send automatic message on forum post deletion

closes lichess-org/tavern#101

app/controllers/ForumPost.scala

@@ -77,14 +77,22 @@ final class ForumPost(env: Env) extends LilaController(env) with ForumController
     }
 
   def delete(categSlug: String, id: String) =
-    Auth { implicit ctx => me =>
+    AuthBody { implicit ctx => me =>
       postApi getPost id flatMap {
         _ ?? { post =>
           if (me.id == ~post.userId && !post.erased)
             postApi.erasePost(post) inject Redirect(routes.ForumPost.redirect(id))
           else
             isGrantedMod(categSlug) flatMap { granted =>
-              (granted | isGranted(_.ModerateForum)) ?? postApi.delete(categSlug, id, me) map { Ok(_) }
+              (granted | isGranted(_.ModerateForum)) ?? postApi.delete(categSlug, id, me) inject {
+                implicit val req = ctx.body
+                for {
+                  userId    <- post.userId
+                  reasonOpt <- forms.deleteWithReason.bindFromRequest().value
+                  reason    <- reasonOpt
+                } env.msg.api.systemPost(userId, lila.msg.MsgPreset forumDeletion reason)
+                NoContent
+              }
             }
         }
       }

app/views/forum/topic.scala

@@ -167,7 +167,7 @@ object topic {
                   if (topic.isSticky) "Unsticky" else "Sticky"
                 )
               ),
-              deleteDialog
+              deleteModal
             )
           )
         ),
@@ -203,15 +203,15 @@ object topic {
       )
     }
 
-  private def deleteDialog(implicit ctx: Context) =
+  private def deleteModal(implicit ctx: Context) =
     div(cls := "forum-delete-modal none")(
       p("Delete the post"),
-      st.form(method := "dialog", cls := "form3")(
+      st.form(method := "post", cls := "form3")(
         st.select(
           name := "reason",
           cls := "form-control"
         )(
-          option(value := "")("No message"),
+          option(value := "")("no message"),
           List(
             "public shaming",
             "disrespecting other players",

modules/forum/src/main/ForumForm.scala

@@ -41,6 +41,10 @@ final private[forum] class ForumForm(
       )(TopicData.apply)(TopicData.unapply)
     )
 
+  val deleteWithReason = Form(
+    single("reason" -> optional(nonEmptyText))
+  )
+
   private def userTextMapping(user: User, inOwnTeam: Boolean) =
     cleanText(minLength = 3)
       .verifying(

modules/msg/src/main/MsgPreset.scala

@@ -37,4 +37,7 @@ To follow new players, you must first unfollow some on https://lichess.org/@/$us
 
 Thank you for your understanding."""
     )
+
+  def forumDeletion(reason: String) =
+    s"""A moderator deleted one of your posts for this reason: $reason. Please read our Forum-Etiquette: https://lichess.org/page/forum-etiquette"""
 }

ui/site/src/forum.ts

@@ -4,11 +4,17 @@ import modal from 'common/modal';
 lichess.load.then(() => {
   $('.forum')
     .on('click', 'a.delete', function (this: HTMLAnchorElement) {
-      console.log(this);
+      const link = this;
       const $wrap = modal($('.forum-delete-modal'));
-      $wrap.find('form').attr('action', this.href);
-      // xhr.text(this.href, { method: 'post' });
-      // $(this).closest('.forum-post').hide();
+      $wrap
+        .find('form')
+        .attr('action', link.href)
+        .on('submit', function (this: HTMLFormElement, e: Event) {
+          e.preventDefault();
+          xhr.formToXhr(this);
+          modal.close();
+          $(link).closest('.forum-post').hide();
+        });
       return false;
     })
     .on('click', 'form.unsub button', function (this: HTMLButtonElement) {