module Vedeu

  # Custom exceptions/errors which Vedeu will raise in certain
  # circumstances.
  #
  # @api private
  #
  module Error

    # Raised with Vedeu attempts to access a client application
    # controller's action that does not exist.
    #
    class ActionNotFound < StandardError

    end # ActionNotFound

    # Raised with Vedeu attempts to access a client application
    # controller that does not exist.
    #
    class ControllerNotFound < StandardError

    end # ControllerNotFound

    # Raised when Vedeu encounters an error it cannot recover from.
    # This would happen if there was not interfaces, or specifically
    # if there were no entries in {Vedeu::Models::Focus}, since the
    # fallback for most of the system when a name is not given or
    # cannot be found is to use the name of the currently focussed
    # interface.
    #
    class Fatal < StandardError

    end # Fatal

    # Raised when Vedeu wishes to exit.
    #
    # @see Vedeu::Runtime::MainLoop
    #
    class Interrupt < StandardError

    end # Interrupt

    # Raised when Vedeu attempts to parse a view or interface and
    # encounters a problem.
    #
    class InvalidSyntax < StandardError

    end # InvalidSyntax

    # Raised when value required by Vedeu to proceed is not given.
    # For example, when a name is not provided for a model when
    # attempting to store it in a repository.
    #
    class MissingRequired < StandardError

    end # MissingRequired

    # Raised with Vedeu attempts to access a named model that does not
    # exist.
    #
    class ModelNotFound < StandardError

    end # ModelNotFound

    # Raised intentionally when the client application wishes to
    # switch between cooked, fake and raw terminal modes.
    #
    # @see Vedeu::Runtime::Application
    #
    class ModeSwitch < StandardError

    end # ModeSwitch

    # Raised to remind me (or client application developers) that the
    # subclass implements the functionality sought.
    #
    # @see Vedeu::Colours::Translator
    #
    class NotImplemented < StandardError

    end # NotImplemented

    # Raised when trying to access an interface column less than 1 or
    # greater than 12. Vedeu is hard-wired to a 12-column layout for
    # the time being.
    #
    # @see Vedeu::Geometry::Grid
    #
    class OutOfRange < StandardError

      # Returns an error message.
      #
      # @return [String]
      def message
        'Valid value is between 1 and 12 inclusive.'.freeze
      end

    end # OutOfRange

    # Raised when a method expecting a block to be given was not given
    # the block.
    #
    class RequiresBlock < StandardError

      # Returns an error message.
      #
      # @return [String]
      def message
        'The required block was not given.'.freeze
      end

    end

  end # Error

end # Vedeu