module Eco::Data::Locations
  # Differences between node before and after
  # @note this works with `Hash` object where basic keys are:
  #   - `nodeId`
  #   - `name`
  #   - `parentId`
  #   - `archived`
  # @note other properties can be part of the `Hash` although
  #   they may not influence the results.
  # @note that for special `exposed` methods question mark `?` on a
  #   property of the model checks if that property changed
  #   (it has nothing to do with checking the boolean value of that property)
  class NodeDiff < Eco::Data::Hashes::DiffResult
    require_relative 'node_diff/accessors'
    require_relative 'node_diff/nodes_diff'

    include Eco::Data::Locations::NodeDiff::Accessors

    key     :nodeId
    # it also adds the snake_methods
    # i.e. `parent_id`, `parent_id_prev`, `parent_id?` (to check if updated)
    attr_expose :nodeId, :name, :parentId, :archived, :archivedToken, :classifications

    compare :parentId, :name, :archived
    compare :classifications #, when_present: true

    case_sensitive false

    # move method, to redefine it
    alias_method :name_src?, :name?
    # Has the property `name` changed?
    # @note should not be part of an insert
    def name?
      name_src? && update?
    end

    alias_method :classifications_src?, :classifications?
    # @note should not be part of an insert
    def classifications?
      classifications_src? && update?
    end

    alias_method :insert?,  :new?
    # node id diff? check should be performed as a `key`
    alias_method :id?,      :key?
    alias_method :nodeId?,  :id?
    alias_method :node_id?, :nodeId?

    # Has any of `id` or `name` properties changed?
    def id_name?
      return true if id?
      return true if name?

      classifications?
    end

    # Has the parent id changed?
    def move?
      return false unless update?

      parent_id?
    end

    def unarchive!
      @marked_for_unarchived = true
    end

    def marked_for_unarchive?
      @marked_for_unarchived || false
    end

    # Has the `archived` property changed and it was `true`?
    def unarchive?
      return true  if     marked_for_unarchive?
      return false if     archived
      return false unless update?

      archived?
    end

    # Has the `archived` property changed and it was `false`?
    def archive?(validate: true)
      return false if archived_prev

      msg  = "Value of archived shouldn't be true, "
      msg << "because node '#{node_id}' doesn't exist "
      msg << "(it's being inserted). "
      msg << "It should have been discarded as a diff"
      raise msg    if validate && archived && insert?

      return true  if del?

      archived
    end
  end
end