package bridge

import (
	"fmt"
	"net"
	"strconv"
	"testing"

	"github.com/dotcloud/docker/engine"
)

func findFreePort(t *testing.T) int {
	l, err := net.Listen("tcp", ":0")
	if err != nil {
		t.Fatal("Failed to find a free port")
	}
	defer l.Close()

	result, err := net.ResolveTCPAddr("tcp", l.Addr().String())
	if err != nil {
		t.Fatal("Failed to resolve address to identify free port")
	}
	return result.Port
}

func newPortAllocationJob(eng *engine.Engine, port int) (job *engine.Job) {
	strPort := strconv.Itoa(port)

	job = eng.Job("allocate_port", "container_id")
	job.Setenv("HostIP", "127.0.0.1")
	job.Setenv("HostPort", strPort)
	job.Setenv("Proto", "tcp")
	job.Setenv("ContainerPort", strPort)
	return
}

func TestAllocatePortDetection(t *testing.T) {
	eng := engine.New()
	eng.Logging = false

	freePort := findFreePort(t)

	// Init driver
	job := eng.Job("initdriver")
	if res := InitDriver(job); res != engine.StatusOK {
		t.Fatal("Failed to initialize network driver")
	}

	// Allocate interface
	job = eng.Job("allocate_interface", "container_id")
	if res := Allocate(job); res != engine.StatusOK {
		t.Fatal("Failed to allocate network interface")
	}

	// Allocate same port twice, expect failure on second call
	job = newPortAllocationJob(eng, freePort)
	if res := AllocatePort(job); res != engine.StatusOK {
		t.Fatal("Failed to find a free port to allocate")
	}
	if res := AllocatePort(job); res == engine.StatusOK {
		t.Fatal("Duplicate port allocation granted by AllocatePort")
	}
}

func TestAllocatePortReclaim(t *testing.T) {
	eng := engine.New()
	eng.Logging = false

	freePort := findFreePort(t)

	// Init driver
	job := eng.Job("initdriver")
	if res := InitDriver(job); res != engine.StatusOK {
		t.Fatal("Failed to initialize network driver")
	}

	// Allocate interface
	job = eng.Job("allocate_interface", "container_id")
	if res := Allocate(job); res != engine.StatusOK {
		t.Fatal("Failed to allocate network interface")
	}

	// Occupy port
	listenAddr := fmt.Sprintf(":%d", freePort)
	tcpListenAddr, err := net.ResolveTCPAddr("tcp", listenAddr)
	if err != nil {
		t.Fatalf("Failed to resolve TCP address '%s'", listenAddr)
	}

	l, err := net.ListenTCP("tcp", tcpListenAddr)
	if err != nil {
		t.Fatalf("Fail to listen on port %d", freePort)
	}

	// Allocate port, expect failure
	job = newPortAllocationJob(eng, freePort)
	if res := AllocatePort(job); res == engine.StatusOK {
		t.Fatal("Successfully allocated currently used port")
	}

	// Reclaim port, retry allocation
	l.Close()
	if res := AllocatePort(job); res != engine.StatusOK {
		t.Fatal("Failed to allocate previously reclaimed port")
	}
}