# (c) Copyright 2020 Ribose Inc.
#

module Jekyll
  module Geolexica
    class Glossary < Hash
      include Configuration

      attr_reader :site

      alias each_concept each_value
      alias each_termid each_key

      def initialize(site)
        @site = site
      end

      def load_glossary
        Jekyll.logger.info('Geolexica:', 'Loading concepts')
        Dir.glob(concepts_glob).each { |path| load_concept(path) }
      end

      def store(concept)
        super(concept.data['termid'], concept)
      end

      def language_statistics
        @language_statistics ||= calculate_language_statistics
      end

      # Defines how Glossary is exposed in Liquid templates.
      def to_liquid
        {
          'language_statistics' => language_statistics
        }
      end

      protected

      def load_concept(concept_file_path)
        Jekyll.logger.debug('Geolexica:',
                            "reading concept from file #{concept_file_path}")

        concept_hash = if glossary_format == 'paneron'
                         read_paneron_concept_file(concept_file_path)
                       else
                         read_concept_file(concept_file_path)
                       end

        preprocess_concept_hash(concept_hash)
        store Concept.new(concept_hash)
      rescue StandardError
        Jekyll.logger.error('Geolexica:',
                            "failed to read concept from file #{concept_file_path}")
        raise
      end

      # Reads and parses concept file located at given path.
      def read_concept_file(path)
        YAML.safe_load(File.read(path), permitted_classes: [Time])
      end

      def read_paneron_concept_file(path)
        safe_load_options = { permitted_classes: [Date, Time] }
        concept = YAML.safe_load(File.read(path), **safe_load_options)
        concept['termid'] = concept['data']['identifier']

        concept['data']['localizedConcepts'].each do |lang, local_concept_id|
          localized_concept_path = File.join(localized_concepts_path, "#{local_concept_id}.yaml")
          concept[lang] = YAML.safe_load(File.read(localized_concept_path), **safe_load_options)['data']

          next unless concept[lang]

          concept['term'] = concept[lang]['terms'].first['designation'] if lang == 'eng'

          if concept[lang]['status'] && !concept[lang]['status'].empty? &&
             (concept[lang]['entry_status'].nil? || concept[lang]['entry_status'].empty?)
            concept['entry_status'] = concept[lang]['status']
          end
        end

        concept
      end

      # Does nothing, but some sites may replace this method.
      def preprocess_concept_hash(concept_hash); end

      def calculate_language_statistics
        unsorted = each_value.lazy
                             .flat_map { |concept| term_languages & concept.data.keys }
                             .group_by(&:itself)
                             .transform_values(&:count)

        # This is not crucial, but gives nicer output, and ensures that
        # all +term_languages+ are present.
        term_languages.to_h { |key| [key, unsorted[key] || 0] }
      end

      class Concept
        attr_reader :data

        # TODO: Maybe some kind of Struct instead of Hash.
        attr_reader :pages

        def initialize(data)
          @data = data
          @pages = LiquidCompatibleHash.new
        end

        def termid
          data['termid']
        end

        class LiquidCompatibleHash < Hash
          def to_liquid
            Jekyll::Utils.stringify_hash_keys(self)
          end
        end
      end
    end
  end
end