// Copyright 2023 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.

#include <cstdint>

#include <string>

#include <utility>

#include "absl/base/attributes.h"

#include "absl/base/casts.h"

#include "absl/base/nullability.h"

#include "absl/log/absl_check.h"

#include "absl/status/status.h"

#include "absl/strings/str_cat.h"

#include "absl/strings/string_view.h"

#include "absl/time/time.h"

#include "common/arena.h"

#include "common/native_type.h"

#include "common/type.h"

#include "common/value.h"

#include "common/value_kind.h"

#include "google/protobuf/arena.h"

#include "google/protobuf/descriptor.h"

#include "google/protobuf/message.h"

namespace cel {

namespace {

struct OptionalValueDispatcher : public OpaqueValueDispatcher {

  using HasValue =

      bool (*)(const OptionalValueDispatcher* absl_nonnull dispatcher,

               CustomValueContent content);

  using Value = void (*)(const OptionalValueDispatcher* absl_nonnull dispatcher,

                         CustomValueContent content,

                         cel::Value* absl_nonnull result);

  absl_nonnull HasValue has_value;

  absl_nonnull Value value;

};

NativeTypeId OptionalValueGetTypeId(const OpaqueValueDispatcher* absl_nonnull,

                                    OpaqueValueContent) {

  return NativeTypeId::For<OptionalValue>();

}

absl::string_view OptionalValueGetTypeName(

    const OpaqueValueDispatcher* absl_nonnull, OpaqueValueContent) {

  return "optional_type";

}

OpaqueType OptionalValueGetRuntimeType(

    const OpaqueValueDispatcher* absl_nonnull, OpaqueValueContent) {

  return OptionalType();

}

std::string OptionalValueDebugString(

    const OpaqueValueDispatcher* absl_nonnull dispatcher,

    OpaqueValueContent content) {

  if (!static_cast<const OptionalValueDispatcher*>(dispatcher)

           ->has_value(static_cast<const OptionalValueDispatcher*>(dispatcher),

                       content)) {

    return "optional.none()";

  }

  Value value;

  static_cast<const OptionalValueDispatcher*>(dispatcher)

      ->value(static_cast<const OptionalValueDispatcher*>(dispatcher), content,

              &value);

  return absl::StrCat("optional.of(", value.DebugString(), ")");

}

bool OptionalValueHasValue(const OptionalValueDispatcher* absl_nonnull,

                           OpaqueValueContent) {

  return true;

}

absl::Status OptionalValueEqual(

    const OpaqueValueDispatcher* absl_nonnull dispatcher,

    OpaqueValueContent content, const OpaqueValue& 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) {

  ABSL_DCHECK(descriptor_pool != nullptr);

  ABSL_DCHECK(message_factory != nullptr);

  ABSL_DCHECK(arena != nullptr);

  ABSL_DCHECK(result != nullptr);

  if (auto other_optional = other.AsOptional(); other_optional) {

    const bool lhs_has_value =

        static_cast<const OptionalValueDispatcher*>(dispatcher)

            ->has_value(static_cast<const OptionalValueDispatcher*>(dispatcher),

                        content);

    const bool rhs_has_value = other_optional->HasValue();

    if (lhs_has_value != rhs_has_value) {

      *result = FalseValue();

      return absl::OkStatus();

    }

    if (!lhs_has_value) {

      *result = TrueValue();

      return absl::OkStatus();

    }

    Value lhs_value;

    Value rhs_value;

    static_cast<const OptionalValueDispatcher*>(dispatcher)

        ->value(static_cast<const OptionalValueDispatcher*>(dispatcher),

                content, &lhs_value);

    other_optional->Value(&rhs_value);

    return lhs_value.Equal(rhs_value, descriptor_pool, message_factory, arena,

                           result);

  }

  *result = FalseValue();

  return absl::OkStatus();

}

google::protobuf::Arena* absl_nullable OptionalValueGetArenaNull(

    const OpaqueValueDispatcher* absl_nonnull, OpaqueValueContent) {

  return nullptr;

}

OpaqueValue OptionalValueClone(

    const OpaqueValueDispatcher* absl_nonnull dispatcher,

    OpaqueValueContent content, google::protobuf::Arena* absl_nonnull arena) {

  return common_internal::MakeOptionalValue(dispatcher, content);

}

bool OptionalValueHasNoValue(const OptionalValueDispatcher* absl_nonnull,

                             CustomValueContent content) {

  return false;

}

void EmptyOptionalValueValue(const OptionalValueDispatcher* absl_nonnull,

                             CustomValueContent content,

                             cel::Value* absl_nonnull result) {

  *result =

      ErrorValue(absl::FailedPreconditionError("optional.none() dereference"));

}

void NullOptionalValueValue(const OptionalValueDispatcher* absl_nonnull,

                            CustomValueContent content,

                            cel::Value* absl_nonnull result) {

  *result = NullValue();

}

void BoolOptionalValueValue(const OptionalValueDispatcher* absl_nonnull,

                            CustomValueContent content,

                            cel::Value* absl_nonnull result) {

  *result = BoolValue(content.To<bool>());

}

void IntOptionalValueValue(const OptionalValueDispatcher* absl_nonnull,

                           CustomValueContent content,

                           cel::Value* absl_nonnull result) {

  *result = IntValue(content.To<int64_t>());

}

void UintOptionalValueValue(const OptionalValueDispatcher* absl_nonnull,

                            CustomValueContent content,

                            cel::Value* absl_nonnull result) {

  *result = UintValue(content.To<uint64_t>());

}

void DoubleOptionalValueValue(const OptionalValueDispatcher* absl_nonnull,

                              CustomValueContent content,

                              cel::Value* absl_nonnull result) {

  *result = DoubleValue(content.To<double>());

}

void DurationOptionalValueValue(const OptionalValueDispatcher* absl_nonnull,

                                CustomValueContent content,

                                cel::Value* absl_nonnull result) {

  *result = UnsafeDurationValue(content.To<absl::Duration>());

}

void TimestampOptionalValueValue(const OptionalValueDispatcher* absl_nonnull,

                                 CustomValueContent content,

                                 cel::Value* absl_nonnull result) {

  *result = UnsafeTimestampValue(content.To<absl::Time>());

}

ABSL_CONST_INIT const OptionalValueDispatcher

    empty_optional_value_dispatcher = {

        {

            .get_type_id = &OptionalValueGetTypeId,

            .get_arena = &OptionalValueGetArenaNull,

            .get_type_name = &OptionalValueGetTypeName,

            .debug_string = &OptionalValueDebugString,

            .get_runtime_type = &OptionalValueGetRuntimeType,

            .equal = &OptionalValueEqual,

            .clone = &OptionalValueClone,

        },

        &OptionalValueHasNoValue,

        &EmptyOptionalValueValue,

};

ABSL_CONST_INIT const OptionalValueDispatcher null_optional_value_dispatcher = {

    {

        .get_type_id = &OptionalValueGetTypeId,

        .get_arena = &OptionalValueGetArenaNull,

        .get_type_name = &OptionalValueGetTypeName,

        .debug_string = &OptionalValueDebugString,

        .get_runtime_type = &OptionalValueGetRuntimeType,

        .equal = &OptionalValueEqual,

        .clone = &OptionalValueClone,

    },

    &OptionalValueHasValue,

    &NullOptionalValueValue,

};

ABSL_CONST_INIT const OptionalValueDispatcher bool_optional_value_dispatcher = {

    {

        .get_type_id = &OptionalValueGetTypeId,

        .get_arena = &OptionalValueGetArenaNull,

        .get_type_name = &OptionalValueGetTypeName,

        .debug_string = &OptionalValueDebugString,

        .get_runtime_type = &OptionalValueGetRuntimeType,

        .equal = &OptionalValueEqual,

        .clone = &OptionalValueClone,

    },

    &OptionalValueHasValue,

    &BoolOptionalValueValue,

};

ABSL_CONST_INIT const OptionalValueDispatcher int_optional_value_dispatcher = {

    {

        .get_type_id = &OptionalValueGetTypeId,

        .get_arena = &OptionalValueGetArenaNull,

        .get_type_name = &OptionalValueGetTypeName,

        .debug_string = &OptionalValueDebugString,

        .get_runtime_type = &OptionalValueGetRuntimeType,

        .equal = &OptionalValueEqual,

        .clone = &OptionalValueClone,

    },

    &OptionalValueHasValue,

    &IntOptionalValueValue,

};

ABSL_CONST_INIT const OptionalValueDispatcher uint_optional_value_dispatcher = {

    {

        .get_type_id = &OptionalValueGetTypeId,

        .get_arena = &OptionalValueGetArenaNull,

        .get_type_name = &OptionalValueGetTypeName,

        .debug_string = &OptionalValueDebugString,

        .get_runtime_type = &OptionalValueGetRuntimeType,

        .equal = &OptionalValueEqual,

        .clone = &OptionalValueClone,

    },

    &OptionalValueHasValue,

    &UintOptionalValueValue,

};

ABSL_CONST_INIT const OptionalValueDispatcher

    double_optional_value_dispatcher = {

        {

            .get_type_id = &OptionalValueGetTypeId,

            .get_arena = &OptionalValueGetArenaNull,

            .get_type_name = &OptionalValueGetTypeName,

            .debug_string = &OptionalValueDebugString,

            .get_runtime_type = &OptionalValueGetRuntimeType,

            .equal = &OptionalValueEqual,

            .clone = &OptionalValueClone,

        },

        &OptionalValueHasValue,

        &DoubleOptionalValueValue,

};

ABSL_CONST_INIT const OptionalValueDispatcher

    duration_optional_value_dispatcher = {

        {

            .get_type_id = &OptionalValueGetTypeId,

            .get_arena = &OptionalValueGetArenaNull,

            .get_type_name = &OptionalValueGetTypeName,

            .debug_string = &OptionalValueDebugString,

            .get_runtime_type = &OptionalValueGetRuntimeType,

            .equal = &OptionalValueEqual,

            .clone = &OptionalValueClone,

        },

        &OptionalValueHasValue,

        &DurationOptionalValueValue,

};

ABSL_CONST_INIT const OptionalValueDispatcher

    timestamp_optional_value_dispatcher = {

        {

            .get_type_id = &OptionalValueGetTypeId,

            .get_arena = &OptionalValueGetArenaNull,

            .get_type_name = &OptionalValueGetTypeName,

            .debug_string = &OptionalValueDebugString,

            .get_runtime_type = &OptionalValueGetRuntimeType,

            .equal = &OptionalValueEqual,

            .clone = &OptionalValueClone,

        },

        &OptionalValueHasValue,

        &TimestampOptionalValueValue,

};

struct OptionalValueContent {

  const Value* absl_nonnull value;

  google::protobuf::Arena* absl_nonnull arena;

};

google::protobuf::Arena* absl_nullable GenericOptionalValueGetArena(

    const OpaqueValueDispatcher* absl_nonnull, OpaqueValueContent content) {

  return content.To<OptionalValueContent>().arena;

}

OpaqueValue GenericOptionalValueClone(

    const OpaqueValueDispatcher* absl_nonnull dispatcher,

    OpaqueValueContent content, google::protobuf::Arena* absl_nonnull arena);

void GenericOptionalValueValue(const OptionalValueDispatcher* absl_nonnull,

                               CustomValueContent content,

                               cel::Value* absl_nonnull result) {

  *result = *content.To<OptionalValueContent>().value;

}

ABSL_CONST_INIT const OptionalValueDispatcher optional_value_dispatcher = {

    {

        .get_type_id = &OptionalValueGetTypeId,

        .get_arena = &GenericOptionalValueGetArena,

        .get_type_name = &OptionalValueGetTypeName,

        .debug_string = &OptionalValueDebugString,

        .get_runtime_type = &OptionalValueGetRuntimeType,

        .equal = &OptionalValueEqual,

        .clone = &GenericOptionalValueClone,

    },

    &OptionalValueHasValue,

    &GenericOptionalValueValue,

};

OpaqueValue GenericOptionalValueClone(

    const OpaqueValueDispatcher* absl_nonnull dispatcher,

    OpaqueValueContent content, google::protobuf::Arena* absl_nonnull arena) {

  ABSL_DCHECK(arena != nullptr);

  cel::Value* absl_nonnull result =

      ::new (arena->AllocateAligned(sizeof(cel::Value), alignof(cel::Value)))

          cel::Value(content.To<OptionalValueContent>().value->Clone(arena));

  if (!ArenaTraits<>::trivially_destructible(result)) {

    arena->OwnDestructor(result);

  }

  return common_internal::MakeOptionalValue(

      &optional_value_dispatcher, OpaqueValueContent::From(OptionalValueContent{

                                      .value = result, .arena = arena}));

}

}  // namespace

OptionalValue OptionalValue::Of(cel::Value value,

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

  ABSL_DCHECK(value.kind() != ValueKind::kError &&

              value.kind() != ValueKind::kUnknown);

  ABSL_DCHECK(arena != nullptr);

  // We can actually fit a lot more of the underlying values, avoiding arena

  // allocations and destructors. For now, we just do scalars.

  switch (value.kind()) {

    case ValueKind::kNull:

      return OptionalValue(&null_optional_value_dispatcher,

                           OpaqueValueContent::Zero());

    case ValueKind::kBool:

      return OptionalValue(

          &bool_optional_value_dispatcher,

          OpaqueValueContent::From(absl::implicit_cast<bool>(value.GetBool())));

    case ValueKind::kInt:

      return OptionalValue(&int_optional_value_dispatcher,

                           OpaqueValueContent::From(

                               absl::implicit_cast<int64_t>(value.GetInt())));

    case ValueKind::kUint:

      return OptionalValue(&uint_optional_value_dispatcher,

                           OpaqueValueContent::From(

                               absl::implicit_cast<uint64_t>(value.GetUint())));

    case ValueKind::kDouble:

      return OptionalValue(&double_optional_value_dispatcher,

                           OpaqueValueContent::From(

                               absl::implicit_cast<double>(value.GetDouble())));

    case ValueKind::kDuration:

      return OptionalValue(

          &duration_optional_value_dispatcher,

          OpaqueValueContent::From(value.GetDuration().ToDuration()));

    case ValueKind::kTimestamp:

      return OptionalValue(

          &timestamp_optional_value_dispatcher,

          OpaqueValueContent::From(value.GetTimestamp().ToTime()));

    default: {

      cel::Value* absl_nonnull result = ::new (

          arena->AllocateAligned(sizeof(cel::Value), alignof(cel::Value)))

          cel::Value(std::move(value));

      if (!ArenaTraits<>::trivially_destructible(result)) {

        arena->OwnDestructor(result);

      }

      return OptionalValue(&optional_value_dispatcher,

                           OpaqueValueContent::From(OptionalValueContent{

                               .value = result, .arena = arena}));

    }

  }

}

OptionalValue OptionalValue::None() {

  return OptionalValue(&empty_optional_value_dispatcher,

                       OpaqueValueContent::Zero());

}

bool OptionalValue::HasValue() const {

  return static_cast<const OptionalValueDispatcher*>(OpaqueValue::dispatcher())

      ->has_value(static_cast<const OptionalValueDispatcher*>(

                      OpaqueValue::dispatcher()),

                  OpaqueValue::content());

}

void OptionalValue::Value(cel::Value* absl_nonnull result) const {

  ABSL_DCHECK(result != nullptr);

  static_cast<const OptionalValueDispatcher*>(OpaqueValue::dispatcher())

      ->value(static_cast<const OptionalValueDispatcher*>(

                  OpaqueValue::dispatcher()),

              OpaqueValue::content(), result);

}

cel::Value OptionalValue::Value() const {

  cel::Value result;

  Value(&result);

  return result;

}

}  // namespace cel