Use callbacks for items, monsters and status effects

Previously, global function names were defined in the respective XML
definitions of items, monsters and status effects. This was reasonable when
they all had the same state, but now they're sharing the single global
Lua state.

Now the Lua API provides access to the ItemClass, MonsterClass and
StatusEffect instances, on which callbacks for both standard and custom
events can be explicitly set.

Reviewed-by: Erik Schilling

2 files changed, 97 insertions, 37 deletions

diff --git a/src/scripting/lua.cpp b/src/scripting/lua.cpp
index 3d59ab98..c6a75d90 100644
--- a/src/scripting/lua.cpp
+++ b/src/scripting/lua.cpp
@@ -46,6 +46,8 @@ extern "C" {
 #include "game-server/postman.h"
 #include "game-server/quest.h"
 #include "game-server/state.h"
+#include "game-server/statuseffect.h"
+#include "game-server/statusmanager.h"
 #include "game-server/trigger.h"
 #include "net/messageout.h"
 #include "scripting/luautil.h"
@@ -210,6 +212,27 @@ static int on_get_special_recharge_cost(lua_State *s)
     return 0;
 }
 
+static int get_item_class(lua_State *s)
+{
+    const char *name = luaL_checkstring(s, 1);
+    LuaItemClass::push(s, itemManager->getItemByName(name));
+    return 1;
+}
+
+static int get_monster_class(lua_State *s)
+{
+    const char *name = luaL_checkstring(s, 1);
+    LuaMonsterClass::push(s, monsterManager->getMonsterByName(name));
+    return 1;
+}
+
+static int get_status_effect(lua_State *s)
+{
+    const char *name = luaL_checkstring(s, 1);
+    LuaStatusEffect::push(s, StatusManager::getStatusByName(name));
+    return 1;
+}
+
 /**
  * mana.npc_message(NPC*, Character*, string): void
  * Callback for sending a NPC_MESSAGE.
@@ -1507,6 +1530,23 @@ static int posY(lua_State *s)
     return 0;
 }
 
+static int monster_class_on_update(lua_State *s)
+{
+    MonsterClass *monsterClass = LuaMonsterClass::check(s, 1);
+    luaL_checktype(s, 2, LUA_TFUNCTION);
+    monsterClass->setUpdateCallback(getScript(s));
+    return 0;
+}
+
+static int monster_class_on(lua_State *s)
+{
+    MonsterClass *monsterClass = LuaMonsterClass::check(s, 1);
+    const char *event = luaL_checkstring(s, 2);
+    luaL_checktype(s, 3, LUA_TFUNCTION);
+    monsterClass->setEventCallback(event, getScript(s));
+    return 0;
+}
+
 /**
  * mana.monster_create(int id || string name, int x, int y): Monster*
  * Callback for creating a monster on the current map.
@@ -1620,32 +1660,6 @@ static int monster_remove(lua_State *s)
 }
 
 /**
- * mana.monster_load_script(Monster*, string script_filename): void
- * loads a LUA script for the given monster.
- */
-static int monster_load_script(lua_State *s)
-{
-    Monster *m = getMonster(s, 1);
-    if (!m)
-    {
-         raiseScriptError(s, "monster_load_script called "
-                          "for a nonexistent monster.");
-         return 0;
-    }
-
-    const char *scriptName = luaL_checkstring(s, 2);
-    if (scriptName[0] == 0)
-    {
-        raiseScriptError(s, "monster_load_script called "
-                         "with empty script file name.");
-        return 0;
-    }
-
-    m->loadScript(scriptName);
-    return 0;
-}
-
-/**
  * mana.chr_get_chest(Character*, string): nil or string
  * Callback for getting a quest variable. Starts a recovery and returns
  * immediatly, if the variable is not known yet.
@@ -1959,9 +1973,8 @@ static int chr_get_post(lua_State *s)
 
 /**
  * mana.being_register(Being*): void
- * Makes the server call the lua functions deathEvent
- * and removeEvent when the being dies or is removed
- * from the map.
+ * Makes the server call the on_being_death and on_being_remove callbacks
+ * when the being dies or is removed from the map.
  */
 static int being_register(lua_State *s)
 {
@@ -2453,6 +2466,15 @@ static int is_walkable(lua_State *s)
     return 1;
 }
 
+static int item_class_on(lua_State *s)
+{
+    ItemClass *itemClass = LuaItemClass::check(s, 1);
+    const char *event = luaL_checkstring(s, 2);
+    luaL_checktype(s, 3, LUA_TFUNCTION);
+    itemClass->setEventCallback(event, getScript(s));
+    return 0;
+}
+
 /**
  * mana.drop_item(int x, int y, int id || string name[, int number]): bool
  * Creates an item stack on the floor.
@@ -2651,6 +2673,14 @@ static int map_object_get_type(lua_State *s)
     return 1;
 }
 
+static int status_effect_on_tick(lua_State *s)
+{
+    StatusEffect *statusEffect = LuaStatusEffect::check(s, 1);
+    luaL_checktype(s, 2, LUA_TFUNCTION);
+    statusEffect->setTickCallback(getScript(s));
+    return 0;
+}
+
 /**
  * mana.announce(text [, sender])
  * Does a global announce
@@ -2719,6 +2749,9 @@ LuaScript::LuaScript():
         { "on_craft",                        &on_craft                        },
         { "on_use_special",                  &on_use_special                  },
         { "on_get_special_recharge_cost",    &on_get_special_recharge_cost    },
+        { "get_item_class",                  &get_item_class                  },
+        { "get_monster_class",               &get_monster_class               },
+        { "get_status_effect",               &get_status_effect               },
         { "npc_create",                      &npc_create                      },
         { "npc_message",                     &npc_message                     },
         { "npc_choice",                      &npc_choice                      },
@@ -2761,7 +2794,6 @@ LuaScript::LuaScript():
         { "monster_get_name",                &monster_get_name                },
         { "monster_change_anger",            &monster_change_anger            },
         { "monster_remove",                  &monster_remove                  },
-        { "monster_load_script",             &monster_load_script             },
         { "being_apply_status",              &being_apply_status              },
         { "being_remove_status",             &being_remove_status             },
         { "being_has_status",                &being_has_status                },
@@ -2809,6 +2841,11 @@ LuaScript::LuaScript():
     luaL_register(mState, "mana", callbacks);
     lua_pop(mState, 1);                     // pop the 'mana' table
 
+    static luaL_Reg const members_ItemClass[] = {
+        { "on",                              &item_class_on                   },
+        { NULL, NULL }
+    };
+
     static luaL_Reg const members_MapObject[] = {
         { "property",                        &map_object_get_property         },
         { "bounds",                          &map_object_get_bounds           },
@@ -2817,7 +2854,21 @@ LuaScript::LuaScript():
         { NULL, NULL }
     };
 
+    static luaL_Reg const members_MonsterClass[] = {
+        { "on_update",                       &monster_class_on_update         },
+        { "on",                              &monster_class_on                },
+        { NULL, NULL }
+    };
+
+    static luaL_Reg const members_StatusEffect[] = {
+        { "on_tick",                         &status_effect_on_tick           },
+        { NULL, NULL }
+    };
+
+    LuaItemClass::registerType(mState, "ItemClass", members_ItemClass);
     LuaMapObject::registerType(mState, "MapObject", members_MapObject);
+    LuaMonsterClass::registerType(mState, "MonsterClass", members_MonsterClass);
+    LuaStatusEffect::registerType(mState, "StatusEffect", members_StatusEffect);
 
     // Make script object available to callback functions.
     lua_pushlightuserdata(mState, const_cast<char *>(&registryKey));
diff --git a/src/scripting/luautil.h b/src/scripting/luautil.h
index 049276fe..2fc7543a 100644
--- a/src/scripting/luautil.h
+++ b/src/scripting/luautil.h
@@ -31,12 +31,14 @@ extern "C" {
 #include <set>
 #include <vector>
 
-#include "game-server/map.h"
-
 class Being;
-class NPC;
 class Character;
+class ItemClass;
+class MapObject;
 class Monster;
+class MonsterClass;
+class NPC;
+class StatusEffect;
 class Thing;
 
 // Report script errors and interrupt the script.
@@ -105,10 +107,16 @@ public:
     /**
      * Pushes a userdata reference to the given object on the stack. Either by
      * creating one, or reusing an existing one.
+     *
+     * When a null-pointer is passed for \a object, the value 'nil' is pushed.
      */
-    static int push(lua_State *s, T *object)
+    static void push(lua_State *s, T *object)
     {
-        if (!UserDataCache::retrieve(s, object))
+        if (!object)
+        {
+            lua_pushnil(s);
+        }
+        else if (!UserDataCache::retrieve(s, object))
         {
             void *userData = lua_newuserdata(s, sizeof(T*));
             * static_cast<T**>(userData) = object;
@@ -118,8 +126,6 @@ public:
 
             UserDataCache::insert(s, object);
         }
-
-        return 1;
     }
 
     /**
@@ -138,7 +144,10 @@ private:
 
 template <typename T> const char * LuaUserData<T>::mTypeName;
 
+typedef LuaUserData<ItemClass> LuaItemClass;
 typedef LuaUserData<MapObject> LuaMapObject;
+typedef LuaUserData<MonsterClass> LuaMonsterClass;
+typedef LuaUserData<StatusEffect> LuaStatusEffect;
 
 
 NPC *getNPC(lua_State *s, int p);