Ratelimit +typing and send +typing=done once only

Fixes: #8
Fixes: #41

4 files changed, 43 insertions, 5 deletions

diff --git a/go.mod b/go.mod
index 6fa2d6d..88f4550 100644
--- a/go.mod
+++ b/go.mod
@@ -6,5 +6,6 @@ require (
 	github.com/gdamore/tcell/v2 v2.3.11
 	github.com/mattn/go-runewidth v0.0.10
 	golang.org/x/term v0.0.0-20201210144234-2321bbc49cbf
+	golang.org/x/time v0.0.0-20210611083556-38a9dc6acbc6
 	gopkg.in/yaml.v2 v2.3.0
 )
diff --git a/go.sum b/go.sum
index a7c2983..c64f2e8 100644
--- a/go.sum
+++ b/go.sum
@@ -14,6 +14,8 @@ golang.org/x/term v0.0.0-20201210144234-2321bbc49cbf h1:MZ2shdL+ZM/XzY3ZGOnh4Nlp
 golang.org/x/term v0.0.0-20201210144234-2321bbc49cbf/go.mod h1:bj7SfCRtBDWHUb9snDiAeCFNEtKQo2Wmx5Cou7ajbmo=
 golang.org/x/text v0.3.0 h1:g61tztE5qeGQ89tm6NTjjM9VPIm088od1l6aSorWRWg=
 golang.org/x/text v0.3.0/go.mod h1:NqM8EUOU14njkJ3fqMW+pc6Ldnwhi/IjpwHt7yyuwOQ=
+golang.org/x/time v0.0.0-20210611083556-38a9dc6acbc6 h1:Vv0JUPWTyeqUq42B2WJ1FeIDjjvGKoA2Ss+Ts0lAVbs=
+golang.org/x/time v0.0.0-20210611083556-38a9dc6acbc6/go.mod h1:tRJNPiyCQ0inRvYxbN9jk5I+vvW/OXSQhTDSoE431IQ=
 gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405 h1:yhCVgyC4o1eVCa2tZl7eS0r+SDo693bJlVdllGtEeKM=
 gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
 gopkg.in/yaml.v2 v2.3.0 h1:clyUAQHOM3G0M3f5vQj7LuJrETvjVot3Z5el9nffUtU=
diff --git a/irc/session.go b/irc/session.go
index dabec03..376015f 100644
--- a/irc/session.go
+++ b/irc/session.go
@@ -11,6 +11,8 @@ import (
 	"time"
 	"unicode"
 	"unicode/utf8"
+
+	"golang.org/x/time/rate"
 )
 
 type SASLClient interface {
@@ -102,8 +104,8 @@ type Session struct {
 	out          chan<- Message
 	closed       bool
 	registered   bool
-	typings      *Typings             // incoming typing notifications.
-	typingStamps map[string]time.Time // user typing instants.
+	typings      *Typings               // incoming typing notifications.
+	typingStamps map[string]typingStamp // user typing instants.
 
 	nick   string
 	nickCf string // casemapped nickname.
@@ -134,7 +136,7 @@ func NewSession(out chan<- Message, params SessionParams) *Session {
 	s := &Session{
 		out:           out,
 		typings:       NewTypings(),
-		typingStamps:  map[string]time.Time{},
+		typingStamps:  map[string]typingStamp{},
 		nick:          params.Nickname,
 		nickCf:        CasemapASCII(params.Nickname),
 		user:          params.Username,
@@ -342,10 +344,19 @@ func (s *Session) Typing(target string) {
 	}
 	targetCf := s.casemap(target)
 	now := time.Now()
-	if t, ok := s.typingStamps[targetCf]; ok && now.Sub(t).Seconds() < 3.0 {
+	t, ok := s.typingStamps[targetCf]
+	if ok && ((t.Type == TypingActive && now.Sub(t.Last).Seconds() < 3.0) || !t.Limit.Allow()) {
 		return
 	}
-	s.typingStamps[targetCf] = now
+	if !ok {
+		t.Limit = rate.NewLimiter(rate.Limit(1.0/3.0), 5)
+		t.Limit.Reserve() // will always be OK
+	}
+	s.typingStamps[targetCf] = typingStamp{
+		Last:  now,
+		Type:  TypingActive,
+		Limit: t.Limit,
+	}
 	s.out <- NewMessage("TAGMSG", target).WithTag("+typing", "active")
 }
 
@@ -353,6 +364,22 @@ func (s *Session) TypingStop(target string) {
 	if !s.HasCapability("message-tags") {
 		return
 	}
+	targetCf := s.casemap(target)
+	now := time.Now()
+	t, ok := s.typingStamps[targetCf]
+	if ok && (t.Type == TypingDone || !t.Limit.Allow()) {
+		// don't send a +typing=done again if the last typing we sent was a +typing=done
+		return
+	}
+	if !ok {
+		t.Limit = rate.NewLimiter(rate.Limit(1), 5)
+		t.Limit.Reserve() // will always be OK
+	}
+	s.typingStamps[targetCf] = typingStamp{
+		Last:  now,
+		Type:  TypingDone,
+		Limit: t.Limit,
+	}
 	s.out <- NewMessage("TAGMSG", target).WithTag("+typing", "done")
 }
 
diff --git a/irc/typing.go b/irc/typing.go
index 5f028e4..5a3073c 100644
--- a/irc/typing.go
+++ b/irc/typing.go
@@ -3,6 +3,8 @@ package irc
 import (
 	"sync"
 	"time"
+
+	"golang.org/x/time/rate"
 )
 
 // Typing is an event of Name actively typing in Target.
@@ -86,3 +88,9 @@ func (ts *Typings) List(target string) []string {
 	}
 	return res
 }
+
+type typingStamp struct {
+	Last  time.Time
+	Type  int
+	Limit *rate.Limiter
+}