From 8cca97ba1b5c1aafe0ec4baa47133d4dffce3c97 Mon Sep 17 00:00:00 2001
From: Shayne Halvorson <N78291@gmail.com>
Date: Tue, 6 May 2014 13:31:16 -0500
Subject: [PATCH] Replace corrosion with a temporary effect.

If your equipment would have been corroded under the old system,
you now get a temporary (but stacking) -5 AC and -3 weapon damage.
Corrosion against armour-wearing monsters instead halves their AC.
---
 crawl-ref/source/attack.cc        |    3 +++
 crawl-ref/source/enum.h           |    2 ++
 crawl-ref/source/items.cc         |   26 ++++++++++----------------
 crawl-ref/source/mon-ench.cc      |   11 +++++++++--
 crawl-ref/source/mon-info.cc      |    4 ++++
 crawl-ref/source/mon-info.h       |    1 +
 crawl-ref/source/monster.cc       |    4 ++++
 crawl-ref/source/output.cc        |   15 ++++++++++++++-
 crawl-ref/source/player-reacts.cc |    8 ++++++++
 crawl-ref/source/player.cc        |    4 ++++
 crawl-ref/source/status.cc        |    2 ++
 crawl-ref/source/wiz-you.cc       |    3 ++-
 12 files changed, 63 insertions(+), 20 deletions(-)

diff --git a/crawl-ref/source/attack.cc b/crawl-ref/source/attack.cc
index 0727a3e..9f9619c 100644
--- a/crawl-ref/source/attack.cc
+++ b/crawl-ref/source/attack.cc
@@ -1365,6 +1365,9 @@ int attack::player_apply_slaying_bonuses(int damage, bool aux)
 
         if (weapon->base_type == OBJ_RODS)
             damage_plus = weapon->special;
+
+        if (you.duration[DUR_CORROSION] && !is_artefact(*weapon))
+            damage_plus -= 3 * you.props["corrosion_amount"].get_int();
     }
     damage_plus += slaying_bonus(PWPN_DAMAGE,
                                  !weapon && wpn_skill == SK_THROWING
diff --git a/crawl-ref/source/enum.h b/crawl-ref/source/enum.h
index d558874..0bbdabb 100644
--- a/crawl-ref/source/enum.h
+++ b/crawl-ref/source/enum.h
@@ -1692,6 +1692,7 @@ enum duration_type
     DUR_ABJURATION_AURA,
     DUR_MESMERISE_IMMUNE,
     DUR_NO_POTIONS,
+    DUR_CORROSION,
     NUM_DURATIONS
 };
 
@@ -1821,6 +1822,7 @@ enum enchant_type
     ENCH_SAP_MAGIC,
     ENCH_SHROUD,
     ENCH_PHANTOM_MIRROR,
+    ENCH_CORROSION,
     // Update enchantment names in mon-ench.cc when adding or removing
     // enchantments.
     NUM_ENCHANTMENTS
diff --git a/crawl-ref/source/items.cc b/crawl-ref/source/items.cc
index a2990ed..5896dd5 100644
--- a/crawl-ref/source/items.cc
+++ b/crawl-ref/source/items.cc
@@ -47,6 +47,7 @@
 #include "makeitem.h"
 #include "message.h"
 #include "misc.h"
+#include "mon-ench.h"
 #include "notes.h"
 #include "options.h"
 #include "orb.h"
@@ -4106,14 +4107,12 @@ void corrode_item(item_def &item, actor *holder)
 
     if (holder && holder->is_player())
     {
-        mprf("The acid corrodes %s!", item.name(DESC_YOUR).c_str());
+        you.increase_duration(DUR_CORROSION, 10 + roll_dice(2, 4), 50,
+                              "The acid corrodes your equipment!");
         xom_is_stimulated(50);
-
-        if (item.base_type == OBJ_ARMOUR)
-            you.redraw_armour_class = true;
-
-        if (you.equip[EQ_WEAPON] == item.link)
-            you.wield_change = true;
+        you.props["corrosion_amount"].get_int()++;
+        you.redraw_armour_class = true;
+        you.wield_change = true;
     }
     else if (holder && holder->type == MONS_PLAYER_SHADOW)
         return; // it's just a temp copy of the item
@@ -4126,18 +4125,13 @@ void corrode_item(item_def &item, actor *holder)
         }
         else
         {
-            mprf("The acid corrodes %s %s!",
-                 apostrophise(holder->name(DESC_THE)).c_str(),
-                 item.name(DESC_PLAIN).c_str());
+            mprf("The acid corrodes %s equipment!",
+                 apostrophise(holder->name(DESC_THE)).c_str());
         }
     }
 
-    how_rusty--;
-
-    if (item.base_type == OBJ_WEAPONS)
-        item.plus2 = how_rusty;
-    else
-        item.plus  = how_rusty;
+    if (holder && holder->is_monster())
+       holder->as_monster()->add_ench(mon_enchant(ENCH_CORROSION, 0));
 }
 
 // If there is only one unidentified subtype left in the item's object type,
diff --git a/crawl-ref/source/mon-ench.cc b/crawl-ref/source/mon-ench.cc
index 7356c19..fecba39 100644
--- a/crawl-ref/source/mon-ench.cc
+++ b/crawl-ref/source/mon-ench.cc
@@ -961,6 +961,11 @@ void monster::remove_enchantment_effect(const mon_enchant &me, bool quiet)
             simple_monster_message(this, " is no longer being sapped.");
         break;
 
+    case ENCH_CORROSION:
+        if (!quiet)
+           simple_monster_message(this, " is no longer covered in acid.");
+        break;
+
     default:
         break;
     }
@@ -1070,7 +1075,7 @@ void monster::timeout_enchantments(int levels)
         case ENCH_BLIND: case ENCH_WORD_OF_RECALL: case ENCH_INJURY_BOND:
         case ENCH_FLAYED: case ENCH_BARBS:
         case ENCH_AGILE: case ENCH_FROZEN: case ENCH_EPHEMERAL_INFUSION:
-        case ENCH_BLACK_MARK: case ENCH_SAP_MAGIC:
+        case ENCH_BLACK_MARK: case ENCH_SAP_MAGIC: case ENCH_CORROSION:
             lose_ench_levels(i->second, levels);
             break;
 
@@ -1286,6 +1291,7 @@ void monster::apply_enchantment(const mon_enchant &me)
     case ENCH_FROZEN:
     case ENCH_EPHEMERAL_INFUSION:
     case ENCH_SAP_MAGIC:
+    case ENCH_CORROSION:
     // case ENCH_ROLLING:
         decay_enchantment(en);
         break;
@@ -2169,7 +2175,7 @@ static const char *enchant_names[] =
 #endif
     "poison_vuln", "icemail", "agile",
     "frozen", "ephemeral_infusion", "black_mark", "grand_avatar",
-    "sap magic", "shroud", "phantom_mirror", "buggy",
+    "sap magic", "shroud", "phantom_mirror", "corrosion", "buggy",
 };
 
 static const char *_mons_enchantment_name(enchant_type ench)
@@ -2326,6 +2332,7 @@ int mon_enchant::calc_duration(const monster* mons,
         cturn = 300 / _mod_speed(25, mons->speed);
         break;
     case ENCH_SLOW:
+    case ENCH_CORROSION:
         cturn = 250 / (1 + modded_speed(mons, 10));
         break;
     case ENCH_FEAR:
diff --git a/crawl-ref/source/mon-info.cc b/crawl-ref/source/mon-info.cc
index 6f6ba1e..24b9a13 100644
--- a/crawl-ref/source/mon-info.cc
+++ b/crawl-ref/source/mon-info.cc
@@ -200,6 +200,8 @@ static monster_info_flags ench_to_mb(const monster& mons, enchant_type ench)
         return MB_SAP_MAGIC;
     case ENCH_SHROUD:
         return MB_SHROUD;
+    case ENCH_CORROSION:
+        return MB_CORROSION;
     default:
         return NUM_MB_FLAGS;
     }
@@ -1602,6 +1604,8 @@ vector<string> monster_info::attributes() const
         v.push_back("magic-sapped");
     if (is(MB_SHROUD))
         v.push_back("shrouded");
+    if (is(MB_CORROSION))
+        v.push_back("covered in acid");
     return v;
 }
 
diff --git a/crawl-ref/source/mon-info.h b/crawl-ref/source/mon-info.h
index fd5e64a..9ba65c9 100644
--- a/crawl-ref/source/mon-info.h
+++ b/crawl-ref/source/mon-info.h
@@ -117,6 +117,7 @@ enum monster_info_flags
     MB_BLACK_MARK,
     MB_SAP_MAGIC,
     MB_SHROUD,
+    MB_CORROSION,
     NUM_MB_FLAGS
 };
 
diff --git a/crawl-ref/source/monster.cc b/crawl-ref/source/monster.cc
index a135d87..3c7f5a4 100644
--- a/crawl-ref/source/monster.cc
+++ b/crawl-ref/source/monster.cc
@@ -3418,10 +3418,14 @@ int monster::armour_class() const
     if (has_ench(ENCH_WITHDRAWN))
         a += 10;
 
+
     // Penalty due to bad temp mutations.
     if (has_ench(ENCH_WRETCHED))
         a -= get_ench(ENCH_WRETCHED).degree;
 
+    if (has_ench(ENCH_CORROSION))
+        a /= 2;
+
     return max(a, 0);
 }
 
diff --git a/crawl-ref/source/output.cc b/crawl-ref/source/output.cc
index 7b45d14..f3ffd7c 100644
--- a/crawl-ref/source/output.cc
+++ b/crawl-ref/source/output.cc
@@ -29,6 +29,7 @@
 #include "godabil.h"
 #include "initfile.h"
 #include "itemname.h"
+#include "itemprop.h"
 #include "items.h"
 #include "lang-fake.h"
 #include "libutil.h"
@@ -750,6 +751,8 @@ static void _print_stats_ac(int x, int y)
     CGOTOXY(x+4, y, GOTO_STAT);
     if (you.duration[DUR_ICY_ARMOUR] || player_stoneskin() || player_icemail_armour_class())
         textcolor(LIGHTBLUE);
+    else if (you.duration[DUR_CORROSION])
+        textcolor(RED);
     else
         textcolor(HUD_VALUE_COLOUR);
     string ac = make_stringf("%2d ", you.armour_class());
@@ -790,7 +793,16 @@ static void _print_stats_wp(int y)
     string text;
     if (you.weapon())
     {
-        const item_def& wpn = *you.weapon();
+        item_def wpn = *you.weapon();
+
+        if (you.duration[DUR_CORROSION] && is_melee_weapon(wpn) &&
+            !is_artefact(wpn))
+        {
+            if (wpn.base_type == OBJ_RODS)
+                wpn.special -= 3 * you.props["corrosion_amount"].get_int();
+            else
+                wpn.plus2 -= 3 * you.props["corrosion_amount"].get_int();
+        }
 
         const string prefix = item_prefix(wpn);
         const int prefcol = menu_colour(wpn.name(DESC_INVENTORY), prefix);
@@ -1044,6 +1056,7 @@ static void _get_status_lights(vector<status_light>& out)
         DUR_BRILLIANCE,
         DUR_MIGHT,
         DUR_NO_POTIONS,
+        DUR_CORROSION,
     };
 
     status_info inf;
diff --git a/crawl-ref/source/player-reacts.cc b/crawl-ref/source/player-reacts.cc
index a706608..a224d11 100644
--- a/crawl-ref/source/player-reacts.cc
+++ b/crawl-ref/source/player-reacts.cc
@@ -1016,6 +1016,14 @@ static void _decrement_durations()
     _decrement_a_duration(DUR_SAP_MAGIC, delay,
                           "Your magic seems less tainted.");
 
+    if (_decrement_a_duration(DUR_CORROSION, delay,
+                          "You repair your equipment."))
+    {
+        you.props["corrosion_amount"] = 0;
+        you.redraw_armour_class = true;
+        you.wield_change = true;
+    }
+
     if (!you.duration[DUR_SAP_MAGIC])
     {
         _decrement_a_duration(DUR_MAGIC_SAPPED, delay,
diff --git a/crawl-ref/source/player.cc b/crawl-ref/source/player.cc
index a214d7f..5817c90 100644
--- a/crawl-ref/source/player.cc
+++ b/crawl-ref/source/player.cc
@@ -4270,6 +4270,7 @@ void display_char_status()
         STATUS_MAGIC_SAPPED,
         DUR_PORTAL_PROJECTILE,
         DUR_NO_POTIONS,
+        DUR_CORROSION,
     };
 
     status_info inf;
@@ -6643,6 +6644,9 @@ int player::armour_class() const
     if (mutation[MUT_ICEMAIL])
         AC += 100 * player_icemail_armour_class();
 
+    if (you.duration[DUR_CORROSION])
+        AC -= 500 * you.props["corrosion_amount"].get_int();
+
     if (!player_is_shapechanged()
         || (form == TRAN_DRAGON && player_genus(GENPC_DRACONIAN))
         || (form == TRAN_STATUE && species == SP_GARGOYLE))
diff --git a/crawl-ref/source/status.cc b/crawl-ref/source/status.cc
index 93f1bec..3c44414 100644
--- a/crawl-ref/source/status.cc
+++ b/crawl-ref/source/status.cc
@@ -167,6 +167,8 @@ static duration_def duration_data[] =
       BLUE, "Abj", "aura of abjuration", "You are abjuring all hostile summons around you." },
     { DUR_NO_POTIONS, false,
       RED, "-Potion", "no potions", "You cannot drink potions." },
+    { DUR_CORROSION, false,
+      RED, "Corr", "corroded equipment", "Your equipment is corroded." },
 };
 
 static int duration_index[NUM_DURATIONS];
diff --git a/crawl-ref/source/wiz-you.cc b/crawl-ref/source/wiz-you.cc
index ed31705..5339023 100644
--- a/crawl-ref/source/wiz-you.cc
+++ b/crawl-ref/source/wiz-you.cc
@@ -878,7 +878,8 @@ static const char* dur_names[] =
     "dragon call cooldown",
     "aura of abjuration",
     "mesmerisation immunity",
-    "no potions"
+    "no potions",
+    "corrosion"
 };
 
 void wizard_edit_durations(void)
-- 
1.7.9.5