From ac578823dc300d3aa62152615d34183fcb3f3d1a Mon Sep 17 00:00:00 2001
From: delthas <delthas@dille.cc>
Date: Mon, 24 Oct 2022 14:56:35 +0200
Subject: [PATCH] Fix clearing webpush targets after any MARKREAD

Previously, we would clear webpush targets after any MARKREAD.

Consider the following scenario (ignore any typos, this is crafted by
hand):

    <<< @time=2020-01-01T00:00:00Z PRIVMSG #foo :hi mark!
    <<< @time=2020-01-02T00:00:00Z PRIVMSG #foo :hi again mark!
    >>> MARKREAD #foo timestamp=2020-01-01T00:00:00Z
    >>> MARKREAD #foo timestamp=2020-01-02T00:00:00Z

The push target was previously cleared on the first MARKREAD, which
means that the second MARKREAD was never broadcast to Firebase, and all
devices would keep the "hi again mark!" notification indefinitely.

This changes the webpush target map so that we store a timestamp of the
last highlight we sent. We only clear the push target when sending a
MARKREAD that is at or after the last message.
---
 downstream.go |  4 +++-
 irc.go        | 14 +++++++++++---
 upstream.go   |  4 +++-
 user.go       |  4 ++--
 4 files changed, 19 insertions(+), 7 deletions(-)

diff --git a/downstream.go b/downstream.go
index 3a452d5..4ba6792 100644
--- a/downstream.go
+++ b/downstream.go
@@ -2818,7 +2818,9 @@ func (dc *downstreamConn) handleMessageRegistered(ctx context.Context, msg *irc.
 
 		if broadcast && network.pushTargets.Has(target) {
 			// TODO: only broadcast if draft/read-marker has been negotiated
-			network.pushTargets.Del(target)
+			if !r.Timestamp.Before(network.pushTargets.Get(target)) {
+				network.pushTargets.Del(target)
+			}
 			go network.broadcastWebPush(&irc.Message{
 				Command: "MARKREAD",
 				Params:  []string{target, timestampStr},
diff --git a/irc.go b/irc.go
index d5e0a69..464d9f8 100644
--- a/irc.go
+++ b/irc.go
@@ -459,10 +459,18 @@ func (cm *monitorCasemapMap) ForEach(f func(name string, online bool)) {
 	}
 }
 
-type casemapSet struct{ casemapMap }
+type pushTargetCasemapMap struct{ casemapMap }
 
-func (cs *casemapSet) Add(name string) {
-	cs.set(name, nil)
+func (cm *pushTargetCasemapMap) Get(name string) (last time.Time) {
+	if v := cm.get(name); v == nil {
+		return time.Time{}
+	} else {
+		return v.(time.Time)
+	}
+}
+
+func (cm *pushTargetCasemapMap) Set(name string, last time.Time) {
+	cm.set(name, last)
 }
 
 func isWordBoundary(r rune) bool {
diff --git a/upstream.go b/upstream.go
index 032e710..5e47dc7 100644
--- a/upstream.go
+++ b/upstream.go
@@ -556,7 +556,9 @@ func (uc *upstreamConn) handleMessage(ctx context.Context, msg *irc.Message) err
 
 		if highlight || uc.isOurNick(target) {
 			go uc.network.broadcastWebPush(msg)
-			uc.network.pushTargets.Add(bufferName)
+			if timestamp, err := time.Parse(xirc.ServerTimeLayout, string(msg.Tags["time"])); err == nil {
+				uc.network.pushTargets.Set(bufferName, timestamp)
+			}
 		}
 
 		uc.produce(bufferName, msg, downstreamID)
diff --git a/user.go b/user.go
index ef9433f..8b83c34 100644
--- a/user.go
+++ b/user.go
@@ -141,7 +141,7 @@ type network struct {
 	conn        *upstreamConn
 	channels    channelCasemapMap
 	delivered   deliveredStore
-	pushTargets casemapSet
+	pushTargets pushTargetCasemapMap
 	lastError   error
 	casemap     casemapping
 }
@@ -162,7 +162,7 @@ func newNetwork(user *user, record *database.Network, channels []database.Channe
 		stopped:     make(chan struct{}),
 		channels:    m,
 		delivered:   newDeliveredStore(),
-		pushTargets: casemapSet{newCasemapMap()},
+		pushTargets: pushTargetCasemapMap{newCasemapMap()},
 		casemap:     casemapRFC1459,
 	}
 }