From 90ba4814c86b41b8e1dcd6cd68896219811d8003 Mon Sep 17 00:00:00 2001
From: Juliusz Chroboczek <jch@irif.fr>
Date: Thu, 8 Oct 2020 14:38:33 +0200
Subject: [PATCH] Discard old history entries.

---
 README                                        |  2 +
 group/group.go                                | 41 ++++++++++++++++++-
 .../webclient_test.go => group/group_test.go  |  8 ++--
 rtpconn/webclient.go                          | 18 +-------
 4 files changed, 47 insertions(+), 22 deletions(-)
 rename rtpconn/webclient_test.go => group/group_test.go (77%)

diff --git a/README b/README
index 5537f67..7d75acc 100644
--- a/README
+++ b/README
@@ -103,6 +103,8 @@ fields, all of which are optional.
    displayed on the landing page for public groups;
  - `max-clients`: the maximum number of clients that may join the group at
    a time;
+ - `max-history-age`: the time, in seconds, during which chat history is
+   kept (default 14400, i.e. 4 hours);
  - `allow-recording`: if true, then recording is allowed in this group;
  - `allow-anonymous`: if true, then users may connect with an empty
    username; this is not recommended, since anonymous users are not
diff --git a/group/group.go b/group/group.go
index 6770e1c..0799d9b 100644
--- a/group/group.go
+++ b/group/group.go
@@ -65,7 +65,7 @@ func IceConfiguration() webrtc.Configuration {
 type ChatHistoryEntry struct {
 	Id    string
 	User  string
-	Time  uint64
+	Time  int64
 	Kind  string
 	Value string
 }
@@ -396,6 +396,18 @@ func (g *Group) Shutdown(message string) {
 	})
 }
 
+func FromJSTime(tm int64) time.Time {
+	if tm == 0 {
+		return time.Time{}
+	}
+	return time.Unix(int64(tm)/1000, (int64(tm)%1000)*1000000)
+}
+
+func ToJSTime(tm time.Time) int64 {
+	return int64((tm.Sub(time.Unix(0, 0)) + time.Millisecond/2) /
+		time.Millisecond)
+}
+
 const maxChatHistory = 50
 
 func (g *Group) ClearChatHistory() {
@@ -404,7 +416,7 @@ func (g *Group) ClearChatHistory() {
 	g.history = nil
 }
 
-func (g *Group) AddToChatHistory(id, user string, time uint64, kind, value string) {
+func (g *Group) AddToChatHistory(id, user string, time int64, kind, value string) {
 	g.mu.Lock()
 	defer g.mu.Unlock()
 
@@ -417,10 +429,34 @@ func (g *Group) AddToChatHistory(id, user string, time uint64, kind, value strin
 	)
 }
 
+func discardObsoleteHistory(h []ChatHistoryEntry, seconds int) []ChatHistoryEntry {
+	now := time.Now()
+	d := 4 * time.Hour
+	if seconds > 0 {
+		d = time.Duration(seconds) * time.Second
+	}
+
+	i := 0
+	for i < len(h) {
+		log.Println(h[i].Time, FromJSTime(h[i].Time), now.Sub(FromJSTime(h[i].Time)))
+		if now.Sub(FromJSTime(h[i].Time)) <= d {
+			break
+		}
+		i++
+	}
+	if i > 0 {
+		copy(h, h[i:])
+		h = h[:len(h)-i]
+	}
+	return h
+}
+
 func (g *Group) GetChatHistory() []ChatHistoryEntry {
 	g.mu.Lock()
 	defer g.mu.Unlock()
 
+	g.history = discardObsoleteHistory(g.history, g.description.MaxHistoryAge)
+
 	h := make([]ChatHistoryEntry, len(g.history))
 	copy(h, g.history)
 	return h
@@ -448,6 +484,7 @@ type description struct {
 	Redirect       string              `json:"redirect,omitempty"`
 	Public         bool                `json:"public,omitempty"`
 	MaxClients     int                 `json:"max-clients,omitempty"`
+	MaxHistoryAge  int                 `json:"max-history-age",omitempty`
 	AllowAnonymous bool                `json:"allow-anonymous,omitempty"`
 	AllowRecording bool                `json:"allow-recording,omitempty"`
 	Op             []ClientCredentials `json:"op,omitempty"`
diff --git a/rtpconn/webclient_test.go b/group/group_test.go
similarity index 77%
rename from rtpconn/webclient_test.go
rename to group/group_test.go
index 4d84b16..d2346ab 100644
--- a/rtpconn/webclient_test.go
+++ b/group/group_test.go
@@ -1,4 +1,4 @@
-package rtpconn
+package group
 
 import (
 	"testing"
@@ -7,9 +7,9 @@ import (
 
 func TestJSTime(t *testing.T) {
 	tm := time.Now()
-	js := toJSTime(tm)
-	tm2 := fromJSTime(js)
-	js2 := toJSTime(tm2)
+	js := ToJSTime(tm)
+	tm2 := FromJSTime(js)
+	js2 := ToJSTime(tm2)
 
 	if js != js2 {
 		t.Errorf("%v != %v", js, js2)
diff --git a/rtpconn/webclient.go b/rtpconn/webclient.go
index b705d8f..b0bc5cb 100644
--- a/rtpconn/webclient.go
+++ b/rtpconn/webclient.go
@@ -147,7 +147,7 @@ type clientMessage struct {
 	Permissions group.ClientPermissions    `json:"permissions,omitempty"`
 	Group       string                     `json:"group,omitempty"`
 	Value       string                     `json:"value,omitempty"`
-	Time        uint64                     `json:"time,omitempty"`
+	Time        int64                      `json:"time,omitempty"`
 	Offer       *webrtc.SessionDescription `json:"offer,omitempty"`
 	Answer      *webrtc.SessionDescription `json:"answer,omitempty"`
 	Candidate   *webrtc.ICECandidateInit   `json:"candidate,omitempty"`
@@ -155,20 +155,6 @@ type clientMessage struct {
 	Request     rateMap                    `json:"request,omitempty"`
 }
 
-func fromJSTime(tm uint64) time.Time {
-	if tm == 0 {
-		return time.Time{}
-	}
-	return time.Unix(int64(tm)/1000, (int64(tm)%1000)*1000000)
-}
-
-func toJSTime(tm time.Time) uint64 {
-	if tm.Before(time.Unix(0, 0)) {
-		return 0
-	}
-	return uint64((tm.Sub(time.Unix(0, 0)) + time.Millisecond/2) / time.Millisecond)
-}
-
 type closeMessage struct {
 	data []byte
 }
@@ -1060,7 +1046,7 @@ func handleClientMessage(c *webClient, m clientMessage) error {
 			log.Printf("ICE: %v", err)
 		}
 	case "chat":
-		tm := toJSTime(time.Now())
+		tm := group.ToJSTime(time.Now())
 		if m.Dest == "" {
 			c.group.AddToChatHistory(
 				m.Id, m.Username, tm, m.Kind, m.Value,