class GraphQL::Analysis::AST::FieldUsage

def extract_deprecated_arguments(argument_values)
  argument_values.each_pair do |_argument_name, argument|
    if argument.definition.deprecation_reason
      @used_deprecated_arguments << argument.definition.path
    end
    if argument.definition.type.kind.input_object?
      extract_deprecated_arguments(argument.value.arguments.argument_values)
    elsif argument.definition.type.list?
      argument
        .value
        .select { |value| value.respond_to?(:arguments) }
        .each { |value| extract_deprecated_arguments(value.arguments.argument_values) }
    end
  end
end

def initialize(query)
  super
  @used_fields = Set.new
  @used_deprecated_fields = Set.new
  @used_deprecated_arguments = Set.new
end

def on_leave_field(node, parent, visitor)
  field_defn = visitor.field_definition
  field = "#{visitor.parent_type_definition.graphql_name}.#{field_defn.graphql_name}"
  @used_fields << field
  @used_deprecated_fields << field if field_defn.deprecation_reason
  extract_deprecated_arguments(visitor.query.arguments_for(node, visitor.field_definition).argument_values)
end

def result
  {
    used_fields: @used_fields.to_a,
    used_deprecated_fields: @used_deprecated_fields.to_a,
    used_deprecated_arguments: @used_deprecated_arguments.to_a,
  }
end