// Copyright 2023 Google LLC
// SPDX-License-Identifier: Apache-2.0
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//      http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

// OrderedDemote2To is not supported by HWY_SCALAR.
#ifndef HWY_DISABLED_TARGETS
#define HWY_DISABLED_TARGETS HWY_SCALAR
#endif

#include <stddef.h>
#include <stdio.h>

#include <algorithm>
#include <array>
#include <cmath>
#include <random>
#include <vector>

#include "hwy/aligned_allocator.h"
#include "hwy/base.h"

// clang-format off
#undef HWY_TARGET_INCLUDE
#define HWY_TARGET_INCLUDE "ops/ops_test.cc"  // NOLINT
// clang-format on
#include "hwy/foreach_target.h"  // IWYU pragma: keep
#include "hwy/highway.h"
#include "hwy/tests/test_util-inl.h"
// After highway.h
#include "gemma/activations.h"
#include "gemma/common.h"
#include "gemma/configs.h"
#include "ops/ops-inl.h"
#include "util/allocator.h"
#include "hwy/tests/hwy_gtest.h"

HWY_BEFORE_NAMESPACE();
namespace gcpp {
namespace HWY_NAMESPACE {

namespace hn = hwy::HWY_NAMESPACE;

template <class Test>
struct ForeachCountAndMisalign {
  template <typename T, class D>
  HWY_NOINLINE void operator()(T /*unused*/, D d) const {
    hwy::RandomState rng;
    const size_t N = Lanes(d);
    const size_t misalignments[3] = {0, N / 4, 3 * N / 5};

    for (size_t count = 0; count < 2 * N; ++count) {
      for (size_t ma : misalignments) {
        for (size_t mb : misalignments) {
          Test()(d, count, ma, mb, rng);
        }
      }
    }
  }
};

template <typename T>
T Random(hwy::RandomState& rng) {
  const int32_t bits = static_cast<int32_t>(Random32(&rng)) & 1023;
  const double val = (bits - 512) / 64.0;
  // Clamp negative to zero for unsigned types.
  return hwy::ConvertScalarTo<T>(
      HWY_MAX(hwy::ConvertScalarTo<double>(hwy::LowestValue<T>()), val));
}

HWY_NOINLINE void SourceAddFrom(const float* HWY_RESTRICT other,
                                float* HWY_RESTRICT x, size_t size) {
  for (size_t i = 0; i < size; ++i) {
    x[i] += other[i];
  }
}

HWY_NOINLINE void SourceMulBy(const float* HWY_RESTRICT other,
                              float* HWY_RESTRICT x, size_t size,
                              size_t max_pos) {
  HWY_DASSERT(max_pos <= size);
  for (size_t i = 0; i < max_pos; ++i) {
    x[i] *= other[i];
  }
}

HWY_NOINLINE void SourceMulByConst(float c, float* HWY_RESTRICT x, size_t size,
                                   size_t max_pos) {
  for (size_t i = 0; i < max_pos; ++i) {
    x[i] *= c;
  }
}

HWY_NOINLINE void SourceMulByConstAndAdd(float c, const float* HWY_RESTRICT x,
                                         float* HWY_RESTRICT out, size_t size,
                                         size_t max_pos) {
  for (size_t i = 0; i < max_pos; ++i) {
    out[i] += x[i] * c;
  }
}

HWY_NOINLINE void SourceSoftmax(float* HWY_RESTRICT x, size_t size,
                                size_t mask_pos) {
  HWY_DASSERT(size != 0);
  HWY_DASSERT(mask_pos <= size);
  float sum = 0.0;
  const float maxval = *std::max_element(x, x + mask_pos);
  for (size_t i = 0; i < mask_pos; ++i) {
    x[i] = std::exp(x[i] - maxval);
    sum += x[i];
  }
  const float scale = 1.0f / sum;
  for (size_t i = 0; i < mask_pos; ++i) {
    x[i] *= scale;
  }
}

template <size_t k>
HWY_NOINLINE std::discrete_distribution<int> SourceCreateDistribution(
    std::array<float, k>& top_k, float temperature) {
  // re-normalize distribution
  for (size_t i = 0; i < k; ++i) {
    top_k[i] = exp(log(top_k[i]) / temperature);
  }
  float denominator = 0.0f;
  for (size_t i = 0; i < k; ++i) {
    denominator += top_k[i];
  }
  denominator = 1.0f / denominator;
  MulByConst(denominator, top_k.data(), k);
  return std::discrete_distribution<int>(std::begin(top_k), std::end(top_k));
}

struct TestAddFrom {
  template <class D>
  void operator()(D d, size_t count, size_t misalign_a, size_t misalign_b,
                  hwy::RandomState& rng) {
    using T = hn::TFromD<D>;

    hwy::AlignedFreeUniquePtr<T[]> px =
        hwy::AllocateAligned<T>(HWY_MAX(1, misalign_a + count));
    hwy::AlignedFreeUniquePtr<T[]> pe =
        hwy::AllocateAligned<T>(HWY_MAX(1, misalign_a + count));
    hwy::AlignedFreeUniquePtr<T[]> po =
        hwy::AllocateAligned<T>(HWY_MAX(1, misalign_b + count));
    HWY_ASSERT(px && pe && po);

    T* x = px.get() + misalign_a;
    T* e = pe.get() + misalign_a;
    T* o = po.get() + misalign_b;

    for (size_t i = 0; i < count; ++i) {
      x[i] = Random<T>(rng);
      e[i] = x[i];
      o[i] = Random<T>(rng);
    }

    SourceAddFrom(o, e, count);
    AddFrom(o, x, count);

    hwy::AssertArraySimilar(e, x, count, hwy::TargetName(HWY_TARGET), __FILE__,
                            __LINE__);
  }
};

struct TestMulBy {
  template <class D>
  void operator()(D d, size_t count, size_t misalign_a, size_t misalign_b,
                  hwy::RandomState& rng) {
    using T = hn::TFromD<D>;

    hwy::AlignedFreeUniquePtr<T[]> px =
        hwy::AllocateAligned<T>(HWY_MAX(1, misalign_a + count));
    hwy::AlignedFreeUniquePtr<T[]> pe =
        hwy::AllocateAligned<T>(HWY_MAX(1, misalign_a + count));
    hwy::AlignedFreeUniquePtr<T[]> po =
        hwy::AllocateAligned<T>(HWY_MAX(1, misalign_b + count));
    HWY_ASSERT(px && pe && po);

    T* x = px.get() + misalign_a;
    T* e = pe.get() + misalign_a;
    T* o = po.get() + misalign_b;

    for (size_t i = 0; i < count; ++i) {
      x[i] = Random<T>(rng);
      e[i] = x[i];
      o[i] = Random<T>(rng);
    }

    SourceMulBy(o, e, count, count);
    MulBy(o, x, count, count);

    hwy::AssertArraySimilar(e, x, count, hwy::TargetName(HWY_TARGET), __FILE__,
                            __LINE__);
  }
};

struct TestMulByConstAndAdd {
  template <class D>
  void operator()(D d, size_t count, size_t misalign_a, size_t misalign_b,
                  hwy::RandomState& rng) {
    using T = hn::TFromD<D>;

    hwy::AlignedFreeUniquePtr<T[]> px =
        hwy::AllocateAligned<T>(HWY_MAX(1, misalign_a + count));
    hwy::AlignedFreeUniquePtr<T[]> pe =
        hwy::AllocateAligned<T>(HWY_MAX(1, misalign_a + count));
    hwy::AlignedFreeUniquePtr<T[]> po =
        hwy::AllocateAligned<T>(HWY_MAX(1, misalign_b + count));
    HWY_ASSERT(px && pe && po);

    T* x = px.get() + misalign_a;
    T* e = pe.get() + misalign_a;
    T* o = po.get() + misalign_b;

    for (size_t i = 0; i < count; ++i) {
      x[i] = Random<T>(rng);
      e[i] = x[i];
      o[i] = Random<T>(rng);
    }
    T constant = Random<T>(rng);

    SourceMulByConstAndAdd(constant, o, e, count, count);
    MulByConstAndAdd(constant, o, x, count, count);

    hwy::AssertArraySimilar(e, x, count, hwy::TargetName(HWY_TARGET), __FILE__,
                            __LINE__);
  }
};

struct TestMulByConst {
  template <class D>
  void operator()(D d, size_t count, size_t misalign_a, size_t misalign_b,
                  hwy::RandomState& rng) {
    if (misalign_b == 0) return;
    using T = hn::TFromD<D>;

    hwy::AlignedFreeUniquePtr<T[]> px =
        hwy::AllocateAligned<T>(HWY_MAX(1, misalign_a + count));
    hwy::AlignedFreeUniquePtr<T[]> pe =
        hwy::AllocateAligned<T>(HWY_MAX(1, misalign_a + count));
    HWY_ASSERT(px && pe);

    T* x = px.get() + misalign_a;
    T* e = pe.get() + misalign_a;

    for (size_t i = 0; i < count; ++i) {
      x[i] = Random<T>(rng);
      e[i] = x[i];
    }
    T constant = Random<T>(rng);

    SourceMulByConst(constant, e, count, count);
    MulByConst(constant, x, count, count);

    hwy::AssertArraySimilar(e, x, count, hwy::TargetName(HWY_TARGET), __FILE__,
                            __LINE__);
  }
};

struct TestSoftmax {
  template <class D>
  void operator()(D d, size_t count, size_t misalign_a, size_t misalign_b,
                  hwy::RandomState& rng) {
    if (count == 0) return;  // *Softmax would assert
    if (misalign_b == 0) return;
    using T = hn::TFromD<D>;

    hwy::AlignedFreeUniquePtr<T[]> px =
        hwy::AllocateAligned<T>(HWY_MAX(1, misalign_a + count));
    hwy::AlignedFreeUniquePtr<T[]> pe =
        hwy::AllocateAligned<T>(HWY_MAX(1, misalign_a + count));
    HWY_ASSERT(px && pe);

    T* x = px.get() + misalign_a;
    T* e = pe.get() + misalign_a;

    for (size_t i = 0; i < count; ++i) {
      x[i] = Random<T>(rng);
      e[i] = x[i];
    }

    SourceSoftmax(e, count, count);
    Softmax(x, count, count);

    T sum = 0.0f;
    for (size_t i = 0; i < count; ++i) {
      sum += x[i];
      double rel = std::abs(x[i] - e[i]) / e[i];
      ASSERT_LT(rel, 1e-6) << "Mismatch on coordinate " << i << " out of "
                           << count;
    }
    ASSERT_NEAR(sum, 1.0, 1e-6);
  }
};

template <size_t k>
struct TestCreateDistribution {
  void operator()(hwy::RandomState& rng) {
    std::array<float, k> x;
    std::array<float, k> e;

    for (size_t i = 0; i < k; ++i) {
      x[i] = Random<float>(rng);
      e[i] = x[i];
    }
    const float constant = Random<float>(rng);
    auto expected = SourceCreateDistribution(e, constant);
    auto output = create_distribution(x, constant);

    AssertEqual(expected, output, hwy::TargetName(HWY_TARGET), __FILE__,
                __LINE__);
  }
};

void TestAllAddFrom() {
  hn::ForPartialVectors<ForeachCountAndMisalign<TestAddFrom>>()(float());
}

void TestAllMulBy() {
  hn::ForPartialVectors<ForeachCountAndMisalign<TestMulBy>>()(float());
}

void TestAllMulByConst() {
  hn::ForPartialVectors<ForeachCountAndMisalign<TestMulByConst>>()(float());
}

void TestAllMulByConstAndAdd() {
  hn::ForPartialVectors<ForeachCountAndMisalign<TestMulByConstAndAdd>>()(
      float());
}

void TestAllSoftmax() {
  hn::ForPartialVectors<ForeachCountAndMisalign<TestSoftmax>>()(float());
}

void TestAllCreateDistribution() {
  TestCreateDistribution<2048>();
  TestCreateDistribution<5000>();
}

void TestSigmoid() {
  std::vector<float> values;
  for (int i = -150; i <= 150; ++i) {
    values.push_back(.1f * i);
  }
  std::vector<float> result = values;
  Sigmoid(result.data(), result.size());

  for (size_t i = 0; i < values.size(); i++) {
    const float max_error = 0.00007;
    float value = values[i];
    float approx = result[i];
    float expected = (1 / (1 + std::exp(-values[i])));
    EXPECT_NEAR(approx, expected, max_error) << "Input: " << value;
  }
}

void TestRopeAndMulBy() {
  using Config = ConfigGemma2_9B<float>;
  int dim_qkv = Config::kQKVDim;
  RowVectorBatch<float> x(1, dim_qkv);

  std::mt19937 gen;
  gen.seed(0x12345678);
  std::normal_distribution<float> r{0.0, 5.0};
  auto random_float = [&r, &gen] { return r(gen); };

  for (int i = 0; i < dim_qkv; ++i) {
    x.All()[i] = random_float();
  }

  const float qmul = ChooseQueryScale<Config>();
  const float kmul = 1.0;

  std::vector<float> qexpected(dim_qkv);
  std::vector<float> qactual(dim_qkv);
  std::vector<float> kexpected(dim_qkv);
  std::vector<float> kactual(dim_qkv);
  RowVectorBatch<float> inv_timescale =
      gcpp::Activations::CreateInvTimescale<Config>();
  // Assert VectorizedRope computation is same as regular rope at different pos.
  for (int pos = 1; pos < 500; pos++) {
    // Rope'd Q embeddings
    RopeAndMulBy(qmul, x.Const(), dim_qkv, inv_timescale.Const(), pos,
                 qexpected.data());
    VectorizedRopeAndMulBy(qmul, x.Const(), dim_qkv, inv_timescale.Const(), pos,
                           qactual.data());

    for (int i = 0; i < dim_qkv; ++i) {
      EXPECT_NEAR(qactual[i], qexpected[i], 1e-4)
          << "qIndex:" << i << "qInput:" << qactual[i];
    }

    // Rope'd K embeddings
    RopeAndMulBy(kmul, x.Const(), dim_qkv, inv_timescale.Const(), pos,
                 kexpected.data());
    VectorizedRopeAndMulBy(kmul, x.Const(), dim_qkv, inv_timescale.Const(), pos,
                           kactual.data());

    for (int i = 0; i < dim_qkv; ++i) {
      EXPECT_NEAR(kactual[i], kexpected[i], 1e-4)
          << "kIndex:" << i << "kInput:" << kactual[i];
    }
  }
}

// NOLINTNEXTLINE(google-readability-namespace-comments)
}  // namespace HWY_NAMESPACE
}  // namespace gcpp
HWY_AFTER_NAMESPACE();

#if HWY_ONCE

namespace gcpp {
HWY_BEFORE_TEST(OpsTest);
HWY_EXPORT_AND_TEST_P(OpsTest, TestAllAddFrom);
HWY_EXPORT_AND_TEST_P(OpsTest, TestAllMulBy);
HWY_EXPORT_AND_TEST_P(OpsTest, TestAllMulByConst);
HWY_EXPORT_AND_TEST_P(OpsTest, TestAllMulByConstAndAdd);
HWY_EXPORT_AND_TEST_P(OpsTest, TestAllSoftmax);
HWY_EXPORT_AND_TEST_P(OpsTest, TestAllCreateDistribution);
HWY_EXPORT_AND_TEST_P(OpsTest, TestSigmoid);
HWY_EXPORT_AND_TEST_P(OpsTest, TestRopeAndMulBy);
HWY_AFTER_TEST();

}  // namespace gcpp

#endif