module ActioncableAutoParam

# File lib/actioncable_auto_param.rb, line 22
def self.prepended(cls)
  cls.class_attribute :auto_param_all_methods
  cls.class_attribute :auto_param_methods
end

# File lib/actioncable_auto_param.rb, line 28
def dispatch_action(action, data)
  method_name = action.to_sym
  if self.class.auto_param?(method_name)
    auto_param_dispatch(method_name, data)
  else
    super
  end
rescue
  puts $!, $!.backtrace
end

# File lib/actioncable_auto_param.rb, line 40
def auto_param_dispatch(method_name, data)
  args, kwargs, rest_index, has_kwrest = [], {}, nil, nil

  method(method_name).parameters.each.with_index do |(type, name), i|
    key_name = name.to_s
    exists = data.key?(key_name)
    value = exists ? data.delete(key_name) : nil

    case type
      when :req
        fail ArgumentError, "#{method_name}: required argument " +
                            "`#{name}' not present" unless exists
        args.push(value)

      when :opt
        args.push(value) if exists

      when :keyreq
        fail ArgumentError, "#{method_name}: required keyword argument " +
                            "`#{name}' not present" unless exists
        kwargs[name] = value

      when :key
        kwargs[name] = value if exists

      when :rest
        rest_index = i

      when :keyrest
        has_kwrest = true

      else
        fail ArgumentError, "#{method_name}: cannot dispatch argument `#{name}', " +
                            "(type: #{type}) from Hash"
    end
  end

  if has_kwrest
    kwargs.merge!(data.map { |k,v| [k.to_sym, v] }.to_h)
  elsif rest_index
    args[rest_index, 0] = data
  end

  if kwargs.empty?
    send(method_name, *args)
  else
    send(method_name, *args, **kwargs)
  end
end