class Rooibos::Transition

# File lib/rooibos/transition.rb, line 19
def self.from(update_return, previous_model)
  case update_return
  when nil
    new(model: previous_model, command: nil)
  when -> (r) { r.respond_to?(:rooibos_command?) && r.rooibos_command? }
    new(model: previous_model, command: update_return)
  when Array
    case update_return
    in [model, command] if command.nil? || (command.respond_to?(:rooibos_command?) && command.rooibos_command?)
      new(model:, command:)
    else
      warn_suspicious_callable(update_return)
      new(model: update_return, command: nil)
    end
  else
    new(model: update_return, command: nil)
  end
end

# File lib/rooibos/transition.rb, line 39
def self.initial(model)
  new(model:, command: nil)
end

# File lib/rooibos/transition.rb, line 74
  def to_a = [model, command]
  alias to_ary to_a
  alias deconstruct to_a

  # Warns if tuple looks like [model, command] but command isn't marked as such.
  private_class_method def self.warn_suspicious_callable(update_return) # :nodoc:
    return unless RatatuiRuby::Debug.enabled?

    _, suspect = update_return
    return unless suspect.respond_to?(:call)
    return if Ractor.shareable?(update_return)

    warn "WARNING: Update returned [model, #{suspect.class}] but #{suspect.class} " \
      "responds to #call without #rooibos_command?. Did you forget to include Command::Custom? " \
      "The tuple will be treated as the model, not as [model, command]. " \
      "To suppress this warning if the array is your model, use Ractor.make_shareable on it."
  end
end

# File lib/rooibos/transition.rb, line 58
def with_added_command(new_command)
  return self unless new_command
  return with_command(new_command) unless command

  with_command(Command.batch(command, new_command))
end

# File lib/rooibos/transition.rb, line 51
def with_command(new_command)
  return self unless new_command

  Transition.new(model:, command: new_command)
end

# File lib/rooibos/transition.rb, line 44
def with_model(new_model)
  return self unless new_model

  Transition.new(model: new_model, command:)
end

# File lib/rooibos/transition.rb, line 66
def with_separate_command(new_command)
  return self unless new_command
  return with_command(new_command) unless command

  with_command(Command.const_get(:Separate).new(commands: [command, new_command]))
end