// Copyright 2018 Xiaomi, Inc.  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.

#ifndef MACE_OPS_RESHAPE_H_
#define MACE_OPS_RESHAPE_H_

#include <vector>

#include "mace/core/operator.h"
#include "mace/kernels/reshape.h"

namespace mace {
namespace ops {

template <DeviceType D, typename T>
class ReshapeOp : public Operator<D, T> {
 public:
  ReshapeOp(const OperatorDef &op_def, Workspace *ws)
      : Operator<D, T>(op_def, ws) {}

  MaceStatus Run(StatsFuture *future) override {
    const Tensor *input = this->Input(INPUT);
    const Tensor *shape = this->Input(SHAPE);
    const index_t num_dims = shape->dim_size() == 0 ? 0 : shape->dim(0);
    Tensor::MappingGuard shape_guard(shape);
    const int32_t *shape_data = shape->data<int32_t>();

    int unknown_idx = -1;
    index_t product = 1;
    std::vector<index_t> out_shape;

    for (int i = 0; i < num_dims; ++i) {
      if (shape_data[i] == -1) {
        MACE_CHECK(unknown_idx == -1) << "Only one input size may be -1";
        unknown_idx = i;
        out_shape.push_back(1);
      } else {
        MACE_CHECK(shape_data[i] >= 0) << "Shape must be non-negative: "
                                   << shape_data[i];
        out_shape.push_back(shape_data[i]);
        product *= shape_data[i];
      }
    }

    if (unknown_idx != -1) {
      MACE_CHECK(product != 0)
          << "Cannot infer shape if there is zero shape size.";
      const index_t missing = input->size() / product;
      MACE_CHECK(missing * product == input->size())
          << "Input size not match reshaped tensor size";
      out_shape[unknown_idx] = missing;
    }

    Tensor *output = this->Output(OUTPUT);

    return functor_(input, out_shape, output, future);
  }

 private:
  kernels::ReshapeFunctor<D, T> functor_;

 private:
  MACE_OP_INPUT_TAGS(INPUT, SHAPE);
  MACE_OP_OUTPUT_TAGS(OUTPUT);
};

}  // namespace ops
}  // namespace mace

#endif  // MACE_OPS_RESHAPE_H_
