AREL examples

measurement_year.rb

# frozen_string_literal: true
require('method_object')

# Handles the measurement year window, including scopes to allow querying of QDM
# models within specified date ranges relative to the measurement year.
MeasurementYear = Struct.new(:program) do
  def initialize(program:)
    super(program)
  end

  def scope(qdm_model)
    Scope.call(program: program, qdm_model: qdm_model)
  end

  def last_date_of_year
    Program
      .program_module(program)
      .current_measurement_year_start_datetime
      .end_of_year
      .to_date
  end

  def patient_age_in_range_at_year_end(min_age, max_age)
    Patient
      .age_in_range_on_date(
        date: last_date_of_year,
        min_age: min_age,
        max_age: max_age,
      )
  end

  def patient_age_in_year_range_at_year_end(min_age, max_age)
    patient_age_in_range_at_year_end(min_age.years, (max_age + 1).years)
  end

  Scope = MethodObject.new(:program, :qdm_model) do
    def call
      qdm_model
        .before_end_of_measurement_year(
          measurement_year_start_datetime:
            current_measurement_year_start_datetime,
        )
        .extending(Scopes).tap do |scope|
          scope.current_measurement_year_start_datetime =
            current_measurement_year_start_datetime
        end
    end

    def current_measurement_year_start_datetime
      Program.program_module(program).current_measurement_year_start_datetime
    end
  end

  # Contains only methods which need to know the measurement year start date
  module Scopes
    attr_writer(:current_measurement_year_start_datetime)

    def in_measurement_year
      in_previous_n_years(1)
    end

    def offset(years)
      @current_measurement_year_start_datetime -= years.years
      self
    end

    def in_previous_n_years(years)
      where(
        start_datetime
        .gteq(beginning_of_next_measurement_year - years.years)
        .and(
          start_datetime.lt(beginning_of_next_measurement_year),
        ),
      )
    end

    def in_previous_n_months(months)
      where(
        start_datetime
        .gteq(beginning_of_next_measurement_year - months.months)
        .and(
          start_datetime.lt(beginning_of_next_measurement_year),
        ),
      )
    end

    def before_6_months_of_end_of_measurement_year
      where(
        start_datetime.lt(beginning_of_next_measurement_year - 6.months),
      )
    end

    private

    def start_datetime
      arel_table[:start_datetime]
    end

    def beginning_of_next_measurement_year
      @current_measurement_year_start_datetime.next_year
    end
  end
end