From c75ac263d18624f51680eccb1533c6ebe81e0a8a Mon Sep 17 00:00:00 2001
From: Olion <oleg70ua@yahoo.com>
Date: Fri, 25 Sep 2015 23:33:44 +0300
Subject: [PATCH] [Core] Trap stealth implementation

Non-rogues may see armed (wild or enemy) traps only having proper invisibility detection and using stealth rules
Rogues may see such traps anyway but if without proper aura, then at the minimal distance (with chance to disarm still)
---
 src/game/Object/GameObject.cpp | 51 +++++++++++++++++++++++++++-------
 1 file changed, 41 insertions(+), 10 deletions(-)

diff --git a/src/game/Object/GameObject.cpp b/src/game/Object/GameObject.cpp
index 7e2bba2a..b4785781 100644
--- a/src/game/Object/GameObject.cpp
+++ b/src/game/Object/GameObject.cpp
@@ -787,6 +787,8 @@ bool GameObject::IsVisibleForInState(Player const* u, WorldObject const* viewPoi
     if (IsTransport() && IsInMap(u))
         { return true; }
 
+    float visibleDistance = GetMap()->GetVisibilityDistance() + (inVisibleList ? World::GetVisibleObjectGreyDistance() : 0.0f);
+
     // quick check visibility false cases for non-GM-mode
     if (!u->isGameMaster())
     {
@@ -795,21 +797,50 @@ bool GameObject::IsVisibleForInState(Player const* u, WorldObject const* viewPoi
             { return false; }
 
         // special invisibility cases
-        /* TODO: implement trap stealth, take look at spell 2836
-        if(GetGOInfo()->type == GAMEOBJECT_TYPE_TRAP && GetGOInfo()->trap.stealthed && u->IsHostileTo(GetOwner()))
+        // implementing armed trap stealth, basing on the spell 2836 structure
+        if (GetGOInfo()->type == GAMEOBJECT_TYPE_TRAP && GetGOInfo()->trap.stealthed && GetGoState() == GO_STATE_READY)
         {
-            if(check stuff here)
-                return false;
-        }*/
+            Unit *owner = GetOwner();
+            if (!owner || u->IsHostileTo(owner))
+            {
+                visibleDistance = 10.5f;
+                //2^3=8 and 300 - from spell 2836, EFFECT_INDEX_1 - SPELL_AURA_MOD_INVISIBILITY_DETECTION; TODO check 200 and improve
+                if (u->GetMaxPositiveAuraModifierByMiscValue(SPELL_AURA_MOD_INVISIBILITY_DETECTION, 8) < 200)
+                {
+                    if (u->getClass() != CLASS_ROGUE)
+                        return false;       // a wild or enemy trap cannot be seen by non-rogues without proper invis detection
+                    visibleDistance = 0.0f; // minimal detection distance, will be normalized below
+                }
 
-        // Smuggled Mana Cell required 10 invisibility type detection/state
-        if (GetEntry() == 187039 && ((u->m_detectInvisibilityMask | u->m_invisibilityMask) & (1 << 10)) == 0)
-            { return false; }
+                if (owner)
+                {
+                    // apply to the "owner" and "u" the rules for usual stealth detection; the fragment is taken from Unit::IsVisibleForOrDetect
+                    // Visible distance based on stealth value (stealth rank 4 300MOD, 10.5 - 3 = 7.5)
+                    visibleDistance -= (owner->getLevel() / 20.0f);  // for rogue stealth (4 spells): modifier = 5*level
+
+                    // Visible distance is modified by
+                    //-Level Diff (every level diff = 1.0f in visible distance)
+                    visibleDistance += int32(u->GetLevelForTarget(owner)) - int32(owner->GetLevelForTarget(u));
+                }
+
+                //-Stealth Detection(negative like paranoia)
+                visibleDistance += (int32(u->GetTotalAuraModifier(SPELL_AURA_MOD_STEALTH_DETECT))) / 5.0f;
+
+                // normalize visible distance
+                if (visibleDistance > MAX_PLAYER_STEALTH_DETECT_RANGE)
+                    visibleDistance = MAX_PLAYER_STEALTH_DETECT_RANGE;
+                else if (visibleDistance < GetGOInfo()->trap.radius + INTERACTION_DISTANCE)
+                    visibleDistance = GetGOInfo()->trap.radius + INTERACTION_DISTANCE;
+            }
+        }
+
+        // [-ZERO] Smuggled Mana Cell required 10 invisibility type detection/state
+        //if (GetEntry() == 187039 && ((u->m_detectInvisibilityMask | u->m_invisibilityMask) & (1 << 10)) == 0)
+        //    { return false; }
     }
 
     // check distance
-    return IsWithinDistInMap(viewPoint, GetMap()->GetVisibilityDistance() +
-                             (inVisibleList ? World::GetVisibleObjectGreyDistance() : 0.0f), false);
+    return IsWithinDistInMap(viewPoint, visibleDistance, false);
 }
 
 void GameObject::Respawn()