// 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_TINT_INSPECTOR_ENTRY_POINT_H_
#define SRC_TINT_INSPECTOR_ENTRY_POINT_H_

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

#include "tint/override_id.h"

#include "src/tint/ast/interpolate_attribute.h"
#include "src/tint/ast/pipeline_stage.h"

namespace tint::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 {
    /// Constructor
    StageVariable();
    /// Copy constructor
    /// @param other the StageVariable to copy
    StageVariable(const StageVariable& other);
    /// Destructor
    ~StageVariable();

    /// Name of the variable in the shader.
    std::string name;
    /// Is location attribute present
    bool has_location_attribute = false;
    /// Value of the location attribute, only valid if #has_location_attribute is
    /// true.
    uint32_t location_attribute;
    /// Is Location attribute present
    /// [DEPRECATED]: Use #has_location_attribute
    bool& has_location_decoration = has_location_attribute;
    /// Value of Location Decoration, only valid if #has_location_decoration is
    /// true.
    /// [DEPRECATED]: Use #location_attribute
    uint32_t& location_decoration = location_attribute;
    /// 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 an override variable referenced by an entry point
struct Override {
    /// Name of the override
    std::string name;

    /// ID of the override
    OverrideId id;

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

    /// Type of the scalar
    Type type;

    /// Does this override have an initializer?
    bool is_initialized = false;

    /// Does this override have a numeric ID specified explicitly?
    bool is_id_specified = false;
};

/// The pipeline stage
enum class PipelineStage { kVertex, kFragment, kCompute };

/// WorkgroupSize describes the dimensions of the workgroup grid for a compute shader.
struct WorkgroupSize {
    /// The 'x' dimension of the workgroup grid
    uint32_t x = 1;
    /// The 'y' dimension of the workgroup grid
    uint32_t y = 1;
    /// The 'z' dimension of the workgroup grid
    uint32_t z = 1;
};

/// 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
    PipelineStage stage;
    /// The workgroup size. If PipelineStage is kCompute and this holds no value, then the workgroup
    /// size is derived from an override-expression. In this situation you first need to run the
    /// tint::transform::SubstituteOverride transform before using the inspector.
    std::optional<WorkgroupSize> workgroup_size;
    /// 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<Override> overrides;
    /// 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;
};

}  // namespace tint::inspector

#endif  // SRC_TINT_INSPECTOR_ENTRY_POINT_H_