class GovukSchemas::RandomContentGenerator

def string_for_regex(pattern)
  case pattern.to_s
  when "^(placeholder|placeholder_.+)$"
    ["placeholder", "placeholder_#{WORDS.sample(random: @random)}"].sample(random: @random)
  when "^[a-f0-9]{8}-[a-f0-9]{4}-[1-5][a-f0-9]{3}-[89ab][a-f0-9]{3}-[a-f0-9]{12}$"
    uuid
  when "^/(([a-zA-Z0-9._~!$&'()*+,;=:@-]|%[0-9a-fA-F]{2})+(/([a-zA-Z0-9._~!$&'()*+,;=:@-]|%[0-9a-fA-F]{2})*)*)?$"
    base_path
  when "^[1-9][0-9]{3}[-/](0[1-9]|1[0-2])[-/](0[1-9]|[12][0-9]|3[0-1])$"
    Date.today.iso8601
  when "^[1-9][0-9]{3}-(0[1-9]|1[0-2])-(0[1-9]|[12][0-9]|3[0-1])$"
    Date.today.iso8601
  when "^(0[0-9]|1[0-9]|2[0-3]):[0-5][0-9]$"
    Time.now.strftime("%H:%m")
  when "^[1-9][0-9]{3}$"
    rand(1000...9999).to_s
  when "^#.+$"
    anchor
  when "[a-z-]"
    random_identifier(separator: "-")
  when "^[a-z_]+$"
    random_identifier(separator: "_")
  when "^/(([a-zA-Z0-9._~!$&'()*+,;=:@-]|%[0-9a-fA-F]{2})+(/([a-zA-Z0-9._~!$&'()*+,;=:@-]|%[0-9a-fA-F]{2})*)*)?(\\?([a-zA-Z0-9._~!$&'()*+,;=:@-]|%[0-9a-fA-F]{2})*)?(#([a-zA-Z0-9._~!$&'()*+,;=:@-]|%[0-9a-fA-F]{2})*)?$"
    base_path
  when "^https://([a-zA-Z0-9]([a-zA-Z0-9-]{0,61}[A-Za-z0-9])?\\.)+campaign\\.gov\\.uk(/(([a-zA-Z0-9._~!$&'()*+,;=:@-]|%[0-9a-fA-F]{2})+(/([a-zA-Z0-9._~!$&'()*+,;=:@-]|%[0-9a-fA-F]{2})*)*)?(\\?([a-zA-Z0-9._~!$&'()*+,;=:@-]|%[0-9a-fA-F]{2})*)?(#([a-zA-Z0-9._~!$&'()*+,;=:@-]|%[0-9a-fA-F]{2})*)?)?$"
    govuk_subdomain_url
  when "^https://([a-zA-Z0-9]([a-zA-Z0-9-]{0,61}[A-Za-z0-9])?\\.)*gov\\.uk(/(([a-zA-Z0-9._~!$&'()*+,;=:@-]|%[0-9a-fA-F]{2})+(/([a-zA-Z0-9._~!$&'()*+,;=:@-]|%[0-9a-fA-F]{2})*)*)?(\\?([a-zA-Z0-9._~!$&'()*+,;=:@-]|%[0-9a-fA-F]{2})*)?(#([a-zA-Z0-9._~!$&'()*+,;=:@-]|%[0-9a-fA-F]{2})*)?)?$"
    govuk_subdomain_url
  when '[a-z0-9\-_]'
    "#{hex}-#{hex}"
  else
    raise <<~DOC
      Don't know how to generate random string for pattern #{pattern.inspect}
      This probably means you've introduced a new regex in to a content
      schema in Publishing API. Because it's very hard to generate a valid
      string from a regex alone, we have to specify a method to generate
      random data for each regex in the schemas.
      This can be fixed by adding your regex to `lib/govuk_schemas/random_content_generator.rb`
      in https://github.com/alphagov/govuk_schemas
    DOC
  end
end