From e10841653d0891f88b5eea0b729fa4aba9572545 Mon Sep 17 00:00:00 2001
From: Allanis <allanis@saracraft.net>
Date: Sat, 10 Aug 2013 16:11:54 +0100
Subject: [PATCH] [Fix] Improved sanity on some AI functions.

---
 scripts/ai/merchant.lua | 18 +++++++++++++++---
 src/ai.c                | 19 +++++++++++++++----
 2 files changed, 30 insertions(+), 7 deletions(-)

diff --git a/scripts/ai/merchant.lua b/scripts/ai/merchant.lua
index 7bceae5..a3ee743 100644
--- a/scripts/ai/merchant.lua
+++ b/scripts/ai/merchant.lua
@@ -6,12 +6,24 @@ control_rate = 2
 -- Required "control" function.
 function control()
  task = ai.taskname()
- if task == "hyperspace" then
+ enemy = ai.getenemy()
+
+ -- Runaway if enemy is near.
+ if task ~= "runaway" and enemy ~= nil and ai.dist(enemy) < 500 then
+   ai.poptask();
+   ai.pushtask(0, "runaway", enemy)
+
+ -- Enter hyperspace if possible.
+ elseif task == "hyperspace" then
   ai.hyperspace() -- Try to go to hyperspace.
+
+ -- Try to jump when far enough away.
  elseif task == "runaway" then
-  if ai.dist(ai.pos(ai.targetid())) > 300 then
+  if ai.dist(ai.pos(ai.targetid())) > 400 then
    ai.hyperspace()
   end
+
+ -- Find something to do.
  elseif task == "none" then
     planet = ai.landplanet()
   -- Planet must exist.
@@ -80,7 +92,7 @@ function stop()
   if ai.isstopped() then
   ai.stop()
     ai.poptask()
-    ai.settimer(0, rnd.int(8000, 15000))
+    ai.settimer(0, rnd.int(8000, 15000)) -- We wait during a while.
     ai.pushtask(0, "land")
  else
   ai.brake()
diff --git a/src/ai.c b/src/ai.c
index 90772d1..68094d3 100644
--- a/src/ai.c
+++ b/src/ai.c
@@ -548,6 +548,7 @@ static int ai_pshield(lua_State* L) {
 static int ai_getdistance(lua_State* L) {
   Vec2* vect;
   Pilot* pilot;
+  unsigned int n;
 
   LLUA_MIN_ARGS(1);
 
@@ -557,13 +558,16 @@ static int ai_getdistance(lua_State* L) {
 
   /* Pilot id as parameter. */
   else if(lua_isnumber(L, 1)) {
+    n = (unsigned int)lua_tonumber(L,1);
     pilot = pilot_get((unsigned int) lua_tonumber(L, 1));
+    if(pilot == NULL) {
+      LLUA_DEBUG("Pilot '%d' not found in stack", n);
+      return 0;
+    }
     vect = &pilot->solid->pos;
-  } else {
+  } else
     /* Wrong parameter. */
     LLUA_INVALID_PARAMETER();
-    return 0;
-  }
 
   lua_pushnumber(L, vect_dist(vect, &cur_pilot->solid->pos));
   return 1;
@@ -917,7 +921,14 @@ static int ai_shoot(lua_State* L) {
 
 /* Get the nearest enemy. */
 static int ai_getenemy(lua_State* L) {
-  lua_pushnumber(L,pilot_getNearestEnemy(cur_pilot));
+  unsigned int p;
+
+  p = pilot_getNearestEnemy(cur_pilot);
+
+  if(p == 0) /* No enemy found. */
+    return 0;
+
+  lua_pushnumber(L,p);
   return 1;
 }