//===-- Unittests for sorting routines ------------------------------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//

#include "src/__support/macros/config.h"
#include "src/stdlib/qsort.h"
#include "test/UnitTest/Test.h"

class SortingTest : public LIBC_NAMESPACE::testing::Test {

  using SortingRoutine = void (*)(void *array, size_t array_len,
                                  size_t elem_size,
                                  int (*compare)(const void *, const void *));

  static int int_compare(const void *l, const void *r) {
    int li = *reinterpret_cast<const int *>(l);
    int ri = *reinterpret_cast<const int *>(r);

    if (li == ri)
      return 0;
    else if (li > ri)
      return 1;
    else
      return -1;
  }

  static void int_sort(SortingRoutine sort_func, int *array, size_t array_len) {
    sort_func(reinterpret_cast<void *>(array), array_len, sizeof(int),
              int_compare);
  }

public:
  void test_sorted_array(SortingRoutine sort_func) {
    int array[25] = {10,   23,   33,   35,   55,   70,    71,   100,  110,
                     123,  133,  135,  155,  170,  171,   1100, 1110, 1123,
                     1133, 1135, 1155, 1170, 1171, 11100, 12310};
    constexpr size_t ARRAY_LEN = sizeof(array) / sizeof(int);

    int_sort(sort_func, array, ARRAY_LEN);

    ASSERT_LE(array[0], 10);
    ASSERT_LE(array[1], 23);
    ASSERT_LE(array[2], 33);
    ASSERT_LE(array[3], 35);
    ASSERT_LE(array[4], 55);
    ASSERT_LE(array[5], 70);
    ASSERT_LE(array[6], 71);
    ASSERT_LE(array[7], 100);
    ASSERT_LE(array[8], 110);
    ASSERT_LE(array[9], 123);
    ASSERT_LE(array[10], 133);
    ASSERT_LE(array[11], 135);
    ASSERT_LE(array[12], 155);
    ASSERT_LE(array[13], 170);
    ASSERT_LE(array[14], 171);
    ASSERT_LE(array[15], 1100);
    ASSERT_LE(array[16], 1110);
    ASSERT_LE(array[17], 1123);
    ASSERT_LE(array[18], 1133);
    ASSERT_LE(array[19], 1135);
    ASSERT_LE(array[20], 1155);
    ASSERT_LE(array[21], 1170);
    ASSERT_LE(array[22], 1171);
    ASSERT_LE(array[23], 11100);
    ASSERT_LE(array[24], 12310);
  }

  void test_reversed_sorted_array(SortingRoutine sort_func) {
    int array[] = {25, 24, 23, 22, 21, 20, 19, 18, 17, 16, 15, 14, 13,
                   12, 11, 10, 9,  8,  7,  6,  5,  4,  3,  2,  1};
    constexpr size_t ARRAY_LEN = sizeof(array) / sizeof(int);

    int_sort(sort_func, array, ARRAY_LEN);

    for (int i = 0; i < int(ARRAY_LEN - 1); ++i)
      ASSERT_EQ(array[i], i + 1);
  }

  void test_all_equal_elements(SortingRoutine sort_func) {
    int array[] = {100, 100, 100, 100, 100, 100, 100, 100, 100,
                   100, 100, 100, 100, 100, 100, 100, 100, 100,
                   100, 100, 100, 100, 100, 100, 100};
    constexpr size_t ARRAY_LEN = sizeof(array) / sizeof(int);

    int_sort(sort_func, array, ARRAY_LEN);

    for (size_t i = 0; i < ARRAY_LEN; ++i)
      ASSERT_EQ(array[i], 100);
  }

  void test_unsorted_array_1(SortingRoutine sort_func) {
    int array[25] = {10,  23,  8,    35,   55,   45,  40,  100, 110,
                     123, 90,  80,   70,   60,   171, 11,  1,   -1,
                     -5,  -10, 1155, 1170, 1171, 12,  -100};
    constexpr size_t ARRAY_LEN = sizeof(array) / sizeof(int);

    int_sort(sort_func, array, ARRAY_LEN);

    ASSERT_EQ(array[0], -100);
    ASSERT_EQ(array[1], -10);
    ASSERT_EQ(array[2], -5);
    ASSERT_EQ(array[3], -1);
    ASSERT_EQ(array[4], 1);
    ASSERT_EQ(array[5], 8);
    ASSERT_EQ(array[6], 10);
    ASSERT_EQ(array[7], 11);
    ASSERT_EQ(array[8], 12);
    ASSERT_EQ(array[9], 23);
    ASSERT_EQ(array[10], 35);
    ASSERT_EQ(array[11], 40);
    ASSERT_EQ(array[12], 45);
    ASSERT_EQ(array[13], 55);
    ASSERT_EQ(array[14], 60);
    ASSERT_EQ(array[15], 70);
    ASSERT_EQ(array[16], 80);
    ASSERT_EQ(array[17], 90);
    ASSERT_EQ(array[18], 100);
    ASSERT_EQ(array[19], 110);
    ASSERT_EQ(array[20], 123);
    ASSERT_EQ(array[21], 171);
    ASSERT_EQ(array[22], 1155);
    ASSERT_EQ(array[23], 1170);
    ASSERT_EQ(array[24], 1171);
  }

  void test_unsorted_array_2(SortingRoutine sort_func) {
    int array[7] = {10, 40, 45, 55, 35, 23, 60};
    constexpr size_t ARRAY_LEN = sizeof(array) / sizeof(int);

    int_sort(sort_func, array, ARRAY_LEN);

    ASSERT_EQ(array[0], 10);
    ASSERT_EQ(array[1], 23);
    ASSERT_EQ(array[2], 35);
    ASSERT_EQ(array[3], 40);
    ASSERT_EQ(array[4], 45);
    ASSERT_EQ(array[5], 55);
    ASSERT_EQ(array[6], 60);
  }

  void test_unsorted_array_duplicated_1(SortingRoutine sort_func) {
    int array[6] = {10, 10, 20, 20, 5, 5};
    constexpr size_t ARRAY_LEN = sizeof(array) / sizeof(int);

    int_sort(sort_func, array, ARRAY_LEN);

    ASSERT_EQ(array[0], 5);
    ASSERT_EQ(array[1], 5);
    ASSERT_EQ(array[2], 10);
    ASSERT_EQ(array[3], 10);
    ASSERT_EQ(array[4], 20);
    ASSERT_EQ(array[5], 20);
  }

  void test_unsorted_array_duplicated_2(SortingRoutine sort_func) {
    int array[10] = {20, 10, 10, 10, 10, 20, 21, 21, 21, 21};
    constexpr size_t ARRAY_LEN = sizeof(array) / sizeof(int);

    int_sort(sort_func, array, ARRAY_LEN);

    ASSERT_EQ(array[0], 10);
    ASSERT_EQ(array[1], 10);
    ASSERT_EQ(array[2], 10);
    ASSERT_EQ(array[3], 10);
    ASSERT_EQ(array[4], 20);
    ASSERT_EQ(array[5], 20);
    ASSERT_EQ(array[6], 21);
    ASSERT_EQ(array[7], 21);
    ASSERT_EQ(array[8], 21);
    ASSERT_EQ(array[9], 21);
  }

  void test_unsorted_array_duplicated_3(SortingRoutine sort_func) {
    int array[10] = {20, 30, 30, 30, 30, 20, 21, 21, 21, 21};
    constexpr size_t ARRAY_LEN = sizeof(array) / sizeof(int);

    int_sort(sort_func, array, ARRAY_LEN);

    ASSERT_EQ(array[0], 20);
    ASSERT_EQ(array[1], 20);
    ASSERT_EQ(array[2], 21);
    ASSERT_EQ(array[3], 21);
    ASSERT_EQ(array[4], 21);
    ASSERT_EQ(array[5], 21);
    ASSERT_EQ(array[6], 30);
    ASSERT_EQ(array[7], 30);
    ASSERT_EQ(array[8], 30);
    ASSERT_EQ(array[9], 30);
  }

  void test_unsorted_three_element_1(SortingRoutine sort_func) {
    int array[3] = {14999024, 0, 3};

    constexpr size_t ARRAY_LEN = sizeof(array) / sizeof(int);

    int_sort(sort_func, array, ARRAY_LEN);

    ASSERT_EQ(array[0], 0);
    ASSERT_EQ(array[1], 3);
    ASSERT_EQ(array[2], 14999024);
  }

  void test_unsorted_three_element_2(SortingRoutine sort_func) {
    int array[3] = {3, 14999024, 0};

    constexpr size_t ARRAY_LEN = sizeof(array) / sizeof(int);

    int_sort(sort_func, array, ARRAY_LEN);

    ASSERT_EQ(array[0], 0);
    ASSERT_EQ(array[1], 3);
    ASSERT_EQ(array[2], 14999024);
  }

  void test_unsorted_three_element_3(SortingRoutine sort_func) {
    int array[3] = {3, 0, 14999024};

    constexpr size_t ARRAY_LEN = sizeof(array) / sizeof(int);

    int_sort(sort_func, array, ARRAY_LEN);

    ASSERT_EQ(array[0], 0);
    ASSERT_EQ(array[1], 3);
    ASSERT_EQ(array[2], 14999024);
  }

  void test_same_three_element(SortingRoutine sort_func) {
    int array[3] = {12345, 12345, 12345};

    constexpr size_t ARRAY_LEN = sizeof(array) / sizeof(int);

    int_sort(sort_func, array, ARRAY_LEN);

    ASSERT_EQ(array[0], 12345);
    ASSERT_EQ(array[1], 12345);
    ASSERT_EQ(array[2], 12345);
  }

  void test_unsorted_two_element_1(SortingRoutine sort_func) {
    int array[] = {14999024, 0};

    constexpr size_t ARRAY_LEN = sizeof(array) / sizeof(int);

    int_sort(sort_func, array, ARRAY_LEN);

    ASSERT_EQ(array[0], 0);
    ASSERT_EQ(array[1], 14999024);
  }

  void test_unsorted_two_element_2(SortingRoutine sort_func) {
    int array[] = {0, 14999024};

    constexpr size_t ARRAY_LEN = sizeof(array) / sizeof(int);

    int_sort(sort_func, array, ARRAY_LEN);

    ASSERT_EQ(array[0], 0);
    ASSERT_EQ(array[1], 14999024);
  }

  void test_same_two_element(SortingRoutine sort_func) {
    int array[] = {12345, 12345};

    constexpr size_t ARRAY_LEN = sizeof(array) / sizeof(int);

    int_sort(sort_func, array, ARRAY_LEN);

    ASSERT_EQ(array[0], 12345);
    ASSERT_EQ(array[1], 12345);
  }

  void test_single_element(SortingRoutine sort_func) {
    int array[] = {12345};

    constexpr size_t ARRAY_LEN = sizeof(array) / sizeof(int);

    int_sort(sort_func, array, ARRAY_LEN);

    ASSERT_EQ(array[0], 12345);
  }

  void test_different_elem_size(SortingRoutine sort_func) {
    // Random order of values [0,50) to avoid only testing pre-sorted handling.
    // Long enough to reach interesting code.
    constexpr uint8_t ARRAY_INITIAL_VALS[] = {
        42, 13, 8,  4,  17, 28, 20, 32, 22, 29, 7,  2,  46, 37, 26, 49, 24,
        38, 10, 18, 40, 36, 47, 15, 11, 48, 44, 33, 1,  5,  16, 35, 39, 41,
        14, 23, 3,  9,  6,  27, 21, 25, 31, 45, 12, 43, 34, 30, 19, 0};

    constexpr size_t ARRAY_LEN = sizeof(ARRAY_INITIAL_VALS);
    constexpr size_t MAX_ELEM_SIZE = 150;
    constexpr size_t BUF_SIZE = ARRAY_LEN * MAX_ELEM_SIZE;

    static_assert(ARRAY_LEN < 256); // so we can encode the values.

    // Minimum alignment to test implementation for bugs related to assuming
    // incorrect association between alignment and element size. The buffer is
    // 'static' as otherwise it will exhaust the stack on the GPU targets.
    alignas(1) static uint8_t buf[BUF_SIZE];

    // GCC still requires capturing the constant ARRAY_INITIAL_VALS in the
    // lambda hence, let's use & to implicitly capture all needed variables
    // automatically.
    const auto fill_buf = [&](size_t elem_size) {
      for (size_t i = 0; i < BUF_SIZE; ++i) {
        buf[i] = 0;
      }

      for (size_t elem_i = 0, buf_i = 0; elem_i < ARRAY_LEN; ++elem_i) {
        const uint8_t elem_val = ARRAY_INITIAL_VALS[elem_i];
        for (size_t elem_byte_i = 0; elem_byte_i < elem_size; ++elem_byte_i) {
          buf[buf_i] = elem_val;
          buf_i += 1;
        }
      }
    };

    for (size_t elem_size = 0; elem_size <= MAX_ELEM_SIZE; ++elem_size) {
      // Fill all bytes with data to ensure mistakes in elem swap are noticed.
      fill_buf(elem_size);

      sort_func(reinterpret_cast<void *>(buf), ARRAY_LEN, elem_size,
                [](const void *a, const void *b) -> int {
                  const uint8_t a_val = *reinterpret_cast<const uint8_t *>(a);
                  const uint8_t b_val = *reinterpret_cast<const uint8_t *>(b);

                  if (a_val < b_val) {
                    return -1;
                  } else if (a_val > b_val) {
                    return 1;
                  } else {
                    return 0;
                  }
                });

      for (size_t elem_i = 0, buf_i = 0; elem_i < ARRAY_LEN; ++elem_i) {
        const uint8_t expected_elem_val = static_cast<uint8_t>(elem_i);

        for (size_t elem_byte_i = 0; elem_byte_i < elem_size; ++elem_byte_i) {
          const uint8_t buf_val = buf[buf_i];
          // Check that every byte in the element has the expected value.
          ASSERT_EQ(buf_val, expected_elem_val)
              << "elem_size: " << elem_size << " buf_i: " << buf_i << '\n';
          buf_i += 1;
        }
      }
    }
  }
};

#define LIST_SORTING_TESTS(Name, Func)                                         \
  using LlvmLibc##Name##Test = SortingTest;                                    \
  TEST_F(LlvmLibc##Name##Test, SortedArray) { test_sorted_array(Func); }       \
  TEST_F(LlvmLibc##Name##Test, ReverseSortedArray) {                           \
    test_reversed_sorted_array(Func);                                          \
  }                                                                            \
  TEST_F(LlvmLibc##Name##Test, AllEqualElements) {                             \
    test_all_equal_elements(Func);                                             \
  }                                                                            \
  TEST_F(LlvmLibc##Name##Test, UnsortedArray1) {                               \
    test_unsorted_array_1(Func);                                               \
  }                                                                            \
  TEST_F(LlvmLibc##Name##Test, UnsortedArray2) {                               \
    test_unsorted_array_2(Func);                                               \
  }                                                                            \
  TEST_F(LlvmLibc##Name##Test, UnsortedArrayDuplicateElements1) {              \
    test_unsorted_array_duplicated_1(Func);                                    \
  }                                                                            \
  TEST_F(LlvmLibc##Name##Test, UnsortedArrayDuplicateElements2) {              \
    test_unsorted_array_duplicated_2(Func);                                    \
  }                                                                            \
  TEST_F(LlvmLibc##Name##Test, UnsortedArrayDuplicateElements3) {              \
    test_unsorted_array_duplicated_3(Func);                                    \
  }                                                                            \
  TEST_F(LlvmLibc##Name##Test, UnsortedThreeElementArray1) {                   \
    test_unsorted_three_element_1(Func);                                       \
  }                                                                            \
  TEST_F(LlvmLibc##Name##Test, UnsortedThreeElementArray2) {                   \
    test_unsorted_three_element_2(Func);                                       \
  }                                                                            \
  TEST_F(LlvmLibc##Name##Test, UnsortedThreeElementArray3) {                   \
    test_unsorted_three_element_3(Func);                                       \
  }                                                                            \
  TEST_F(LlvmLibc##Name##Test, SameElementThreeElementArray) {                 \
    test_same_three_element(Func);                                             \
  }                                                                            \
  TEST_F(LlvmLibc##Name##Test, UnsortedTwoElementArray1) {                     \
    test_unsorted_two_element_1(Func);                                         \
  }                                                                            \
  TEST_F(LlvmLibc##Name##Test, UnsortedTwoElementArray2) {                     \
    test_unsorted_two_element_2(Func);                                         \
  }                                                                            \
  TEST_F(LlvmLibc##Name##Test, SameElementTwoElementArray) {                   \
    test_same_two_element(Func);                                               \
  }                                                                            \
  TEST_F(LlvmLibc##Name##Test, SingleElementArray) {                           \
    test_single_element(Func);                                                 \
  }                                                                            \
  TEST_F(LlvmLibc##Name##Test, DifferentElemSizeArray) {                       \
    test_different_elem_size(Func);                                            \
  }                                                                            \
  static_assert(true)