require 'securerandom'

module DraftjsHtml
  module Draftjs
    class RawBuilder
      def self.build(&block)
        instance = new
        instance.instance_eval(&block)
        instance.to_h
      end

      def initialize
        @blocks = []
        @entity_map = {}
      end

      def text_block(text, depth: 0)
        typed_block('unstyled', text, depth: depth)
      end

      def typed_block(type, text, depth: 0)
        @blocks << { 'key' => SecureRandom.urlsafe_base64(10), 'text' => text, 'type' => type, 'depth' => depth }
      end

      def inline_style(style_name, range)
        (@blocks.last['inlineStyleRanges'] ||= []) << { 'style' => style_name, 'offset' => range.begin, 'length' => range.size }
      end

      def entity_range(key, range)
        (@blocks.last['entityRanges'] ||= []) << { 'key' => key, 'offset' => range.begin, 'length' => range.size }
      end

      def apply_entity(type, range, data: {}, mutability: 'IMMUTABLE', key: SecureRandom.uuid)
        @entity_map[key] = {
          'type' => type,
          'mutability' => mutability,
          'data' => deep_stringify_keys(data),
        }

        entity_range(key, range)
      end

      def has_blocks?
        @blocks.any?
      end

      def to_h
        {
          'blocks' => @blocks,
          'entityMap' => @entity_map,
        }
      end

      def to_s
        draftjs = DraftjsHtml::Draftjs.parse(to_h)
        draftjs.blocks.reduce('') do |acc, block|
          acc << "typed_block '#{block.type}', '#{block.text}', depth: #{block.depth}\n"
          block.inline_styles.each do |style|
            acc << "inline_style '#{style.name}', #{style.range.begin}..#{style.range.end} # (#{style.offset} + #{style.length})\n"
          end
          block.entity_ranges.each do |entity_range|
            entity = draftjs.entity_map[entity_range.name]
            acc << "apply_entity '#{entity.type}', #{entity_range.range.begin}..#{entity_range.range.end}\n"
          end
          acc
        end
      end

      private

      def deep_stringify_keys(object)
        case object
        when Hash
          object.each_with_object({}) do |(key, value), result|
            result[key.to_s] = deep_stringify_keys(value)
          end
        when Array then object.map { |e| deep_stringify_keys(e) }
        else
          object
        end
      end
    end
  end
end