// Copyright 2021 The Tint Authors.
//
// 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 SRC_TINT_TRANSFORM_DECOMPOSE_MEMORY_ACCESS_H_
#define SRC_TINT_TRANSFORM_DECOMPOSE_MEMORY_ACCESS_H_

#include <string>

#include "src/tint/ast/internal_attribute.h"
#include "src/tint/transform/transform.h"

namespace tint {

// Forward declarations
class CloneContext;

namespace transform {

/// DecomposeMemoryAccess is a transform used to replace storage and uniform
/// buffer accesses with a combination of load, store or atomic functions on
/// primitive types.
class DecomposeMemoryAccess final
    : public Castable<DecomposeMemoryAccess, Transform> {
 public:
  /// Intrinsic is an InternalAttribute that's used to decorate a stub function
  /// so that the HLSL transforms this into calls to
  /// `[RW]ByteAddressBuffer.Load[N]()` or `[RW]ByteAddressBuffer.Store[N]()`,
  /// with a possible cast.
  class Intrinsic final : public Castable<Intrinsic, ast::InternalAttribute> {
   public:
    /// Intrinsic op
    enum class Op {
      kLoad,
      kStore,
      kAtomicLoad,
      kAtomicStore,
      kAtomicAdd,
      kAtomicSub,
      kAtomicMax,
      kAtomicMin,
      kAtomicAnd,
      kAtomicOr,
      kAtomicXor,
      kAtomicExchange,
      kAtomicCompareExchangeWeak,
    };

    /// Intrinsic data type
    enum class DataType {
      kU32,
      kF32,
      kI32,
      kVec2U32,
      kVec2F32,
      kVec2I32,
      kVec3U32,
      kVec3F32,
      kVec3I32,
      kVec4U32,
      kVec4F32,
      kVec4I32,
    };

    /// Constructor
    /// @param program_id the identifier of the program that owns this node
    /// @param o the op of the intrinsic
    /// @param sc the storage class of the buffer
    /// @param ty the data type of the intrinsic
    Intrinsic(ProgramID program_id, Op o, ast::StorageClass sc, DataType ty);
    /// Destructor
    ~Intrinsic() override;

    /// @return a short description of the internal attribute which will be
    /// displayed as `@internal(<name>)`
    std::string InternalName() const override;

    /// Performs a deep clone of this object using the CloneContext `ctx`.
    /// @param ctx the clone context
    /// @return the newly cloned object
    const Intrinsic* Clone(CloneContext* ctx) const override;

    /// The op of the intrinsic
    const Op op;

    /// The storage class of the buffer this intrinsic operates on
    ast::StorageClass const storage_class;

    /// The type of the intrinsic
    const DataType type;
  };

  /// Constructor
  DecomposeMemoryAccess();
  /// Destructor
  ~DecomposeMemoryAccess() override;

  /// @param program the program to inspect
  /// @param data optional extra transform-specific input data
  /// @returns true if this transform should be run for the given program
  bool ShouldRun(const Program* program,
                 const DataMap& data = {}) const override;

 protected:
  /// Runs the transform using the CloneContext built for transforming a
  /// program. Run() is responsible for calling Clone() on the CloneContext.
  /// @param ctx the CloneContext primed with the input program and
  /// ProgramBuilder
  /// @param inputs optional extra transform-specific input data
  /// @param outputs optional extra transform-specific output data
  void Run(CloneContext& ctx,
           const DataMap& inputs,
           DataMap& outputs) const override;

  struct State;
};

}  // namespace transform
}  // namespace tint

#endif  // SRC_TINT_TRANSFORM_DECOMPOSE_MEMORY_ACCESS_H_