# frozen_string_literal: true

require 'prolog/dry_types'

require_relative './constants'

# Generate blog post/article fixture data, with embedded marker tag pairs.
module ArticleFixtureGen
  # Maintain configuration information for app.
  class Config
    # Builds hash with correct keys based on input. What's the value of this,
    # you ask? Two things:
    # 1. It defines `*_given` entries which are `true` if their corresponding
    #    entries are specified, whether those other entries are truthy or not;
    # 2. It confirms filtering of the input hash, offering a guarantee that any
    #    entry accepted is one supported elsehwere in our code.
    #
    # And yes, this class is *awfully* procedural. Got ideas for a fix? We'd
    # appreciate your PR!
    class Builder
      def self.call(options_hash)
        new.call options_hash
      end

      def call(options)
        @options = options
        hashes
      end

      private

      attr_reader :options

      def config_hash
        value = options[:config]
        given = Internals.string_given?(value)
        { config_given: given }.tap do |ret|
          ret[:config] = value || ''
        end
      end

      def generate_config_hash
        value = options[:generate_config]
        given = Internals.string_given?(value)
        { generate_config_given: given }.tap do |ret|
          ret[:generate_config] = value || ''
        end
      end

      def hashes
        items = hash_items
        {}.tap do |ret|
          items.each { |item| ret.merge! item }
        end
      end

      def hash_items
        items = [:config_hash, :generate_config_hash, :other_hash]
        items.map { |sym| send(sym) }
      end

      def other_hash
        ret = Internals.other_specified_values(options)
        ret.merge! Internals.defaults_not_in(ret)
      end

      # Stateless methods.
      module Internals
        def self.defaults_not_in(hash)
          keys = _other_keys_not_in(hash)
          _defaults_for(keys)
        end

        def self.other_specified_values(options)
          keys = _other_hash_keys
          options.select { |key, _| keys.include? key }
        end

        def self.string_given?(value)
          !value.to_s.empty?
        end

        def self._defaults_for(keys)
          Constants::DEFAULTS.select { |key| keys.include? key }
        end

        def self._other_hash_keys
          [:article_count, :para_count_max, :para_count_min, :sent_count_max,
           :sent_count_min, :pmtp_count, :pmtp_text, :smtp_count, :smtp_text]
        end

        def self._other_keys_not_in(hash)
          _other_hash_keys.reject { |key| hash.key? key }
        end
      end
      private_constant :Internals
    end # class ArticleFixtureGen::Config::Builder
  end # class ArticleFixtureGen::Config
end