module SSHKit

  class Coordinator

    attr_accessor :hosts

    def initialize(raw_hosts)
      @raw_hosts = Array(raw_hosts)
      @hosts = @raw_hosts.any? ? resolve_hosts : []
    end

    def each(options={}, &block)
      if hosts
        options = default_options.merge(options)
        case options[:in]
        when :parallel then Runner::Parallel
        when :sequence then Runner::Sequential
        when :groups   then Runner::Group
        else
          raise RuntimeError, "Don't know how to handle run style #{options[:in].inspect}"
        end.new(hosts, options, &block).execute
      else
        Runner::Null.new(hosts, options, &block).execute
      end
    end

    private

      def default_options
        { in: :parallel }
      end

      def resolve_hosts
        @raw_hosts.collect { |rh| rh.is_a?(Host) ? rh : Host.new(rh) }.uniq
      end

  end

end
