class Google::Cloud::Storage::Bucket::DefaultAcl

def self.predefined_rule_for rule_name
  RULES[rule_name.to_s]
end

def add_owner entity
  gapi = @service.insert_default_acl @bucket, entity, "OWNER",
                                     user_project: user_project
  entity = gapi.entity
  @owners&.push entity
  entity
end

def add_reader entity
  gapi = @service.insert_default_acl @bucket, entity, "READER",
                                     user_project: user_project
  entity = gapi.entity
  @readers&.push entity
  entity
end

def auth! if_metageneration_match: nil
  update_predefined_default_acl! "authenticatedRead", if_metageneration_match: if_metageneration_match
end

def clear!
  @owners  = nil
  @readers = nil
  self
end

def delete entity
  @service.delete_default_acl @bucket, entity,
                              user_project: user_project
  @owners&.delete entity
  @readers&.delete entity
  true
end

def entities_from_acls acls, role
  selected = acls.select { |acl| acl.role == role }
  selected.map(&:entity)
end

def initialize bucket
  @bucket = bucket.name
  @service = bucket.service
  @user_project = bucket.user_project
  @owners  = nil
  @readers = nil
end

def owner_full! if_metageneration_match: nil
  update_predefined_default_acl! "bucketOwnerFullControl", if_metageneration_match: if_metageneration_match
end

def owner_read! if_metageneration_match: nil
  update_predefined_default_acl! "bucketOwnerRead", if_metageneration_match: if_metageneration_match
end

def owners
  reload! if @owners.nil?
  @owners
end

def private! if_metageneration_match: nil
  update_predefined_default_acl! "private", if_metageneration_match: if_metageneration_match
end

def project_private! if_metageneration_match: nil
  update_predefined_default_acl! "projectPrivate", if_metageneration_match: if_metageneration_match
end

def public! if_metageneration_match: nil
  update_predefined_default_acl! "publicRead", if_metageneration_match: if_metageneration_match
end

def readers
  reload! if @readers.nil?
  @readers
end

def reload!
  gapi = @service.list_default_acls @bucket,
                                    user_project: user_project
  acls = Array(gapi.items).map do |acl|
    next acl if acl.is_a? Google::Apis::StorageV1::ObjectAccessControl
    raise "Unknown ACL format: #{acl.class}" unless acl.is_a? Hash
    Google::Apis::StorageV1::ObjectAccessControl.from_json acl.to_json
  end
  @owners  = entities_from_acls acls, "OWNER"
  @readers = entities_from_acls acls, "READER"
end

def update_predefined_default_acl! acl_role, if_metageneration_match: nil
  @service.patch_bucket @bucket, predefined_default_acl: acl_role,
                                 user_project: user_project,
                                 if_metageneration_match: if_metageneration_match
  clear!
end