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#include "upbc/names.h"

#include <string>

#include "absl/strings/match.h"
#include "google/protobuf/descriptor.h"

namespace upbc {

namespace protobuf = ::google::protobuf;

static constexpr absl::string_view kClearAccessor = "clear_";
static constexpr absl::string_view kSetAccessor = "set_";

// List of generated accessor prefixes to check against.
// Example:
//     optional repeated string phase = 236;
//     optional bool clear_phase = 237;
static constexpr absl::string_view kAccessorPrefixes[] = {
    kClearAccessor, "delete_", "add_", "resize_", kSetAccessor,
};

std::string ResolveFieldName(const protobuf::FieldDescriptor* field,
                             const NameToFieldDescriptorMap& field_names) {
  absl::string_view field_name = field->name();
  for (const auto prefix : kAccessorPrefixes) {
    // If field name starts with a prefix such as clear_ and the proto
    // contains a field name with trailing end, depending on type of field
    // (repeated, map, message) we have a conflict to resolve.
    if (absl::StartsWith(field_name, prefix)) {
      auto match = field_names.find(field_name.substr(prefix.size()));
      if (match != field_names.end()) {
        const auto* candidate = match->second;
        if (candidate->is_repeated() || candidate->is_map() ||
            (candidate->cpp_type() ==
                 protobuf::FieldDescriptor::CPPTYPE_STRING &&
             prefix == kClearAccessor) ||
            prefix == kSetAccessor) {
          return absl::StrCat(field_name, "_");
        }
      }
    }
  }
  return std::string(field_name);
}

// Returns field map by name to use for conflict checks.
NameToFieldDescriptorMap CreateFieldNameMap(
    const protobuf::Descriptor* message) {
  NameToFieldDescriptorMap field_names;
  for (int i = 0; i < message->field_count(); i++) {
    const protobuf::FieldDescriptor* field = message->field(i);
    field_names.emplace(field->name(), field);
  }
  return field_names;
}

}  // namespace upbc