-------------------
-- Initilization --
-------------------
    -- Diasble AddOn if not a DK.
    -- if select(2, UnitClass("player")) ~= "DEATHKNIGHT" then return end

    local addonName, addonTable = ...

-----------------------
-- Local Definitions --
-----------------------
    -- AddOn Frame
    local frame = CreateFrame("Frame", addonName.."Frame", UIParent)

    -- Table to hold all of the damage events and their timestamp
    local damageTable = {}

    -- OnUpdate Interval
    local updateInterval = 0.1

    -- GUID Types
    local knownTypes = {
        "player",
        "world object",
        "NPC",
        "pet",
        "vehicle"
    }

    -- Upsourcing
    local pairs = pairs
    local time = time
    local tonumber = tonumber
    local strsub = strsub

    -- Player GUID
    local playerGUID

    -- Index to name the key for the damageTable
    local eventIndex = 0

----------
-- Core --
----------
    -- Setup font display
    local fontString = frame:CreateFontString(addonName.."FontString", "OVERLAY", "GameFontHighlight")
    fontString:SetFont(STANDARD_TEXT_FONT, 25, "OUTLINE")
    fontString:SetPoint("CENTER", UIParent, "CENTER", 0, 0)

    -- OnEvent function to handle all the registered events firing.
    frame:SetScript("OnEvent", function(self, event, ...)
        if event == "PLAYER_LOGIN" then
            -- Get and set the playerGUID for use later.
            playerGUID = UnitGUID("player")
            -- Unregister PLAYER_LOGIN as it is no longer needed.
            frame:UnregisterEvent("PLAYER_LOGIN")
        elseif event == "COMBAT_LOG_EVENT_UNFILTERED" then
            eventIndex = eventIndex + 1
            local t = time()
            local _, eventType, _, sourceGUID, _, _, _, destGUID = ...
            local maskedTypeBit = tonumber(strsub(sourceGUID, 5, 5), 16) % 8
            if eventType == "SWING_DAMAGE" and destGUID == playerGUID and knownTypes[maskedTypeBit] == "NPC" then
                local _, _, _, _, _, _, _, _, _, _, _, amount = ...
                damageTable[eventIndex] = {t, amount}
            elseif eventType == "SPELL_DAMAGE" and destGUID == playerGUID and knownTypes[maskedTypeBit] == "NPC" then
                local _, _, _, _, _, _, _, _, _, _, _, _, _, _, amount = ...
                damageTable[eventIndex] = {t, amount}
            elseif eventType == "SPELL_PERIODIC_DAMAGE" and destGUID == playerGUID and knownTypes[maskedTypeBit] == "NPC" then
                local _, _, _, _, _, _, _, _, _, _, _, _, _, _, amount = ...
                damageTable[eventIndex] = {t, amount}
            end -- if eventType
        end -- if event
    end)

    -- OnUpdate function to constantly poll the damageTable and make sure the damage text is up to date.
    local totalTime = 0
    local totalDamage = 0
    frame:SetScript("OnUpdate", function(self, elapsed)
        totalTime = totalTime + elapsed
        if totalTime >= updateInterval then
            local t = time() - 5
            for k, v in pairs(damageTable) do
                if v[1] < t then
                    damageTable[k] = nil
                else
                    totalDamage = totalDamage + v[2]
                end -- if k < t...
            end -- for k, v...

            if totalDamage > 0 then
                fontString:SetText(totalDamage)
            else
                fontString:SetText("")
            end

            totalDamage = 0
            totalTime = 0
        end -- if totalTime
    end)

------------
-- Events --
------------
    frame:RegisterEvent("COMBAT_LOG_EVENT_UNFILTERED")
    frame:RegisterEvent("PLAYER_LOGIN")