module Hashid::Rails::ClassMethods

def decode_id(ids, fallback: false)
  if ids.is_a?(Array)
    ids.map { |id| hashid_decode(id, fallback: fallback) }
  else
    hashid_decode(ids, fallback: fallback)
  end
end

def encode_id(ids)
  if ids.is_a?(Array)
    ids.map { |id| hashid_encode(id) }
  else
    hashid_encode(ids)
  end
end

def find(*ids)
  expects_array = ids.first.is_a?(Array)
  uniq_ids = ids.flatten.compact.uniq
  uniq_ids = uniq_ids.first unless expects_array || uniq_ids.size > 1
  if hashid_configuration.override_find
    super(decode_id(uniq_ids, fallback: true))
  else
    super
  end
end

def find_by_hashid(hashid)
  find_by(id: decode_id(hashid, fallback: false))
end

def find_by_hashid!(hashid)
  find_by!(id: decode_id(hashid, fallback: false))
end

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

def hashid_config(options = {})
  config = Hashid::Rails.configuration.dup
  config.pepper = table_name
  options.each do |attr, value|
    config.public_send("#{attr}=", value)
  end
  @hashid_configuration = config
end

def hashid_configuration
  @hashid_configuration || hashid_config
end

def hashid_decode(id, fallback:)
  fallback_value = fallback ? id : nil
  decoded_hashid = hashids.decode(id.to_s)
  if hashid_configuration.sign_hashids
    valid_hashid?(decoded_hashid) ? decoded_hashid.last : fallback_value
  else
    decoded_hashid.first || fallback_value
  end
rescue Hashids::InputError
  fallback_value
end

def hashid_encode(id)
  return nil if id.nil?
  if hashid_configuration.sign_hashids
    hashids.encode(HASHID_TOKEN, id)
  else
    hashids.encode(id)
  end
end

def hashids
  Hashids.new(*hashid_configuration.to_args)
end

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

def reset_hashid_config
  @hashid_configuration = nil
end

def valid_hashid?(decoded_hashid)
  decoded_hashid.size == 2 && decoded_hashid.first == HASHID_TOKEN
end