# frozen_string_literal: true

module Cocina
  module Generator
    # Class for generating a vocab
    class Vocab
      CLASS_COMMENT = {
        'ObjectType' => 'This vocabulary defines the top level object type',
        'FileSetType' => 'This vocabulary defines the types of file sets'
      }.freeze

      def self.generate(schemas, output_dir:)
        new(schemas, output_dir: output_dir).generate
      end

      def initialize(schemas, output_dir:)
        @schemas = schemas
        @output_dir = output_dir
      end

      def generate
        names.each do |namespace, v|
          filepath = File.join(output_dir, "#{namespace.underscore}.rb")
          File.write(filepath, contents(namespace, v))
        end
      end

      def contents(namespace, methods)
        <<~RUBY
          # frozen_string_literal: true

          module Cocina
            module Models
              # #{CLASS_COMMENT.fetch(namespace)}
              class #{namespace}
          #{draw_ruby_methods(methods, 6)}
              end
            end
          end
        RUBY
      end

      private

      attr_reader :schemas, :output_dir

      BASE = 'https://cocina.sul.stanford.edu/models/'

      def vocabs
        type_properties = schemas.values.map { |schema| schema.properties['type'] }.compact
        type_properties.map(&:enum).flat_map(&:to_a)
                       .filter { |vocab| vocab.start_with?(BASE) }
                       .uniq
                       .sort
      end

      def names
        @names ||= vocabs.each_with_object({}) do |vocab, object|
          # Note special handling of 3d
          namespaced = vocab.delete_prefix(BASE)
                            .gsub('-', '_').gsub('3d', 'three_dimensional')
          namespace, name = namespaced.include?('/') ? namespaced.split('/') : ['ObjectType', namespaced]
          namespace = 'FileSetType' if namespace == 'resources'
          object[namespace] ||= {}
          object[namespace][name] = vocab
        end
      end

      def draw_ruby_methods(methods, indent)
        spaces = ' ' * indent
        methods.map do |name, vocab|
          "#{spaces}def self.#{name}\n#{spaces}  '#{vocab}'\n#{spaces}end"
        end.join("\n\n")
      end
    end
  end
end