package engine

import (
	"bytes"
	"fmt"
	"github.com/dotcloud/docker/pkg/beam"
	"strings"
	"testing"
	"time"
)

func TestHelloWorld(t *testing.T) {
	testRemote(t,

		// Sender side
		func(eng *Engine) {
			job := eng.Job("echo", "hello", "world")
			out := &bytes.Buffer{}
			job.Stdout.Add(out)
			job.Run()
			if job.status != StatusOK {
				t.Fatalf("#%v", job.StatusCode())
			}
			if out.String() != "hello world\n" {
				t.Fatalf("%#v", out.String())
			}
		},

		// Receiver side
		func(eng *Engine) {
			eng.Register("echo", func(job *Job) Status {
				fmt.Fprintf(job.Stdout, "%s\n", strings.Join(job.Args, " "))
				return StatusOK
			})
		},
	)
}

func testRemote(t *testing.T, senderSide, receiverSide func(*Engine)) {
	sndConn, rcvConn, err := beam.USocketPair()
	if err != nil {
		t.Fatal(err)
	}
	defer sndConn.Close()
	defer rcvConn.Close()
	sender := NewSender(sndConn)
	receiver := NewReceiver(rcvConn)

	// Setup the sender side
	eng := New()
	sender.Install(eng)

	// Setup the receiver side
	receiverSide(receiver.Engine)
	go receiver.Run()

	timeout(t, func() {
		senderSide(eng)
	})
}

func timeout(t *testing.T, f func()) {
	onTimeout := time.After(100 * time.Millisecond)
	onDone := make(chan bool)
	go func() {
		f()
		close(onDone)
	}()
	select {
	case <-onTimeout:
		t.Fatalf("timeout")
	case <-onDone:
	}
}