#include "simdutf.h"

#include <array>

#include <tests/helpers/fixed_string.h>
#include <tests/helpers/random_int.h>
#include <tests/helpers/test.h>
#include <tests/helpers/transcode_test_base.h>

namespace {
constexpr std::array<size_t, 7> input_size{7, 16, 12, 64, 67, 128, 256};
constexpr simdutf::endianness LE = simdutf::endianness::LITTLE;

using simdutf::tests::helpers::transcode_utf32_to_utf16_test_base;

} // namespace

TEST_LOOP(convert_into_2_UTF16_bytes) {
  // range for 2 UTF-16 bytes
  simdutf::tests::helpers::RandomIntRanges random(
      {{0x0000, 0xd7ff}, {0xe000, 0xffff}}, seed);

  auto procedure = [&implementation](const char32_t *utf32, size_t size,
                                     char16_t *utf16) -> size_t {
    return implementation.convert_utf32_to_utf16le(utf32, size, utf16);
  };
  auto size_procedure = [&implementation](const char32_t *utf32,
                                          size_t size) -> size_t {
    return implementation.utf16_length_from_utf32(utf32, size);
  };
  for (size_t size : input_size) {
    transcode_utf32_to_utf16_test_base test(LE, random, size);
    ASSERT_TRUE(test(procedure));
    ASSERT_TRUE(test.check_size(size_procedure));
  }
}

TEST_LOOP(convert_into_4_UTF16_bytes) {
  // range for 4 UTF-16 bytes
  simdutf::tests::helpers::RandomIntRanges random({{0x10000, 0x10ffff}}, seed);

  auto procedure = [&implementation](const char32_t *utf32, size_t size,
                                     char16_t *utf16) -> size_t {
    return implementation.convert_utf32_to_utf16le(utf32, size, utf16);
  };
  auto size_procedure = [&implementation](const char32_t *utf32,
                                          size_t size) -> size_t {
    return implementation.utf16_length_from_utf32(utf32, size);
  };
  for (size_t size : input_size) {
    transcode_utf32_to_utf16_test_base test(LE, random, size);
    ASSERT_TRUE(test(procedure));
    ASSERT_TRUE(test.check_size(size_procedure));
  }
}

TEST_LOOP(convert_into_2_or_4_UTF16_bytes) {
  // range for 2 or 4 UTF-16 bytes (all codepoints)
  simdutf::tests::helpers::RandomIntRanges random(
      {{0x0000, 0xd7ff}, {0xe000, 0xffff}, {0x10000, 0x10ffff}}, seed);

  auto procedure = [&implementation](const char32_t *utf32, size_t size,
                                     char16_t *utf16) -> size_t {
    return implementation.convert_utf32_to_utf16le(utf32, size, utf16);
  };
  auto size_procedure = [&implementation](const char32_t *utf32,
                                          size_t size) -> size_t {
    return implementation.utf16_length_from_utf32(utf32, size);
  };
  for (size_t size : input_size) {
    transcode_utf32_to_utf16_test_base test(LE, random, size);
    ASSERT_TRUE(test(procedure));
    ASSERT_TRUE(test.check_size(size_procedure));
  }
}

TEST(convert_fails_if_there_is_surrogate) {
  auto procedure = [&implementation](const char32_t *utf32, size_t size,
                                     char16_t *utf16) -> size_t {
    return implementation.convert_utf32_to_utf16le(utf32, size, utf16);
  };
  const size_t size = 64;
  transcode_utf32_to_utf16_test_base test(LE, []() { return '*'; }, size + 32);

  for (char32_t surrogate = 0xd800; surrogate <= 0xdfff; surrogate++) {
    for (size_t i = 0; i < size; i++) {
      const auto old = test.input_utf32[i];
      test.input_utf32[i] = surrogate;
      ASSERT_TRUE(test(procedure));
      test.input_utf32[i] = old;
    }
  }
}

TEST(convert_fails_if_input_too_large) {
  uint32_t seed{1234};
  simdutf::tests::helpers::RandomInt generator(0x110000, 0xffffffff, seed);

  auto procedure = [&implementation](const char32_t *utf32, size_t size,
                                     char16_t *utf16) -> size_t {
    return implementation.convert_utf32_to_utf16le(utf32, size, utf16);
  };
  const size_t size = 64;
  transcode_utf32_to_utf16_test_base test(LE, []() { return '*'; }, size + 32);

  for (size_t j = 0; j < 1000; j++) {
    uint32_t wrong_value = generator();
    for (size_t i = 0; i < size; i++) {
      auto old = test.input_utf32[i];
      test.input_utf32[i] = wrong_value;
      ASSERT_TRUE(test(procedure));
      test.input_utf32[i] = old;
    }
  }
}

#if SIMDUTF_CPLUSPLUS23

namespace {
template <auto input> constexpr auto size() {
  return simdutf::utf16_length_from_utf32(input);
}

template <auto input> constexpr auto convert() {
  using namespace simdutf::tests::helpers;
  CTString<char16_t, size<input>()> tmp;
  const auto ret = simdutf::convert_utf32_to_utf16(input, tmp);
  if (ret != tmp.size()) {
    throw "unexpected write size";
  }
  return tmp;
}
} // namespace

TEST(compile_time_convert_utf32_to_utf16) {
  using namespace simdutf::tests::helpers;
  constexpr auto input = U"köttbulle"_utf32;
  constexpr auto expected = u"köttbulle"_utf16;
  constexpr auto output = convert<input>();
  static_assert(output == expected);
}

namespace {

template <auto input> constexpr auto convert_le() {
  using namespace simdutf::tests::helpers;
  CTString<char16_t, size<input>(), std::endian::little> tmp;
  const auto ret = simdutf::convert_utf32_to_utf16le(input, tmp);
  if (ret != tmp.size()) {
    throw "unexpected write size";
  }
  return tmp;
}
} // namespace

TEST(compile_time_convert_utf32_to_utf16le) {
  using namespace simdutf::tests::helpers;
  constexpr auto input = U"köttbulle"_utf32;
  constexpr auto expected = u"köttbulle"_utf16le;
  constexpr auto output = convert_le<input>();
  static_assert(output == expected);
}

#endif

TEST_MAIN
