Make wards invisible unless you get close to them (#912)

* Make wards invisible unless you get close to them

* Make invisiaura invisible

game/scripts/vscripts/components/glyph/glyph.lua

@@ -1,4 +1,5 @@
 LinkLuaModifier("modifier_kill", LUA_MODIFIER_MOTION_NONE)
+LinkLuaModifier("modifier_ward_invisibility", "modifiers/modifier_ward_invisibility.lua", LUA_MODIFIER_MOTION_NONE)
 
 if Glyph == nil then
   Debug.EnabledModules['filters:glyph'] = false
@@ -62,6 +63,7 @@ function Glyph:CastWard(playerID)
 
   local ward = CreateUnitByName("npc_dota_observer_wards", position, true, nil, hero, hero:GetTeam())
   ward:AddNewModifier(ward, nil, "modifier_kill", { duration = 360 })
+  ward:AddNewModifier(ward, nil, "modifier_ward_invisibility", { })
 end
 
 function Glyph:ResetWardCooldown(playerID)

game/scripts/vscripts/modifiers/modifier_ward_invisibility.lua

@@ -0,0 +1,67 @@
+LinkLuaModifier('modifier_ward_invisibility_enemy', 'modifiers/modifier_ward_invisibility.lua', LUA_MODIFIER_MOTION_NONE)
+
+modifier_ward_invisibility = class({})
+modifier_ward_invisibility_enemy = class({})
+
+function modifier_ward_invisibility_enemy:IsHidden()
+  return true
+end
+
+function modifier_ward_invisibility:OnCreated()
+  self.isInvis = true
+  self.id = "ward_" .. tostring(math.random())
+end
+function modifier_ward_invisibility:OnRefresh()
+  self.isInvis = true
+  self.id = "ward_" .. tostring(math.random())
+end
+
+function modifier_ward_invisibility:CheckState()
+  return {
+    [MODIFIER_STATE_INVISIBLE] = self.isInvis,
+  }
+end
+
+function modifier_ward_invisibility:IsHidden()
+  return true
+end
+
+--------------------------------------------------------------------------
+-- aura stuff
+
+function modifier_ward_invisibility:IsAura()
+  return true
+end
+
+function modifier_ward_invisibility:GetAuraSearchType()
+  return DOTA_UNIT_TARGET_HERO
+end
+
+function modifier_ward_invisibility:GetAuraSearchTeam()
+  return DOTA_UNIT_TARGET_TEAM_ENEMY
+end
+
+function modifier_ward_invisibility:GetAuraRadius()
+  return 300
+end
+
+function modifier_ward_invisibility:GetModifierAura()
+  return "modifier_ward_invisibility_enemy"
+end
+
+function modifier_ward_invisibility:GetAuraEntityReject(entity)
+  if self.isInvis then
+    print(self.id .. ': showing self')
+  end
+  self.isInvis = false
+
+  Timers:RemoveTimer(self.id)
+  Timers:CreateTimer(self.id, {
+    endTime = 3,
+    callback = function()
+      print(self.id .. ': hiding self')
+      self.isInvis = true
+    end
+  })
+  return false
+end