ifelse_3.rb

# Before
module SearchService1
  # Metrics/AbcSize: Assignment Branch Condition size for perform is too high.
  # Metrics/CyclomaticComplexity: Cyclomatic complexity for perform is too high.
  # Metrics/MethodLength: Method has too many lines.
  # Metrics/PerceivedComplexity: Perceived complexity for perform is too high.
  def self.perform(params = {})
    scope = ::User.active

    if params['id'].present?
      scope = scope.where(id: params['id'])
    end

    %w[first_name last_name email city gender].each do |item|
      next unless params[item].present?
      scope = scope.where(item => params[item])
    end

    if params['height_after'].present?
      scope = scope.where(height: { '$gt' => params['height_after'] })
    end

    if params['height_before'].present?
      scope = scope.where(height: { '$lt' => params['height_before'] })
    end

    if params['weight_after'].present?
      scope = scope.where(weight: { '$gt' => params['weight_after'] })
    end

    if params['weight_before'].present?
      scope = scope.where(weight: { '$lt' => params['weight_before'] })
    end

    if params['gender'].present?
      scope = scope.where(gender: params['gender'])
    end

    scope
  end
end

# After
module SearchService2
  PARAMS_MAP = {
    'id' => ->(value) { { id: value } },
    'first_name' => ->(value) { { 'first_name' => value } },
    'last_name' => ->(value) { { 'last_name' => value } },
    'email' => ->(value) { { 'email' => value } },
    'city' => ->(value) { { 'city' => value } },
    'gender' => ->(value) { { gender: value } },
    'height_after' => ->(value) { { height: { '$gt' => value } } },
    'height_before' => ->(value) { { height: { '$lt' => value } } },
    'weight_after' => ->(value) { { weight: { '$gt' => value } } },
    'weight_before' => ->(value) { { weight: { '$lt' => value } } },
  }.freeze

  def self.perform(params = {})
    where_params = {}

    PARAMS_MAP.keys.each do |item|
      next unless params[item].present?
      where_params.merge!(PARAMS_MAP[item][params[item]])
    end

    ::User.active.where(where_params)
  end
end