PLT-3462 Add the ability to clear push notifications after channel is viewed (#3834)

* Add the ability to clear push notifications after channel is viewed

* Fix race condition between updating the mention count and reading it when sending push notifications

8 files changed, 178 insertions, 67 deletions

diff --git a/api/channel.go b/api/channel.go
index faa39e13c..e2c67f18b 100644
--- a/api/channel.go
+++ b/api/channel.go
@@ -846,8 +846,24 @@ func updateLastViewedAt(c *Context, w http.ResponseWriter, r *http.Request) {
 	params := mux.Vars(r)
 	id := params["channel_id"]
 
+	doClearPush := false
+	if *utils.Cfg.EmailSettings.SendPushNotifications && !c.Session.IsMobileApp() {
+		if result := <-Srv.Store.User().GetUnreadCountForChannel(c.Session.UserId, id); result.Err != nil {
+			l4g.Error(utils.T("api.channel.update_last_viewed_at.get_unread_count_for_channel.error"), c.Session.UserId, id, result.Err.Error())
+		} else {
+			if result.Data.(int64) > 0 {
+				doClearPush = true
+			}
+		}
+	}
+
 	Srv.Store.Channel().UpdateLastViewedAt(id, c.Session.UserId)
 
+	// Must be after update so that unread count is correct
+	if doClearPush {
+		go clearPushNotification(c.Session.UserId, id)
+	}
+
 	preference := model.Preference{
 		UserId:   c.Session.UserId,
 		Category: model.PREFERENCE_CATEGORY_LAST,
diff --git a/api/post.go b/api/post.go
index 8639938e2..bfd22084b 100644
--- a/api/post.go
+++ b/api/post.go
@@ -711,6 +711,15 @@ func sendNotifications(c *Context, post *model.Post, team *model.Team, channel *
 		}
 	}
 
+	// Make sure all mention updates are complete to prevent race
+	// Probably better to batch these DB updates in the future
+	// MUST be completed before push notifications send
+	for _, uchan := range updateMentionChans {
+		if result := <-uchan; result.Err != nil {
+			l4g.Warn(utils.T("api.post.update_mention_count_and_forget.update_error"), post.Id, post.ChannelId, result.Err)
+		}
+	}
+
 	sendPushNotifications := false
 	if *utils.Cfg.EmailSettings.SendPushNotifications {
 		pushServer := *utils.Cfg.EmailSettings.PushNotificationServer
@@ -773,14 +782,6 @@ func sendNotifications(c *Context, post *model.Post, team *model.Team, channel *
 		message.Add("mentions", model.ArrayToJson(mentionedUsersList))
 	}
 
-	// Make sure all mention updates are complete to prevent race
-	// Probably better to batch these DB updates in the future
-	for _, uchan := range updateMentionChans {
-		if result := <-uchan; result.Err != nil {
-			l4g.Warn(utils.T("api.post.update_mention_count_and_forget.update_error"), post.Id, post.ChannelId, result.Err)
-		}
-	}
-
 	go Publish(message)
 }
 
@@ -888,12 +889,10 @@ func getMessageForNotification(post *model.Post, translateFunc i18n.TranslateFun
 }
 
 func sendPushNotification(post *model.Post, user *model.User, channel *model.Channel, senderName string, wasMentioned bool) {
-	var sessions []*model.Session
-	if result := <-Srv.Store.Session().GetSessions(user.Id); result.Err != nil {
-		l4g.Error(utils.T("api.post.send_notifications_and_forget.sessions.error"), user.Id, result.Err)
+	session := getMobileAppSession(user.Id)
+
+	if session == nil {
 		return
-	} else {
-		sessions = result.Data.([]*model.Session)
 	}
 
 	var channelName string
@@ -906,65 +905,98 @@ func sendPushNotification(post *model.Post, user *model.User, channel *model.Cha
 
 	userLocale := utils.GetUserTranslations(user.Locale)
 
-	for _, session := range sessions {
-		if len(session.DeviceId) > 0 &&
-			(strings.HasPrefix(session.DeviceId, model.PUSH_NOTIFY_APPLE+":") || strings.HasPrefix(session.DeviceId, model.PUSH_NOTIFY_ANDROID+":")) {
+	msg := model.PushNotification{}
+	if badge := <-Srv.Store.User().GetUnreadCount(user.Id); badge.Err != nil {
+		msg.Badge = 1
+		l4g.Error(utils.T("store.sql_user.get_unread_count.app_error"), user.Id, badge.Err)
+	} else {
+		msg.Badge = int(badge.Data.(int64))
+	}
+	msg.Type = model.PUSH_TYPE_MESSAGE
+	msg.ChannelId = channel.Id
+	msg.ChannelName = channel.Name
 
-			msg := model.PushNotification{}
-			if badge := <-Srv.Store.User().GetUnreadCount(user.Id); badge.Err != nil {
-				msg.Badge = 1
-				l4g.Error(utils.T("store.sql_user.get_unread_count.app_error"), user.Id, badge.Err)
-			} else {
-				msg.Badge = int(badge.Data.(int64))
-			}
-			msg.ServerId = utils.CfgDiagnosticId
-			msg.ChannelId = channel.Id
-			msg.ChannelName = channel.Name
-
-			if strings.HasPrefix(session.DeviceId, model.PUSH_NOTIFY_APPLE+":") {
-				msg.Platform = model.PUSH_NOTIFY_APPLE
-				msg.DeviceId = strings.TrimPrefix(session.DeviceId, model.PUSH_NOTIFY_APPLE+":")
-			} else if strings.HasPrefix(session.DeviceId, model.PUSH_NOTIFY_ANDROID+":") {
-				msg.Platform = model.PUSH_NOTIFY_ANDROID
-				msg.DeviceId = strings.TrimPrefix(session.DeviceId, model.PUSH_NOTIFY_ANDROID+":")
-			}
+	msg.SetDeviceIdAndPlatform(session.DeviceId)
 
-			if *utils.Cfg.EmailSettings.PushNotificationContents == model.FULL_NOTIFICATION {
-				if channel.Type == model.CHANNEL_DIRECT {
-					msg.Category = model.CATEGORY_DM
-					msg.Message = "@" + senderName + ": " + model.ClearMentionTags(post.Message)
-				} else {
-					msg.Message = senderName + userLocale("api.post.send_notifications_and_forget.push_in") + channelName + ": " + model.ClearMentionTags(post.Message)
-				}
-			} else {
-				if channel.Type == model.CHANNEL_DIRECT {
-					msg.Category = model.CATEGORY_DM
-					msg.Message = senderName + userLocale("api.post.send_notifications_and_forget.push_message")
-				} else if wasMentioned {
-					msg.Message = senderName + userLocale("api.post.send_notifications_and_forget.push_mention") + channelName
-				} else {
-					msg.Message = senderName + userLocale("api.post.send_notifications_and_forget.push_non_mention") + channelName
-				}
-			}
+	if *utils.Cfg.EmailSettings.PushNotificationContents == model.FULL_NOTIFICATION {
+		if channel.Type == model.CHANNEL_DIRECT {
+			msg.Category = model.CATEGORY_DM
+			msg.Message = "@" + senderName + ": " + model.ClearMentionTags(post.Message)
+		} else {
+			msg.Message = senderName + userLocale("api.post.send_notifications_and_forget.push_in") + channelName + ": " + model.ClearMentionTags(post.Message)
+		}
+	} else {
+		if channel.Type == model.CHANNEL_DIRECT {
+			msg.Category = model.CATEGORY_DM
+			msg.Message = senderName + userLocale("api.post.send_notifications_and_forget.push_message")
+		} else if wasMentioned {
+			msg.Message = senderName + userLocale("api.post.send_notifications_and_forget.push_mention") + channelName
+		} else {
+			msg.Message = senderName + userLocale("api.post.send_notifications_and_forget.push_non_mention") + channelName
+		}
+	}
 
-			tr := &http.Transport{
-				TLSClientConfig: &tls.Config{InsecureSkipVerify: *utils.Cfg.ServiceSettings.EnableInsecureOutgoingConnections},
-			}
-			httpClient := &http.Client{Transport: tr}
-			request, _ := http.NewRequest("POST", *utils.Cfg.EmailSettings.PushNotificationServer+model.API_URL_SUFFIX_V1+"/send_push", strings.NewReader(msg.ToJson()))
+	l4g.Debug(utils.T("api.post.send_notifications_and_forget.push_notification.debug"), msg.DeviceId, msg.Message)
+	sendToPushProxy(msg)
+}
 
-			l4g.Debug(utils.T("api.post.send_notifications_and_forget.push_notification.debug"), msg.DeviceId, msg.Message)
-			if resp, err := httpClient.Do(request); err != nil {
-				l4g.Error(utils.T("api.post.send_notifications_and_forget.push_notification.error"), user.Id, err)
-			} else {
-				ioutil.ReadAll(resp.Body)
-				resp.Body.Close()
-			}
+func clearPushNotification(userId string, channelId string) {
+	session := getMobileAppSession(userId)
+
+	if session == nil {
+		return
+	}
+
+	msg := model.PushNotification{}
+	msg.Type = model.PUSH_TYPE_CLEAR
+	msg.ChannelId = channelId
+	msg.ContentAvailable = 0
+	if badge := <-Srv.Store.User().GetUnreadCount(userId); badge.Err != nil {
+		msg.Badge = 0
+		l4g.Error(utils.T("store.sql_user.get_unread_count.app_error"), userId, badge.Err)
+	} else {
+		msg.Badge = int(badge.Data.(int64))
+	}
+
+	msg.SetDeviceIdAndPlatform(session.DeviceId)
 
-			// notification sent, don't need to check other sessions
-			break
+	l4g.Debug(utils.T("api.post.send_notifications_and_forget.clear_push_notification.debug"), msg.DeviceId, msg.ChannelId)
+	sendToPushProxy(msg)
+}
+
+func sendToPushProxy(msg model.PushNotification) {
+	msg.ServerId = utils.CfgDiagnosticId
+
+	tr := &http.Transport{
+		TLSClientConfig: &tls.Config{InsecureSkipVerify: *utils.Cfg.ServiceSettings.EnableInsecureOutgoingConnections},
+	}
+	httpClient := &http.Client{Transport: tr}
+	request, _ := http.NewRequest("POST", *utils.Cfg.EmailSettings.PushNotificationServer+model.API_URL_SUFFIX_V1+"/send_push", strings.NewReader(msg.ToJson()))
+
+	if resp, err := httpClient.Do(request); err != nil {
+		l4g.Error(utils.T("api.post.send_notifications_and_forget.push_notification.error"), msg.DeviceId, err)
+	} else {
+		ioutil.ReadAll(resp.Body)
+		resp.Body.Close()
+	}
+}
+
+func getMobileAppSession(userId string) *model.Session {
+	var sessions []*model.Session
+	if result := <-Srv.Store.Session().GetSessions(userId); result.Err != nil {
+		l4g.Error(utils.T("api.post.send_notifications_and_forget.sessions.error"), userId, result.Err)
+		return nil
+	} else {
+		sessions = result.Data.([]*model.Session)
+	}
+
+	for _, session := range sessions {
+		if session.IsMobileApp() {
+			return session
 		}
 	}
+
+	return nil
 }
 
 func sendOutOfChannelMentions(c *Context, post *model.Post, profiles map[string]*model.User, outOfChannelMentions map[string]bool) {
diff --git a/i18n/en.json b/i18n/en.json
index f2a2d2cd0..cdb05f14b 100644
--- a/i18n/en.json
+++ b/i18n/en.json
@@ -152,6 +152,10 @@
     "translation": "%v added to the channel by %v"
   },
   {
+    "id": "api.channel.update_last_viewed_at.get_unread_count_for_channel.errord",
+    "translation": "Unable to get the unread count for user_id=%v and channel_id=%v, err=%v"
+  },
+  {
     "id": "api.channel.add_member.find_channel.app_error",
     "translation": "Failed to find channel"
   },
@@ -1297,11 +1301,15 @@
   },
   {
     "id": "api.post.send_notifications_and_forget.push_notification.debug",
-    "translation": "Sending push notification to %v wi msg of '%v'"
+    "translation": "Sending push notification to %v with msg of '%v'"
+  },
+  {
+    "id": "api.post.send_notifications_and_forget.clear_push_notification.debug",
+    "translation": "Clearing push notification to %v with channel_id %v"
   },
   {
     "id": "api.post.send_notifications_and_forget.push_notification.error",
-    "translation": "Failed to send push notificationid=%v, err=%v"
+    "translation": "Failed to send push device_id=%v, err=%v"
   },
   {
     "id": "api.post.send_notifications_and_forget.send.error",
@@ -4456,6 +4464,10 @@
     "translation": "We could not get the unread message count for the user"
   },
   {
+    "id": "store.sql_user.get_unread_count_for_channel.app_error",
+    "translation": "We could not get the unread message count for the user and channel"
+  },
+  {
     "id": "store.sql_user.migrate_theme.critical",
     "translation": "Failed to migrate User.ThemeProps to Preferences table %v"
   },
diff --git a/model/push_notification.go b/model/push_notification.go
index 666dd8f7d..d4c380291 100644
--- a/model/push_notification.go
+++ b/model/push_notification.go
@@ -6,12 +6,16 @@ package model
 import (
 	"encoding/json"
 	"io"
+	"strings"
 )
 
 const (
 	PUSH_NOTIFY_APPLE   = "apple"
 	PUSH_NOTIFY_ANDROID = "android"
 
+	PUSH_TYPE_MESSAGE = "message"
+	PUSH_TYPE_CLEAR   = "clear"
+
 	CATEGORY_DM = "DIRECT_MESSAGE"
 
 	MHPNS = "https://push.mattermost.com"
@@ -28,6 +32,7 @@ type PushNotification struct {
 	ContentAvailable int    `json:"cont_ava"`
 	ChannelId        string `json:"channel_id"`
 	ChannelName      string `json:"channel_name"`
+	Type             string `json:"type"`
 }
 
 func (me *PushNotification) ToJson() string {
@@ -39,6 +44,16 @@ func (me *PushNotification) ToJson() string {
 	}
 }
 
+func (me *PushNotification) SetDeviceIdAndPlatform(deviceId string) {
+	if strings.HasPrefix(deviceId, PUSH_NOTIFY_APPLE+":") {
+		me.Platform = PUSH_NOTIFY_APPLE
+		me.DeviceId = strings.TrimPrefix(deviceId, PUSH_NOTIFY_APPLE+":")
+	} else if strings.HasPrefix(deviceId, PUSH_NOTIFY_ANDROID+":") {
+		me.Platform = PUSH_NOTIFY_ANDROID
+		me.DeviceId = strings.TrimPrefix(deviceId, PUSH_NOTIFY_ANDROID+":")
+	}
+}
+
 func PushNotificationFromJson(data io.Reader) *PushNotification {
 	decoder := json.NewDecoder(data)
 	var me PushNotification
diff --git a/model/session.go b/model/session.go
index ef51374db..e8b04fbe2 100644
--- a/model/session.go
+++ b/model/session.go
@@ -6,6 +6,7 @@ package model
 import (
 	"encoding/json"
 	"io"
+	"strings"
 )
 
 const (
@@ -109,6 +110,11 @@ func (me *Session) GetTeamByTeamId(teamId string) *TeamMember {
 	return nil
 }
 
+func (me *Session) IsMobileApp() bool {
+	return len(me.DeviceId) > 0 &&
+		(strings.HasPrefix(me.DeviceId, PUSH_NOTIFY_APPLE+":") || strings.HasPrefix(me.DeviceId, PUSH_NOTIFY_ANDROID+":"))
+}
+
 func SessionsToJson(o []*Session) string {
 	if b, err := json.Marshal(o); err != nil {
 		return "[]"
diff --git a/store/sql_user_store.go b/store/sql_user_store.go
index 027dcbd75..61bfa35b8 100644
--- a/store/sql_user_store.go
+++ b/store/sql_user_store.go
@@ -921,3 +921,22 @@ func (us SqlUserStore) GetUnreadCount(userId string) StoreChannel {
 
 	return storeChannel
 }
+
+func (us SqlUserStore) GetUnreadCountForChannel(userId string, channelId string) StoreChannel {
+	storeChannel := make(StoreChannel)
+
+	go func() {
+		result := StoreResult{}
+
+		if count, err := us.GetReplica().SelectInt("SELECT SUM(CASE WHEN c.Type = 'D' THEN (c.TotalMsgCount - cm.MsgCount) ELSE cm.MentionCount END) FROM Channels c INNER JOIN ChannelMembers cm ON c.Id = :ChannelId AND cm.ChannelId = :ChannelId AND cm.UserId = :UserId", map[string]interface{}{"ChannelId": channelId, "UserId": userId}); err != nil {
+			result.Err = model.NewLocAppError("SqlUserStore.GetMentionCountForChannel", "store.sql_user.get_unread_count_for_channel.app_error", nil, err.Error())
+		} else {
+			result.Data = count
+		}
+
+		storeChannel <- result
+		close(storeChannel)
+	}()
+
+	return storeChannel
+}
diff --git a/store/sql_user_store_test.go b/store/sql_user_store_test.go
index e44cee99d..74c27dbea 100644
--- a/store/sql_user_store_test.go
+++ b/store/sql_user_store_test.go
@@ -660,6 +660,16 @@ func TestUserUnreadCount(t *testing.T) {
 	if badge != 3 {
 		t.Fatal("should have 3 unread messages")
 	}
+
+	badge = (<-store.User().GetUnreadCountForChannel(u2.Id, c1.Id)).Data.(int64)
+	if badge != 1 {
+		t.Fatal("should have 1 unread messages for that channel")
+	}
+
+	badge = (<-store.User().GetUnreadCountForChannel(u2.Id, c2.Id)).Data.(int64)
+	if badge != 2 {
+		t.Fatal("should have 2 unread messages for that channel")
+	}
 }
 
 func TestUserStoreUpdateMfaSecret(t *testing.T) {
diff --git a/store/store.go b/store/store.go
index 78db41e77..d3b908106 100644
--- a/store/store.go
+++ b/store/store.go
@@ -153,6 +153,7 @@ type UserStore interface {
 	PermanentDelete(userId string) StoreChannel
 	AnalyticsUniqueUserCount(teamId string) StoreChannel
 	GetUnreadCount(userId string) StoreChannel
+	GetUnreadCountForChannel(userId string, channelId string) StoreChannel
 }
 
 type SessionStore interface {