class GovukSchemas::RandomContentGenerator

def anchor
  "##{hex}"
end

def base_path
  "/#{@random.rand(1..5).times.map { uuid }.join('/')}"
end

def bool
  @random.rand(2) == 1
end

def content_block_order_item
  [
    %w[addresses contact_links email_addresses telephones].sample,
    ".",
    random_identifier,
  ].join
end

def domain_name(domain_suffix: nil)
  [
    WORDS.sample(random: @random).downcase,
    domain_suffix || DOMAIN_SUFFIXES.sample(random: @random),
  ].join(".")
end

def govuk_subdomain_url
  uri(domain_suffix: "gov.uk", include_anchor: false)
end

def hex(length = 10)
  length.times.map { bool ? random_letter : random_number }.join("")
end

def initialize(random: Random.new)
  @random = random
end

def random_identifier(separator: "-")
  WORDS.sample(@random.rand(1..10), random: @random)
    .join(separator)
    .gsub(/[^a-z0-9\-_]+/i, separator)
    .downcase
end

def random_letter
  letters = ("a".."f").to_a
  letters[@random.rand(0..letters.count - 1)]
end

def random_number
  numbers = ("0".."9").to_a
  numbers[@random.rand(0..numbers.count - 1)]
end

def string(minimum_chars = nil, maximum_chars = nil)
  minimum_chars ||= 0
  maximum_chars ||= 100
  WORDS.sample(@random.rand(minimum_chars..maximum_chars), random: @random).join(" ")
end

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}"
  when "^addresses|contact_links|email_addresses|telephones.[a-z0-9]+(?:-[a-z0-9]+)*$"
    content_block_order_item
  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

def string_for_type(type)
  case type
  when "date-time"
    time
  when "uri"
    uri
  when "email"
    [username, domain_name].join("@")
  else
    raise <<~DOC
       Unsupported JSON schema type `#{type}`
       Supported formats are:
         - date-time
         - uri
         - email
       This can be fixed by adding a type to the `string_for_type` method in
      `lib/govuk_schemas/random_content_generator.rb` in https://github.com/alphagov/govuk_schemas
    DOC
  end
end

def time
  arbitrary_time = Time.new(2012, 2, 1)
  (arbitrary_time + @random.rand(0..500_000_000)).iso8601
end

def uri(domain_suffix: nil, include_anchor: true)
  "https://#{domain_name(domain_suffix:)}#{base_path}#{include_anchor ? anchor : nil}"
end

def username
  WORDS.sample(random: @random).downcase
end

def uuid
  # matches uuid regex e.g. e058aad7-ce86-5181-8801-4ddcb3c8f27c
  # /^[a-f0-9]{8}-[a-f0-9]{4}-[1-5][a-f0-9]{3}-[89ab][a-f0-9]{3}-[a-f0-9]{12}$/
  "#{hex(8)}-#{hex(4)}-1#{hex(3)}-a#{hex(3)}-#{hex(12)}"
end