/* Copyright (c) 2016 PaddlePaddle Authors. All Rights Reserved.

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. */

#pragma once
#include <type_traits>
#include "paddle/fluid/operators/math/detail/activation_functions.h"
#include "paddle/fluid/operators/math/lstm_compute.h"

namespace paddle {
namespace operators {
namespace math {
namespace detail {

#ifndef __NVCC__

template <class T, class Op>
void naive_lstm_forward_one_sequence(Op op, LstmMetaValue<T> value,
                                     int frame_size, ActivationType active_node,
                                     ActivationType active_gate,
                                     ActivationType active_state) {
  T r_value_in;
  T r_value_ig;
  T r_value_fg;
  T r_value_og;
  T r_checkI;
  T r_checkF;
  T r_checkO;
  T r_state;
  T r_prev_state = 0;
  T r_state_atv;
  T r_out;

  T *value_in = value.gate_value;
  T *value_ig = value.gate_value + frame_size;
  T *value_fg = value.gate_value + frame_size * 2;
  T *value_og = value.gate_value + frame_size * 3;

  for (int i = 0; i < frame_size; i++) {
    r_value_in = value_in[i];
    r_value_ig = value_ig[i];
    r_value_fg = value_fg[i];
    r_value_og = value_og[i];
    r_checkI = value.check_ig ? value.check_ig[i] : 0;
    r_checkF = value.check_fg ? value.check_fg[i] : 0;
    r_checkO = value.check_og ? value.check_og[i] : 0;

    if (value.prev_state_value) {
      r_prev_state = value.prev_state_value[i];
    }

    op(r_value_in, r_value_ig, r_value_fg, r_value_og, r_prev_state, r_state,
       r_state_atv, r_out, r_checkI, r_checkF, r_checkO, active_node,
       active_gate, active_state);

    value_in[i] = r_value_in;
    value_ig[i] = r_value_ig;
    value_fg[i] = r_value_fg;
    value_og[i] = r_value_og;
    value.state_value[i] = r_state;
    value.state_active_value[i] = r_state_atv;
    value.output_value[i] = r_out;
  }
}

template <class T, class Op>
void naive_lstm_backward_one_sequence(Op op, LstmMetaValue<T> value,
                                      LstmMetaGrad<T> grad, int frame_size,
                                      ActivationType active_node,
                                      ActivationType active_gate,
                                      ActivationType active_state) {
  T r_value_in;
  T r_value_ig;
  T r_value_fg;
  T r_value_og;
  T r_grad_in;
  T r_grad_ig;
  T r_grad_fg;
  T r_grad_og;
  T r_prev_state = 0;
  T r_prev_state_grad;
  T r_state;
  T r_state_grad;
  T r_state_atv;
  T r_output_grad;
  T r_checkI;
  T r_checkF;
  T r_checkO;
  T r_checkIGrad;
  T r_checkFGrad;
  T r_checkOGrad;

  T *value_in = value.gate_value;
  T *value_ig = value.gate_value + frame_size;
  T *value_fg = value.gate_value + frame_size * 2;
  T *value_og = value.gate_value + frame_size * 3;
  T *grad_in = grad.gate_grad;
  T *grad_ig = grad.gate_grad + frame_size;
  T *grad_fg = grad.gate_grad + frame_size * 2;
  T *grad_og = grad.gate_grad + frame_size * 3;

  for (int i = 0; i < frame_size; i++) {
    r_value_in = value_in[i];
    r_value_ig = value_ig[i];
    r_value_fg = value_fg[i];
    r_value_og = value_og[i];
    r_checkI = value.check_ig ? value.check_ig[i] : 0;
    r_checkF = value.check_fg ? value.check_fg[i] : 0;
    r_checkO = value.check_og ? value.check_og[i] : 0;
    r_state = value.state_value[i];
    r_state_atv = value.state_active_value[i];
    r_output_grad = grad.output_grad[i];
    r_state_grad = grad.state_grad[i];
    if (value.prev_state_value) {
      r_prev_state = value.prev_state_value[i];
    }

    op(r_value_in, r_value_ig, r_value_fg, r_value_og, r_grad_in, r_grad_ig,
       r_grad_fg, r_grad_og, r_prev_state, r_prev_state_grad, r_state,
       r_state_grad, r_state_atv, r_output_grad, r_checkI, r_checkF, r_checkO,
       r_checkIGrad, r_checkFGrad, r_checkOGrad, active_node, active_gate,
       active_state);

    grad_in[i] = r_grad_in;
    grad_ig[i] = r_grad_ig;
    grad_fg[i] = r_grad_fg;
    grad_og[i] = r_grad_og;
    grad.state_grad[i] = r_state_grad;

    if (grad.prev_state_grad) grad.prev_state_grad[i] = r_prev_state_grad;
    if (value.prev_state_value) {
      if (grad.check_ig_grad) grad.check_ig_grad[i] += r_checkIGrad;
      if (grad.check_fg_grad) grad.check_fg_grad[i] += r_checkFGrad;
    }
    if (grad.check_og_grad) grad.check_og_grad[i] += r_checkOGrad;
  }
}

template <class T, class Op>
void avx_lstm_forward_one_sequence(Op op, LstmMetaValue<T> value,
                                   int frame_size, ActivationType active_node,
                                   ActivationType active_gate,
                                   ActivationType active_state) {
#ifdef __AVX__
  __m256 r_value_in;
  __m256 r_value_ig;
  __m256 r_value_fg;
  __m256 r_value_og;
  __m256 r_checkI = _mm256_set1_ps(0.0f);
  __m256 r_checkF = _mm256_set1_ps(0.0f);
  __m256 r_checkO = _mm256_set1_ps(0.0f);
  __m256 r_state;
  __m256 r_prev_state = _mm256_set1_ps(0.0f);
  __m256 r_state_atv;
  __m256 r_out;

  __m256 *value_in = (__m256 *)value.gate_value;
  __m256 *value_ig = (__m256 *)(value.gate_value + frame_size);
  __m256 *value_fg = (__m256 *)(value.gate_value + frame_size * 2);
  __m256 *value_og = (__m256 *)(value.gate_value + frame_size * 3);

  for (int i = 0; i < frame_size / 8; i++) {
    r_value_in = value_in[i];
    r_value_ig = value_ig[i];
    r_value_fg = value_fg[i];
    r_value_og = value_og[i];
    if (value.check_ig) {
      r_checkI = ((__m256 *)value.check_ig)[i];
      r_checkF = ((__m256 *)value.check_fg)[i];
      r_checkO = ((__m256 *)value.check_og)[i];
    }

    if (value.prev_state_value) {
      r_prev_state = ((__m256 *)value.prev_state_value)[i];
    }

    op(r_value_in, r_value_ig, r_value_fg, r_value_og, r_prev_state, r_state,
       r_state_atv, r_out, r_checkI, r_checkF, r_checkO, active_node,
       active_gate, active_state);

    value_in[i] = r_value_in;
    value_ig[i] = r_value_ig;
    value_fg[i] = r_value_fg;
    value_og[i] = r_value_og;
    ((__m256 *)value.state_value)[i] = r_state;
    ((__m256 *)value.state_active_value)[i] = r_state_atv;
    ((__m256 *)value.output_value)[i] = r_out;
  }
#endif
}

template <class T, class Op>
void avx_lstm_backward_one_sequence(Op op, LstmMetaValue<T> value,
                                    LstmMetaGrad<T> grad, int frame_size,
                                    ActivationType active_node,
                                    ActivationType active_gate,
                                    ActivationType active_state) {
#ifdef __AVX__
  __m256 r_value_in;
  __m256 r_value_ig;
  __m256 r_value_fg;
  __m256 r_value_og;
  __m256 r_grad_in;
  __m256 r_grad_ig;
  __m256 r_grad_fg;
  __m256 r_grad_og;
  __m256 r_prev_state = _mm256_set1_ps(0.0f);
  __m256 r_prev_state_grad;
  __m256 r_state_grad;
  __m256 r_state;
  __m256 r_state_atv;
  __m256 r_output_grad;
  __m256 r_checkI = _mm256_set1_ps(0.0f);
  __m256 r_checkF = _mm256_set1_ps(0.0f);
  __m256 r_checkO = _mm256_set1_ps(0.0f);
  __m256 r_checkIGrad;
  __m256 r_checkFGrad;
  __m256 r_checkOGrad;

  __m256 *value_in = (__m256 *)value.gate_value;
  __m256 *value_ig = (__m256 *)(value.gate_value + frame_size);
  __m256 *value_fg = (__m256 *)(value.gate_value + frame_size * 2);
  __m256 *value_og = (__m256 *)(value.gate_value + frame_size * 3);
  __m256 *grad_in = (__m256 *)grad.gate_grad;
  __m256 *grad_ig = (__m256 *)(grad.gate_grad + frame_size);
  __m256 *grad_fg = (__m256 *)(grad.gate_grad + frame_size * 2);
  __m256 *grad_og = (__m256 *)(grad.gate_grad + frame_size * 3);

  for (int i = 0; i < frame_size / 8; i++) {
    r_value_in = value_in[i];
    r_value_ig = value_ig[i];
    r_value_fg = value_fg[i];
    r_value_og = value_og[i];
    if (value.check_ig) {
      r_checkI = ((__m256 *)value.check_ig)[i];
      r_checkF = ((__m256 *)value.check_fg)[i];
      r_checkO = ((__m256 *)value.check_og)[i];
    }
    r_state = ((__m256 *)value.state_value)[i];
    r_state_atv = ((__m256 *)value.state_active_value)[i];
    r_output_grad = ((__m256 *)grad.output_grad)[i];
    r_state_grad = ((__m256 *)grad.state_grad)[i];
    if (value.prev_state_value) {
      r_prev_state = ((__m256 *)value.prev_state_value)[i];
    }

    op(r_value_in, r_value_ig, r_value_fg, r_value_og, r_grad_in, r_grad_ig,
       r_grad_fg, r_grad_og, r_prev_state, r_prev_state_grad, r_state,
       r_state_grad, r_state_atv, r_output_grad, r_checkI, r_checkF, r_checkO,
       r_checkIGrad, r_checkFGrad, r_checkOGrad, active_node, active_gate,
       active_state);

    grad_in[i] = r_grad_in;
    grad_ig[i] = r_grad_ig;
    grad_fg[i] = r_grad_fg;
    grad_og[i] = r_grad_og;
    ((__m256 *)grad.state_grad)[i] = r_state_grad;

    if (grad.prev_state_grad)
      ((__m256 *)grad.prev_state_grad)[i] = r_prev_state_grad;
    if (value.prev_state_value) {
      if (grad.check_ig_grad) ((__m256 *)grad.check_ig_grad)[i] += r_checkIGrad;
      if (grad.check_fg_grad) ((__m256 *)grad.check_fg_grad)[i] += r_checkFGrad;
    }
    if (grad.check_og_grad) ((__m256 *)grad.check_og_grad)[i] += r_checkOGrad;
  }
#endif
}

template <class T, class Op>
void cpu_lstm_forward(Op op, LstmMetaValue<T> value, int frame_size,
                      ActivationType active_node, ActivationType active_gate,
                      ActivationType active_state) {
  if (Op::avx && !(frame_size & (8 - 1)) && (std::is_same<T, float>::value)) {
    avx_lstm_forward_one_sequence<T>(op, value, frame_size, active_node,
                                     active_gate, active_state);
  } else {
    naive_lstm_forward_one_sequence<T>(op, value, frame_size, active_node,
                                       active_gate, active_state);
  }
}

template <class T, class Op>
void cpu_lstm_backward(Op op, LstmMetaValue<T> value, LstmMetaGrad<T> grad,
                       int frame_size, ActivationType active_node,
                       ActivationType active_gate,
                       ActivationType active_state) {
  if (Op::avx && !(frame_size & (8 - 1)) && (std::is_same<T, float>::value)) {
    avx_lstm_backward_one_sequence<T>(op, value, grad, frame_size, active_node,
                                      active_gate, active_state);
  } else {
    naive_lstm_backward_one_sequence<T>(op, value, grad, frame_size,
                                        active_node, active_gate, active_state);
  }
}

#endif

}  // namespace detail
}  // namespace math
}  // namespace operators
}  // namespace paddle
