// Copyright 2022 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_ENABLE_H_
#define SRC_TINT_AST_ENABLE_H_

#include <string>
#include <unordered_set>
#include <utility>

#include "src/tint/ast/access.h"
#include "src/tint/ast/expression.h"

namespace tint::ast {

/// An instance of this class represents one extension mentioned in a
/// "enable" derictive. Example:
///       // Enable an extension named "f16"
///       enable f16;
class Enable : public Castable<Enable, Node> {
 public:
  ///  The enum class identifing each supported WGSL extension
  enum class ExtensionKind {
    /// An internal reserved extension for test, named
    /// "InternalExtensionForTesting"
    kInternalExtensionForTesting = -2,
    kNotAnExtension = -1,
  };

  /// Convert a string of extension name into one of ExtensionKind enum value,
  /// the result will be ExtensionKind::kNotAnExtension if the name is not a
  /// known extension name. A extension node of kind kNotAnExtension must not
  /// exist in the AST tree, and using a unknown extension name in WGSL code
  /// should result in a shader-creation error.
  /// @param name string of the extension name
  /// @return the ExtensionKind enum value for the extension of given name, or
  /// kNotAnExtension if no known extension has the given name
  static ExtensionKind NameToKind(const std::string& name);

  /// Convert the ExtensionKind enum value to corresponding extension name
  /// string. If the given enum value is kNotAnExtension or don't have a known
  /// name, return an empty string instead.
  /// @param kind the ExtensionKind enum value
  /// @return string of the extension name corresponding to the given kind, or
  /// an empty string if the given enum value is kNotAnExtension or don't have a
  /// known corresponding name
  static std::string KindToName(ExtensionKind kind);

  /// Create a extension
  /// @param pid the identifier of the program that owns this node
  /// @param src the source of this node
  /// @param name the name of extension
  Enable(ProgramID pid, const Source& src, const std::string& name);
  /// Move constructor
  Enable(Enable&&);

  ~Enable() override;

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

  /// The extension name
  const std::string name;

  /// The extension kind
  const ExtensionKind kind;
};

///  A set of extension kinds
using ExtensionSet = std::unordered_set<Enable::ExtensionKind>;

}  // namespace tint::ast

#endif  // SRC_TINT_AST_ENABLE_H_