NULL, 10) : 1024;

  n_writes = (argc > 2) ? (unsigned)strtoul(argv[2], NULL, 10) : size * 1024;

  test_failed_alloc();
  test_ring(size);
  return 0;
}