module ObfuscatesId

def decode_id(id)
  if id.is_a?(Array)
    id.map { |single_id| decode_single_id(single_id) }
  else
    decode_single_id(id)
  end
end

def decode_single_id(id)
  return id if id.to_i > 0
  hashids.decode(id).first
end

def encode_id(id)
  hashids.encode(id)
end

def find(*ids)
  super(*ids.map { |id| decode_id(id) })
end

def find_by_obfuscated_id(id)
  find_by(id: decode_id(id))
end

def has_many(*args, &block)
  options = args.extract_options!
  options[:extend] = Array(options[:extend]).push(ClassMethods)
  super(*args, **options, &block)
end

def hashids
  # ⚠️ Changing anything in this method will invalidate any URLs with obfuscated IDs that are in the wild.
  # You should not change any of these settings after going live unless you're OK breaking links in sent emails,
  # breaking bookmarks to pages within your application, etc. For this reason, we don't want the Hashids salt
  # configurable via an ENV value.
  # We don't include digits in our alphabet because it sometimes results in fully numeric strings being generated,
  # and we can't differentiate those from normal IDs that we still need to be able to deal with.
  @hashids ||= Hashids.new "Default ID Obfuscation Salt for #{name}", 6, "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ"
end

def obfuscated_id
  @obfuscated_id ||= self.class.encode_id(id)
end

def relation
  super.tap { |r| r.extend ClassMethods }
end

def to_param
  obfuscated_id
end