// Copyright (c) 2023 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 <ostream>

#include "paddle/ir/core/cast_utils.h"
#include "paddle/ir/core/type_id.h"

namespace ir {
class TypeStorage;
class AbstractType;
class IrContext;
class Dialect;
///
/// \brief Unified interface of the Type class. Derivation of all Type classes
/// only derives interfaces, not members. For example, DenseTensorType,
/// Float32Type, etc. are all derived classes of Type, but no new member
/// variables will be added.
///
class IR_API Type {
 public:
  using Storage = TypeStorage;

  Type() = default;

  Type(const Storage *storage)  // NOLINT
      : storage_(const_cast<Storage *>(storage)) {}

  Type(const Type &other) = default;

  Type &operator=(const Type &other) = default;

  ///
  /// \brief Some operators are overloaded.
  ///
  bool operator==(Type other) const { return storage_ == other.storage_; }

  bool operator!=(Type other) const { return storage_ != other.storage_; }

  explicit operator bool() const { return storage_; }

  bool operator!() const { return storage_ == nullptr; }

  ///
  /// \brief Some type attribute acquisition interfaces.
  ///
  TypeId type_id();

  const AbstractType &abstract_type();

  const Storage *storage() const { return storage_; }

  Dialect &dialect() const;

  IrContext *ir_context() const;

  ///
  /// \brief Methods for type judgment and cast.
  ///
  static bool classof(Type) { return true; }

  template <typename T>
  bool isa() const {
    return ir::isa<T>(*this);
  }

  template <typename U>
  U dyn_cast() const {
    return ir::dyn_cast<U>(*this);
  }

  void Print(std::ostream &os) const;

  static Type Parse(std::istream &is, IrContext *ctx);

  ///
  /// \brief Enable hashing Type.
  ///
  friend struct std::hash<Type>;

 protected:
  const Storage *storage_{nullptr};
};

IR_API std::ostream &operator<<(std::ostream &os, Type type);

}  // namespace ir

///
/// \brief This class represents the base of a type interface.
///

// template <typename ConcreteType>
// class TypeInterface : public ir::DialectInterface<ConcreteType, Type> {
//  public:
//   using Base = TypeInterface<ConcreteType>;
//   using DialectInterfaceBase = ir::DialectInterface<ConcreteType, Type>;
//   using DialectInterfaceBase::Base;

//  private:
//   /// Returns the impl interface instance for the given type.
//   static typename InterfaceBase::Concept *getInterfaceFor(Type type) {
//     return type.getAbstractType().getInterface<ConcreteType>();
//   }

//   /// Allow access to 'getInterfaceFor'.
//   friend InterfaceBase;
// };

namespace std {
///
/// \brief Enable hashing Type.
///
template <>
struct hash<ir::Type> {
  std::size_t operator()(const ir::Type &obj) const {
    return std::hash<const ir::Type::Storage *>()(obj.storage_);
  }
};
}  // namespace std
