From 4bdae89134ad99c62a01d1ccd96addef3f53a079 Mon Sep 17 00:00:00 2001
From: Christian Pointner <equinox@helsinki.at>
Date: Sat, 18 Jul 2015 01:43:28 +0200
Subject: added ntp client handling


diff --git a/src/helsinki.at/rhrdtime/rhrdtime.go b/src/helsinki.at/rhrdtime/rhrdtime.go
index 58ba896..806e64e 100644
--- a/src/helsinki.at/rhrdtime/rhrdtime.go
+++ b/src/helsinki.at/rhrdtime/rhrdtime.go
@@ -37,13 +37,7 @@ import (
 	"github.com/tuxychandru/pubsub"
 )
 
-type timeUpdate struct {
-	Timestamp int64 `json:"timestamp"`
-	TZOffset  int   `json:"tz_offset"`
-	Week      uint8 `json:"week"`
-}
-
-func getTimeUpdate() []byte {
+func getRDWeekAndOffset(t time.Time) (uint8, int) {
 	//
 	// This computes the current Rivendell Week based on the number
 	// of weeks since epoch.
@@ -64,15 +58,25 @@ func getTimeUpdate() []byte {
 	loc, err := time.LoadLocation("Europe/Vienna")
 	if err != nil {
 		fmt.Println(err)
-		return []byte{'{', '}'}
+		return 0, 0
 	}
 
-	now := time.Now().In(loc)
-	_, offset := now.Zone()
+	t = t.In(loc)
+	_, offset := t.Zone()
+
+	sEpoch := t.Unix() + int64(offset)
+	return uint8(math.Floor(math.Mod((((float64(sEpoch)+259200)/604800)+2), 4)) + 1), offset
+}
 
-	sEpoch := now.Unix() + int64(offset)
-	week := uint8(math.Floor(math.Mod((((float64(sEpoch)+259200)/604800)+2), 4)) + 1)
+type timeUpdate struct {
+	Timestamp int64 `json:"timestamp"`
+	TZOffset  int   `json:"tz_offset"`
+	Week      uint8 `json:"week"`
+}
 
+func getTimeUpdate() []byte {
+	now := time.Now()
+	week, offset := getRDWeekAndOffset(now)
 	update := timeUpdate{(now.Unix() * 1000) + int64(now.Nanosecond()/1000000), offset, week}
 	update_json, err := json.Marshal(update)
 	if err != nil {
@@ -118,11 +122,67 @@ func handleTimeUpdateClient(w http.ResponseWriter, r *http.Request, ps *pubsub.P
 	}
 }
 
+type ntpMessage struct {
+	T1       int64 `json:"t1"`
+	T2       int64 `json:"t2"`
+	T3       int64 `json:"t3"`
+	T4       int64 `json:"t4"`
+	TZOffset int   `json:"tz_offset"`
+	Week     uint8 `json:"week"`
+}
+
+func handleNTPClient(w http.ResponseWriter, r *http.Request, ps *pubsub.PubSub) {
+	ws, err := websocket.Upgrade(w, r, nil, 1024, 1024)
+	if _, ok := err.(websocket.HandshakeError); ok {
+		http.Error(w, "Not a websocket handshake", 400)
+		return
+	} else if err != nil {
+		fmt.Println(err)
+		return
+	}
+	fmt.Println("Client connected", ws.RemoteAddr())
+
+	for {
+		msgtype, msg, err := ws.ReadMessage()
+		if err != nil {
+			fmt.Println("Client connected", ws.RemoteAddr())
+			return
+		}
+		now_t2 := time.Now()
+		if msgtype == websocket.TextMessage {
+
+			var n ntpMessage
+			if err := json.Unmarshal(msg, &n); err != nil {
+				fmt.Println("mallformed NTP message", err)
+				continue
+			}
+
+			n.T2 = (now_t2.Unix() * 1000) + int64(now_t2.Nanosecond()/1000000)
+			n.Week, n.TZOffset = getRDWeekAndOffset(now_t2)
+
+			now_t3 := time.Now()
+			n.T3 = (now_t3.Unix() * 1000) + int64(now_t3.Nanosecond()/1000000)
+
+			ntp_json, err := json.Marshal(n)
+			if err != nil {
+				fmt.Println(err)
+				continue
+			}
+			if err := ws.WriteMessage(websocket.TextMessage, ntp_json); err != nil {
+				return
+			}
+		}
+	}
+}
+
 func RunMartini(ps *pubsub.PubSub, addr string) {
 	m := martini.Classic()
 	m.Get("/time", func(w http.ResponseWriter, r *http.Request) {
 		handleTimeUpdateClient(w, r, ps)
 	})
+	// m.Get("/ntp", func(w http.ResponseWriter, r *http.Request) {
+	// 	handleTimeUpdateClient(w, r, ps)
+	// })
 
 	m.RunOnAddr(addr)
 }
-- 
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