class VaccinationDescriptionStringParser

# File app/lib/vaccination_description_string_parser.rb, line 36
  def self.call(...) = new(...).call

  private_class_method :new

  private

  attr_reader :string

  KNOWN_PROGRAMMES = {
    "Flu" => "Flu",
    "HPV" => "HPV",
    "Human Papillomavirus" => "HPV",
    "MMR" => "MMR",
    "Measles/Mumps/Rubella" => "MMR",
    "MenACWY" => "MenACWY",
    "Meningococcal conjugate A,C, W135 + Y" => "MenACWY",
    "Td/IPV" => "Td/IPV"
  }.freeze
end

# File app/lib/vaccination_description_string_parser.rb, line 4
def initialize(string)
  @string = string
end

# File app/lib/vaccination_description_string_parser.rb, line 8
def call
  return nil if string.blank?

  known_programme = KNOWN_PROGRAMMES.keys.find { string.starts_with?(it) }

  programme_name = KNOWN_PROGRAMMES[known_programme]
  return nil if known_programme.present? && programme_name.nil?

  vaccine_name = (string.split(" ").first if known_programme.blank?)
  return nil if known_programme.blank? && vaccine_name.blank?

  dose_sequence_string =
    if vaccine_name.present?
      string[vaccine_name.length..]
    elsif known_programme.present?
      string[known_programme.length..]
    end

  dose_sequence =
    begin
      Integer(dose_sequence_string)
    rescue ArgumentError, TypeError
      dose_sequence_string&.strip&.presence
    end

  { programme_name:, vaccine_name:, dose_sequence: }.compact
end