class Audited::Audit

def self.as_user(user)
  last_audited_user = ::Audited.store[:audited_user]
  ::Audited.store[:audited_user] = user
  yield
ensure
  ::Audited.store[:audited_user] = last_audited_user
end

def self.assign_revision_attributes(record, attributes)
  attributes.each do |attr, val|
    record = record.dup if record.frozen?
    if record.respond_to?("#{attr}=")
      record.attributes.key?(attr.to_s) ?
        record[attr] = val :
        record.send("#{attr}=", val)
    end
  end
  record
end

def self.audited_classes
  audited_class_names.map(&:constantize)
end

def self.collection_cache_key(collection = all, *)
  super(collection, :created_at)
end

def self.reconstruct_attributes(audits)
  audits.each_with_object({}) do |audit, all|
    all.merge!(audit.new_attributes)
    all[:audit_version] = audit.version
  end
end

def ancestors
  self.class.ascending.auditable_finder(auditable_id, auditable_type).to_version(version)
end

def new_attributes
  (audited_changes || {}).each_with_object({}.with_indifferent_access) do |(attr, values), attrs|
    attrs[attr] = (action == "update" ? values.last : values)
  end
end

def old_attributes
  (audited_changes || {}).each_with_object({}.with_indifferent_access) do |(attr, values), attrs|
    attrs[attr] = (action == "update" ? values.first : values)
  end
end

def revision
  clazz = auditable_type.constantize
  (clazz.find_by_id(auditable_id) || clazz.new).tap do |m|
    self.class.assign_revision_attributes(m, self.class.reconstruct_attributes(ancestors).merge(audit_version: version))
  end
end

def set_audit_user
  self.user ||= ::Audited.store[:audited_user] # from .as_user
  self.user ||= ::Audited.store[:current_user].try!(:call) # from Sweeper
  nil # prevent stopping callback chains
end

def set_remote_address
  self.remote_address ||= ::Audited.store[:current_remote_address]
end

def set_request_uuid
  self.request_uuid ||= ::Audited.store[:current_request_uuid]
  self.request_uuid ||= SecureRandom.uuid
end

def set_version_number
  if action == "create"
    self.version = 1
  else
    collection = Rails::VERSION::MAJOR >= 6 ? self.class.unscoped : self.class
    max = collection.auditable_finder(auditable_id, auditable_type).maximum(:version) || 0
    self.version = max + 1
  end
end

def undo
  case action
  when "create"
    # destroys a newly created record
    auditable.destroy!
  when "destroy"
    # creates a new record with the destroyed record attributes
    auditable_type.constantize.create!(audited_changes)
  when "update"
    # changes back attributes
    auditable.update!(audited_changes.transform_values(&:first))
  else
    raise StandardError, "invalid action given #{action}"
  end
end

def user_as_string
  user_as_model || username
end

def user_as_string=(user)
  # reset both either way
  self.user_as_model = self.username = nil
  user.is_a?(::ActiveRecord::Base) ?
    self.user_as_model = user :
    self.username = user
end