// Copyright 2026 The ODML 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 THIRD_PARTY_ODML_LITERT_LM_RUNTIME_COMPONENTS_CONSTRAINED_DECODING_LLG_CONSTRAINT_PROVIDER_H_
#define THIRD_PARTY_ODML_LITERT_LM_RUNTIME_COMPONENTS_CONSTRAINED_DECODING_LLG_CONSTRAINT_PROVIDER_H_

#include <cstdint>
#include <memory>
#include <utility>
#include <vector>

#include "absl/status/statusor.h"  // from @com_google_absl
#include "runtime/components/constrained_decoding/constraint.h"
#include "runtime/components/constrained_decoding/constraint_provider.h"
#include "runtime/components/constrained_decoding/constraint_provider_config.h"
#include "runtime/components/constrained_decoding/llg_constraint_config.h"
#include "runtime/components/tokenizer.h"
#include "llguidance.h"

namespace litert::lm {

class LlgConstraintProvider : public ConstraintProvider {
 public:
  static absl::StatusOr<std::unique_ptr<ConstraintProvider>> Create(
      const Tokenizer& tokenizer, LlGuidanceConfig llg_config);

  // LlgTokenizer must be valid. Takes ownership of LlgTokenizer.
  explicit LlgConstraintProvider(std::vector<uint32_t>&& token_lens,
                                 std::vector<uint8_t>&& token_bytes,
                                 LlgTokenizer* llg_tokenizer,
                                 LlGuidanceConfig llg_config)
      : token_lens_(std::move(token_lens)),
        token_bytes_(std::move(token_bytes)),
        llg_tokenizer_(std::move(llg_tokenizer)),
        llg_config_(std::move(llg_config)) {}

  ~LlgConstraintProvider() override;

  absl::StatusOr<std::unique_ptr<Constraint>> CreateConstraint(
      ConstraintArg constraint_arg) const override;

 private:
  const std::vector<uint32_t> token_lens_;
  const std::vector<uint8_t> token_bytes_;
  LlgTokenizer* llg_tokenizer_;  // Owned.
  LlGuidanceConfig llg_config_;
};

}  // namespace litert::lm

#endif  // THIRD_PARTY_ODML_LITERT_LM_RUNTIME_COMPONENTS_CONSTRAINED_DECODING_LLG_CONSTRAINT_PROVIDER_H_