// Copyright 2025 Google LLC

//

// 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

//

//     https://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 THIRD_PARTY_CEL_CPP_RUNTIME_INTERNAL_ATTRIBUTE_MATCHER_H_

#define THIRD_PARTY_CEL_CPP_RUNTIME_INTERNAL_ATTRIBUTE_MATCHER_H_

#include "base/attribute.h"

namespace cel::runtime_internal {

// Interface for matching unknown and missing attributes against the

// observed attribute trail at runtime.

class AttributeMatcher {

 public:

  using MatchResult = cel::AttributePattern::MatchType;

  virtual ~AttributeMatcher() = default;

  // Checks whether the attribute trail matches any unknown patterns.

  // Used to identify and collect referenced unknowns in an UnknownValue.

  virtual MatchResult CheckForUnknown(const Attribute& attr

                                      [[maybe_unused]]) const {

    return MatchResult::NONE;

  };

  // Checks whether the attribute trail matches any missing patterns.

  // Used to identify missing attributes, and report an error if referenced

  // directly.

  virtual MatchResult CheckForMissing(const Attribute& attr

                                      [[maybe_unused]]) const {

    return MatchResult::NONE;

  };

};

}  // namespace cel::runtime_internal

#endif  // THIRD_PARTY_CEL_CPP_RUNTIME_INTERNAL_ATTRIBUTE_MATCHER_H_