Improve class switch pedestals

- Related to #183 and #216
 - Holographic items are now removed when you place a new pedestal, or when you destroy it
 - Pedestals are only diggable by admins (but punchable with a tool handling cracky 3 level)

mods/pclasses/nodes.lua

@@ -42,18 +42,22 @@ minetest.register_entity("pclasses:item", {
 		self.object:set_properties(prop)
 	end,
 	on_rightclick = function(self, clicker)
-		print(clicker:get_player_name())
-		print(self.class)
 		pclasses.api.set_player_class(clicker:get_player_name(), self.class)
 	end,
 	on_activate = function(self, staticdata)
+		local tab = minetest.deserialize(staticdata)
+		if tab then
+			self.itemname = tab.itemname
+			self.class = tab.class
+		else
 			self.itemname = staticdata:split("|")[1]
 			self.class = staticdata:split("|")[2]
+		end
 		self.object:set_armor_groups({immortal=1})
 		self:set_item(self.itemname)
 	end,
 	get_staticdata = function(self)
-		return self.itemname .. "|" ..  self.class
+		return minetest.serialize({itemname = self.itemname, class = self.class})
 	end,
 })
 
@@ -69,7 +73,6 @@ function pclasses.register_class_switch(cname, params)
 	local color = params.color or { r = 255, g = 255, b = 255 }
 	local txtcolor = string.format("#%02x%02x%02x", color.r, color.g, color.b)
 	local overlay = "pclasses_class_switch_orb_overlay.png"
-	print((params.tile or overlay))
 	minetest.register_node(":pclasses:class_switch_" .. cname, {
 		description = "Class switch orb (" .. cname .. ")",
 		tiles = {(params.tile or overlay) .. "^[colorize:" .. txtcolor .. ":200"},
@@ -80,20 +83,55 @@ function pclasses.register_class_switch(cname, params)
 			{-0.25, -6/16, -0.25, 0.25, 11/16, 0.25}, -- pillar
 			{-7/16, 11/16, -7/16, 7/16, 12/16, 7/16}, -- top plate
 		}},
-		drop = "",
+		can_dig = function(pos, player) return minetest.get_player_privs(player:get_player_name()).server == true end,
-		can_dig = function() return false end,
-		diggable = false,
 		sunlight_propagates = true,
 		light_source = 10,
 		sounds = default.node_sound_glass_defaults(),
-		groups = {cracky = 1},
+		groups = {unbreakable = 1},
 		after_place_node = function(pos)
 			pos.y = pos.y + 1
+
+			-- Clean remaining entities
+			for _,ref in pairs(minetest.get_objects_inside_radius(pos, 1)) do
+				local e = ref:get_luaentity()
+				if e and e.name == "pclasses:item" then
+					ref:remove()
+				end
+			end
+
 			local obj = minetest.add_entity(pos, "pclasses:item")
 			if obj then
 				obj:get_luaentity():set_item(classes_items[cname])
 				obj:get_luaentity():set_class(cname)
 			end
+			pos.y = pos.y - 1
+			local timer = minetest.get_node_timer(pos)
+			timer:start(3)
+		end,
+		on_timer = function(pos)
+			pos.y = pos.y + 1
+			for _,ref in pairs(minetest.get_objects_inside_radius(pos, 1)) do
+				local e = ref:get_luaentity()
+				if e and e.name == "pclasses:item" then
+					return true
+				end
+			end
+
+			local obj = minetest.add_entity(pos, "pclasses:item")
+			if obj then
+				obj:get_luaentity():set_item(classes_items[cname])
+				obj:get_luaentity():set_class(cname)
+			end
+			return true
+		end,
+		on_destruct = function(pos)
+			pos.y = pos.y + 1
+			for _,ref in pairs(minetest.get_objects_inside_radius(pos, 1)) do
+				local e = ref:get_luaentity()
+				if e and e.name == "pclasses:item" then
+					ref:remove()
+				end
+			end
 		end,
 	})
 end