Implement RuneOfPowerRemains() condition.

diff --git a/OvaleSimulationCraft.lua b/OvaleSimulationCraft.lua
index 1542a8c..81e79d2 100644
--- a/OvaleSimulationCraft.lua
+++ b/OvaleSimulationCraft.lua
@@ -335,7 +335,6 @@ do
 				tinsert(simc.symbols, "molten_armor_buff")
 				return "if BuffExpires(molten_armor_buff) Spell(molten_armor)"
 			end,
-		["^rune_of_power$"] = false, -- XXX
 		["^water_elemental$"] = "if pet.Present(no) Spell(water_elemental)",
 		-- Monk
 		["^chi_sphere$"] = false,
@@ -641,6 +640,7 @@ do
 				tinsert(simc.symbols, "arcane_charge_debuff")
 				return "DebuffStacks(arcane_charge_debuff)"
 			end,
+		["^buff%.rune_of_power%.remains$"] = "RuneOfPowerRemains()",
 		-- Monk
 		["^dot%.zen_sphere%.ticking$"] = function(simc, action)
 				tinsert(simc.symbols, "zen_sphere_buff")
diff --git a/conditions/RuneOfPowerRemains.lua b/conditions/RuneOfPowerRemains.lua
new file mode 100644
index 0000000..ffb078d
--- /dev/null
+++ b/conditions/RuneOfPowerRemains.lua
@@ -0,0 +1,55 @@
+--[[--------------------------------------------------------------------
+    Ovale Spell Priority
+    Copyright (C) 2014 Johnny C. Lam
+
+    This program is free software; you can redistribute it and/or modify
+    it under the terms of the GNU General Public License in the LICENSE
+    file accompanying this program.
+--]]--------------------------------------------------------------------
+
+local _, Ovale = ...
+
+do
+	local OvaleCondition = Ovale.OvaleCondition
+	local OvaleState = Ovale.OvaleState
+
+	local type = type
+	local API_GetTotemInfo = GetTotemInfo
+	local Compare = OvaleCondition.Compare
+	local TestValue = OvaleCondition.TestValue
+	local state = OvaleState.state
+
+	local RUNE_OF_POWER_BUFF = 116014
+
+	--- Get the remaining time in seconds before the latest Rune of Power expires.
+	--- Returns non-zero only if the player is standing within an existing Rune of Power.
+	-- @name RuneOfPowerRemains
+	-- @paramsig number or boolean
+	-- @param operator Optional. Comparison operator: less, atMost, equal, atLeast, more.
+	-- @param number Optional. The number to compare against.
+	-- @return The number of seconds.
+	-- @return A boolean value for the result of the comparison.
+	-- @usage
+	-- if RuneOfPowerRemains() < CastTime(rune_of_power) Spell(rune_of_power)
+
+	local function RuneOfPowerRemains(condition)
+		local comparator, limit = condition[1], condition[2]
+		local aura = state:GetAura("player", RUNE_OF_POWER_BUFF, "HELPFUL")
+		if aura then
+			local start, ending
+			for totemSlot = 1, 2 do
+				local haveTotem, name, startTime, duration = API_GetTotemInfo(totemSlot)
+				if haveTotem and startTime and (not start or startTime > start) then
+					start = startTime
+					ending = startTime + duration
+				end
+			end
+			if start then
+				return TestValue(start, ending, ending - start, start, -1, comparator, limit)
+			end
+		end
+		return Compare(0, comparator, limit)
+	end
+
+	OvaleCondition:RegisterCondition("runeofpowerremains", false, RuneOfPowerRemains)
+end
diff --git a/conditions/files.xml b/conditions/files.xml
index 25086c1..81491ee 100644
--- a/conditions/files.xml
+++ b/conditions/files.xml
@@ -76,6 +76,7 @@
 	<Script file="RelativeLevel.lua" />
 	<Script file="RemainingCastTime.lua" />
 	<Script file="RuneCount.lua" />
+	<Script file="RuneOfPowerRemains.lua" />
 	<Script file="Runes.lua" />
 	<Script file="Snapshot.lua" />
 	<Script file="Speed.lua" />