Add teacher privilege

gui.lua

@@ -24,9 +24,19 @@ local function get_group(context)
 	end
 end
 
-sfinv.register_page("edu", {
+sfinv.register_page("classroom:edu", {
 	title = "Classroom",
+	check_perm = function(self, player)
+		return minetest.check_player_privs(player:get_player_name(), { teacher = true })
+	end,
+	is_in_nav = function(self, player, context)
+		return self:check_perm(player)
+	end,
 	get = function(self, player, context)
+		if not self:check_perm(player) then
+			return "label[0,0;Access denied]"
+		end
+
 		local fs = {
 			"tablecolumns[color;text"
 		}
@@ -156,6 +166,11 @@ sfinv.register_page("edu", {
 		return sfinv.make_formspec(player, context, table.concat(fs, ""), false)
 	end,
 	on_player_receive_fields = function(self, player, context, fields)
+		if not self:check_perm(player) then
+			sfinv.set_page(player, sfinv.get_homepage_name(player))
+			return true
+		end
+
 		if fields.students then
 			local evt = minetest.explode_table_event(fields.students)
 			local i = (evt.row or 0) - 1
@@ -212,3 +227,21 @@ sfinv.register_page("edu", {
 		end
 	end,
 })
+
+local function on_grant_revoke(grantee, granter, priv)
+    if priv ~= "teacher" then
+        return
+    end
+
+    local player = minetest.get_player_by_name(grantee)
+    if not player then
+        return
+    end
+
+	minetest.after(0, function()
+		sfinv.set_player_inventory_formspec(player)
+	end)
+end
+
+minetest.register_on_priv_grant(on_grant_revoke)
+minetest.register_on_priv_revoke(on_grant_revoke)

init.lua

@@ -3,3 +3,7 @@ classroom = {}
 dofile(minetest.get_modpath("classroom") .. "/api.lua")
 dofile(minetest.get_modpath("classroom") .. "/gui.lua")
 dofile(minetest.get_modpath("classroom") .. "/actions.lua")
+
+minetest.register_privilege("teacher", {
+	give_to_singleplayer = false
+})