# See the Pagy documentation: https://ddnexus.github.io/pagy/docs/extras/calendar
# frozen_string_literal: true

require 'pagy/calendar'
require 'pagy/calendar/helper'

class Pagy # :nodoc:
  # Add pagination filtering by calendar unit (:year, :quarter, :month, :week, :day) to the regular pagination
  module CalendarExtra
    # Additions for the Backend module
    module BackendAddOn
      CONF_KEYS = (Calendar::UNITS + %i[pagy active]).freeze

      private

      # Take a collection and a conf Hash with keys in CONF_KEYS and return an array with 3 items: [calendar, pagy, results]
      def pagy_calendar(collection, conf)
        raise ArgumentError, "keys must be in #{CONF_KEYS.inspect}" \
              unless conf.is_a?(Hash) && (conf.keys - CONF_KEYS).empty?

        conf[:pagy] ||= {}
        unless conf.key?(:active) && !conf[:active]
          calendar, from, to = Calendar::Helper.send(:init, conf, pagy_calendar_period(collection), params)
          collection         = pagy_calendar_filter(collection, from, to)
        end
        pagy, results = send(conf[:pagy][:backend] || :pagy, collection, conf[:pagy])  # use backend: :pagy when omitted
        [calendar, pagy, results]
      end

      # This method must be implemented by the application
      def pagy_calendar_period(*)
        raise NoMethodError, 'the pagy_calendar_period method must be implemented by the application ' \
                             '(see https://ddnexus.github.io/pagy/docs/extras/calendar/#pagy-calendar-period-collection)'
      end

      # This method must be implemented by the application
      def pagy_calendar_filter(*)
        raise NoMethodError, 'the pagy_calendar_filter method must be implemented by the application ' \
                             '(see https://ddnexus.github.io/pagy/docs/extras/calendar/#pagy-calendar-filter-collection-from-to)'
      end
    end

    # Additions for the Frontend module
    module UrlHelperAddOn
      # Return the url for the calendar page at time
      def pagy_calendar_url_at(calendar, time, **opts)
        pagy_url_for(calendar.send(:calendar_at, time, **opts), 1, **opts)
      end
    end
  end
  Backend.prepend CalendarExtra::BackendAddOn, CalendarExtra::UrlHelperAddOn
  Frontend.prepend CalendarExtra::UrlHelperAddOn
end