-- ExpBar.lua
local _;
local min = math.min;
local IsResting = IsResting;
local UnitXP, UnitXPMax, GetXPExhaustion = UnitXP, UnitXPMax, GetXPExhaustion;
local CTimerAfter = C_Timer.After;

local width = 300;
local running = false;
local frame = CreateFrame("Frame", "OmaArtifactBar", UIParent);

local function expBar()
    frame:SetPoint("BOTTOM", UIParent, "BOTTOM", 0, 8);
    frame:SetWidth(width);
    frame:SetHeight(8);
    frame.base = frame:CreateTexture(nil, "BACKGROUND");
    frame.base:SetAllPoints();
    frame.base:SetColorTexture(0, 0, 0, 0.5);
    frame.bar = frame:CreateTexture(nil, "BORDER");
    frame.bar:SetPoint("TOPLEFT", frame.base, "TOPLEFT");
    frame.bar:SetPoint("BOTTOMLEFT", frame.base, "BOTTOMLEFT");
    frame.bar:SetColorTexture(1, 1, 1);
    frame.rest = frame:CreateTexture(nil, "BORDER");
    frame.rest:SetPoint("TOPLEFT", frame.bar, "TOPRIGHT");
    frame.rest:SetPoint("BOTTOMLEFT", frame.bar, "BOTTOMRIGHT");
    frame.rest:SetColorTexture(0, 0.3, 1, 0.7);
    frame.text = frame:CreateFontString(nil, "ARTWORK", "GameFontHighlight");
    frame.text:SetPoint("BOTTOM");
    frame.text:Hide();

    local function updateXP()
        local xp, xpmax = UnitXP("player"), UnitXPMax("player");
        local rested = GetXPExhaustion();
        local current = xp/xpmax*width;
        local space = width - current;
        frame.bar:SetWidth(current);
        if rested then
            local restw = rested/xpmax*width;
            frame.rest:SetWidth(min(space, restw));
            frame.rest:Show();
            frame.text:SetFormattedText("%d / %d (+%d)", xp, xpmax, rested/2);
            frame.bar:SetVertexColor(0, 0.5, 1, 0.9);
        else
            frame.rest:Hide();
            frame.text:SetFormattedText("%d / %d", xp, xpmax);
            frame.bar:SetVertexColor(0.6, 0.2, 1, 0.9);
        end
    end
    local function updater()
        updateXP();
        if running then CTimerAfter(10, updater) end
    end
    updateXP();

    frame:SetScript("OnEvent", function(self, event)
        if event == "PLAYER_XP_UPDATE" or event == "PLAYER_LEVEL_UP" then
            updateXP();
        elseif event == "PLAYER_UPDATE_RESTING" or event == "PLAYER_ENTERING_WORLD" then
            if IsResting() then
                running = true;
                CTimerAfter(6, updater);
            else
                running = false;
            end
        end
    end);
    frame:UnregisterAllEvents();
    frame:RegisterEvent("PLAYER_XP_UPDATE");
    frame:RegisterEvent("PLAYER_LEVEL_UP");
    frame:RegisterEvent("PLAYER_UPDATE_RESTING");
    frame:RegisterEvent("PLAYER_ENTERING_WORLD");
    -- from FrameXML/MainMenuBar.lua
    frame:SetScript("OnEnter", function(frame) frame.text:Show(); end);
    frame:SetScript("OnLeave", function(frame) frame.text:Hide(); end);
end

frame:SetScript("OnEvent", function(self, event)
    if UnitLevel("player") < 60 and not IsXPUserDisabled() then
        return expBar();
    end
end);
frame:RegisterEvent("PLAYER_LOGIN");