// Copyright (c) 2021 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 <llvm/ADT/ArrayRef.h>

namespace infrt {
namespace tensor {

/**
 * TensorShape represents the shape of a Tensor, all the dimensions should be
 * known.
 */
class TensorShape {
 public:
  TensorShape() = default;
  explicit TensorShape(llvm::ArrayRef<int64_t> dims);
  explicit TensorShape(std::initializer_list<int64_t> dims);

  int GetRank() const;

  int64_t GetDim(int idx) const;

  int GetNumElements() const;

  friend llvm::raw_ostream& operator<<(llvm::raw_ostream& os,
                                       const TensorShape& v);
  friend bool operator==(const TensorShape& a, const TensorShape& b) {
    return a.dims_ == b.dims_;
  }

  friend bool operator!=(const TensorShape& a, const TensorShape& b) {
    return !(a == b);
  }

 private:
  llvm::SmallVector<int64_t, 4> dims_;
};

/**
 * DynamicTensorShape represents the shape of a Tensor, with some dimensions or
 * even the rank is unknown.
 */
class DynamicTensorShape {
 public:
  explicit DynamicTensorShape(llvm::Optional<llvm::ArrayRef<int64_t>> dims);

  //! Returns the rank if rank is known, or kUnknownDimSize.
  int GetRank() const;

  int64_t GetDim(int idx) const;

  bool IsShapeKnown() const;

  //! Convert to a TensorShape if all the dimensions are known.
  llvm::Optional<TensorShape> ToTensorShape() const;

  static constexpr int64_t kUnknownDimSize = -1;

  static bool IsDimUnknown(int64_t dim) { return dim == kUnknownDimSize; }

  friend std::ostream& operator<<(std::ostream& os,
                                  const DynamicTensorShape& v);
  friend bool operator==(const DynamicTensorShape& a,
                         const DynamicTensorShape& b) {
    return a.dims_ == b.dims_;
  }

 private:
  //! Will be std::nullopt if no dim is known.
  llvm::Optional<llvm::SmallVector<int64_t, 4>> dims_;
};

}  // namespace tensor
}  // namespace infrt