[Freeciv-Dev] (PR#12896) Diplomat fixes

["Per I. Mathisen" <per@xxxxxxxxxxx>]

<URL: http://bugs.freeciv.org/Ticket/Display.html?id=12896 >

This patch fixes some issues reported with diplomats, but I was unable to
find the relevant ticket(s), so I made a new one.

CHANGES:
 - Diplomat combat calculation now more fair. Does not rely on diplchance.
 - Give a message to reveal why a diplomat was caught when trying to steal
   from a city you have stolen from before.
 - Allow auto-success for diplomats (diplchance=100).
 - Limit diplchance to a minimum of 50 to restrict diplchance cheating.
   (Players setting diplchance to some absurd low value without other
   players noticing.)
 - Improve server helptext for diplchance.

  - Per

Index: server/diplomats.c
===================================================================
RCS file: /home/freeciv/CVS/freeciv/server/diplomats.c,v
retrieving revision 1.70
diff -u -r1.70 diplomats.c
--- server/diplomats.c  21 Mar 2005 12:21:28 -0000      1.70
+++ server/diplomats.c  26 Apr 2005 11:32:54 -0000
@@ -566,10 +566,17 @@
     }
   }
   if (count > 0) {
-    notify_player_ex(pplayer, pcity->tile, E_MY_DIPLOMAT_FAILED,
-                    _("Your %s was caught in the attempt of"
-                      " stealing technology from %s."),
-                    unit_name(pdiplomat->type), pcity->name);
+    if (pcity->steal > 0 && !unit_flag (pdiplomat, F_SPY)) {
+      notify_player_ex(pplayer, pcity->tile, E_MY_DIPLOMAT_FAILED,
+                      _("%s was expecting your attempt to steal technology "
+                         "again. Your %s was caught and executed."),
+                      pcity->name, unit_name(pdiplomat->type));
+    } else {
+      notify_player_ex(pplayer, pcity->tile, E_MY_DIPLOMAT_FAILED,
+                      _("Your %s was caught in the attempt of"
+                        " stealing technology from %s."),
+                      unit_name(pdiplomat->type), pcity->name);
+    }
     notify_player_ex(cplayer, pcity->tile, E_ENEMY_DIPLOMAT_FAILED,
                     _("%s's %s failed to steal technology from %s."),
                     pplayer->name, unit_name(pdiplomat->type), pcity->name);
@@ -1088,44 +1095,38 @@
 /**************************************************************************
   This determines if a diplomat/spy succeeds against some defender,
   who is also a diplomat or spy.
-  (Note: This is weird in order to try to conform to Civ2 rules.)
-
-  - Depends entirely upon game.diplchance and the defender:
-    - Spies are much better.
-    - Veterans are somewhat better.
 
-  - Return TRUE if the "attacker" succeeds.
+  Return TRUE if the "attacker" succeeds.
 **************************************************************************/
 static bool diplomat_success_vs_defender (struct unit *pattacker, 
        struct unit *pdefender, struct tile *pdefender_tile)
 {
-  int att = game.diplchance;
-  int def = 100 - game.diplchance;
+  int chance = 50; /* Base 50% chance */
 
   if (unit_flag(pdefender, F_SUPERSPY)) {
     return TRUE;
   }
   if (unit_flag (pattacker, F_SPY)) {
-    att *= 2;
+    chance += 25;
   }
   if (unit_flag (pdefender, F_SPY)) {
-    def *= 2;
+    chance -= 25;
   }
 
-  att += (att/5.0) * pattacker->veteran;
-  def += (def/5.0) * pdefender->veteran;
+  chance += 15 * pattacker->veteran;
+  chance -= 15 * pdefender->veteran;
 
   if (pdefender_tile->city) {
-    def = def * (100 + get_city_bonus(pdefender_tile->city,
-                                     EFT_SPY_RESISTANT)) / 100;
+    chance -= chance * get_city_bonus(pdefender_tile->city,
+                                      EFT_SPY_RESISTANT) / 100;
   } else {
     if (tile_has_special(pdefender_tile, S_FORTRESS)
        || tile_has_special(pdefender_tile, S_AIRBASE)) {
-       def = (def * 5) / 4;/* +25% */ 
+       chance -= chance * 25 / 100; /* 25% penalty */
     }
   }
   
-  return myrand(att) > myrand(def);
+  return myrand(100) > chance;
 }
 
 /**************************************************************************
Index: server/settings.c
===================================================================
RCS file: /home/freeciv/CVS/freeciv/server/settings.c,v
retrieving revision 1.20
diff -u -r1.20 settings.c
--- server/settings.c   21 Mar 2005 13:05:21 -0000      1.20
+++ server/settings.c   26 Apr 2005 11:40:27 -0000
@@ -722,17 +722,11 @@
 
   GEN_INT("diplchance", game.diplchance,
          SSET_RULES_FLEXIBLE, SSET_MILITARY, SSET_SITUATIONAL, SSET_TO_CLIENT,
-         N_("Chance in diplomat/spy contests"),
+         N_("Base chance for diplomats and spies to succeed."),
          /* xgettext:no-c-format */
-         N_("A diplomatic unit acting against a city which has one or "
-            "more defending diplomatic units has a diplchance "
-            "(percent) chance to defeat each such defender. Also, the "
-            "chance of a spy returning from a successful mission is "
-            "diplchance percent (diplomats never return).  This value is "
-            "also the basic chance of success for diplomats and spies. "
-            "Defending spies are generally twice as capable as "
-            "diplomats; veteran units are 50% more capable than "
-            "non-veteran ones."), NULL, 
+         N_("The chance of a spy returning from a successful mission and "
+            "the base chance of success for diplomats and spies."),
+          NULL,
          GAME_MIN_DIPLCHANCE, GAME_MAX_DIPLCHANCE, GAME_DEFAULT_DIPLCHANCE)
 
   GEN_BOOL("spacerace", game.spacerace,
Index: common/game.h
===================================================================
RCS file: /home/freeciv/CVS/freeciv/common/game.h,v
retrieving revision 1.181
diff -u -r1.181 game.h
--- common/game.h       21 Apr 2005 00:28:27 -0000      1.181
+++ common/game.h       26 Apr 2005 11:40:27 -0000
@@ -363,8 +363,8 @@
 #define GAME_MAX_DIPLOMACY           4
 
 #define GAME_DEFAULT_DIPLCHANCE      80
-#define GAME_MIN_DIPLCHANCE          1
-#define GAME_MAX_DIPLCHANCE          99
+#define GAME_MIN_DIPLCHANCE          50
+#define GAME_MAX_DIPLCHANCE          100
 
 #define GAME_DEFAULT_FREECOST        0
 #define GAME_MIN_FREECOST            0