Add module to track Steady Focus for marksmanship hunters.

diff --git a/Ovale.toc b/Ovale.toc
index b11f237..1f3e235 100644
--- a/Ovale.toc
+++ b/Ovale.toc
@@ -61,6 +61,7 @@ OvaleRecount.lua
 OvaleRunes.lua
 OvaleSkada.lua
 OvaleSpellDamage.lua
+OvaleSteadyFocus.lua
 OvaleSwing.lua
 class\files.xml
 conditions\files.xml
diff --git a/OvaleSteadyFocus.lua b/OvaleSteadyFocus.lua
new file mode 100644
index 0000000..3fb6018
--- /dev/null
+++ b/OvaleSteadyFocus.lua
@@ -0,0 +1,148 @@
+--[[--------------------------------------------------------------------
+    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.
+--]]-------------------------------------------------------------------
+
+--[[
+	This addon tracks the status of the buff from Steady Focus on a MM hunter.
+
+	Steady Focus description from wowhead.com:
+
+		When you Steady Shot twice in a row, your ranged attack speed will
+		be increased by 15% and your Steady Shot will generate 3 additional
+		Focus for 20 sec.
+
+	Mechanically, there is a hidden buff that is added after a Steady Shot is
+	fired that is cleared if any other ranged attack other than Steady Shot
+	is fired next.
+
+	This addon manages the hidden aura in OvaleAura using events triggered by
+	attacking with ranged attacks.  The aura ID of the hidden aura is set to
+	53224, the spell ID of Steady Focus, and can be checked like any other
+	aura using OvaleAura's public or state methods.
+--]]
+
+local _, Ovale = ...
+local OvaleSteadyFocus = Ovale:NewModule("OvaleSteadyFocus", "AceEvent-3.0")
+Ovale.OvaleSteadyFocus = OvaleSteadyFocus
+
+--<private-static-properties>
+-- Forward declarations for module dependencies.
+local OvaleAura = nil
+
+local API_GetTime = GetTime
+local API_UnitClass = UnitClass
+local API_UnitGUID = UnitGUID
+
+-- Player's class.
+local _, self_class = API_UnitClass("player")
+-- Player's GUID.
+local self_guid = nil
+
+-- Steady Focus spell ID from spellbook; re-used has as the aura ID of the hidden buff.
+local PRE_STEADY_FOCUS = 53224
+-- Steady Focus aura ID for visible buff.
+local STEADY_FOCUS = 53220
+-- Steady Shot spell Id.
+local STEADY_SHOT = 56641
+-- Spell IDs of abilities that clear "pre-Steady Focus".
+local RANGED_ATTACKS_MM = {
+	[  1978] = "Serpent Sting",
+	[  2643] = "Multi-Shot",
+	[  3044] = "Arcane Shot",
+	[ 13813] = "Explosive Trap",
+	[ 19434] = "Aimed Shot",
+	[ 19503] = "Scatter Shot",
+	[ 34490] = "Silencing Shot",
+	[ 53209] = "Chimera Shot",
+	[ 53351] = "Kill Shot",
+	[109259] = "Powershot",
+	[117050] = "Glaive Toss",
+}
+--</private-static-properties>
+
+--<public-static-properties>
+OvaleSteadyFocus.start = 0
+OvaleSteadyFocus.ending = 0
+OvaleSteadyFocus.stacks = 0
+--</public-static-properties>
+
+--<public-static-methods>
+function OvaleSteadyFocus:OnInitialize()
+	-- Resolve module dependencies.
+	OvaleAura = Ovale.OvaleAura
+end
+
+function OvaleSteadyFocus:OnEnable()
+	if self_class == "HUNTER" then
+		self_guid = API_UnitGUID("player")
+		self:RegisterMessage("Ovale_SpecializationChanged")
+	end
+end
+
+function OvaleSteadyFocus:OnDisable()
+	if self_class == "HUNTER" then
+		self:UnregisterMessage("Ovale_SpecializationChanged")
+	end
+end
+
+function OvaleSteadyFocus:Ovale_SpecializationChanged(event, specialization, previousSpecialization)
+	if specialization == "marksmanship" then
+		self:RegisterEvent("COMBAT_LOG_EVENT_UNFILTERED")
+		self:RegisterMessage("Ovale_AuraAdded")
+		self:RegisterMessage("Ovale_AuraChanged", "Ovale_AuraAdded")
+	else
+		self:UnregisterEvent("COMBAT_LOG_EVENT_UNFILTERED")
+		self:UnregisterMessage("Ovale_AuraAdded")
+		self:UnregisterMessage("Ovale_AuraChanged")
+	end
+end
+
+function OvaleSteadyFocus:COMBAT_LOG_EVENT_UNFILTERED(event, timestamp, cleuEvent, hideCaster, sourceGUID, sourceName, sourceFlags, sourceRaidFlags, destGUID, destName, destFlags, destRaidFlags, ...)
+	local arg12, arg13, arg14, arg15, arg16, arg17, arg18, arg19, arg20, arg21, arg22, arg23 = ...
+	if sourceGUID == self_guid and cleuEvent == "SPELL_DAMAGE" then
+		local spellId = arg12
+		if spellId == STEADY_SHOT and self.stacks == 0 then
+			local now = API_GetTime()
+			if now - self.ending > 1 then
+				self:GainedAura(now)
+			end
+		elseif RANGED_ATTACKS_MM[spellId] and self.stacks > 0 then
+			local now = API_GetTime()
+			self:LostAura(now)
+		end
+	end
+end
+
+function OvaleSteadyFocus:Ovale_AuraAdded(event, timestamp, target, auraId, caster)
+	if target == self_guid and auraId == STEADY_FOCUS and self.stacks > 0 then
+		self:LostAura(timestamp)
+	end
+end
+
+function OvaleSteadyFocus:GainedAura(atTime)
+	self.start = atTime
+	self.ending = math.huge
+	self.stacks = self.stacks + 1
+	OvaleAura:GainedAuraOnGUID(self_guid, self.start, PRE_STEADY_FOCUS, self_guid, "HELPFUL", nil, 1, nil, math.huge, self.ending, nil, "Pre-Steady Focus", nil, nil, nil)
+end
+
+function OvaleSteadyFocus:LostAura(atTime)
+	self.ending = atTime
+	self.stacks = 0
+	OvaleAura:LostAuraOnGUID(self_guid, atTime, PRE_STEADY_FOCUS, self_guid)
+end
+
+function OvaleSteadyFocus:Debug()
+	local aura = OvaleAura:GetAuraByGUID(self_guid, PRE_STEADY_FOCUS, "HELPFUL", true)
+	if aura then
+		Ovale:FormatPrint("Player has pre-Steady Focus aura with start=%s, end=%s, stacks=%d.", aura.start, aura.ending, aura.stacks)
+	else
+		Ovale:Print("Player has no pre-Steady Focus aura!")
+	end
+end
+--</public-static-methods>