add chatcommand banners_fix

fixes #7
provides a work-around for the engine problem with entities.

.luacheckrc

@@ -8,5 +8,7 @@ read_globals = {
     "dump",
     "factions",
     "inventory_plus",
+    "table" = { "insert_all" },
     "unified_inventory",
+    "vector",
 }

chatcommands.lua

@@ -0,0 +1,53 @@
+-- Due to some engine troubles there are sometimes stray
+-- banner entities and more rarely there are banner nodes without entities.
+-- Calling this command fixes both situations.
+core.register_chatcommand("banners_fix", {
+    description = "recreates the banner-visuals in your area",
+    func = function(name)
+        local player = core.get_player_by_name(name)
+        if not player then
+            return
+        end
+
+        local pos = player:get_pos()
+        local t1 = core.get_us_time()
+
+        local radius = 10
+        local entity_count = 0
+        local objects = core.get_objects_inside_radius(pos, radius)
+        for _, v in ipairs(objects) do
+            local e = v:get_luaentity()
+            if e and e.name == "banners:banner_ent" then
+                entity_count = entity_count + 1
+                v:remove()
+            end
+        end
+
+        local pos1 = vector.subtract(pos, radius)
+        local pos2 = vector.add(pos, radius)
+        local nodes = {
+            "banners:wooden_banner",
+            "banners:steel_banner",
+        }
+        if core.get_modpath("factions") then
+            table.insert_all(nodes, {
+                "banners:power_banner",
+                "banners:death_banner",
+
+            })
+        end
+        local pos_list = core.find_nodes_in_area(pos1, pos2, nodes)
+
+        for _, node_pos in ipairs(pos_list) do
+            core.add_entity(node_pos, "banners:banner_ent")
+        end
+
+        local t2 = core.get_us_time()
+        local diff = t2 - t1
+        local millis = diff / 1000
+
+        return true, "Removed " .. entity_count .. " banner entities and restored "
+            .. #pos_list .. " banners in " .. millis .. " ms"
+    end
+})
+

init.lua

@@ -352,4 +352,5 @@ end
 dofile(MP .. "items.lua")
 dofile(MP .. "nodes.lua")
 dofile(MP .. "crafts.lua")
+dofile(MP .. "chatcommands.lua")