// Copyright 2024 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.

// IWYU pragma: private, include "common/value.h"

// IWYU pragma: friend "common/value.h"

#ifndef THIRD_PARTY_CEL_CPP_COMMON_VALUES_PARSED_MESSAGE_VALUE_H_

#define THIRD_PARTY_CEL_CPP_COMMON_VALUES_PARSED_MESSAGE_VALUE_H_

#include <cstddef>

#include <cstdint>

#include <memory>

#include <ostream>

#include <string>

#include <utility>

#include "google/protobuf/any.pb.h"

#include "google/protobuf/struct.pb.h"

#include "absl/base/attributes.h"

#include "absl/base/nullability.h"

#include "absl/log/absl_check.h"

#include "absl/status/status.h"

#include "absl/status/statusor.h"

#include "absl/strings/string_view.h"

#include "absl/types/span.h"

#include "base/attribute.h"

#include "common/memory.h"

#include "common/type.h"

#include "common/value_kind.h"

#include "common/values/custom_struct_value.h"

#include "common/values/values.h"

#include "runtime/runtime_options.h"

#include "google/protobuf/arena.h"

#include "google/protobuf/descriptor.h"

#include "google/protobuf/io/zero_copy_stream.h"

#include "google/protobuf/message.h"

namespace cel {

namespace interop_internal {

bool IsUnsafeParsedMessageValue(const ParsedMessageValue& value);

}

class MessageValue;

class StructValue;

class Value;

class ParsedMessageValue final

    : private common_internal::StructValueMixin<ParsedMessageValue> {

 public:

  static constexpr ValueKind kKind = ValueKind::kStruct;

  using element_type = const google::protobuf::Message;

  ParsedMessageValue(

      const google::protobuf::Message* absl_nonnull value ABSL_ATTRIBUTE_LIFETIME_BOUND,

      google::protobuf::Arena* absl_nonnull arena ABSL_ATTRIBUTE_LIFETIME_BOUND)

      : value_(value), arena_(arena) {

    ABSL_DCHECK(value != nullptr);

    ABSL_DCHECK(arena != nullptr);

    ABSL_DCHECK(!value_ || !IsWellKnownMessageType(value_->GetDescriptor()))

        << value_->GetTypeName() << " is a well known type";

    ABSL_DCHECK(!value_ || value_->GetReflection() != nullptr)

        << value_->GetTypeName() << " is missing reflection";

    ABSL_DCHECK_OK(CheckArena(value_, arena_));

  }

  // Places the `ParsedMessageValue` into a special state where it is logically

  // equivalent to the default instance of `google.protobuf.Empty`, however

  // dereferencing via `operator*` or `operator->` is not allowed.

  ParsedMessageValue();

  ParsedMessageValue(const ParsedMessageValue&) = default;

  ParsedMessageValue(ParsedMessageValue&&) = default;

  ParsedMessageValue& operator=(const ParsedMessageValue&) = default;

  ParsedMessageValue& operator=(ParsedMessageValue&&) = default;

  static constexpr ValueKind kind() { return kKind; }

  absl::string_view GetTypeName() const { return GetDescriptor()->full_name(); }

  MessageType GetRuntimeType() const { return MessageType(GetDescriptor()); }

  const google::protobuf::Descriptor* absl_nonnull GetDescriptor() const {

    return (*this)->GetDescriptor();

  }

  const google::protobuf::Reflection* absl_nonnull GetReflection() const {

    return (*this)->GetReflection();

  }

  const google::protobuf::Message& operator*() const ABSL_ATTRIBUTE_LIFETIME_BOUND {

    return *value_;

  }

  const google::protobuf::Message* absl_nonnull operator->() const { return value_; }

  const google::protobuf::Message* absl_nonnull message() const { return value_; }

  bool IsZeroValue() const;

  std::string DebugString() const;

  // See Value::SerializeTo().

  absl::Status SerializeTo(

      const google::protobuf::DescriptorPool* absl_nonnull descriptor_pool,

      google::protobuf::MessageFactory* absl_nonnull message_factory,

      google::protobuf::io::ZeroCopyOutputStream* absl_nonnull output) const;

  // See Value::ConvertToJson().

  absl::Status ConvertToJson(

      const google::protobuf::DescriptorPool* absl_nonnull descriptor_pool,

      google::protobuf::MessageFactory* absl_nonnull message_factory,

      google::protobuf::Message* absl_nonnull json) const;

  // See Value::ConvertToJsonObject().

  absl::Status ConvertToJsonObject(

      const google::protobuf::DescriptorPool* absl_nonnull descriptor_pool,

      google::protobuf::MessageFactory* absl_nonnull message_factory,

      google::protobuf::Message* absl_nonnull json) const;

  absl::Status Equal(const Value& other,

                     const google::protobuf::DescriptorPool* absl_nonnull descriptor_pool,

                     google::protobuf::MessageFactory* absl_nonnull message_factory,

                     google::protobuf::Arena* absl_nonnull arena,

                     Value* absl_nonnull result) const;

  using StructValueMixin::Equal;

  ParsedMessageValue Clone(google::protobuf::Arena* absl_nonnull arena) const;

  absl::Status GetFieldByName(

      absl::string_view name, ProtoWrapperTypeOptions unboxing_options,

      const google::protobuf::DescriptorPool* absl_nonnull descriptor_pool,

      google::protobuf::MessageFactory* absl_nonnull message_factory,

      google::protobuf::Arena* absl_nonnull arena, Value* absl_nonnull result) const;

  using StructValueMixin::GetFieldByName;

  absl::Status GetFieldByNumber(

      int64_t number, ProtoWrapperTypeOptions unboxing_options,

      const google::protobuf::DescriptorPool* absl_nonnull descriptor_pool,

      google::protobuf::MessageFactory* absl_nonnull message_factory,

      google::protobuf::Arena* absl_nonnull arena, Value* absl_nonnull result) const;

  using StructValueMixin::GetFieldByNumber;

  absl::StatusOr<bool> HasFieldByName(absl::string_view name) const;

  absl::StatusOr<bool> HasFieldByNumber(int64_t number) const;

  using ForEachFieldCallback = CustomStructValueInterface::ForEachFieldCallback;

  absl::Status ForEachField(

      ForEachFieldCallback callback,

      const google::protobuf::DescriptorPool* absl_nonnull descriptor_pool,

      google::protobuf::MessageFactory* absl_nonnull message_factory,

      google::protobuf::Arena* absl_nonnull arena) const;

  absl::Status Qualify(

      absl::Span<const SelectQualifier> qualifiers, bool presence_test,

      const google::protobuf::DescriptorPool* absl_nonnull descriptor_pool,

      google::protobuf::MessageFactory* absl_nonnull message_factory,

      google::protobuf::Arena* absl_nonnull arena, Value* absl_nonnull result,

      int* absl_nonnull count) const;

  using StructValueMixin::Qualify;

  friend void swap(ParsedMessageValue& lhs, ParsedMessageValue& rhs) noexcept {

    using std::swap;

    swap(lhs.value_, rhs.value_);

    swap(lhs.arena_, rhs.arena_);

  }

  absl::Status GetField(

      const google::protobuf::FieldDescriptor* absl_nonnull field,

      ProtoWrapperTypeOptions unboxing_options,

      const google::protobuf::DescriptorPool* absl_nonnull descriptor_pool,

      google::protobuf::MessageFactory* absl_nonnull message_factory,

      google::protobuf::Arena* absl_nonnull arena, Value* absl_nonnull result) const;

  bool HasField(const google::protobuf::FieldDescriptor* absl_nonnull field) const;

 private:

  friend std::pointer_traits<ParsedMessageValue>;

  friend class StructValue;

  friend class common_internal::ValueMixin<ParsedMessageValue>;

  friend class common_internal::StructValueMixin<ParsedMessageValue>;

  friend ParsedMessageValue UnsafeParsedMessageValue(

      const google::protobuf::Message* absl_nonnull value);

  friend bool interop_internal::IsUnsafeParsedMessageValue(

      const ParsedMessageValue& value);

  explicit ParsedMessageValue(

      const google::protobuf::Message* absl_nonnull value ABSL_ATTRIBUTE_LIFETIME_BOUND)

      : value_(value), arena_(nullptr) {

    ABSL_DCHECK(value != nullptr);

    ABSL_DCHECK(!value_ || !IsWellKnownMessageType(value_->GetDescriptor()))

        << value_->GetTypeName() << " is a well known type";

    ABSL_DCHECK(!value_ || value_->GetReflection() != nullptr)

        << value_->GetTypeName() << " is missing reflection";

  }

  static absl::Status CheckArena(const google::protobuf::Message* absl_nullable message,

                                 google::protobuf::Arena* absl_nonnull arena) {

    if (message != nullptr && message->GetArena() != nullptr &&

        message->GetArena() != arena) {

      return absl::InvalidArgumentError(

          "message arena must be the same as arena");

    }

    return absl::OkStatus();

  }

  bool is_unsafe() const { return arena_ == nullptr; }

  const google::protobuf::Message* absl_nonnull value_;

  // The arena attributed as Owning this value. Null if the value is created by

  // UnsafeParsedMessageValue() or derived from such a value. This is used to

  // identify externally managed messages and propagating the unsafe field

  // access behavior.

  google::protobuf::Arena* absl_nullable arena_;

};

inline std::ostream& operator<<(std::ostream& out,

                                const ParsedMessageValue& value) {

  return out << value.DebugString();

}

// Creates a `ParsedMessageValue` without specifying a managing arena.

// The message must outlive the `ParsedMessageValue` or any value that might

// be derived from it. Prefer to use `cel::Value::WrapMessageUnsafe()`.

inline ParsedMessageValue UnsafeParsedMessageValue(

    const google::protobuf::Message* absl_nonnull value) {

  return ParsedMessageValue(value);

}

}  // namespace cel

namespace std {

template <>

struct pointer_traits<cel::ParsedMessageValue> {

  using pointer = cel::ParsedMessageValue;

  using element_type = typename cel::ParsedMessageValue::element_type;

  using difference_type = ptrdiff_t;

  static element_type* to_address(const pointer& p) noexcept {

    return cel::to_address(p.value_);

  }

};

}  // namespace std

#endif  // THIRD_PARTY_CEL_CPP_COMMON_VALUES_PARSED_MESSAGE_VALUE_H_