/*
 *  ******************************************************************************
 *  *
 *  *
 *  * This program and the accompanying materials are made available under the
 *  * terms of the Apache License, Version 2.0 which is available at
 *  * https://www.apache.org/licenses/LICENSE-2.0.
 *  *
 *  * See the NOTICE file distributed with this work for additional
 *  * information regarding copyright ownership.
 *  * 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.
 *  *
 *  * SPDX-License-Identifier: Apache-2.0
 *  *****************************************************************************
 */

// lstmBlock: Full LSTM layer in one op
// @author Alex Black
//

#include <system/op_boilerplate.h>
#if NOT_EXCLUDED(OP_lstmBlock)

#include <ops/declarable/CustomOperations.h>
#include <ops/declarable/helpers/lstmBlock.h>

namespace sd {
namespace ops {

//////////////////////////////////////////////////////////////////////////
CUSTOM_OP_IMPL(lstmBlock, 9, 7, false, 2, 2) {
  auto maxTSLength = INPUT_VARIABLE(0);
  auto x = INPUT_VARIABLE(1);      // input [seqLen, bS, nIn] at time t
  auto cLast = INPUT_VARIABLE(2);  // previous cell state  [bS, nOut], time t-1
  auto yLast = INPUT_VARIABLE(3);  // previous output [bS, nOut], time t-1

  auto W = INPUT_VARIABLE(4);
   // Weights - concatenated (input-to-hidden, hidden-to-hidden weights)  weights, [(nIn+nOut), 4*nOut]
  auto Wci = INPUT_VARIABLE(5);  // weights - cell peephole (t-1) connections to input modulation gate, [nOut]
  auto Wcf = INPUT_VARIABLE(6);  // weights - cell peephole (t-1) connections to forget gate, [nOut]
  auto Wco = INPUT_VARIABLE(7);  // weights - cell peephole (t) connections to output gate, [nOut]
  auto b = INPUT_VARIABLE(8);    // biases, [4*nOut]

  auto i = OUTPUT_VARIABLE(0);  // Output - input modulation gate activations [seqLen, bS, nOut]
  auto c = OUTPUT_VARIABLE(1);  // Activations, cell state (pre tanh) [seqLen, bs, nOut]
  auto f = OUTPUT_VARIABLE(2);  // Output - forget gate activations [seqLen, bs, nOut]
  auto o = OUTPUT_VARIABLE(3);  // Output - output gate activations [seqLen, bs, nOut]
  auto z = OUTPUT_VARIABLE(4);  // Output - input gate activations [seqLen, bs, nOut]
  auto h = OUTPUT_VARIABLE(5);  // Cell state, post tanh [seqLen, bs, nOut]
  auto y = OUTPUT_VARIABLE(6);  // current cell output [seqLen, bS, numProj], time t

  const int peephole = INT_ARG(0);    // if 1, provide peephole connections
  const int dataFormat = INT_ARG(1);  // 0=TNS=[seqLen,bS,nIn]; 1=NST=[bS,nIn,seqLen]; 2=NTS=[bS,seqLen,nIn]
  const double forgetBias = T_ARG(0);
  const double clippingCellValue = T_ARG(1);
  // clipping value for ct, if it is not equal to zero, then cell state is clipped

  REQUIRE_TRUE(x->rankOf() == 3, 0, "lstmBlock: Input array 1 (x) rank must be got input with rank %i", x->rankOf());
  REQUIRE_TRUE(cLast->rankOf() == 2 && yLast->rankOf() == 2, 0,
               "lstmBlock: Input ranks must be 2 for inputs 2/3 (cLast, yLast) - got %i, %i", cLast->rankOf(),
               yLast->rankOf());
  REQUIRE_TRUE(W->rankOf() == 2, 0, "lstmBlock: Weights array rank must be 2");
  REQUIRE_TRUE(b->rankOf() == 1, 0, "lstmBlock: Biases must be rank 1");
  REQUIRE_TRUE(i->rankOf() == 3 && c->rankOf() == 3 && f->rankOf() == 3 && o->rankOf() == 3 && z->rankOf() == 3 &&
                   h->rankOf() == 3 && y->rankOf() == 3,
               0, "lstmBlock: Output arrays must all be rank 3");

  helpers::lstmBlockTimeLoop(maxTSLength, x, cLast, yLast, W, Wci, Wcf, Wco, b, i, c, f, o, z, h, y,
                             {(double)peephole, forgetBias, clippingCellValue}, dataFormat);

  return Status::OK;
}

DECLARE_TYPES(lstmBlock) {
  getOpDescriptor()->setAllowedInputTypes(ANY)->setAllowedOutputTypes({ALL_FLOATS});
}

DECLARE_SHAPE_FN(lstmBlock) {
  auto x = inputShape->at(1);
  auto cLast = inputShape->at(2);
  auto yLast = inputShape->at(3);
  auto W = inputShape->at(4);
  auto b = inputShape->at(8);

  REQUIRE_TRUE(shape::rank(x) == 3, 0, "lstmBlock: Input array 1 (x) rank must be got input with rank %i",
               shape::rank(x));
  REQUIRE_TRUE(shape::rank(cLast) == 2 && shape::rank(yLast) == 2, 0,
               "lstmBlock: Input ranks must be 2 for inputs 2/3 (cLast, yLast) - got %i, %i", shape::rank(cLast),
               shape::rank(yLast));
  REQUIRE_TRUE(shape::rank(W) == 2, 0, "lstmBlock: Weights array rank must be 2");
  REQUIRE_TRUE(shape::rank(b) == 1, 0, "lstmBlock: Biases must be rank 1");

  const int dataFormat = INT_ARG(1);  // 0=TNS=[seqLen,bS,size]; 1=NST=[bS,size,seqLen]; 2=NTS=[bS,seqLen,size]
  int bs;
  int t;
  int nOut = cLast[2];  // rank, bs, nOut, ...]

  LongType *s(nullptr);
  ALLOCATE(s, block.getWorkspace(), shape::shapeInfoLength(3), sd::LongType);  // [time, bS, nOut]
  s[0] = 3;
  if (dataFormat == 0) {
    //[rank, seqLen, bs, nIn, ...]
    s[1] = x[1];  // seqLen
    s[2] = x[2];  // bS
    s[3] = nOut;
  } else if (dataFormat == 1) {
    //[rank, bs, nIn, seqLen, ...]
    s[1] = x[1];  // bS
    s[2] = nOut;
    s[3] = x[3];  // seqLen
  } else {
    //[rank, bs, seqLen, nIn, ...]
    s[1] = x[1];  // bS
    s[2] = x[2];  // seqLen
    s[3] = nOut;
  }
  ShapeUtils::updateStridesAndType(s, x, 'c');

  auto s1 = CONSTANT(s);

  // 7 outputs, all same shape/type
  return SHAPELIST(s1, s1, s1, s1, s1, s1, s1);
}

}  // namespace ops
}  // namespace sd

#endif