/* SPDX-License-Identifier: Apache-2.0 */

#include "testing/testing.h"
#include <cstring>

#include "BLI_array.h"
#include "BLI_stack.h"
#include "BLI_utildefines.h"

#define SIZE 1024

/* number of items per chunk. use a small value to expose bugs */
#define STACK_CHUNK_SIZE 8

/* Ensure block size is set to #STACK_NEW_EX_ARGS */
#define BLI_stack_new(esize, descr) BLI_stack_new_ex(esize, descr, esize *STACK_CHUNK_SIZE)

TEST(stack, Empty)
{
  BLI_Stack *stack;

  stack = BLI_stack_new(sizeof(int), __func__);
  EXPECT_TRUE(BLI_stack_is_empty(stack));
  EXPECT_EQ(BLI_stack_count(stack), 0);
  BLI_stack_free(stack);
}

TEST(stack, One)
{
  BLI_Stack *stack;
  unsigned int in = -1, out = 1;

  stack = BLI_stack_new(sizeof(in), __func__);

  BLI_stack_push(stack, (void *)&in);
  EXPECT_FALSE(BLI_stack_is_empty(stack));
  EXPECT_EQ(BLI_stack_count(stack), 1);
  BLI_stack_pop(stack, (void *)&out);
  EXPECT_EQ(out, in);
  EXPECT_TRUE(BLI_stack_is_empty(stack));
  EXPECT_EQ(BLI_stack_count(stack), 0);
  BLI_stack_free(stack);
}

TEST(stack, Range)
{
  const int tot = SIZE;
  BLI_Stack *stack;
  int in, out;

  stack = BLI_stack_new(sizeof(in), __func__);

  for (in = 0; in < tot; in++) {
    BLI_stack_push(stack, (void *)&in);
  }

  for (in = tot - 1; in >= 0; in--) {
    EXPECT_FALSE(BLI_stack_is_empty(stack));
    BLI_stack_pop(stack, (void *)&out);
    EXPECT_EQ(out, in);
  }
  EXPECT_TRUE(BLI_stack_is_empty(stack));

  BLI_stack_free(stack);
}

TEST(stack, String)
{
  const int tot = SIZE;
  int i;

  BLI_Stack *stack;
  char in[] = "hello world!";
  char out[sizeof(in)];

  stack = BLI_stack_new(sizeof(in), __func__);

  for (i = 0; i < tot; i++) {
    *((int *)in) = i;
    BLI_stack_push(stack, (void *)in);
  }

  for (i = tot - 1; i >= 0; i--) {
    EXPECT_FALSE(BLI_stack_is_empty(stack));
    *((int *)in) = i;
    BLI_stack_pop(stack, (void *)&out);
    EXPECT_STREQ(in, out);
  }
  EXPECT_TRUE(BLI_stack_is_empty(stack));

  BLI_stack_free(stack);
}

TEST(stack, Peek)
{
  const int tot = SIZE;
  int i;

  BLI_Stack *stack;
  const short in[] = {1, 10, 100, 1000};

  stack = BLI_stack_new(sizeof(*in), __func__);

  for (i = 0; i < tot; i++) {
    BLI_stack_push(stack, &in[i % ARRAY_SIZE(in)]);
  }

  for (i = tot - 1; i >= 0; i--, BLI_stack_discard(stack)) {
    short *ret = (short *)BLI_stack_peek(stack);
    EXPECT_EQ(*ret, in[i % ARRAY_SIZE(in)]);
  }

  EXPECT_TRUE(BLI_stack_is_empty(stack));

  BLI_stack_free(stack);
}

/* Check that clearing the stack leaves in it a correct state. */
TEST(stack, Clear)
{
  const int tot_rerun = 4;
  int rerun;

  /* based on range test */
  int tot = SIZE;
  BLI_Stack *stack;
  int in, out;

  /* use a small chunk size to ensure we test */
  stack = BLI_stack_new(sizeof(in), __func__);

  for (rerun = 0; rerun < tot_rerun; rerun++) {
    for (in = 0; in < tot; in++) {
      BLI_stack_push(stack, (void *)&in);
    }

    BLI_stack_clear(stack);
    EXPECT_TRUE(BLI_stack_is_empty(stack));

    /* and again, this time check it is valid */
    for (in = 0; in < tot; in++) {
      BLI_stack_push(stack, (void *)&in);
    }

    for (in = tot - 1; in >= 0; in--) {
      EXPECT_FALSE(BLI_stack_is_empty(stack));
      BLI_stack_pop(stack, (void *)&out);
      EXPECT_EQ(out, in);
    }

    EXPECT_TRUE(BLI_stack_is_empty(stack));

    /* without this, we won't test case when mixed free/used */
    tot /= 2;
  }

  BLI_stack_free(stack);
}

TEST(stack, Reuse)
{
  const int sizes[] = {3, 11, 81, 400, 999, 12, 1, 9721, 7, 99, 5, 0};
  int sizes_test[ARRAY_SIZE(sizes)];
  const int *s;
  int out, i;
  int sum, sum_test;

  BLI_Stack *stack;

  stack = BLI_stack_new(sizeof(i), __func__);

  /* add a bunch of numbers, ensure we get same sum out */
  sum = 0;
  for (s = sizes; *s; s++) {
    for (i = *s; i != 0; i--) {
      BLI_stack_push(stack, (void *)&i);
      sum += i;
    }
  }
  sum_test = 0;
  while (!BLI_stack_is_empty(stack)) {
    BLI_stack_pop(stack, (void *)&out);
    sum_test += out;
  }
  EXPECT_EQ(sum, sum_test);

  /* add and remove all except last */
  for (s = sizes; *s; s++) {
    for (i = *s; i >= 0; i--) {
      BLI_stack_push(stack, (void *)&i);
    }
    for (i = *s; i > 0; i--) {
      BLI_stack_pop(stack, (void *)&out);
    }
  }

  i = ARRAY_SIZE(sizes) - 1;
  while (!BLI_stack_is_empty(stack)) {
    i--;
    BLI_stack_pop(stack, (void *)&sizes_test[i]);
    EXPECT_EQ(sizes_test[i], sizes[i]);
    EXPECT_GT(i, -1);
  }
  EXPECT_EQ(0, i);
  EXPECT_EQ(memcmp(sizes, sizes_test, sizeof(sizes) - sizeof(int)), 0);

  /* finally test BLI_stack_pop_n */
  for (i = ARRAY_SIZE(sizes); i--;) {
    BLI_stack_push(stack, (void *)&sizes[i]);
  }
  EXPECT_EQ(BLI_stack_count(stack), ARRAY_SIZE(sizes));
  BLI_stack_pop_n(stack, (void *)sizes_test, ARRAY_SIZE(sizes));
  EXPECT_EQ(memcmp(sizes, sizes_test, sizeof(sizes) - sizeof(int)), 0);

  BLI_stack_free(stack);
}