require "ostruct"
require "erb"

module Pumi
  module Bot
    module Wikipedia
      class DistrictsInCambodiaArticle < Article
        PAGE_TITLE = "List_of_districts,_municipalities_and_sections_in_Cambodia".freeze

        INTRO_TEXT = "This is a list of [[Cambodia]]'s %<districts_count>s districts ({{lang|km|ស្រុក}} ''srok''), %<municipalities_count>s district-level municipalities ({{lang|km|ក្រុង}} ''krong'') and %<sections_count>s sections ({{lang|km|ខណ្ឌ}} ''khan'') organized by each [[Provinces of Cambodia|province]] and an [[Provinces of Cambodia|autonomous municipality]] ([[Phnom Penh]]).".freeze
        DISTRICTS_TEMPLATE = File.read("#{__dir__}/templates/district_list.wikitext.erb")

        Misspelling = Struct.new(:incorrect_text, :correct_text, keyword_init: true)

        MISSPELLINGS = [
          Misspelling.new(
            incorrect_text: "Phnom Penh (autonomous municipality)",
            correct_text: "Phnom Penh"
          )
        ].freeze

        def publish
          page = client.get_page(title: PAGE_TITLE)
          source = page.fetch(:source).dup

          replace_intro(source:, replacement: generate_intro)
          replace_number_of_districts(source:, replacement: District.all.size)

          Pumi::Province.all.each do |province|
            section = find_section_by_title(source:, title: province.name_en)
            new_section = generate_districts_section(province:)
            source.sub!(section[1], new_section)
          end

          client.update_page(title: PAGE_TITLE, source:, comment: "Update page")
        end

        private

        def generate_districts_section(province:)
          districts = Pumi::District.where(province_id: province.id)

          data = OpenStruct.new(
            province:,
            districts:,
            districts_summary: generate_districts_summary(districts:)
          )
          result = ERB.new(DISTRICTS_TEMPLATE, trim_mode: "-").result(data.instance_eval { binding })
          "\n\n#{result}\n"
        end

        def generate_districts_summary(districts:)
          village_administrative_unit = Pumi::Village.all.first.administrative_unit

          summary = districts_by_type(collection: districts).map do |au, d|
            next if Array(d).empty?

            text = "#{format_number(d.size)} #{au.name_en}"
            if d.size > 1
              au.name_en.end_with?("y") ? text.chomp!("y") << "ies" : text << "s"
            end
            text << " (#{au.name_km} #{au.name_latin})"
          end

          number_of_villages = 0
          districts.each do |district|
            number_of_villages += Pumi::Village.where(district_id: district.id).size
          end
          villages_text = "#{format_number(number_of_villages)} #{village_administrative_unit.name_en}"
          villages_text << "s" if number_of_villages > 1
          villages_text << " (#{village_administrative_unit.name_km} #{village_administrative_unit.name_latin})"

          summary << villages_text

          if summary.size <= 2
            summary.join(" and ")
          else
            [summary[0..-2].join(", "), summary[-1]].join(" and ")
          end
        end

        def find_section_by_title(source:, title:)
          misspelling = MISSPELLINGS.find { |m| m.correct_text == title }
          search_term = misspelling&.incorrect_text || title

          section = source.match(/==\s*\[\[[[:word:]\s]+\|#{Regexp.escape(search_term)}\]\].+?==(.+?(?===))/m)

          raise "Missing section for #{search_term}" if section.nil?

          section
        end

        def generate_intro
          all_districts = districts_by_type

          format(
            INTRO_TEXT,
            districts_count: fetch_districts_by_type("District", collection: all_districts).size,
            municipalities_count: fetch_districts_by_type(
              "Municipality",
              collection: all_districts
            ).size,
            sections_count: fetch_districts_by_type("Section", collection: all_districts).size
          )
        end

        def replace_number_of_districts(source:, replacement:)
          source.sub!(/current_number\s*=\s*\d+/, "current_number = #{replacement}")
        end

        def replace_intro(source:, replacement:)
          source.sub!(/This is a list of.+/, replacement)
        end

        def districts_by_type(collection: Pumi::District.all)
          collection.each_with_object({}) do |district, result|
            administrative_unit = district.administrative_unit
            result[administrative_unit] ||= []
            result[administrative_unit] << district
          end
        end

        def fetch_districts_by_type(type, collection:)
          administrative_unit = collection.keys.find { |au| au.name_en == type }
          Array(collection[administrative_unit])
        end

        def format_number(number)
          number.to_s.gsub(/(\d)(?=(\d\d\d)+(?!\d))/, "\\1,")
        end
      end
    end
  end
end