class AASM::Core::Event

def ==(event)
  if event.is_a? Symbol
    name == event
  else
    name == event.name
  end
end

def _fire(obj, options={}, to_state=::AASM::NO_VALUE, *args)
  result = options[:test_only] ? false : nil
  clear_failed_callbacks
  transitions = @transitions.select { |t| t.from == obj.aasm(state_machine.name).current_state || t.from == nil}
  return result if transitions.size == 0
  if to_state == ::AASM::NO_VALUE
    to_state = nil
  elsif !(to_state.respond_to?(:to_sym) && transitions.map(&:to).flatten.include?(to_state.to_sym))
    # to_state is an argument
    args.unshift(to_state)
    to_state = nil
  end
  
  # nop, to_state is a valid to-state
  transitions.each do |transition|
    next if to_state and !Array(transition.to).include?(to_state)
    if (options.key?(:may_fire) && transition.eql?(options[:may_fire])) ||
       (!options.key?(:may_fire) && transition.allowed?(obj, *args))
      if options[:test_only]
        result = transition
      else
        result = to_state || Array(transition.to).first
        Array(transition.to).each {|to| @valid_transitions[obj.object_id][to] = transition }
        transition.execute(obj, *args)
      end
      break
    end
  end
  result
end

def attach_event_guards(definitions)
  unless @guards.empty?
    given_guards = Array(definitions.delete(:guard) || definitions.delete(:guards) || definitions.delete(:if))
    definitions[:guards] = @guards + given_guards # from aasm4
  end
  unless @unless.empty?
    given_unless = Array(definitions.delete(:unless))
    definitions[:unless] = given_unless + @unless
  end
  definitions
end

def clear_failed_callbacks
  # https://github.com/aasm/aasm/issues/383, https://github.com/aasm/aasm/issues/599
  transitions.each { |transition| transition.failures.clear }
end

def failed_callbacks
  transitions.flat_map(&:failures)
end

def fire(obj, options={}, to_state=::AASM::NO_VALUE, *args)
  _fire(obj, options, to_state, *args) # false indicates this is not a test (fire!)
end

def fire_callbacks(callback_name, record, *args)
  # strip out the first element in args if it's a valid to_state
  # #given where we're coming from, this condition implies args not empty
  invoke_callbacks(@options[callback_name], record, args)
end

def fire_global_callbacks(callback_name, record, *args)
  invoke_callbacks(state_machine.global_callbacks[callback_name], record, args)
end

def fire_transition_callbacks(obj, *args)
  from_state = obj.aasm(state_machine.name).current_state
  transition = @valid_transitions[obj.object_id][from_state]
  transition.invoke_success_callbacks(obj, *args) if transition
  @valid_transitions.delete(obj.object_id)
end

def initialize(name, state_machine, options = {}, &block)
  @name = name
  @state_machine = state_machine
  @transitions = []
  @valid_transitions = Hash.new { |h, k| h[k] = {} }
  @guards = Array(options[:guard] || options[:guards] || options[:if])
  @unless = Array(options[:unless]) #TODO: This could use a better name
  @default_display_name = name.to_s.gsub(/_/, ' ').capitalize
  # from aasm4
  @options = options # QUESTION: .dup ?
  add_options_from_dsl(@options, [
    :after,
    :after_commit,
    :after_transaction,
    :before,
    :before_transaction,
    :ensure,
    :error,
    :before_success,
    :success,
  ], &block) if block
end

def initialize_copy(orig)
  super
  @transitions = @transitions.collect { |transition| transition.clone }
  @guards      = @guards.dup
  @unless      = @unless.dup
  @options     = {}
  orig.options.each_pair { |name, setting| @options[name] = setting.is_a?(Hash) || setting.is_a?(Array) ? setting.dup : setting }
end

def invoke_callbacks(code, record, args)
  Invoker.new(code, record, args)
         .with_default_return_value(false)
         .invoke
end

def may_fire?(obj, to_state=::AASM::NO_VALUE, *args)
  _fire(obj, {:test_only => true}, to_state, *args) # true indicates test firing
end

def to_s
  name.to_s
end

def transitions(definitions=nil, &block)
  if definitions # define new transitions
    # Create a separate transition for each from-state to the given state
    Array(definitions[:from]).each do |s|
      @transitions << AASM::Core::Transition.new(self, attach_event_guards(definitions.merge(:from => s.to_sym)), &block)
    end
    # Create a transition if :to is specified without :from (transitions from ANY state)
    if !definitions[:from] && definitions[:to]
      @transitions << AASM::Core::Transition.new(self, attach_event_guards(definitions), &block)
    end
  end
  @transitions
end

def transitions_from_state(state)
  @transitions.select { |t| t.from.nil? or t.from == state }
end

def transitions_from_state?(state)
  transitions_from_state(state).any?
end

def transitions_to_state(state)
  @transitions.select { |t| t.to == state }
end

def transitions_to_state?(state)
  transitions_to_state(state).any?
end