PLT-7537: Move channel CLI command posts system message to channel. (#8161)

* [PTL-7537] implement feature and test

* [PTL-7537] Update feature to post the the room requiring a username flag to be used

* [PTL-7537] update tests with username

* update test to remove changes to the test helper struct

* use the basic team and user

6 files changed, 80 insertions, 8 deletions

diff --git a/app/channel.go b/app/channel.go
index e4bf48654..8ac1f421c 100644
--- a/app/channel.go
+++ b/app/channel.go
@@ -1359,7 +1359,7 @@ func (a *App) PermanentDeleteChannel(channel *model.Channel) *model.AppError {
 
 // This function is intended for use from the CLI. It is not robust against people joining the channel while the move
 // is in progress, and therefore should not be used from the API without first fixing this potential race condition.
-func (a *App) MoveChannel(team *model.Team, channel *model.Channel) *model.AppError {
+func (a *App) MoveChannel(team *model.Team, channel *model.Channel, user *model.User) *model.AppError {
 	// Check that all channel members are in the destination team.
 	if channelMembers, err := a.GetChannelMembersPage(channel.Id, 0, 10000000); err != nil {
 		return err
@@ -1378,11 +1378,37 @@ func (a *App) MoveChannel(team *model.Team, channel *model.Channel) *model.AppEr
 		}
 	}
 
-	// Change the Team ID of the channel.
+	// keep instance of the previous team
+	var previousTeam *model.Team
+	if result := <-a.Srv.Store.Team().Get(channel.TeamId); result.Err != nil {
+		return result.Err
+	} else {
+		previousTeam = result.Data.(*model.Team)
+	}
 	channel.TeamId = team.Id
 	if result := <-a.Srv.Store.Channel().Update(channel); result.Err != nil {
 		return result.Err
 	}
+	a.postChannelMoveMessage(user, channel, previousTeam)
+
+	return nil
+}
+
+func (a *App) postChannelMoveMessage(user *model.User, channel *model.Channel, previousTeam *model.Team) *model.AppError {
+
+	post := &model.Post{
+		ChannelId: channel.Id,
+		Message:   fmt.Sprintf(utils.T("api.team.move_channel.success"), previousTeam.Name),
+		Type:      model.POST_MOVE_CHANNEL,
+		UserId:    user.Id,
+		Props: model.StringInterface{
+			"username": user.Username,
+		},
+	}
+
+	if _, err := a.CreatePost(post, channel, false); err != nil {
+		return model.NewAppError("postChannelMoveMessage", "api.team.move_channel.post.error", nil, err.Error(), http.StatusInternalServerError)
+	}
 
 	return nil
 }
diff --git a/app/channel_test.go b/app/channel_test.go
index a414fbb35..d315fbae6 100644
--- a/app/channel_test.go
+++ b/app/channel_test.go
@@ -97,7 +97,7 @@ func TestMoveChannel(t *testing.T) {
 		t.Fatal(err)
 	}
 
-	if err := th.App.MoveChannel(targetTeam, channel1); err == nil {
+	if err := th.App.MoveChannel(targetTeam, channel1, th.BasicUser); err == nil {
 		t.Fatal("Should have failed due to mismatched members.")
 	}
 
@@ -105,7 +105,7 @@ func TestMoveChannel(t *testing.T) {
 		t.Fatal(err)
 	}
 
-	if err := th.App.MoveChannel(targetTeam, channel1); err != nil {
+	if err := th.App.MoveChannel(targetTeam, channel1, th.BasicUser); err != nil {
 		t.Fatal(err)
 	}
 }
diff --git a/cmd/platform/channel.go b/cmd/platform/channel.go
index 98bdcebb8..5d86ad9da 100644
--- a/cmd/platform/channel.go
+++ b/cmd/platform/channel.go
@@ -106,6 +106,8 @@ func init() {
 	channelCreateCmd.Flags().String("purpose", "", "Channel purpose")
 	channelCreateCmd.Flags().Bool("private", false, "Create a private channel.")
 
+	moveChannelsCmd.Flags().String("username", "", "Required. Username who is moving the channel.")
+
 	deleteChannelsCmd.Flags().Bool("confirm", false, "Confirm you really want to delete the channels.")
 
 	modifyChannelCmd.Flags().Bool("private", false, "Convert the channel to a private channel")
@@ -319,26 +321,33 @@ func moveChannelsCmdF(cmd *cobra.Command, args []string) error {
 		return errors.New("Unable to find destination team '" + args[0] + "'")
 	}
 
+	username, erru := cmd.Flags().GetString("username")
+	if erru != nil || username == "" {
+		return errors.New("Username is required")
+	}
+	user := getUserFromUserArg(a, username)
+
 	channels := getChannelsFromChannelArgs(a, args[1:])
 	for i, channel := range channels {
 		if channel == nil {
 			CommandPrintErrorln("Unable to find channel '" + args[i] + "'")
 			continue
 		}
-		if err := moveChannel(a, team, channel); err != nil {
+		originTeamID := channel.TeamId
+		if err := moveChannel(a, team, channel, user); err != nil {
 			CommandPrintErrorln("Unable to move channel '" + channel.Name + "' error: " + err.Error())
 		} else {
-			CommandPrettyPrintln("Moved channel '" + channel.Name + "'")
+			CommandPrettyPrintln("Moved channel '" + channel.Name + "' to " + team.Name + "(" + team.Id + ") from " + originTeamID + ".")
 		}
 	}
 
 	return nil
 }
 
-func moveChannel(a *app.App, team *model.Team, channel *model.Channel) *model.AppError {
+func moveChannel(a *app.App, team *model.Team, channel *model.Channel, user *model.User) *model.AppError {
 	oldTeamId := channel.TeamId
 
-	if err := a.MoveChannel(team, channel); err != nil {
+	if err := a.MoveChannel(team, channel, user); err != nil {
 		return err
 	}
 
diff --git a/cmd/platform/channel_test.go b/cmd/platform/channel_test.go
index 1e6915679..cf8603cf3 100644
--- a/cmd/platform/channel_test.go
+++ b/cmd/platform/channel_test.go
@@ -44,6 +44,33 @@ func TestRemoveChannel(t *testing.T) {
 	checkCommand(t, "channel", "remove", th.BasicTeam.Name+":"+channel.Name, th.BasicUser2.Email)
 }
 
+func TestMoveChannel(t *testing.T) {
+	th := api.Setup().InitBasic()
+	defer th.TearDown()
+
+	client := th.BasicClient
+	team1 := th.BasicTeam
+	team2 := th.CreateTeam(client)
+	user1 := th.BasicUser
+	th.LinkUserToTeam(user1, team2)
+	channel := th.BasicChannel
+
+	th.LinkUserToTeam(user1, team1)
+	th.LinkUserToTeam(user1, team2)
+
+	adminEmail := user1.Email
+	adminUsername := user1.Username
+	origin := team1.Name + ":" + channel.Name
+	dest := team2.Name
+
+	checkCommand(t, "channel", "add", origin, adminEmail)
+
+	// should fail with nill because errors are logged instead of returned when a channel does not exist
+	require.Nil(t, runCommand(t, "channel", "move", dest, team1.Name+":doesnotexist", "--username", adminUsername))
+
+	checkCommand(t, "channel", "move", dest, origin, "--username", adminUsername)
+}
+
 func TestListChannels(t *testing.T) {
 	th := api.Setup().InitBasic()
 	defer th.TearDown()
diff --git a/i18n/en.json b/i18n/en.json
index 1a04aeeed..21f0661cc 100644
--- a/i18n/en.json
+++ b/i18n/en.json
@@ -3131,6 +3131,14 @@
     "translation": "Cannot move a channel unless all its members are already members of the destination team."
   },
   {
+    "id": "api.team.move_channel.success",
+    "translation": "This channel has been moved to this team from %v."
+  },
+  {
+    "id": "api.team.move_channel.post.error",
+    "translation": "Failed to post channel move message."
+  },
+  {
     "id": "app.channel.post_update_channel_purpose_message.post.error",
     "translation": "Failed to post channel purpose message"
   },
diff --git a/model/post.go b/model/post.go
index 391b948f4..7cf0f1b35 100644
--- a/model/post.go
+++ b/model/post.go
@@ -28,6 +28,7 @@ const (
 	POST_ADD_REMOVE             = "system_add_remove" // Deprecated, use POST_ADD_TO_CHANNEL or POST_REMOVE_FROM_CHANNEL instead
 	POST_ADD_TO_CHANNEL         = "system_add_to_channel"
 	POST_REMOVE_FROM_CHANNEL    = "system_remove_from_channel"
+	POST_MOVE_CHANNEL           = "system_move_channel"
 	POST_ADD_TO_TEAM            = "system_add_to_team"
 	POST_REMOVE_FROM_TEAM       = "system_remove_from_team"
 	POST_HEADER_CHANGE          = "system_header_change"
@@ -196,6 +197,7 @@ func (o *Post) IsValid() *AppError {
 		POST_LEAVE_TEAM,
 		POST_ADD_TO_CHANNEL,
 		POST_REMOVE_FROM_CHANNEL,
+		POST_MOVE_CHANNEL,
 		POST_ADD_TO_TEAM,
 		POST_REMOVE_FROM_TEAM,
 		POST_SLACK_ATTACHMENT,