module Eco
  module API
    class UseCases
      class UseCase < BaseCase
        @types = BaseCase.types

        attr_reader :name, :type, :times_launched
        attr_reader :options

        def initialize(name, type:, root:, &block)
          raise InvalidType.new("Invalid type for '#{name}'.", type: type, types: self.class.types) unless self.class.valid_type?(type)

          self.root = root
          @callback = block
          @name     = name
          @type     = type
          @times_launched = 0
        end

        def chainer
          # TODO: root is a Eco::API::UseCases that will not point to this new case.
          # => Moreover, the name and type will be the same as self
          Eco::API::UseCases::UseCaseChain.new(usecase: self, root: @root)
        end

        def root=(value)
          raise "Root should be a Eco::API::UseCases. Given: #{value.class}" if !value.is_a?(Eco::API::UseCases)
          @root = value
        end

        # Actual launch of the usecase
        # @param io [Eco::API::UseCases::BaseIO] an input/output helper with the necessary parameters.
        # @param kargs [Hash] hash with symbol keys.
        # @option kargs [Eco::API::Common::People::Entries, Eco::API::Organization::People] :input the input data of reference.
        # @option kargs [Eco::API::Organization::People] :people object.
        # @option kargs [Eco::API:Session] :session
        # @option kargs [Hash] :options hash with symbol keys (i.e. behaviour modifiers, cli trackers, filters, etc.)
        def launch(io: nil, **kargs)
          params = io&.params(keyed: true, all: true) || {}
          kargs  = params.merge(kargs).merge(usecase: self)

          UseCaseIO.new(**kargs).tap do |uio|
            @options   = uio.options
            uio.session.logger.debug("#{self.class}: going to process '#{name}'")
            uio.output = @callback.call(*uio.params)
            @times_launched += 1
          end
        end

        protected

        def callback
          @callback
        end

      end

    end
  end
end