From aa765ac3dd39f06b1e32bfe02fb6b5ca7e7b3a7e Mon Sep 17 00:00:00 2001
From: kolaente <k@knt.li>
Date: Sat, 13 Feb 2021 21:34:16 +0100
Subject: [PATCH] Send notification to subscribers for task comment

---
 magefile.go                 |  2 +-
 pkg/models/listeners.go     | 57 +++++++++++++++++++++++++++++++++++++
 pkg/models/notifications.go | 29 +++++++++++++++++++
 pkg/models/subscription.go  | 29 +++++++++++++++++++
 4 files changed, 116 insertions(+), 1 deletion(-)

diff --git a/magefile.go b/magefile.go
index a4733b431..1aac4d31f 100644
--- a/magefile.go
+++ b/magefile.go
@@ -827,7 +827,7 @@ func (s *` + name + `) Name() string {
 	return "` + listenerName + `"
 }
 
-// Hanlde is executed when the event ` + name + ` listens on is fired
+// Handle is executed when the event ` + name + ` listens on is fired
 func (s *` + name + `) Handle(payload message.Payload) (err error) {
 	event := &` + event + `{}
 	err = json.Unmarshal(payload, event)
diff --git a/pkg/models/listeners.go b/pkg/models/listeners.go
index 74826f76a..00241f652 100644
--- a/pkg/models/listeners.go
+++ b/pkg/models/listeners.go
@@ -17,9 +17,14 @@
 package models
 
 import (
+	"code.vikunja.io/api/pkg/db"
 	"code.vikunja.io/api/pkg/events"
+	"code.vikunja.io/api/pkg/log"
 	"code.vikunja.io/api/pkg/metrics"
 	"code.vikunja.io/api/pkg/modules/keyvalue"
+	"code.vikunja.io/api/pkg/notifications"
+	"code.vikunja.io/api/pkg/user"
+	"encoding/json"
 	"github.com/ThreeDotsLabs/watermill/message"
 )
 
@@ -33,6 +38,7 @@ func RegisterListeners() {
 	events.RegisterListener((&TaskDeletedEvent{}).Name(), &DecreaseTaskCounter{})
 	events.RegisterListener((&TeamDeletedEvent{}).Name(), &DecreaseTeamCounter{})
 	events.RegisterListener((&TeamCreatedEvent{}).Name(), &IncreaseTeamCounter{})
+	events.RegisterListener((&TaskCommentCreatedEvent{}).Name(), &SendTaskCommentNotification{})
 }
 
 //////
@@ -66,6 +72,57 @@ func (s *DecreaseTaskCounter) Handle(payload message.Payload) (err error) {
 	return keyvalue.DecrBy(metrics.TaskCountKey, 1)
 }
 
+// SendTaskCommentNotification  represents a listener
+type SendTaskCommentNotification struct {
+}
+
+// Name defines the name for the SendTaskCommentNotification listener
+func (s *SendTaskCommentNotification) Name() string {
+	return "send.task.comment.notification"
+}
+
+// Handle is executed when the event SendTaskCommentNotification listens on is fired
+func (s *SendTaskCommentNotification) Handle(payload message.Payload) (err error) {
+	event := &TaskCommentCreatedEvent{}
+	err = json.Unmarshal(payload, event)
+	if err != nil {
+		return err
+	}
+
+	doer, is := event.Doer.(*user.User)
+	if !is {
+		return
+	}
+
+	sess := db.NewSession()
+	defer sess.Close()
+
+	subscribers, err := getSubscribersForEntity(sess, SubscriptionEntityTask, event.Task.ID)
+	if err != nil {
+		return err
+	}
+
+	log.Debugf("Sending task comment notifications to %d subscribers for task %d", len(subscribers), event.Task.ID)
+
+	for _, subscriber := range subscribers {
+		if subscriber.UserID == doer.ID {
+			continue
+		}
+
+		n := &TaskCommentNotification{
+			Doer:    doer,
+			Task:    event.Task,
+			Comment: event.Comment,
+		}
+		err = notifications.Notify(subscriber.User, n)
+		if err != nil {
+			return
+		}
+	}
+
+	return
+}
+
 ///////
 // List Event Listeners
 
diff --git a/pkg/models/notifications.go b/pkg/models/notifications.go
index af655aaae..10a06f1d0 100644
--- a/pkg/models/notifications.go
+++ b/pkg/models/notifications.go
@@ -17,7 +17,9 @@
 package models
 
 import (
+	"bufio"
 	"strconv"
+	"strings"
 
 	"code.vikunja.io/api/pkg/config"
 	"code.vikunja.io/api/pkg/notifications"
@@ -45,3 +47,30 @@ func (n *ReminderDueNotification) ToMail() *notifications.Mail {
 func (n *ReminderDueNotification) ToDB() interface{} {
 	return nil
 }
+
+// TaskCommentNotification represents a TaskCommentNotification notification
+type TaskCommentNotification struct {
+	Doer    *user.User
+	Task    *Task
+	Comment *TaskComment
+}
+
+// ToMail returns the mail notification for TaskCommentNotification
+func (n *TaskCommentNotification) ToMail() *notifications.Mail {
+
+	mail := notifications.NewMail().
+		Subject("Re: " + n.Task.Title)
+
+	lines := bufio.NewScanner(strings.NewReader(n.Comment.Comment))
+	for lines.Scan() {
+		mail.Line(lines.Text())
+	}
+
+	return mail.
+		Action("View Task", config.ServiceFrontendurl.GetString()+"tasks/"+strconv.FormatInt(n.Task.ID, 10))
+}
+
+// ToDB returns the TaskCommentNotification notification in a format which can be saved in the db
+func (n *TaskCommentNotification) ToDB() interface{} {
+	return n
+}
diff --git a/pkg/models/subscription.go b/pkg/models/subscription.go
index b20a3bc08..3a5807486 100644
--- a/pkg/models/subscription.go
+++ b/pkg/models/subscription.go
@@ -222,3 +222,32 @@ func GetSubscription(s *xorm.Session, entityType SubscriptionEntityType, entityI
 		Get(subscription)
 	return
 }
+
+func getSubscribersForEntity(s *xorm.Session, entityType SubscriptionEntityType, entityID int64) (subscriptions []*Subscription, err error) {
+	if err := entityType.validate(); err != nil {
+		return nil, err
+	}
+
+	cond := getSubscriberCondForEntity(entityType, entityID)
+	err = s.
+		Where(cond).
+		Find(&subscriptions)
+	if err != nil {
+		return
+	}
+
+	userIDs := []int64{}
+	for _, subscription := range subscriptions {
+		userIDs = append(userIDs, subscription.UserID)
+	}
+
+	users, err := user.GetUsersByIDs(s, userIDs)
+	if err != nil {
+		return
+	}
+
+	for _, subscription := range subscriptions {
+		subscription.User = users[subscription.UserID]
+	}
+	return
+}