#pragma once

// DO NOT DEFINE STATIC DATA IN THIS HEADER!
// See Note [Do not compile initializers with AVX]

#include <ATen/cpu/vec256/intrinsics.h>
#include <ATen/cpu/vec256/vec256_base.h>
// Sleef offers vectorized versions of some transcedentals
// such as sin, cos, tan etc..
// However for now opting for STL, since we are not building
// with Sleef for mobile yet.

namespace at {
namespace vec256 {
// See Note [Acceptable use of anonymous namespace in header]
namespace {

// Right now contains only aarch64 implementation.
// Due to follow two reasons aarch32 is not currently supported.
// 1. Due to difference in ISA been aarch32 and aarch64, intrinsics
//    that work for aarch64 dont work for aarch32.
// 2. Android NDK r21 has problems with compiling aarch32.
//    Clang seg faults.
//    https://github.com/android/ndk/issues/1248
//    https://bugs.llvm.org/show_bug.cgi?id=45824
// Most likely we will do aarch32 support with inline asm.
#if defined(__aarch64__)

#ifdef __BIG_ENDIAN__
#error "Big endian is not supported."
#endif

template<int index, bool mask_val>
struct BlendRegs {
  static float32x4_t impl(
    const float32x4_t& a, const float32x4_t& b, float32x4_t& res);
};

template<int index>
struct BlendRegs<index, true>{
  static float32x4_t impl(
      const float32x4_t& a, const float32x4_t& b, float32x4_t& res) {
    return vsetq_lane_f32(vgetq_lane_f32(b, index), res, index);
  }
};

template<int index>
struct BlendRegs<index, false>{
  static float32x4_t impl(
      const float32x4_t& a, const float32x4_t& b, float32x4_t& res) {
    return vsetq_lane_f32(vgetq_lane_f32(a, index), res, index);
  }
};

template <> class Vec256<float> {
private:
  float32x4x2_t values;
public:
  using value_type = float;
  static constexpr int size() {
    return 8;
  }
  Vec256() {}
  Vec256(float32x4x2_t v) : values(v) {}
  Vec256(float val) : values{vdupq_n_f32(val), vdupq_n_f32(val) } {}
  Vec256(float val0, float val1, float val2, float val3,
         float val4, float val5, float val6, float val7) :
         values{val0, val1, val2, val3, val4, val5, val6, val7} {}
  Vec256(float32x4_t val0, float32x4_t val1) : values{val0, val1} {}
  operator float32x4x2_t() const {
    return values;
  }
  template <int64_t mask>
  static Vec256<float> blend(const Vec256<float>& a, const Vec256<float>& b) {
    Vec256<float> vec;
    // 0.
    vec.values.val[0] =
      BlendRegs<0, (mask & 0x01)!=0>::impl(
          a.values.val[0], b.values.val[0], vec.values.val[0]);
    vec.values.val[0] =
      BlendRegs<1, (mask & 0x02)!=0>::impl(
          a.values.val[0], b.values.val[0], vec.values.val[0]);
    vec.values.val[0] =
      BlendRegs<2, (mask & 0x04)!=0>::impl(
          a.values.val[0], b.values.val[0], vec.values.val[0]);
    vec.values.val[0] =
      BlendRegs<3, (mask & 0x08)!=0>::impl(
          a.values.val[0], b.values.val[0], vec.values.val[0]);
    // 1.
    vec.values.val[1] =
      BlendRegs<0, (mask & 0x10)!=0>::impl(
          a.values.val[1], b.values.val[1], vec.values.val[1]);
    vec.values.val[1] =
      BlendRegs<1, (mask & 0x20)!=0>::impl(
          a.values.val[1], b.values.val[1], vec.values.val[1]);
    vec.values.val[1] =
      BlendRegs<2, (mask & 0x40)!=0>::impl(
          a.values.val[1], b.values.val[1], vec.values.val[1]);
    vec.values.val[1] =
      BlendRegs<3, (mask & 0x80)!=0>::impl(
          a.values.val[1], b.values.val[1], vec.values.val[1]);
    return vec;
  }
  static Vec256<float> blendv(const Vec256<float>& a, const Vec256<float>& b,
                              const Vec256<float>& mask) {
    // TODO
    // NB: This requires that each value, i.e., each uint value,
    // of the mask either all be zeros or all be 1s.
    // We perhaps need some kind of an assert?
    // But that will affect performance.
    Vec256<float> vec(mask.values);
    vec.values.val[0] = vbslq_f32(
        vreinterpretq_u32_f32(vec.values.val[0]),
        b.values.val[0],
        a.values.val[0]);
    vec.values.val[1] = vbslq_f32(
        vreinterpretq_u32_f32(vec.values.val[1]),
        b.values.val[1],
        a.values.val[1]);
    return vec;
  }
  template<typename step_t>
  static Vec256<float> arange(float base = 0.f, step_t step = static_cast<step_t>(1)) {
    const Vec256<float> base_vec(base);
    const Vec256<float> step_vec(step);
    const Vec256<float> step_sizes(0, 1, 2, 3, 4, 5, 6, 7);
    return fmadd(step_sizes, step_vec, base_vec);
  }
  static Vec256<float> set(const Vec256<float>& a, const Vec256<float>& b,
                           int64_t count = size()) {
    switch (count) {
      case 0:
        return a;
      case 1:
        {
          Vec256<float> vec;
          static uint32x4_t mask_low = {0xFFFFFFFF, 0x0, 0x0, 0x0};
          vec.values.val[0] = vreinterpretq_f32_u32(mask_low);
          vec.values.val[1] = a.values.val[1];
          vec.values.val[0] = vbslq_f32(
              vreinterpretq_u32_f32(vec.values.val[0]),
              b.values.val[0],
              a.values.val[0]);
          return vec;
        }
      case 2:
        {
          Vec256<float> vec;
          static uint32x4_t mask_low = {0xFFFFFFFF, 0xFFFFFFFF, 0x0, 0x0};
          vec.values.val[0] = vreinterpretq_f32_u32(mask_low);
          vec.values.val[1] = a.values.val[1];
          vec.values.val[0] = vbslq_f32(
              vreinterpretq_u32_f32(vec.values.val[0]),
              b.values.val[0],
              a.values.val[0]);
          return vec;
        }
      case 3:
        {
          Vec256<float> vec;
          static uint32x4_t mask_low = {0xFFFFFFFF, 0xFFFFFFFF, 0xFFFFFFFF, 0x0};
          vec.values.val[0] = vreinterpretq_f32_u32(mask_low);
          vec.values.val[1] = a.values.val[1];
          vec.values.val[0] = vbslq_f32(
              vreinterpretq_u32_f32(vec.values.val[0]),
              b.values.val[0],
              a.values.val[0]);
          return vec;
        }
      case 4:
        return Vec256<float>(b.values.val[0], a.values.val[1]);
      case 5:
        {
          Vec256<float> vec;
          static uint32x4_t mask_high = {0xFFFFFFFF, 0x0, 0x0, 0x0};
          vec.values.val[0] = b.values.val[0];
          vec.values.val[1] = vreinterpretq_f32_u32(mask_high);
          vec.values.val[1] = vbslq_f32(
              vreinterpretq_u32_f32(vec.values.val[1]),
              b.values.val[1],
              a.values.val[1]);
          return vec;
        }
      case 6:
        {
          Vec256<float> vec;
          static uint32x4_t mask_high = {0xFFFFFFFF, 0xFFFFFFFF, 0x0, 0x0};
          vec.values.val[0] = b.values.val[0];
          vec.values.val[1] = vreinterpretq_f32_u32(mask_high);
          vec.values.val[1] = vbslq_f32(
              vreinterpretq_u32_f32(vec.values.val[1]),
              b.values.val[1],
              a.values.val[1]);
          return vec;
        }
      case 7:
        {
          Vec256<float> vec;
          static uint32x4_t mask_high = {0xFFFFFFFF, 0xFFFFFFFF, 0xFFFFFFFF, 0x0};
          vec.values.val[0] = b.values.val[0];
          vec.values.val[1] = vreinterpretq_f32_u32(mask_high);
          vec.values.val[1] = vbslq_f32(
              vreinterpretq_u32_f32(vec.values.val[1]),
              b.values.val[1],
              a.values.val[1]);
          return vec;
        }
    }
    return b;
  }
  static Vec256<float> loadu(const void* ptr, int64_t count = size()) {
    if (count == size()) {
      return vld1q_f32_x2(reinterpret_cast<const float*>(ptr));
    }
    else if (count == (size() >> 1)) {
      Vec256<float> res;
      res.values.val[0] = vld1q_f32(reinterpret_cast<const float*>(ptr));
      res.values.val[1] = vdupq_n_f32(0.f);
      return res;
    }
    else {
      __at_align32__ float tmp_values[size()];
      for (auto i = 0; i < size(); ++i) {
        tmp_values[i] = 0.0;
      }
      std::memcpy(
          tmp_values,
          reinterpret_cast<const float*>(ptr),
          count * sizeof(float));
      return vld1q_f32_x2(reinterpret_cast<const float*>(tmp_values));
    }
  }
  void store(void* ptr, int64_t count = size()) const {
    if (count == size()) {
      vst1q_f32_x2(reinterpret_cast<float*>(ptr), values);
    }
    else if (count == (size() >> 1)) {
      vst1q_f32(reinterpret_cast<float*>(ptr), values.val[0]);
    }
    else {
      float tmp_values[size()];
      vst1q_f32_x2(reinterpret_cast<float*>(tmp_values), values);
      std::memcpy(ptr, tmp_values, count * sizeof(float));
    }
  }
  inline const float32x4_t& get_low() const {
    return values.val[0];
  }
  inline float32x4_t& get_low() {
    return values.val[0];
  }
  inline const float32x4_t& get_high() const {
    return values.val[1];
  }
  inline float32x4_t& get_high() {
    return values.val[1];
  }
  // Very slow implementation of indexing.
  // Only required because vec256_qint refers to this.
  // Once we specialize that implementation for ARM
  // this should be removed. TODO (kimishpatel)
  float operator[](int idx) const {
    __at_align32__ float tmp[size()];
    store(tmp);
    return tmp[idx];
  }
  float operator[](int idx) {
    __at_align32__ float tmp[size()];
    store(tmp);
    return tmp[idx];
  }
  // For boolean version where we want to if any 1/all zero
  // etc. can be done faster in a different way.
  int zero_mask() const {
    __at_align32__ float tmp[size()];
    store(tmp);
    int mask = 0;
    for (int i = 0; i < size(); ++ i) {
      if (tmp[i] == 0.f) {
        mask |= (1 << i);
      }
    }
    return mask;
  }
  Vec256<float> map(float (*f)(float)) const {
    __at_align32__ float tmp[size()];
    store(tmp);
    for (int64_t i = 0; i < size(); i++) {
      tmp[i] = f(tmp[i]);
    }
    return loadu(tmp);
  }
  Vec256<float> abs() const {
    return Vec256<float>(vabsq_f32(values.val[0]), vabsq_f32(values.val[1]));
  }
  Vec256<float> angle() const {
    return Vec256<float>(0.f);
  }
  Vec256<float> real() const {
    return *this;
  }
  Vec256<float> imag() const {
    return Vec256<float>(0.f);
  }
  Vec256<float> conj() const {
    return *this;
  }
  Vec256<float> acos() const {
    return map(std::acos);
  }
  Vec256<float> asin() const {
    return map(std::asin);
  }
  Vec256<float> atan() const {
    return map(std::atan);
  }
  Vec256<float> atan2(const Vec256<float> &exp) const {
    __at_align32__ float tmp[size()];
    __at_align32__ float tmp_exp[size()];
    store(tmp);
    exp.store(tmp_exp);
    for (int64_t i = 0; i < size(); i++) {
      tmp[i] = std::atan2(tmp[i], tmp_exp[i]);
    }
    return loadu(tmp);
  }
  Vec256<float> erf() const {
    return map(std::erf);
  }
  Vec256<float> erfc() const {
    return map(std::erfc);
  }
  Vec256<float> erfinv() const {
    return map(calc_erfinv);
  }
  Vec256<float> exp() const {
    return map(std::exp);
  }
  Vec256<float> expm1() const {
    return map(std::expm1);
  }
  Vec256<float> fmod(const Vec256<float>& q) const {
    __at_align32__ float tmp[size()];
    __at_align32__ float tmp_q[size()];
    store(tmp);