// 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.

#include "extensions/protobuf/internal/qualify.h"

#include <string>

#include <utility>

#include "absl/functional/overload.h"

#include "absl/log/absl_check.h"

#include "absl/status/status.h"

#include "absl/status/statusor.h"

#include "absl/strings/str_cat.h"

#include "absl/types/optional.h"

#include "absl/types/variant.h"

#include "base/attribute.h"

#include "base/builtins.h"

#include "common/kind.h"

#include "common/memory.h"

#include "extensions/protobuf/internal/map_reflection.h"

#include "internal/status_macros.h"

#include "runtime/internal/errors.h"

#include "runtime/runtime_options.h"

#include "google/protobuf/descriptor.h"

#include "google/protobuf/map_field.h"

#include "google/protobuf/message.h"

#include "google/protobuf/reflection.h"

#undef GetMessage

namespace cel::extensions::protobuf_internal {

namespace {

const google::protobuf::FieldDescriptor* GetNormalizedFieldByNumber(

    const google::protobuf::Descriptor* descriptor, const google::protobuf::Reflection* reflection,

    int field_number) {

  const google::protobuf::FieldDescriptor* field_desc =

      descriptor->FindFieldByNumber(field_number);

  if (field_desc == nullptr && reflection != nullptr) {

    field_desc = reflection->FindKnownExtensionByNumber(field_number);

  }

  return field_desc;

}

// JSON container types and Any have special unpacking rules.

//

// Not considered for qualify traversal for simplicity, but

// could be supported in a follow-up if needed.

bool IsUnsupportedQualifyType(const google::protobuf::Descriptor& desc) {

  switch (desc.well_known_type()) {

    case google::protobuf::Descriptor::WELLKNOWNTYPE_ANY:

    case google::protobuf::Descriptor::WELLKNOWNTYPE_STRUCT:

    case google::protobuf::Descriptor::WELLKNOWNTYPE_VALUE:

    case google::protobuf::Descriptor::WELLKNOWNTYPE_LISTVALUE:

      return true;

    default:

      return false;

  }

}

constexpr int kKeyTag = 1;

constexpr int kValueTag = 2;

bool MatchesMapKeyType(const google::protobuf::FieldDescriptor* key_desc,

                       const cel::AttributeQualifier& key) {

  switch (key_desc->cpp_type()) {

    case google::protobuf::FieldDescriptor::CPPTYPE_BOOL:

      return key.kind() == cel::Kind::kBool;

    case google::protobuf::FieldDescriptor::CPPTYPE_INT32:

      // fall through

    case google::protobuf::FieldDescriptor::CPPTYPE_INT64:

      return key.kind() == cel::Kind::kInt64;

    case google::protobuf::FieldDescriptor::CPPTYPE_UINT32:

      // fall through

    case google::protobuf::FieldDescriptor::CPPTYPE_UINT64:

      return key.kind() == cel::Kind::kUint64;

    case google::protobuf::FieldDescriptor::CPPTYPE_STRING:

      return key.kind() == cel::Kind::kString;

    default:

      return false;

  }

}

absl::StatusOr<absl::optional<google::protobuf::MapValueConstRef>> LookupMapValue(

    const google::protobuf::Message* message, const google::protobuf::Reflection* reflection,

    const google::protobuf::FieldDescriptor* field_desc,

    const google::protobuf::FieldDescriptor* key_desc,

    const cel::AttributeQualifier& key) {

  if (!MatchesMapKeyType(key_desc, key)) {

    return runtime_internal::CreateInvalidMapKeyTypeError(

        key_desc->cpp_type_name());

  }

  google::protobuf::MapKey proto_key;

  switch (key_desc->cpp_type()) {

    case google::protobuf::FieldDescriptor::CPPTYPE_BOOL:

      proto_key.SetBoolValue(*key.GetBoolKey());

      break;

    case google::protobuf::FieldDescriptor::CPPTYPE_INT32: {

      int64_t key_value = *key.GetInt64Key();

      if (key_value > std::numeric_limits<int32_t>::max() ||

          key_value < std::numeric_limits<int32_t>::lowest()) {

        return absl::OutOfRangeError("integer overflow");

      }

      proto_key.SetInt32Value(key_value);

    } break;

    case google::protobuf::FieldDescriptor::CPPTYPE_INT64:

      proto_key.SetInt64Value(*key.GetInt64Key());

      break;

    case google::protobuf::FieldDescriptor::CPPTYPE_STRING: {

      proto_key.SetStringValue(*key.GetStringKey());

    } break;

    case google::protobuf::FieldDescriptor::CPPTYPE_UINT32: {

      uint64_t key_value = *key.GetUint64Key();

      if (key_value > std::numeric_limits<uint32_t>::max()) {

        return absl::OutOfRangeError("unsigned integer overflow");

      }

      proto_key.SetUInt32Value(key_value);

    } break;

    case google::protobuf::FieldDescriptor::CPPTYPE_UINT64: {

      proto_key.SetUInt64Value(*key.GetUint64Key());

    } break;

    default:

      return runtime_internal::CreateInvalidMapKeyTypeError(

          key_desc->cpp_type_name());

  }

  // Look the value up

  google::protobuf::MapValueConstRef value_ref;

  bool found = cel::extensions::protobuf_internal::LookupMapValue(

      *reflection, *message, *field_desc, proto_key, &value_ref);

  if (!found) {

    return std::nullopt;

  }

  return value_ref;

}

bool FieldIsPresent(const google::protobuf::Message* message,

                    const google::protobuf::FieldDescriptor* field_desc,

                    const google::protobuf::Reflection* reflection) {

  if (field_desc->is_map()) {

    // When the map field appears in a has(msg.map_field) expression, the map

    // is considered 'present' when it is non-empty. Since maps are repeated

    // fields they don't participate with standard proto presence testing

    // since the repeated field is always at least empty.

    return reflection->FieldSize(*message, field_desc) != 0;

  }

  if (field_desc->is_repeated()) {

    // When the list field appears in a has(msg.list_field) expression, the

    // list is considered 'present' when it is non-empty.

    return reflection->FieldSize(*message, field_desc) != 0;

  }

  // Standard proto presence test for non-repeated fields.

  return reflection->HasField(*message, field_desc);

}

}  // namespace

absl::Status ProtoQualifyState::ApplySelectQualifier(

    const cel::SelectQualifier& qualifier, MemoryManagerRef memory_manager) {

  return absl::visit(

      absl::Overload(

          [&](const cel::AttributeQualifier& qualifier) -> absl::Status {

            if (repeated_field_desc_ == nullptr) {

              return absl::UnimplementedError(

                  "dynamic field access on message not supported");

            }

            return ApplyAttributeQualifer(qualifier, memory_manager);

          },

          [&](const cel::FieldSpecifier& field_specifier) -> absl::Status {

            if (repeated_field_desc_ != nullptr) {

              return absl::UnimplementedError(

                  "strong field access on container not supported");

            }

            return ApplyFieldSpecifier(field_specifier, memory_manager);

          }),

      qualifier);

}

absl::Status ProtoQualifyState::ApplyLastQualifierHas(

    const cel::SelectQualifier& qualifier, MemoryManagerRef memory_manager) {

  const cel::FieldSpecifier* specifier =

      absl::get_if<cel::FieldSpecifier>(&qualifier);

  return absl::visit(

      absl::Overload(

          [&](const cel::AttributeQualifier& qualifier) mutable

          -> absl::Status {

            if (qualifier.kind() != cel::Kind::kString ||

                repeated_field_desc_ == nullptr ||

                !repeated_field_desc_->is_map()) {

              SetResultFromError(

                  runtime_internal::CreateNoMatchingOverloadError("has"),

                  memory_manager);

              return absl::OkStatus();

            }

            return MapHas(qualifier, memory_manager);

          },

          [&](const cel::FieldSpecifier& field_specifier) mutable

          -> absl::Status {

            const auto* field_desc = GetNormalizedFieldByNumber(

                descriptor_, reflection_, specifier->number);

            if (field_desc == nullptr) {

              SetResultFromError(

                  runtime_internal::CreateNoSuchFieldError(specifier->name),

                  memory_manager);

              return absl::OkStatus();

            }

            SetResultFromBool(

                FieldIsPresent(message_, field_desc, reflection_));

            return absl::OkStatus();

          }),

      qualifier);

}

absl::Status ProtoQualifyState::ApplyLastQualifierGet(

    const cel::SelectQualifier& qualifier, MemoryManagerRef memory_manager) {

  return absl::visit(

      absl::Overload(

          [&](const cel::AttributeQualifier& attr_qualifier) mutable

          -> absl::Status {

            if (repeated_field_desc_ == nullptr) {

              return absl::UnimplementedError(

                  "dynamic field access on message not supported");

            }

            if (repeated_field_desc_->is_map()) {

              return ApplyLastQualifierGetMap(attr_qualifier, memory_manager);

            }

            return ApplyLastQualifierGetList(attr_qualifier, memory_manager);

          },

          [&](const cel::FieldSpecifier& specifier) mutable -> absl::Status {

            if (repeated_field_desc_ != nullptr) {

              return absl::UnimplementedError(

                  "strong field access on container not supported");

            }

            return ApplyLastQualifierMessageGet(specifier, memory_manager);

          }),

      qualifier);

}

absl::Status ProtoQualifyState::ApplyFieldSpecifier(

    const cel::FieldSpecifier& field_specifier,

    MemoryManagerRef memory_manager) {

  const google::protobuf::FieldDescriptor* field_desc = GetNormalizedFieldByNumber(

      descriptor_, reflection_, field_specifier.number);

  if (field_desc == nullptr) {

    SetResultFromError(

        runtime_internal::CreateNoSuchFieldError(field_specifier.name),

        memory_manager);

    return absl::OkStatus();

  }

  if (field_desc->is_repeated()) {

    repeated_field_desc_ = field_desc;

    return absl::OkStatus();

  }

  if (field_desc->cpp_type() != google::protobuf::FieldDescriptor::CPPTYPE_MESSAGE ||

      IsUnsupportedQualifyType(*field_desc->message_type())) {

    CEL_RETURN_IF_ERROR(SetResultFromField(message_, field_desc,

                                           ProtoWrapperTypeOptions::kUnsetNull,

                                           memory_manager));

    return absl::OkStatus();

  }

  message_ = &reflection_->GetMessage(*message_, field_desc);

  descriptor_ = message_->GetDescriptor();

  reflection_ = message_->GetReflection();

  return absl::OkStatus();

}

absl::StatusOr<int> ProtoQualifyState::CheckListIndex(

    const cel::AttributeQualifier& qualifier) const {

  if (qualifier.kind() != cel::Kind::kInt64) {

    return runtime_internal::CreateNoMatchingOverloadError(

        cel::builtin::kIndex);

  }

  int index = *qualifier.GetInt64Key();

  int size = reflection_->FieldSize(*message_, repeated_field_desc_);

  if (index < 0 || index >= size) {

    return absl::InvalidArgumentError(

        absl::StrCat("index out of bounds: index=", index, " size=", size));

  }

  return index;

}

absl::Status ProtoQualifyState::ApplyAttributeQualifierList(

    const cel::AttributeQualifier& qualifier, MemoryManagerRef memory_manager) {

  ABSL_DCHECK_NE(repeated_field_desc_, nullptr);

  ABSL_DCHECK(!repeated_field_desc_->is_map());

  ABSL_DCHECK_EQ(repeated_field_desc_->cpp_type(),

                 google::protobuf::FieldDescriptor::CPPTYPE_MESSAGE);

  auto index_or = CheckListIndex(qualifier);

  if (!index_or.ok()) {

    SetResultFromError(std::move(index_or).status(), memory_manager);

    return absl::OkStatus();

  }

  if (IsUnsupportedQualifyType(*repeated_field_desc_->message_type())) {

    CEL_RETURN_IF_ERROR(SetResultFromRepeatedField(

        message_, repeated_field_desc_, *index_or, memory_manager));

    return absl::OkStatus();

  }

  message_ = &reflection_->GetRepeatedMessage(*message_, repeated_field_desc_,

                                              *index_or);

  descriptor_ = message_->GetDescriptor();

  reflection_ = message_->GetReflection();

  repeated_field_desc_ = nullptr;

  return absl::OkStatus();

}

absl::StatusOr<google::protobuf::MapValueConstRef> ProtoQualifyState::CheckMapIndex(

    const cel::AttributeQualifier& qualifier) const {

  const auto* key_desc =

      repeated_field_desc_->message_type()->FindFieldByNumber(kKeyTag);

  CEL_ASSIGN_OR_RETURN(

      absl::optional<google::protobuf::MapValueConstRef> value_ref,

      LookupMapValue(message_, reflection_, repeated_field_desc_, key_desc,

                     qualifier));

  if (!value_ref.has_value()) {

    std::string key_string = qualifier.ToString();

    return runtime_internal::CreateNoSuchKeyError(key_string);

  }

  return std::move(value_ref).value();

}

absl::Status ProtoQualifyState::ApplyAttributeQualifierMap(

    const cel::AttributeQualifier& qualifier, MemoryManagerRef memory_manager) {

  ABSL_DCHECK_NE(repeated_field_desc_, nullptr);

  ABSL_DCHECK(repeated_field_desc_->is_map());

  ABSL_DCHECK_EQ(repeated_field_desc_->cpp_type(),

                 google::protobuf::FieldDescriptor::CPPTYPE_MESSAGE);

  absl::StatusOr<google::protobuf::MapValueConstRef> value_ref = CheckMapIndex(qualifier);

  if (!value_ref.ok()) {

    SetResultFromError(std::move(value_ref).status(), memory_manager);

    return absl::OkStatus();

  }

  const auto* value_desc =

      repeated_field_desc_->message_type()->FindFieldByNumber(kValueTag);

  if (value_desc->cpp_type() != google::protobuf::FieldDescriptor::CPPTYPE_MESSAGE ||

      IsUnsupportedQualifyType(*value_desc->message_type())) {

    CEL_RETURN_IF_ERROR(SetResultFromMapField(message_, value_desc, *value_ref,

                                              memory_manager));

    return absl::OkStatus();

  }

  message_ = &(value_ref->GetMessageValue());

  descriptor_ = message_->GetDescriptor();

  reflection_ = message_->GetReflection();

  repeated_field_desc_ = nullptr;

  return absl::OkStatus();

}

absl::Status ProtoQualifyState::ApplyAttributeQualifer(

    const cel::AttributeQualifier& qualifier, MemoryManagerRef memory_manager) {

  ABSL_DCHECK_NE(repeated_field_desc_, nullptr);

  if (repeated_field_desc_->cpp_type() !=

      google::protobuf::FieldDescriptor::CPPTYPE_MESSAGE) {

    return absl::InternalError("Unexpected qualify intermediate type");

  }

  if (repeated_field_desc_->is_map()) {

    return ApplyAttributeQualifierMap(qualifier, memory_manager);

  }  // else simple repeated

  return ApplyAttributeQualifierList(qualifier, memory_manager);

}

absl::Status ProtoQualifyState::MapHas(const cel::AttributeQualifier& key,

                                       MemoryManagerRef memory_manager) {

  const auto* key_desc =

      repeated_field_desc_->message_type()->FindFieldByNumber(kKeyTag);

  absl::StatusOr<absl::optional<google::protobuf::MapValueConstRef>> value_ref =

      LookupMapValue(message_, reflection_, repeated_field_desc_, key_desc,

                     key);

  if (!value_ref.ok()) {

    SetResultFromError(std::move(value_ref).status(), memory_manager);

    return absl::OkStatus();

  }

  SetResultFromBool(value_ref->has_value());

  return absl::OkStatus();

}

absl::Status ProtoQualifyState::ApplyLastQualifierMessageGet(

    const cel::FieldSpecifier& specifier, MemoryManagerRef memory_manager) {

  const auto* field_desc =

      GetNormalizedFieldByNumber(descriptor_, reflection_, specifier.number);

  if (field_desc == nullptr) {

    SetResultFromError(runtime_internal::CreateNoSuchFieldError(specifier.name),

                       memory_manager);

    return absl::OkStatus();

  }

  return SetResultFromField(message_, field_desc,

                            ProtoWrapperTypeOptions::kUnsetNull,

                            memory_manager);

}

absl::Status ProtoQualifyState::ApplyLastQualifierGetList(

    const cel::AttributeQualifier& qualifier, MemoryManagerRef memory_manager) {

  ABSL_DCHECK(!repeated_field_desc_->is_map());

  absl::StatusOr<int> index = CheckListIndex(qualifier);

  if (!index.ok()) {

    SetResultFromError(std::move(index).status(), memory_manager);

    return absl::OkStatus();

  }

  return SetResultFromRepeatedField(message_, repeated_field_desc_, *index,

                                    memory_manager);

}

absl::Status ProtoQualifyState::ApplyLastQualifierGetMap(

    const cel::AttributeQualifier& qualifier, MemoryManagerRef memory_manager) {

  ABSL_DCHECK(repeated_field_desc_->is_map());

  absl::StatusOr<google::protobuf::MapValueConstRef> value_ref = CheckMapIndex(qualifier);

  if (!value_ref.ok()) {

    SetResultFromError(std::move(value_ref).status(), memory_manager);

    return absl::OkStatus();

  }

  const auto* value_desc =

      repeated_field_desc_->message_type()->FindFieldByNumber(kValueTag);

  return SetResultFromMapField(message_, value_desc, *value_ref,

                               memory_manager);

}

}  // namespace cel::extensions::protobuf_internal