insurance_plan_type_query.rb

class InsurancePlanTypeQuery
  MANUAL_PLAN_TYPES_JOIN = 'INNER JOIN accepted_plan_types '\
    'ON accepted_plan_types.accepted_insurer_id = accepted_insurers.id'.freeze

  def self.call(scope, search)
    new(scope).call(search)
  end

  def initialize(scope)
    @scope = scope
  end

  def call(search)
    if search.plan_type_id.present?
      contracted_accepted_plan_types(search)
    else
      scope
    end
  end

  private

  attr_reader :scope

  def contracted_accepted_plan_types(search)
    scope.
      joins(plan_types_join).
      where(accepted_plan_types: plan_type_conditions_from(search))
  end

  # The passed in scope may already have `joins(accepted_insurers: :insurance_payor)`
  # Attempting to then `joins(accepted_insurers: :accepted_plan_types)` duplicates the
  # `accepted_insurers` join. So, we detect if this join is already in place and if so
  # we use a manual SQL string to do just the additional join we need.
  def plan_types_join
    if joined_to_accepted_insurers?
      MANUAL_PLAN_TYPES_JOIN
    else
      { accepted_insurers: :accepted_plan_types }
    end
  end

  def joined_to_accepted_insurers?
    scope.joins_values.any? do |join|
      case join
      when Hash
        join.keys.include?(:accepted_insurers)
      else
        join == :accepted_insurers
      end
    end
  end

  def plan_type_conditions_from(search)
    {
      plan_type_id: search.plan_type_id,
      status: plan_statuses(search)
    }
  end

  def plan_statuses(search)
    if search.display_unknown_insurance_plans?
      [:contracted, :unknown]
    else
      [:contracted]
    end
  end
end