Add post priority to incoming and outgoing webhook (#26671)

* Added priority to incoming and outgoing webhook

* fixed fat finger

* Added priority tests

* fixed golint

---------

Co-authored-by: Mattermost Build <build@mattermost.com>

server/channels/app/webhook.go

@@ -180,7 +180,7 @@ func (a *App) TriggerWebhook(c request.CTX, payload *model.OutgoingWebhookPayloa
 				if *a.Config().ServiceSettings.EnablePostIconOverride && hook.IconURL != "" && webhookResp.IconURL == "" {
 					webhookResp.IconURL = hook.IconURL
 				}
-				if _, err := a.CreateWebhookPost(c, hook.CreatorId, channel, text, webhookResp.Username, webhookResp.IconURL, "", webhookResp.Props, webhookResp.Type, postRootId); err != nil {
+				if _, err := a.CreateWebhookPost(c, hook.CreatorId, channel, text, webhookResp.Username, webhookResp.IconURL, "", webhookResp.Props, webhookResp.Type, postRootId, webhookResp.Priority); err != nil {
 					c.Logger().Error("Failed to create response post.", mlog.Err(err))
 				}
 			}
@@ -304,13 +304,23 @@ func SplitWebhookPost(post *model.Post, maxPostSize int) ([]*model.Post, *model.
 	return splits, nil
 }
 
-func (a *App) CreateWebhookPost(c request.CTX, userID string, channel *model.Channel, text, overrideUsername, overrideIconURL, overrideIconEmoji string, props model.StringInterface, postType string, postRootId string) (*model.Post, *model.AppError) {
+func (a *App) CreateWebhookPost(c request.CTX, userID string, channel *model.Channel, text, overrideUsername, overrideIconURL, overrideIconEmoji string, props model.StringInterface, postType string, postRootId string, priority *model.PostPriority) (*model.Post, *model.AppError) {
 	// parse links into Markdown format
 	text = linkWithTextRegex.ReplaceAllString(text, "[${2}](${1})")
 
 	post := &model.Post{UserId: userID, ChannelId: channel.Id, Message: text, Type: postType, RootId: postRootId}
 	post.AddProp("from_webhook", "true")
 
+	if priority != nil {
+		if priority.Priority == nil {
+			err := model.NewAppError("CreateWebhookPost", "api.context.invalid_param.app_error", map[string]any{"Name": "webhook.priority.priority"}, "Setting the priority of a post is required to use priority.", http.StatusBadRequest)
+			return nil, err
+		}
+		post.Metadata = &model.PostMetadata{
+			Priority: priority,
+		}
+	}
+
 	if strings.HasPrefix(post.Type, model.PostSystemMessagePrefix) {
 		err := model.NewAppError("CreateWebhookPost", "api.context.invalid_param.app_error", map[string]any{"Name": "post.type"}, "", http.StatusBadRequest)
 		return nil, err
@@ -830,7 +840,7 @@ func (a *App) HandleIncomingWebhook(c request.CTX, hookID string, req *model.Inc
 		overrideIconURL = req.IconURL
 	}
 
-	_, err := a.CreateWebhookPost(c, hook.UserId, channel, text, overrideUsername, overrideIconURL, req.IconEmoji, req.Props, webhookType, "")
+	_, err := a.CreateWebhookPost(c, hook.UserId, channel, text, overrideUsername, overrideIconURL, req.IconEmoji, req.Props, webhookType, "", req.Priority)
 	return err
 }