// pushMetric adds the metric to the end of the list and returns a comma separated string of the
// previous 61 entries.  We return 61 instead of 60 (an hour) because the chart on the client
// tracks deltas between these values - there is nothing to compare the first value against.
func pushMetric(history *list.List, ev expvar.Var) string {
	history.PushBack(ev.String())
	if history.Len() > 61 {
		history.Remove(history.Front())
	}
	return JoinStringList(history)
}

func SetRate(m Map, key string, value expvar.Var, timeframe, unit time.Duration) {
	if value != nil {
		v, _ := strconv.ParseInt(value.String(), 10, 64)
		m.Set(key, newRate(v, timeframe, unit))
	} else {
		m.Set(key, zeroValue)
	}
}

func SetAverage(m Map, key string, totalVar, casesVar expvar.Var, scale int64, defaultValue string) {
	if totalVar != nil && casesVar != nil {
		total, _ := strconv.ParseInt(totalVar.String(), 10, 64)
		cases, _ := strconv.ParseInt(casesVar.String(), 10, 64)
		m.Set(key, newAverage(total, cases, scale, defaultValue))
	} else {
		m.Set(key, zeroValue)
	}
}

// statToValue converts from a stats.Stat type to a JSON representable value.
// This is preferred to just calling the String() for things like numbers, so that
// InfluxDB can also represent the metrics as numbers.
// TODO(aaijazi): this needs to be extended to support better serialization of other types..
// It's probably good to do this after InfluxDB 0.9 is released, as it has has better support
// for arbitrary dict values (as tags).
func statToValue(v expvar.Var) interface{} {
	switch v := v.(type) {
	case *stats.Float:
		return v.Get()
	case *stats.Int:
		return v.Get()
	case stats.FloatFunc:
		return v()
	case stats.IntFunc:
		return v()
	default:
		return v.String()
	}
}

// Requires Internet access and can be flaky if the server or the internet is
// slow.
func TestDHTLarge(t *testing.T) {
	if testing.Short() {
		t.Skip("TestDHTLarge requires internet access and can be flaky. Skipping in short mode.")
	}
	defer stats(t)
	c := NewConfig()
	c.SaveRoutingTable = false
	node, err := New(c)
	if err != nil {
		t.Fatalf("dht New: %v", err)
	}
	if err = node.Start(); err != nil {
		t.Fatalf("node.Run: %v", err)
	}
	realDHTNodes := []string{
		"1.a.magnets.im",
		"router.utorrent.com",
	}
	for _, addr := range realDHTNodes {
		ip, err := net.LookupHost(addr)
		if err != nil {
			t.Error(err)
			continue
		}
		node.AddNode(ip[0] + ":6881")
	}

	// Test that we can reach at least one node.
	success := false
	var (
		reachable int
		v         expvar.Var
	)
	for i := 0; i < 10; i++ {
		v = expvar.Get("totalNodesReached")
		reachable, err = strconv.Atoi(v.String())
		if err != nil {
			t.Errorf("totalNodesReached conversion to int failed: %v", err)
			continue
		}
		if reachable > 0 {
			t.Logf("Contacted %d DHT nodes.", reachable)
			success = true
			break
		}
		time.Sleep(time.Second)
	}
	if !success {
		t.Fatal("No external DHT node could be contacted.")
	}

	// Test that we can find peers for a known torrent in a timely fashion.
	//
	// Torrent from: http://www.clearbits.net/torrents/244-time-management-for-anarchists-1
	infoHash := InfoHash("\xb4\x62\xc0\xa8\xbc\xef\x1c\xe5\xbb\x56\xb9\xfd\xb8\xcf\x37\xff\xd0\x2f\x5f\x59")
	go node.PeersRequest(string(infoHash), true)
	var infoHashPeers map[InfoHash][]string
	select {
	case infoHashPeers = <-node.PeersRequestResults:
		t.Logf("Found %d peers.", len(infoHashPeers[infoHash]))
	case <-time.Tick(10 * time.Second):
		t.Fatal("Could not find new peers: timed out")
	}
	for ih, peers := range infoHashPeers {
		if infoHash != ih {
			t.Fatal("Unexpected infohash returned")
		}
		if len(peers) == 0 {
			t.Fatal("Could not find new torrent peers.")
		}
		for _, peer := range peers {
			t.Logf("peer found: %v", nettools.BinaryToDottedPort(peer))
		}
	}
}

// Requires Internet access and can be flaky if the server or the internet is
// slow.
func TestDHTLarge(t *testing.T) {
	if testing.Short() {
		t.Skip("TestDHTLarge requires internet access and can be flaky. Skipping in short mode.")
	}
	defer stats(t)
	c := NewConfig()
	c.Port = 6060 // ...
	//c.SaveRoutingTable = false
	node, err := New(c)
	if err != nil {
		t.Fatalf("dht New: %v", err)
	}
	go node.Run()
	realDHTNodes := []string{
		"1.a.magnets.im",
		"router.utorrent.com",
	}
	for _, addr := range realDHTNodes {
		ip, err := net.LookupHost(addr)
		if err != nil {
			t.Error(err)
			continue
		}
		node.AddNode(ip[0]+":6881", "")
	}

	node.AddNode("117.78.1.52:6891", "")
	node.AddNode("88.183.138.12:52804", "")

	// Test that we can reach at least one node.
	success := false
	var (
		reachable int
		v         expvar.Var
	)
	for i := 0; i < 10; i++ {
		v = expvar.Get("totalNodesReached")
		reachable, err = strconv.Atoi(v.String())
		if err != nil {
			t.Errorf("totalNodesReached conversion to int failed: %v", err)
			continue
		}
		if reachable > 0 {
			t.Logf("Contacted %d DHT nodes.", reachable)
			success = true
			break
		}
		time.Sleep(time.Second)
	}
	if !success {
		t.Fatal("No external DHT node could be contacted.")
	}

	// Test that we can find peers for a known torrent in a timely fashion.
	//
	// Torrent from: http://www.clearbits.net/torrents/244-time-management-for-anarchists-1
	//infoHash := InfoHash("\xb4\x62\xc0\xa8\xbc\xef\x1c\xe5\xbb\x56\xb9\xfd\xb8\xcf\x37\xff\xd0\x2f\x5f\x59")
	infoHash := InfoHash("\xc0\x66\x42\x34\xb4\x4f\x25\xde\x6c\xc7\xb5\x36\xa7\x98\xc6\x5f\x85\x80\x79\xcb")
	//c0 66 42 34 b4 4f 25 de 6c c7 b5 36 a7 98 c6 5f 85 80 79 cb
	go node.PeersRequest(infoHash, true)
	timeout := make(chan bool, 1)
	go func() {
		time.Sleep(30 * time.Second)
		timeout <- true
	}()
	var infoHashPeers map[InfoHash][]string
	select {
	case infoHashPeers = <-node.PeersRequestResults:
		t.Logf("Found %d peers.", len(infoHashPeers[infoHash]))
	case <-timeout:
		t.Fatal("Could not find new peers: timed out")
	}
	for ih, peers := range infoHashPeers {
		if infoHash != ih {
			t.Fatal("Unexpected infohash returned")
		}
		if len(peers) == 0 {
			t.Fatal("Could not find new torrent peers.")
		}
		for _, peer := range peers {
			t.Logf("peer found: %v", nettools.BinaryToDottedPort(peer))
		}
	}
}

// Requires Internet access and can be flaky if the server or the internet is
// slow.
func TestDHTLarge(t *testing.T) {
	node := startDHTNode(t)
	realDHTNodes := []string{
		"1.a.magnets.im",
	}
	for _, addr := range realDHTNodes {
		ip, err := net.LookupHost(addr)
		if err != nil {
			t.Error(err)
			continue
		}
		node.AddNode(ip[0] + ":6881")
	}

	// Test that we can reach at least one node.
	success := false
	var (
		reachable int
		v         expvar.Var
		err       error
	)
	for i := 0; i < 10; i++ {
		v = expvar.Get("totalReachableNodes")
		reachable, err = strconv.Atoi(v.String())
		if err != nil {
			t.Errorf("totalReachableNodes conversion to int failed: %v", err)
			continue
		}
		if reachable > 0 {
			t.Logf("Contacted %d DHT nodes.", reachable)
			success = true
			break
		}
		time.Sleep(time.Second)
	}
	if !success {
		t.Fatal("No external DHT node could be contacted.")
	}

	// Test that we can find peers for a known torrent in a timely fashion.
	//
	// Torrent from: http://www.clearbits.net/torrents/244-time-management-for-anarchists-1
	infoHash := InfoHash("\xb4\x62\xc0\xa8\xbc\xef\x1c\xe5\xbb\x56\xb9\xfd\xb8\xcf\x37\xff\xd0\x2f\x5f\x59")
	go node.PeersRequest(string(infoHash), true)
	timeout := make(chan bool, 1)
	go func() {
		time.Sleep(10 * time.Second)
		timeout <- true
	}()
	var infoHashPeers map[InfoHash][]string
	select {
	case infoHashPeers = <-node.PeersRequestResults:
		t.Logf("Found %d peers.", len(infoHashPeers[infoHash]))
	case <-timeout:
		t.Fatal("Could not find new peers: timed out")
	}
	for ih, peers := range infoHashPeers {
		if infoHash != ih {
			t.Fatal("Unexpected infohash returned")
		}
		if len(peers) == 0 {
			t.Fatal("Could not find new torrent peers.")
		}
		for _, peer := range peers {
			t.Logf("peer found: %v", nettools.BinaryToDottedPort(peer))
		}
	}
	t.Logf("=== Stats ===")
	t.Logf("totalReachableNodes: %v", totalReachableNodes)
	t.Logf("totalDupes: %v", totalDupes)
	t.Logf("totalPeers: %v", totalPeers)
	t.Logf("totalSentGetPeers: %v", totalSentGetPeers)
}