prevent players from setting ranks of higher level than their own

rank.conf

@@ -10,15 +10,17 @@
 -- with /rank <player> <rank> Put a list of the privileges for the rank in the privileges table.
 -- Put each privilege on a new line, each line seperated by a comma. You must be a owner or operator
 -- to manage rankings. The owner will automatically be set to the value of the "admin" minetest.conf
--- variable.
+-- variable. The level value is used to make sure that (for example) a operator could not set their
+-- rank to owner. Multiple ranks can have the same level, but if the rank has the "setrank" capability
+-- they could set their rank to any of that level, or a lower level.
 
 -- ENABLED RANKS
 st.ranks = {
   default = "player",
   -- player
-  { name = "player", prefix = "", privs = { interact = true, shout = true, fast = true }, },
+  { name = "player", level = 1, prefix = "", privs = { interact = true, shout = true, fast = true }, },
   -- moderator
-  { name = "moderator", prefix = "[moderator]", colour = "#f1c40f", cmd = "mod", privs = {
+  { name = "moderator", level = 2, prefix = "[moderator]", colour = "#f1c40f", cmd = "mod", privs = {
     interact = true,
     shout = true,
     fast = true,
@@ -32,7 +34,7 @@ st.ranks = {
     "getrank",
   }, },
   -- operator
-  { name = "operator", prefix = "[operator]", colour = "#d35400", cmd = "op", privs = {
+  { name = "operator", level = 3, prefix = "[operator]", colour = "#d35400", cmd = "op", privs = {
     interact = true,
     shout = true,
     fast = true,
@@ -51,7 +53,7 @@ st.ranks = {
     "getrank",
   }, },
   -- owner
-  { name = "owner", prefix = "[owner]", colour = "#e74c3c", privs = {
+  { name = "owner", level = 10, prefix = "[owner]", colour = "#e74c3c", privs = {
     interact = true,
     shout = true,
     fast = true,

rank.lua

@@ -26,6 +26,15 @@ function servertools.get_rank_privs(rank)
   end
 end
 
+-- get rank level
+function servertools.get_rank_level(rank)
+  for _,i in ipairs(st.ranks) do -- find rank
+    if i.name == rank then
+      return i.level -- return level
+    end
+  end
+end
+
 -- get rank value
 function servertools.get_rank_value(rank, value)
   for _,i in ipairs(st.ranks) do -- find rank
@@ -52,7 +61,7 @@ function servertools.player_can(player, capability)
 end
 
 -- set rank
-function servertools.set_player_rank(name, newrank)
+function servertools.set_player_rank(from, name, newrank)
   -- check params
   if not servertools.get_player_rank(name) then
     return "Invalid player ("..name..")"
@@ -66,6 +75,11 @@ function servertools.set_player_rank(name, newrank)
     return "Rank nonexistent."
   end
 
+  -- check level
+  if servertools.get_rank_level(servertools.get_player_rank(from)) < servertools.get_rank_level(newrank) then
+    return "You cannot set the rank of "..name.." to a rank of higher level than your own."
+  end
+
   -- update player privileges
   if minetest.set_player_privs(name, rank_privs) then return "Failed to set privileges." end -- unsuccessful
   -- TODO: fix setting table value
@@ -173,7 +187,7 @@ minetest.register_chatcommand("rank", {
         return true, "Please enter a valid target username and new rank."
       elseif newrank and target then -- if fields available, continue operation
         -- if new rank does not exist, return error
-        local set_rank = servertools.set_player_rank(target, newrank)
+        local set_rank = servertools.set_player_rank(name, target, newrank)
         if set_rank then -- if unsuccessful, return error
           return false, set_rank
         else -- else, return success message
@@ -214,7 +228,7 @@ for _,i in ipairs(st.ranks) do
           -- if not param, return usage
           if not param then return "Usage: /"..i.cmd.." <player>" end
           -- if error while setting rank, return message
-          local set_rank = servertools.set_player_rank(param, i.name)
+          local set_rank = servertools.set_player_rank(name, param, i.name)
           if set_rank then
             return false, set_rank
           else -- else, return success message