Interrupt Tracker

local spells = {
    [1766]   = 15,  -- kick
    [6552]   = 15,  -- pummel
    [2139]   = 20,  -- counterspell
    [19647]  = 24,  -- spell lock
    [103135] = 24,  -- spell lock (gos)
    [115782] = 24,  -- optical blast
    [47528]  = 15,  -- mind freeze
    [57994]  = 12,  -- wind shear
    [34490]  = 24,  -- silencing shot
    [147362] = 24,  -- counter shot
    [96231]  = 15,  -- rebuke
    [80964]  = 15,  -- skull bash (cat)
    [80965]  = 15,  -- skull bash (bear)
    [116705] = 15,  -- spear hand strike
    [15487]  = 45,  -- priest silence
    [47476]  = 60,  -- strangulate
    [108194] = 30,  -- asphyxiate
    [8122]   = 30,  -- psychic scream
    [19503]  = 30,  -- scatter shot
    [23920]  = 25,  -- spell reflect
    [114028] = 60,  -- aoe reflect
    [48707]  = 45,  -- ams
}
local frameStack
local firstTimer, lastTimer
local events = CreateFrame("Frame")

local function Reposition(timer)
    timer.frame:ClearAllPoints()
    if timer == firstTimer then
        timer.frame:SetPoint("TOPRIGHT", "ChatFrame1", 61, 3)
    else
        timer.frame:SetPoint("LEFT", timer.prev.frame, 32, 0)
    end
end

local function HideFrame(frame)
    if frame:IsShown() and not frame:IsVisible() then
        return
    end
    local timer = frame.timer
    if not timer.prev then
        firstTimer = timer.next
    else
        timer.prev.next = timer.next
    end
    if not timer.next then
        lastTimer = timer.prev
    else
        timer.next.prev = timer.prev
        Reposition(timer.next)
    end
    frame.timer = nil
    frame.next = frameStack
    frameStack = frame
end

local function GetFrame()
    local frame = frameStack
    if frame then
        frameStack = frame.next
    else
        frame = CreateFrame("Cooldown", nil, UIParent, "CooldownFrameTemplate")
        frame:SetSize(30, 30)
        frame.icon = frame:CreateTexture(nil, "BACKGROUND")
        frame.icon:SetAllPoints()
        frame:SetScript("OnHide", HideFrame)
    end
    return frame
end

local function ShowCooldown(spellID, unitID)
    local frame = GetFrame()
    local _, _, texture = GetSpellInfo(spellID)
    frame.icon:SetTexture(texture)
    frame.icon:SetTexCoord(.08, .92, .08, .92)
    local timer = {spellID = spellID, unitID = unitID, frame = frame}
    if not firstTimer then
        firstTimer = timer
        lastTimer = timer
    else
        timer.prev = lastTimer
        lastTimer.next = timer
        lastTimer = timer
    end
    frame.timer = timer
    CooldownFrame_SetTimer(frame, GetTime(), spells[spellID], 1)
    Reposition(timer)
end

local function ResetCooldown(spellID, unitID)
    local timer = firstTimer
    while timer do
        if timer.spellID == spellID and timer.unitID == unitID then
            timer.frame:SetCooldown(0, 0)
            break
        end
        timer = timer.next
    end
end

function events:UNIT_SPELLCAST_SUCCEEDED(unitID, spell, rank, lineID, spellID)
    if not unitID:find("arena") then return end
    if spells[spellID] then
        ShowCooldown(spellID, unitID)
    end
end

local lastSpellID, lastSourceGUID
function events:COMBAT_LOG_EVENT_UNFILTERED(...)
    local timestamp, event, hideCaster, sourceGUID, sourceName, sourceFlags, sourceRaidFlags,
        destGUID, destName, destFlags, destRaidFlags, spellID, spellName = ...
    local isSourceEnemy = (bit.band(sourceFlags, COMBATLOG_OBJECT_REACTION_HOSTILE) == COMBATLOG_OBJECT_REACTION_HOSTILE)
    if event ~= "SPELL_CAST_SUCCESS" or not isSourceEnemy then
        return
    end
    if spells[spellID] then
        if lastSpellID == spellID and lastSourceGUID == sourceGUID then -- check for duplicates
            return
        end
        ShowCooldown(spellID, sourceGUID)
        lastSpellID, lastSourceGUID = spellID, sourceGUID
    end
end

function events:PLAYER_ENTERING_WORLD()
    local _, instanceType = GetInstanceInfo()
    if instanceType == "arena" then
        self:UnregisterEvent("COMBAT_LOG_EVENT_UNFILTERED")
        self:RegisterEvent("UNIT_SPELLCAST_SUCCEEDED")
    else
        self:UnregisterEvent("UNIT_SPELLCAST_SUCCEEDED")
        self:RegisterEvent("COMBAT_LOG_EVENT_UNFILTERED")
    end
    local timer = firstTimer
    while timer do
        timer.frame:Hide()
        timer = timer.next
    end
end

events:SetScript("OnEvent", function(self, event, ...) return self[event](self, ...) end)
events:RegisterEvent("PLAYER_ENTERING_WORLD")