// 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_AST_INTERPOLATE_ATTRIBUTE_H_
#define SRC_TINT_AST_INTERPOLATE_ATTRIBUTE_H_

#include <ostream>
#include <string>

#include "src/tint/ast/attribute.h"

namespace tint {
namespace ast {

/// The interpolation type.
enum class InterpolationType { kPerspective, kLinear, kFlat };

/// The interpolation sampling.
enum class InterpolationSampling { kNone = -1, kCenter, kCentroid, kSample };

/// An interpolate attribute
class InterpolateAttribute final
    : public Castable<InterpolateAttribute, Attribute> {
 public:
  /// Create an interpolate attribute.
  /// @param pid the identifier of the program that owns this node
  /// @param src the source of this node
  /// @param type the interpolation type
  /// @param sampling the interpolation sampling
  InterpolateAttribute(ProgramID pid,
                       const Source& src,
                       InterpolationType type,
                       InterpolationSampling sampling);
  ~InterpolateAttribute() override;

  /// @returns the WGSL name for the attribute
  std::string Name() const override;

  /// Clones this node and all transitive child nodes using the `CloneContext`
  /// `ctx`.
  /// @param ctx the clone context
  /// @return the newly cloned node
  const InterpolateAttribute* Clone(CloneContext* ctx) const override;

  /// The interpolation type
  const InterpolationType type;

  /// The interpolation sampling
  const InterpolationSampling sampling;
};

/// @param out the std::ostream to write to
/// @param type the interpolation type
/// @return the std::ostream so calls can be chained
std::ostream& operator<<(std::ostream& out, InterpolationType type);

/// @param out the std::ostream to write to
/// @param sampling the interpolation sampling
/// @return the std::ostream so calls can be chained
std::ostream& operator<<(std::ostream& out, InterpolationSampling sampling);

}  // namespace ast
}  // namespace tint

#endif  // SRC_TINT_AST_INTERPOLATE_ATTRIBUTE_H_