From ef9ed26d8fa943e3c730690335a1103fa82c997e Mon Sep 17 00:00:00 2001
From: emersion <contact@emersion.fr>
Date: Thu, 11 Jan 2018 18:17:11 +0100
Subject: [PATCH] events: add event manager

---
 cmd/hydroxide/hydroxide.go |  9 +++--
 events/events.go           | 68 ++++++++++++++++++++++++++++++++++++++
 2 files changed, 74 insertions(+), 3 deletions(-)
 create mode 100644 events/events.go

diff --git a/cmd/hydroxide/hydroxide.go b/cmd/hydroxide/hydroxide.go
index 931a678..f9b241a 100644
--- a/cmd/hydroxide/hydroxide.go
+++ b/cmd/hydroxide/hydroxide.go
@@ -15,6 +15,7 @@ import (
 
 	"github.com/emersion/hydroxide/auth"
 	"github.com/emersion/hydroxide/carddav"
+	"github.com/emersion/hydroxide/events"
 	"github.com/emersion/hydroxide/protonmail"
 	smtpbackend "github.com/emersion/hydroxide/smtp"
 )
@@ -155,6 +156,8 @@ func main() {
 			port = "8080"
 		}
 
+		eventsManager := events.NewManager()
+
 		sessions := auth.NewManager(newClient)
 		handlers := make(map[string]http.Handler)
 
@@ -183,9 +186,9 @@ func main() {
 
 				h, ok := handlers[username]
 				if !ok {
-					events := make(chan *protonmail.Event)
-					go receiveEvents(c, "", events)
-					h = carddav.NewHandler(c, privateKeys, events)
+					ch := make(chan *protonmail.Event)
+					eventsManager.Register(c, username, ch)
+					h = carddav.NewHandler(c, privateKeys, ch)
 
 					handlers[username] = h
 				}
diff --git a/events/events.go b/events/events.go
new file mode 100644
index 0000000..6f513ff
--- /dev/null
+++ b/events/events.go
@@ -0,0 +1,68 @@
+package events
+
+import (
+	"log"
+	"sync"
+	"time"
+
+	"github.com/emersion/hydroxide/protonmail"
+)
+
+const pollInterval = time.Minute
+
+type receiver struct {
+	channels []chan<- *protonmail.Event
+	locker sync.Mutex
+}
+
+func (r *receiver) receiveEvents(c *protonmail.Client, last string) {
+	t := time.NewTicker(pollInterval)
+	defer t.Stop()
+
+	for range t.C {
+		event, err := c.GetEvent(last)
+		if err != nil {
+			log.Println("cannot receive event:", err)
+			continue
+		}
+
+		if event.ID == last {
+			continue
+		}
+		last = event.ID
+
+		r.locker.Lock()
+		for _, ch := range r.channels {
+			ch <- event
+		}
+		r.locker.Unlock()
+	}
+}
+
+type Manager struct {
+	receivers map[string]*receiver
+	locker sync.Mutex
+}
+
+func NewManager() *Manager {
+	return &Manager{
+		receivers: make(map[string]*receiver),
+	}
+}
+
+func (m *Manager) Register(c *protonmail.Client, username string, ch chan<- *protonmail.Event) {
+	m.locker.Lock()
+	defer m.locker.Unlock()
+
+	if r, ok := m.receivers[username]; ok {
+		r.locker.Lock()
+		r.channels = append(r.channels, ch)
+		r.locker.Unlock()
+	} else {
+		r = &receiver{
+			channels: []chan<- *protonmail.Event{ch},
+		}
+		go r.receiveEvents(c, "")
+		m.receivers[username] = r
+	}
+}