# Copyright (C) 2012-2023 Zammad Foundation, https://zammad-foundation.org/

class FormUpdater::Updater
  include Mixin::RequiredSubPaths

  # Context from GraphQL or possibly other environments.
  # It must respond to :current_user and :current_user? for session information (see Gql::Context::CurrentUserAware).
  # It may respond to :schema with an object providing :id_for_object to perform ID mappings like in Gql::ZammadSchema.
  attr_reader :context, :current_user, :relation_fields, :meta, :data, :id, :object, :result

  def initialize(context:, relation_fields:, meta:, data:, id: nil)
    @context         = context
    @meta            = meta
    @data            = data
    @id              = id
    @current_user    = context[:current_user]

    @result = {}

    # Build lookup for relation fields for better usage.
    @relation_fields = relation_fields.each_with_object({}) do |relation_field, lookup|
      lookup[relation_field[:name]] = relation_field.to_h
    end
  end

  def object_type
    raise NotImplementedError
  end

  def self.updaters
    descendants
  end

  def self.requires_authentication
    true
  end

  def authorized?
    # The authorized function needs to be implemented for any updaters which have a `id`.
    if id
      @object = Gql::ZammadSchema.authorized_object_from_id id, type: object_type, user: current_user
    end

    true
  end

  def resolve
    if self.class.included_modules.include?(FormUpdater::Concerns::ChecksCoreWorkflow)
      validate_workflows
    end

    if relation_fields.present?
      resolve_relation_fields
    end

    result
  end

  private

  def resolve_relation_fields
    relation_fields.each do |name, relation_field|
      relation_resolver = get_relation_resolver(relation_field)

      result_initialize_field(name)

      result[relation_field[:name]][:options] = relation_resolver.options
    end
  end

  RELATION_CLASS_PREFIX = 'FormUpdater::Relation::'.freeze

  def get_relation_resolver(relation_field)
    relation_class = "#{RELATION_CLASS_PREFIX}#{relation_field[:name].humanize}".safe_constantize
    if !relation_class
      relation_class = "#{RELATION_CLASS_PREFIX}#{relation_field[:relation]}".constantize
    end

    relation_class.new(
      context:      context,
      current_user: current_user,
      data:         data,
      filter_ids:   relation_field[:filter_ids],
    )
  rescue
    raise "Cannot resolve relation type #{relation_field[:relation]} (#{relation_field[:name]})."
  end

  def result_initialize_field(name)
    result[name] ||= {}
  end
end