/*******************************************************************************
* Copyright 2018-2022 Intel Corporation
*
* 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.
*******************************************************************************/

/*
 * Common for RNN and LSTM cell execution
 */
#include "common/bfloat16.hpp"
#include "common/dnnl_thread.hpp"

#include "cpu/rnn/ref_rnn.hpp"
#include "cpu/simple_q10n.hpp"

namespace dnnl {
namespace impl {
namespace cpu {
using namespace rnn_utils;
using namespace dnnl::impl::utils;

template <prop_kind_t aprop, data_type_t src_type, data_type_t weights_type,
        data_type_t acc_type>
rnn_cell_execution_sig((_ref_rnn_common_t<aprop, src_type, weights_type,
        acc_type>::cell_execution_ref)) {
    const auto weights_scales = pd_->attr()->rnn_weights_qparams_.scales_;
    const auto weights_projection_scales = rnn.is_lstm_projection
            ? pd_->attr()->rnn_weights_projection_qparams_.scales_
            : nullptr;

    const auto src_layer_ld = rnn.src_layer_ld(cell_position);
    const auto src_iter_ld = rnn.src_iter_ld(cell_position);

    if (rnn.need_gemm_layer(cell_position)) {
        CHECK((this->*gemm_layer_func)('N', 'N', rnn.n_gates * rnn.dhc, rnn.mb,
                rnn.slc, 1.0f, w_layer_[0], rnn.weights_layer_ld, src_layer_,
                src_layer_ld, 0.0f, scratch_gates_, rnn.scratch_gates_ld));
    }
    CHECK((this->*gemm_iter_func)('N', 'N', rnn.n_gates * rnn.dhc, rnn.mb,
            rnn.sic, 1.0f, w_iter_[0], rnn.weights_iter_ld, src_iter_,
            src_iter_ld, 1.0f, scratch_gates_, rnn.scratch_gates_ld));

    // Note: here proj_ht is scratchpad if inference or workspace if training
    const auto dst_postgemm = rnn.is_lstm_projection ? proj_ht_ : dst_layer_;
    // for lstmp, the copy to dst_iter happens after the projection
    const auto dst_iter_postgemm = rnn.is_lstm_projection ? nullptr : dst_iter_;
    rnn_postgemm_->execute(rnn, cell_position, ws_gates_, scratch_gates_,
            augru_attention_, dst_postgemm, dst_iter_c_, src_iter_, src_iter_c_,
            diff_src_layer_, diff_augru_attention_, diff_src_iter_,
            diff_src_iter_c_, diff_dst_layer_, diff_dst_iter_, diff_dst_iter_c_,
            weights_peephole_, bias_[0], ws_grid_, scratch_cell_,
            dst_iter_postgemm, weights_scales, rnn.dhc * sizeof(scratch_t));

    if (rnn.is_lstm_projection) {
        const auto dst_layer_ld = rnn.dst_layer_ld(cell_position, true);

        // Here, because the accumulation type is different
        // than dst_layer, we have to use scratch to hold temporary
        // accumulators
        assert(rnn.scratch_gates_ld >= rnn.dlc);
        gemm_acc_t *dst_proj = rnn.dt_conf == all_f32 ? (gemm_acc_t *)dst_layer_
                                                      : scratch_gates_;
        const int dst_proj_ld
                = rnn.dt_conf == all_f32 ? dst_layer_ld : rnn.scratch_gates_ld;

        CHECK((this->*gemm_projection_func)('N', 'N', rnn.dic, rnn.mb, rnn.dhc,
                1.0f, w_projection_[0], rnn.weights_projection_ld, dst_postgemm,
                rnn.proj_ht_ld, 0.0f, dst_proj, dst_proj_ld));

        // we have to downconvert the output to dst_layer_t and copy to dst_iter if needed
        rnn_postgemm_->execute_part2(rnn, cell_position, nullptr, dst_proj,
                nullptr, dst_layer_, nullptr, nullptr, w_proj_comp, nullptr,
                nullptr, nullptr, nullptr, nullptr, nullptr, nullptr, nullptr,
                nullptr, nullptr, nullptr, dst_iter_, weights_projection_scales,
                rnn.dlc * sizeof(dst_layer_t));
    }

    return dnnl_success;
}

template rnn_cell_execution_sig(ref_rnn_fwd_f32_t::cell_execution_ref);
template rnn_cell_execution_sig(ref_rnn_fwd_bf16_t::cell_execution_ref);
template rnn_cell_execution_sig(ref_rnn_fwd_u8s8_t::cell_execution_ref);
template rnn_cell_execution_sig(ref_rnn_fwd_s8s8_t::cell_execution_ref);

template <typename scratch_data_t, typename acc_data_t>
void lstm_bwd_weights_peephole_and_bias(const rnn_utils::rnn_conf_t &rnn,
        cell_position_t cell_position, const void *src_iter_c_,
        const void *dst_iter_c_, const scratch_data_t *scratch_gates_,
        float *diff_weights_peephole_, acc_data_t *diff_bias_) {
    const int dst_iter_c_ld = rnn.dst_iter_c_ld(cell_position);
    const int src_iter_c_ld = rnn.src_iter_c_ld(cell_position);

    const auto dst_iter_c = rnn_utils::make_raw_aoc(dst_iter_c_,
            types::data_type_size(rnn.dst_iter_c_dt), rnn.ws_states_iter_c_nld,
            dst_iter_c_ld);
    const auto src_iter_c = rnn_utils::make_raw_aoc(src_iter_c_,
            types::data_type_size(rnn.src_iter_c_dt), rnn.ws_states_iter_c_nld,
            src_iter_c_ld);

    const ws_gates_aoc<const scratch_data_t> scratch_gates(rnn, scratch_gates_);
    const weights_peephole_aoc_t<float> diff_weights_peephole(
            rnn, diff_weights_peephole_);

    parallel(0, [&](int ithr, int nthr) {
        int g_dhc_start {}, g_dhc_stop {};
        const int gates_to_process = 5; // 3 -- weights peephole +
                // 2 -- bias (process a pair at once)
        balance211(gates_to_process * rnn.dhc, nthr, ithr, g_dhc_start,
                g_dhc_stop);
        int g = g_dhc_start / rnn.dhc;
        int dhc = g_dhc_start % rnn.dhc;
        while (g_dhc_start++ < g_dhc_stop) {
            if (g < 3) {
                // weights peephole
                auto &c_states = g < 2 ? src_iter_c : dst_iter_c;
                const auto c_states_dt
                        = g < 2 ? rnn.src_iter_c_dt : rnn.dst_iter_c_dt;

                const int scratch_g = g < 2 ? g : 3;
                for (int mb = 0; mb < rnn.mb; ++mb) {
                    diff_weights_peephole(g, dhc)
                            += to_float(c_states(mb, dhc), c_states_dt)
                            * scratch_gates(mb, scratch_g, dhc);
                }
            } else {
                // bias
                const int bias_g_start = 2 * (g - 3);
                const int bias_g_end = bias_g_start + 2;
                for_(int bias_g = bias_g_start; bias_g < bias_g_end; ++bias_g)
                for (int mb = 0; mb < rnn.mb; ++mb)
                    diff_bias_[bias_g * rnn.dhc + dhc]
                            += scratch_gates(mb, bias_g, dhc);
            }
            if (++dhc == rnn.dhc) {
                dhc = 0;
                g++;
            }
        }
    });
}

template <typename T1, typename T2, typename T3, typename T4, typename T5,
        typename T6, typename T7, typename weights_data_t, typename src_data_t,
        typename acc_data_t, typename scratch_data_t>
dnnl_status_t common_bwd_cell_exec_template(T1 gemm_layer_f, T2 gemm_iter_f,
        T3 gemm_proj_f, T4 gemm_weights_layer_f, T5 gemm_weights_iter_f,
        T6 gemm_weights_proj_f, T7 rnn_postgemm,
        const rnn_utils::rnn_conf_t &rnn, const cell_position_t cell_position,
        src_data_t *dst_layer_, void *dst_iter_c_, acc_data_t *diff_src_layer_,
        acc_data_t *diff_augru_attention_, acc_data_t *diff_src_iter_,
        acc_data_t *diff_src_iter_c_, weights_data_t **w_layer_,
        weights_data_t **w_iter_, weights_data_t **w_proj_,
        const float *weights_peephole_, void **bias_,
        const src_data_t *src_layer_, const src_data_t *augru_attention_,
        const src_data_t *src_iter_, const void *src_iter_c_,
        acc_data_t *diff_dst_layer_, acc_data_t *diff_dst_iter_,
        acc_data_t *diff_dst_iter_c_, acc_data_t *diff_w_layer_,
        acc_data_t *diff_w_iter_, float *diff_weights_projection_,
        float *diff_weights_peephole_, acc_data_t *diff_bias_,
        src_data_t *ws_gates_, scratch_data_t *scratch_gates_,
        src_data_t *ws_ht_, acc_data_t *scratch_diff_ht_, src_data_t *ws_grid_,
        scratch_data_t *scratch_cell_, src_data_t *dst_iter_) {

    if (rnn.is_lstm_projection) {
        parallel_nd(rnn.mb, [&](dim_t i) {
            PRAGMA_OMP_SIMD()
            for (int j = 0; j < rnn.dlc; j++)
                scratch_diff_ht_[i * rnn.scratch_diff_ht_ld + j]
                        = diff_dst_layer_[i * rnn.ws_diff_states_layer_ld + j]
                        + diff_dst_iter_[i * rnn.ws_diff_states_iter_ld + j];
        });

        CHECK(gemm_weights_proj_f(
                scratch_diff_ht_, ws_ht_, diff_weights_projection_));
        CHECK(gemm_proj_f(w_proj_[0], scratch_diff_ht_, diff_dst_layer_));
    }

    rnn_postgemm->execute(rnn, cell_position, ws_gates_, scratch_gates_,
            augru_attention_, dst_layer_, dst_iter_c_, src_iter_, src_iter_c_,
            diff_src_layer_, diff_augru_attention_, diff_src_iter_,
            diff_src_iter_c_, diff_dst_layer_, diff_dst_iter_, diff_dst_iter_c_,
            weights_peephole_, bias_[0], ws_grid_, scratch_cell_, dst_iter_,
            nullptr, 0);

    /// bwd by data on the cell
    CHECK(gemm_iter_f(w_iter_[0], scratch_gates_, diff_src_iter_));

    /// bwd by weights on the cell
    if (rnn.need_gemm_layer(cell_position))
        CHECK(gemm_weights_layer_f(scratch_gates_, src_layer_, diff_w_layer_));

    if (!rnn.merge_gemm_layer)
        CHECK(gemm_layer_f(w_layer_[0], scratch_gates_, diff_src_layer_));

    if (!rnn.merge_gemm_iter)
        CHECK(gemm_weights_iter_f(scratch_gates_, src_iter_, diff_w_iter_));

    if (rnn.is_lstm_peephole) {
        /// bwd by weights peephole and bias
        lstm_bwd_weights_peephole_and_bias(rnn, cell_position, src_iter_c_,
                dst_iter_c_, scratch_gates_, diff_weights_peephole_,
                diff_bias_);
    } else {
        /// bwd by bias we just accumulate diffs from the gates
        gates_reduction(rnn, scratch_gates_, diff_bias_);
    }
    return dnnl_success;
}

template <>
rnn_cell_execution_sig(ref_rnn_bwd_f32_t::cell_execution_ref) {
    const auto gemm_layer = [&](const float *A, const float *B, float *C) {
        return (this->*gemm_layer_func)('N', 'N', rnn.slc, rnn.mb,
                rnn.n_gates * rnn.dhc, 1.0, A, rnn.weights_layer_ld, B,
                rnn.scratch_gates_ld, 0.0, C, rnn.ws_diff_states_layer_ld);
    };
    const auto gemm_iter = [&](const float *A, const float *B, float *C) {
        return (this->*gemm_iter_func)('N', 'N', rnn.sic, rnn.mb,
                rnn.n_gates * rnn.dhc, 1.0, A, rnn.weights_iter_ld, B,
                rnn.scratch_gates_ld, 0.0, C, rnn.ws_diff_states_iter_ld);
    };
    const auto gemm_proj = [&](const float *A, const float *B, float *C) {
        return (this->*gemm_projection_func)('N', 'N', rnn.dhc, rnn.mb, rnn.dic,
                1.0, A, rnn.weights_projection_ld, B, rnn.scratch_diff_ht_ld,
                0.0f, C, rnn.ws_diff_states_layer_ld);
    };
    const auto gemm_weights_layer
            = [&](const float *A, const float *B, float *C) {
                  auto src_layer_ld = rnn.src_layer_ld(cell_position);
                  return gemm('N', 'T', rnn.n_gates * rnn.dhc, rnn.slc, rnn.mb,
                          1.0, A, rnn.scratch_gates_ld, B, src_layer_ld, 1.0, C,
                          rnn.diff_weights_layer_ld);
              };
    const auto gemm_weights_iter
            = [&](const float *A, const float *B, float *C) {
                  auto src_iter_ld = rnn.src_iter_ld(cell_position);
                  return gemm('N', 'T', rnn.n_gates * rnn.dhc, rnn.sic, rnn.mb,
                          1.0, A, rnn.scratch_gates_ld, B, src_iter_ld, 1.0, C,
                          rnn.diff_weights_iter_ld);
              };
    const auto gemm_weights_proj
            = [&](const float *A, const float *B, float *C) {
                  return gemm('N', 'T', rnn.dlc, rnn.dhc, rnn.mb, 1.0f, A,
                          rnn.scratch_diff_ht_ld, B, rnn.ws_ht_ld, 1.0f, C,
                          rnn.diff_weights_projection_ld);
              };
    return common_bwd_cell_exec_template(gemm_layer, gemm_iter, gemm_proj,
            gemm_weights_layer, gemm_weights_iter, gemm_weights_proj,
            rnn_postgemm_, rnn, cell_position, dst_layer_, dst_iter_c_,
            diff_src_layer_, diff_augru_attention_, diff_src_iter_,
            diff_src_iter_c_, w_layer_, w_iter_, w_projection_,
            weights_peephole_, bias_, src_layer_, augru_attention_, src_iter_,
            src_iter_c_, diff_dst_layer_, diff_dst_iter_, diff_dst_iter_c_,
            diff_w_layer_, diff_w_iter_, diff_weights_projection_,
            diff_weights_peephole_, diff_bias_, ws_gates_, scratch_gates_,
            proj_ht_, scratch_diff_ht_, ws_grid_, scratch_cell_, dst_iter_);
}

template <>
rnn_cell_execution_sig(ref_rnn_bwd_bf16_t::cell_execution_ref) {
    const auto gemm_layer = [&](const bfloat16_t *A, const bfloat16_t *B,
                                    float *C) {
        return (this->*gemm_layer_func)('N', 'N', rnn.slc, rnn.mb,
                rnn.n_gates * rnn.dhc, 1.0, A, rnn.weights_layer_ld, B,
                rnn.scratch_gates_ld, 0.0, C, rnn.ws_diff_states_layer_ld);
    };
    const auto gemm_iter = [&](const bfloat16_t *A, const bfloat16_t *B,
                                   float *C) {
        return (this->*gemm_iter_func)('N', 'N', rnn.sic, rnn.mb,
                rnn.n_gates * rnn.dhc, 1.0, A, rnn.weights_iter_ld, B,
                rnn.scratch_gates_ld, 0.0, C, rnn.ws_diff_states_iter_ld);
    };
    const auto gemm_proj = [&](const bfloat16_t *, const float *, float *) {
        assert(!"unimplemented");
        return dnnl_unimplemented;
    };
    const auto gemm_weights_layer
            = [&](const bfloat16_t *A, const bfloat16_t *B, float *C) {
                  auto src_layer_ld = rnn.src_layer_ld(cell_position);
                  return gemm('N', 'T', rnn.n_gates * rnn.dhc, rnn.slc, rnn.mb,
                          1.0, A, rnn.scratch_gates_ld, B, src_layer_ld, 1.0, C,
                          rnn.diff_weights_layer_ld);
              };
    const auto gemm_weights_iter
            = [&](const bfloat16_t *A, const bfloat16_t *B, float *C) {
                  auto src_iter_ld = rnn.src_iter_ld(cell_position);
                  return gemm('N', 'T', rnn.n_gates * rnn.dhc, rnn.sic, rnn.mb,
                          1.0, A, rnn.scratch_gates_ld, B, src_iter_ld, 1.0, C,
                          rnn.diff_weights_iter_ld);
              };
    const auto gemm_weights_proj
            = [&](const float *, const bfloat16_t *, float *) {
                  assert(!"unimplemented");
                  return dnnl_unimplemented;
              };
    return common_bwd_cell_exec_template(gemm_layer, gemm_iter, gemm_proj,
            gemm_weights_layer, gemm_weights_iter, gemm_weights_proj,
            rnn_postgemm_, rnn, cell_position, dst_layer_, dst_iter_c_,
            diff_src_layer_, diff_augru_attention_, diff_src_iter_,
            diff_src_iter_c_, w_layer_, w_iter_, w_projection_,
            weights_peephole_, bias_, src_layer_, augru_attention_, src_iter_,
            src_iter_c_, diff_dst_layer_, diff_dst_iter_, diff_dst_iter_c_,
            diff_w_layer_, diff_w_iter_, diff_weights_projection_,
            diff_weights_peephole_, diff_bias_, ws_gates_, scratch_gates_,
            proj_ht_, scratch_diff_ht_, ws_grid_, scratch_cell_, dst_iter_);
}

template <prop_kind_t aprop, data_type_t src_type, data_type_t weights_type,
        data_type_t acc_type>
rnn_merged_layer_execution_sig((_ref_rnn_common_t<aprop, src_type, weights_type,
        acc_type>::merged_layer_execution_ref)) {
    const auto src_layer_ld = rnn.src_layer_ld(cell_position);
    // If we avoid copying the last iteration, the corresponding
    // input states appear in `dst_iter_` instead of `ws_states_layer`,
    // hence we cannot merge all iterations.
    // This is not applicable for the first layer though, since
    // all the states come from user's `src_layer_`.
    const int n_iter
            = (cell_position & first_layer) && rnn.skip_src_layer_copy()
            ? rnn.n_iter
            : rnn.n_iter - (rnn.skip_dst_iter_copy() ? 1 : 0);

    if (aprop == prop_kind::forward) {
        CHECK((this->*gemm_layer_func)('N', 'N', rnn.n_gates * rnn.dhc,
                rnn.mb * n_iter, rnn.slc, 1.0, w_layer_[0],
                rnn.weights_layer_ld, src_layer_, src_layer_ld, 0.0,
                (gemm_acc_t *)scratch_gates_, rnn.scratch_gates_ld));
    } else if (aprop == prop_kind::backward) {
        CHECK((this->*gemm_layer_func)('N', 'N', rnn.slc, rnn.mb * rnn.n_iter,
                rnn.n_gates * rnn.dhc, 1.0, w_layer_[0], rnn.weights_layer_ld,
                (gates_t *)scratch_gates_, rnn.scratch_gates_ld, 0.0,
                diff_src_layer_, rnn.ws_diff_states_layer_ld));
        CHECK(gemm('N', 'T', rnn.n_gates * rnn.dhc, rnn.slc, rnn.mb * n_iter,
                1.0, (weights_t *)scratch_gates_, rnn.scratch_gates_ld,
                src_layer_, src_layer_ld, 1.0, diff_w_layer_,
                rnn.diff_weights_layer_ld));
    } else {
        assert(!"unimplemented");
    }

    return dnnl_success;
}

template rnn_merged_layer_execution_sig(
        ref_rnn_fwd_f32_t::merged_layer_execution_ref);
template rnn_merged_layer_execution_sig(
        ref_rnn_fwd_bf16_t::merged_layer_execution_ref);
template rnn_merged_layer_execution_sig(
        ref_rnn_fwd_u8s8_t::merged_layer_execution_ref);
template rnn_merged_layer_execution_sig(
        ref_rnn_fwd_s8s8_t::merged_layer_execution_ref);
template rnn_merged_layer_execution_sig(
        ref_rnn_bwd_f32_t::merged_layer_execution_ref);
template rnn_merged_layer_execution_sig(
        ref_rnn_bwd_bf16_t::merged_layer_execution_ref);

} // namespace cpu
} // namespace impl
} // namespace dnnl
