// Copyright 2020 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_INSPECTOR_ENTRY_POINT_H_
#define SRC_INSPECTOR_ENTRY_POINT_H_

#include <string>
#include <tuple>
#include <vector>

#include "src/ast/interpolate_decoration.h"
#include "src/ast/pipeline_stage.h"

namespace tint {
namespace inspector {

/// Base component type of a stage variable.
enum class ComponentType {
  kUnknown = -1,
  kFloat,
  kUInt,
  kSInt,
};

/// Composition of components of a stage variable.
enum class CompositionType {
  kUnknown = -1,
  kScalar,
  kVec2,
  kVec3,
  kVec4,
};

/// Type of interpolation of a stage variable.
enum class InterpolationType { kUnknown = -1, kPerspective, kLinear, kFlat };

/// Type of interpolation sampling of a stage variable.
enum class InterpolationSampling {
  kUnknown = -1,
  kNone,
  kCenter,
  kCentroid,
  kSample
};

/// Reflection data about an entry point input or output.
struct StageVariable {
  /// Name of the variable in the shader.
  std::string name;
  /// Is Location Decoration present
  bool has_location_decoration = false;
  /// Value of Location Decoration, only valid if |has_location_decoration| is
  /// true.
  uint32_t location_decoration;
  /// Scalar type that the variable is composed of.
  ComponentType component_type = ComponentType::kUnknown;
  /// How the scalars are composed for the variable.
  CompositionType composition_type = CompositionType::kUnknown;
  /// Interpolation type of the variable.
  InterpolationType interpolation_type = InterpolationType::kUnknown;
  /// Interpolation sampling of the variable.
  InterpolationSampling interpolation_sampling =
      InterpolationSampling::kUnknown;
};

/// Convert from internal ast::InterpolationType to public ::InterpolationType.
/// @param ast_type internal value to convert from
/// @returns the publicly visible equivalent
InterpolationType ASTToInspectorInterpolationType(
    ast::InterpolationType ast_type);

/// Convert from internal ast::InterpolationSampling to public
/// ::InterpolationSampling
/// @param sampling internal value to convert from
/// @returns the publicly visible equivalent
InterpolationSampling ASTToInspectorInterpolationSampling(
    ast::InterpolationSampling sampling);

/// Reflection data about a pipeline overridable constant referenced by an entry
/// point
struct OverridableConstant {
  /// Name of the constant
  std::string name;

  /// Type of the scalar
  enum class Type {
    kBool,
    kFloat32,
    kUint32,
    kInt32,
  };

  /// Type of the scalar
  Type type;

  /// Does this pipeline overridable constant have an initializer?
  bool is_initialized = false;
};

/// Reflection data for an entry point in the shader.
struct EntryPoint {
  /// Constructors
  EntryPoint();
  /// Copy Constructor
  EntryPoint(EntryPoint&);
  /// Move Constructor
  EntryPoint(EntryPoint&&);
  ~EntryPoint();

  /// The entry point name
  std::string name;
  /// Remapped entry point name in the backend
  std::string remapped_name;
  /// The entry point stage
  ast::PipelineStage stage = ast::PipelineStage::kNone;
  /// The workgroup x size
  uint32_t workgroup_size_x = 0;
  /// The workgroup y size
  uint32_t workgroup_size_y = 0;
  /// The workgroup z size
  uint32_t workgroup_size_z = 0;
  /// List of the input variable accessed via this entry point.
  std::vector<StageVariable> input_variables;
  /// List of the output variable accessed via this entry point.
  std::vector<StageVariable> output_variables;
  /// List of the pipeline overridable constants accessed via this entry point.
  std::vector<OverridableConstant> overridable_constants;
  /// Does the entry point use the sample_mask builtin as an input builtin
  /// variable.
  bool input_sample_mask_used = false;
  /// Does the entry point use the sample_mask builtin as an output builtin
  /// variable.
  bool output_sample_mask_used = false;
  /// Does the entry point use the position builtin as an input builtin
  /// variable.
  bool input_position_used = false;
  /// Does the entry point use the front_facing builtin
  bool front_facing_used = false;
  /// Does the entry point use the sample_index builtin
  bool sample_index_used = false;
  /// Does the entry point use the num_workgroups builtin
  bool num_workgroups_used = false;

  /// @returns the size of the workgroup in {x,y,z} format
  std::tuple<uint32_t, uint32_t, uint32_t> workgroup_size() {
    return std::tuple<uint32_t, uint32_t, uint32_t>(
        workgroup_size_x, workgroup_size_y, workgroup_size_z);
  }
};

}  // namespace inspector
}  // namespace tint

#endif  // SRC_INSPECTOR_ENTRY_POINT_H_