3 files changed, 89 insertions, 14 deletions

diff --git a/src/scripting/lua.cpp b/src/scripting/lua.cpp
index 790d6d91..da47d931 100644
--- a/src/scripting/lua.cpp
+++ b/src/scripting/lua.cpp
@@ -59,7 +59,6 @@ extern "C" {
  * http://doc.manasource.org/scripting
  */
 
-
 /**
  * Callback for sending a NPC_MESSAGE.
  * mana.npc_message(npc, character, string)
@@ -79,7 +78,7 @@ static int npc_message(lua_State *s)
     msg.writeShort(p->getPublicID());
     msg.writeString(std::string(m), l);
     gameHandler->sendTo(q, msg);
-    return 0;
+    return 1;
 }
 
 /**
@@ -442,44 +441,106 @@ static int chr_inv_count(lua_State *s)
 /**
  * Callback for trading between a player and an NPC.
  * mana.npc_trade(npc, character, bool sell, table items)
+ * Let the player buy or sell only a subset of predeterminded items.
+ * @param table items: a subset of buyable/sellable items.
+ * When selling, if the 4 parameter is omitted or invalid,
+ * everything in the player inventory can be sold.
+ * @return 0 if something to buy/sell, 1 if no items, 2 in case of errors.
  */
 static int npc_trade(lua_State *s)
 {
     NPC *p = getNPC(s, 1);
     Character *q = getCharacter(s, 2);
-    if (!p || !q || !lua_isboolean(s, 3) || !lua_istable(s, 4))
+    if (!p || !q || !lua_isboolean(s, 3))
     {
-        raiseScriptError(s, "npc_trade called with incorrect parameters.");
-        return 0;
+        raiseWarning(s, "npc_trade called with incorrect parameters.");
+        lua_pushinteger(s, 2); // return value
+        return 1; // Returns 1 parameter
     }
-    BuySell *t = new BuySell(q, lua_toboolean(s, 3));
+
+    bool sellMode = lua_toboolean(s, 3);
+    BuySell *t = new BuySell(q, sellMode);
+    if (!lua_istable(s, 4))
+    {
+        if (sellMode)
+        {
+            // Can sell everything
+            if (!t->registerPlayerItems())
+            {
+                // No items to sell in player inventory
+                t->cancel();
+                lua_pushinteger(s, 1);
+                return 1;
+            }
+
+            if (t->start(p))
+            {
+              lua_pushinteger(s, 0);
+              return 1;
+            }
+            else
+            {
+              lua_pushinteger(s, 1);
+              return 1;
+            }
+        }
+        else
+        {
+            raiseWarning(s, "npc_trade[Buy] called with invalid or empty items table parameter.");
+            t->cancel();
+            lua_pushinteger(s, 2);
+            return 1;
+        }
+    }
+
+    int nbItems = 0;
+
     lua_pushnil(s);
     while (lua_next(s, 4))
     {
         if (!lua_istable(s, -1))
         {
-            raiseScriptError(s, "npc_trade called with incorrect parameters.");
+            raiseWarning(s, "npc_trade called with invalid or empty items table parameter.");
             t->cancel();
-            return 0;
+            lua_pushinteger(s, 2);
+            return 1;
         }
+
         int v[3];
         for (int i = 0; i < 3; ++i)
         {
             lua_rawgeti(s, -1, i + 1);
             if (!lua_isnumber(s, -1))
             {
-                raiseScriptError(s, "rpc_trade called with incorrect parameters.");
+                raiseWarning(s, "npc_trade called with incorrect parameters in item table.");
                 t->cancel();
-                return 0;
+                lua_pushinteger(s, 2);
+                return 1;
             }
             v[i] = lua_tointeger(s, -1);
             lua_pop(s, 1);
         }
-        t->registerItem(v[0], v[1], v[2]);
+        if (t->registerItem(v[0], v[1], v[2]))
+            nbItems++;
         lua_pop(s, 1);
     }
-    t->start(p);
-    return 0;
+
+    if (nbItems == 0)
+    {
+        t->cancel();
+        lua_pushinteger(s, 1);
+        return 1;
+    }
+    if (t->start(p))
+    {
+      lua_pushinteger(s, 0);
+      return 1;
+    }
+    else
+    {
+      lua_pushinteger(s, 1);
+      return 1;
+    }
 }
 
 /**
diff --git a/src/scripting/luautil.cpp b/src/scripting/luautil.cpp
index 02de6adc..a3602d2a 100644
--- a/src/scripting/luautil.cpp
+++ b/src/scripting/luautil.cpp
@@ -34,10 +34,21 @@ void raiseScriptError(lua_State *s, const char *format, ...)
     vsprintf(message, format, args);
     va_end( args );
 
-    LOG_WARN("Lua script error: "<<message);
+    LOG_WARN("Lua script error: "<< message);
     luaL_error(s, message);
 }
 
+void raiseWarning(lua_State *s, const char *format, ...)
+{
+    va_list args;
+    va_start(args, format);
+    char message[1024];
+    vsprintf(message, format, args);
+    va_end( args );
+
+    LOG_WARN("Lua script error: "<< message);
+}
+
 /* Functions below are unsafe, as they assume the script has passed pointers
    to objects which have not yet been destroyed. If the script never keeps
    pointers around, there will be no problem. In order to be safe, the engine
diff --git a/src/scripting/luautil.hpp b/src/scripting/luautil.hpp
index de138e24..aec2c5c2 100644
--- a/src/scripting/luautil.hpp
+++ b/src/scripting/luautil.hpp
@@ -36,8 +36,11 @@ class NPC;
 class Character;
 class Thing;
 
+// Report script errors and interrupt the script.
 void raiseScriptError(lua_State *s, const char *format, ...);
 
+void raiseWarning(lua_State *s, const char *format, ...);
+
 NPC *getNPC(lua_State *s, int p);
 Character *getCharacter(lua_State *s, int p);
 Being *getBeing(lua_State *s, int p);