From 0a5875221f38c71ba567f52f80dede3d1e03f324 Mon Sep 17 00:00:00 2001
From: Thibault Duplessis <thibault.duplessis@gmail.com>
Date: Mon, 20 Apr 2020 13:58:12 -0600
Subject: [PATCH] limit heavy class features to reaonably sized classes

---
 app/controllers/Clas.scala            | 30 +++++++++++++++++++--------
 app/views/clas/bits.scala             |  2 +-
 app/views/clas/teacherDashboard.scala | 16 ++++++++++++++
 3 files changed, 38 insertions(+), 10 deletions(-)

diff --git a/app/controllers/Clas.scala b/app/controllers/Clas.scala
index 76e131490c..6943a3bc97 100644
--- a/app/controllers/Clas.scala
+++ b/app/controllers/Clas.scala
@@ -127,8 +127,10 @@ final class Clas(
 
   def notifyStudents(id: String) = Secure(_.Teacher) { implicit ctx => me =>
     WithClass(me, id) { clas =>
-      env.clas.api.student.activeWithUsers(clas) map { students =>
-        Ok(html.clas.clas.notify(clas, students, env.clas.forms.clas.notifyText))
+      env.clas.api.student.activeWithUsers(clas) flatMap { students =>
+        Reasonable(clas, students, "notify") {
+          Ok(html.clas.clas.notify(clas, students, env.clas.forms.clas.notifyText)).fuccess
+        }
       }
     }
   }
@@ -144,11 +146,13 @@ final class Clas(
             },
           text =>
             env.clas.api.student.activeWithUsers(clas) flatMap { students =>
-              val url  = routes.Clas.show(clas.id.value).url
-              val full = if (text contains url) text else s"$text\n\n${env.net.baseUrl}$url"
-              env.msg.api.multiPost(me, students.map(_.user.id), full)
-            } inject
-              Redirect(routes.Clas.show(clas.id.value)).flashSuccess
+              Reasonable(clas, students, "notify") {
+                val url  = routes.Clas.show(clas.id.value).url
+                val full = if (text contains url) text else s"$text\n\n${env.net.baseUrl}$url"
+                env.msg.api.multiPost(me, students.map(_.user.id), full) inject
+                  Redirect(routes.Clas.show(clas.id.value)).flashSuccess
+              }
+            }
         )
     }
   }
@@ -165,8 +169,10 @@ final class Clas(
     lila.rating.PerfType(key) ?? { perfType =>
       WithClass(me, id) { clas =>
         env.clas.api.student.activeWithUsers(clas) flatMap { students =>
-          env.clas.progressApi(perfType, days, students) map { progress =>
-            views.html.clas.teacherDashboard.progress(clas, students, progress)
+          Reasonable(clas, students, "progress") {
+            env.clas.progressApi(perfType, days, students) map { progress =>
+              views.html.clas.teacherDashboard.progress(clas, students, progress)
+            }
           }
         }
       }
@@ -406,6 +412,12 @@ final class Clas(
     Redirect("https://forms.gle/b19pDZZuotncxtbRA")
   }
 
+  private def Reasonable(clas: lila.clas.Clas, students: List[lila.clas.Student.WithUser], active: String)(
+      f: => Fu[Result]
+  )(implicit ctx: Context): Fu[Result] =
+    if (students.size <= lila.clas.Clas.maxStudents) f
+    else Unauthorized(views.html.clas.teacherDashboard.unreasonable(clas, students, active)).fuccess
+
   private def WithClass(me: lila.user.User, clasId: String)(
       f: lila.clas.Clas => Fu[Result]
   ): Fu[Result] =
diff --git a/app/views/clas/bits.scala b/app/views/clas/bits.scala
index a4cf2b8a4e..fe9257814b 100644
--- a/app/views/clas/bits.scala
+++ b/app/views/clas/bits.scala
@@ -6,7 +6,7 @@ import lila.app.templating.Environment._
 import lila.app.ui.ScalatagsTemplate._
 import lila.clas.{ Clas, Student }
 
-private object bits {
+object bits {
 
   def layout(
       title: String,
diff --git a/app/views/clas/teacherDashboard.scala b/app/views/clas/teacherDashboard.scala
index b79c7f9e88..0c050b0cc7 100644
--- a/app/views/clas/teacherDashboard.scala
+++ b/app/views/clas/teacherDashboard.scala
@@ -80,6 +80,22 @@ object teacherDashboard {
         studentList(c, archived)
     }
 
+  def unreasonable(c: Clas, students: List[Student.WithUser], active: String)(implicit ctx: Context) =
+    layout(c, students, active)(
+      div(cls := "box__pad students__empty")(
+        p(
+          "This feature is only available for classes of ",
+          lila.clas.Clas.maxStudents,
+          " or fewer students."
+        ),
+        p(
+          "This class has ",
+          students.size,
+          " students. You could maybe create more classes to split the students."
+        )
+      )
+    )
+
   def progress(
       c: Clas,
       students: List[Student.WithUser],