whippy-edition/app/lib/admin/metrics/measure/new_users_measure.rb

# frozen_string_literal: true

class Admin::Metrics::Measure::NewUsersMeasure < Admin::Metrics::Measure::BaseMeasure
  include Admin::Metrics::Measure::QueryHelper

  def key
    'new_users'
  end

  protected

  def perform_total_query
    User.where(created_at: time_period).count
  end

  def perform_previous_total_query
    User.where(created_at: previous_time_period).count
  end

  def sql_array
    [sql_query_string, { start_at: @start_at, end_at: @end_at }]
  end

  def sql_query_string
    <<~SQL.squish
      SELECT axis.*, (
        WITH new_users AS (
          SELECT users.id
          FROM users
          WHERE date_trunc('day', users.created_at)::date = axis.period
        )
        SELECT count(*) FROM new_users
      ) AS value
      FROM (
        SELECT generate_series(date_trunc('day', :start_at::timestamp)::date, date_trunc('day', :end_at::timestamp)::date, interval '1 day') AS period
      ) AS axis
    SQL
  end
end