# frozen_string_literal: true

module Jekyll
  module Filters
    module DateLocal
      # Translates month and day names.  This requires certain values on
      # your _data/LANG.yml
      #
      # Example usage:
      #
      # {{ page.date | date_local: '%e de %B de %Y' }}
      #
      # @see {_data/es.yml}
      # @param [String|Date|Time|DateTime]
      # @param [String]
      # @return [String]
      def date_local(input, format)
        require 'date'

        input = ::Jekyll::Utils.parse_date(input) unless input.respond_to? :mon

        # Return early if we don't need to translate
        return input.strftime(format) unless /%(|\^)[aAbBpP]/ =~ format

        input.strftime translate_localization_format(input, format)
      rescue ArgumentError, TypeError, ::Jekyll::Errors::InvalidDateError => e
        Jekyll.logger.warn "#{input} is not a valid date: #{e.message}"
        input
      end

      private

      # Adapted from the i18n gem
      # @see {https://github.com/ruby-i18n/i18n/blob/a8f4fdcb197e56b5a698d1bc68007dd0871c03bf/lib/i18n/backend/base.rb}
      def translate_localization_format(object, format)
        format.to_s.gsub(/%(|\^)[aAbBpP]/) do |match|
          case match
          when '%a'  then i18n.dig('date', 'abbr_day_names', object.wday - 1)
          when '%^a' then i18n.dig('date', 'abbr_day_names', object.wday - 1)&.upcase
          when '%A'  then i18n.dig('date', 'day_names', object.wday - 1)
          when '%^A' then i18n.dig('date', 'day_names', object.wday - 1)&.upcase
          when '%b'  then i18n.dig('date', 'abbr_month_names', object.mon - 1)
          when '%^b' then i18n.dig('date', 'abbr_month_names', object.mon - 1)&.upcase
          when '%B'  then i18n.dig('date', 'month_names', object.mon - 1)
          when '%^B' then i18n.dig('date', 'month_names', object.mon - 1)&.upcase
          when '%p'  then i18n.dig('time', object.hour < 12 ? 'am' : 'pm')&.upcase if object.respond_to? :hour
          when '%P'  then i18n.dig('time', object.hour < 12 ? 'am' : 'pm')&.downcase if object.respond_to? :hour
          end
        end
      end

      def site
        @site ||= @context.registers[:site]
      end

      def i18n
        @i18n ||= site.data.dig site.config['lang']
      end
    end
  end
end

Liquid::Template.register_filter(Jekyll::Filters::DateLocal)