benilla-octo/crates/benilla-app/assets/ui/ErrorsFrame.xml

<Ui>
    <!--
        The real client's UIErrorsFrame (ref UIErrorsFrame.xml/.lua; ErrorFont =
        GameFontNormalLarge, ref Fonts.xml:258): a 512×60 MessageFrame at TOP (0,-122),
        displayDuration 5, insertMode TOP — the newest message takes the top line and older ones
        shift down, up to the ~3 lines the 60px box holds. UI_INFO_MESSAGE shows YELLOW (1,1,0) —
        the quest objective-progress toasts land here — and UI_ERROR_MESSAGE red (1,0.1,0.1), the
        ref handler verbatim (UIErrorsFrame.lua:8-16; its SYSMSG arm is unwired — no engine
        producer yet). This engine has no MessageFrame widget, so the message list is this file's
        Lua over three stacked FontStrings: hold 5 s (the ref displayDuration), then fade out
        (INTERIM 1 s — the ref MessageFrame's post-hold fade curve is unpinned), oldest dropped
        past the visible three. `BenillaErrorsFrame_AddMessage(text, r, g, b)` is the Lua-callable
        seam (the ref's `UIErrorsFrame:AddMessage`) for FrameXML-side producers — the quest log's
        watch guards use it.
    -->
    <Script><![CDATA[
        BENILLA_ERRORS_LINES = 3
        BENILLA_ERRORS_HOLD = 5.0   -- ref displayDuration="5"
        BENILLA_ERRORS_FADE = 1.0   -- INTERIM (comment above)

        function BenillaErrorsFrame_AddMessage(text, r, g, b)
            local frame = getglobal("UIErrorsFrame")
            -- insertMode="TOP": newest first, older lines shift down and off the list.
            table.insert(frame.messages, 1, { text = text, r = r, g = g, b = b, age = 0 })
            while table.getn(frame.messages) > BENILLA_ERRORS_LINES do
                table.remove(frame.messages)
            end
            BenillaErrorsFrame_Paint(frame)
            frame:Show()
        end

        function BenillaErrorsFrame_Paint(frame)
            for i = 1, BENILLA_ERRORS_LINES do
                local line = getglobal("UIErrorsFrameLine" .. i)
                local msg = frame.messages[i]
                if msg then
                    line:SetText(msg.text)
                    line:SetTextColor(msg.r, msg.g, msg.b)
                    local over = msg.age - BENILLA_ERRORS_HOLD
                    if over > 0 then
                        line:SetAlpha(1.0 - over / BENILLA_ERRORS_FADE)
                    else
                        line:SetAlpha(1.0)
                    end
                    line:Show()
                else
                    line:Hide()
                end
            end
        end

        function UIErrorsFrame_OnLoad()
            local frame = this
            frame.messages = {}
            frame:RegisterEvent("UI_INFO_MESSAGE")
            frame:RegisterEvent("UI_ERROR_MESSAGE")
            frame:Hide()
        end

        -- ref UIErrorsFrame_OnEvent(event, message) (UIErrorsFrame.lua:8-15) — the message is the
        -- DECLARED second parameter, not the `arg1` global: the XML passes `arg1` into it exactly
        -- as the reference's own does, and an addon calling the 1.12 arity is then read correctly.
        function UIErrorsFrame_OnEvent(event, message)
            local frame = this
            if not message then return end
            if event == "UI_INFO_MESSAGE" then
                BenillaErrorsFrame_AddMessage(message, 1.0, 1.0, 0.0) -- ref UIErrorsFrame.lua:12
            elseif event == "UI_ERROR_MESSAGE" then
                BenillaErrorsFrame_AddMessage(message, 1.0, 0.1, 0.1) -- ref UIErrorsFrame.lua:14
            end
        end

        function BenillaErrorsFrame_OnUpdate(frame, elapsed)
            for i = table.getn(frame.messages), 1, -1 do
                local msg = frame.messages[i]
                msg.age = msg.age + elapsed
                if msg.age > BENILLA_ERRORS_HOLD + BENILLA_ERRORS_FADE then
                    table.remove(frame.messages, i)
                end
            end
            BenillaErrorsFrame_Paint(frame)
            if table.getn(frame.messages) == 0 then
                frame:Hide()
            end
        end
    ]]></Script>

    <!-- frameStrata HIGH is the ref's own (`UIErrorsFrame.xml` l.4). It matters here: this frame is
         512x60 anchored TOP (0,-122), which overlaps the right edge of every left-slot panel window
         (character, quest log, loot, merchant, mail, trainer, taxi — all at TOPLEFT (0,-104)). Its
         own content is flat FontString REGIONS at level 0 while those panels carry dozens of nested
         child frames at level 1+, so left in the default MEDIUM its toasts draw UNDER whichever
         panel is open — invisible in exactly the state you most want to read them. Decision 0597. -->
    <Frame name="UIErrorsFrame" frameStrata="HIGH">
        <Size><AbsDimension x="512" y="60"/></Size>
        <Anchors>
            <Anchor point="TOP" relativePoint="TOP">
                <Offset><AbsDimension x="0" y="-122"/></Offset>
            </Anchor>
        </Anchors>
        <Layers>
            <Layer level="OVERLAY">
                <FontString name="UIErrorsFrameLine1" inherits="GameFontNormalLarge" justifyH="CENTER">
                    <Size><AbsDimension x="512" y="0"/></Size>
                    <Anchors><Anchor point="TOP" relativePoint="TOP"/></Anchors>
                </FontString>
                <FontString name="UIErrorsFrameLine2" inherits="GameFontNormalLarge" justifyH="CENTER">
                    <Size><AbsDimension x="512" y="0"/></Size>
                    <Anchors><Anchor point="TOP" relativeTo="UIErrorsFrameLine1" relativePoint="BOTTOM"><Offset><AbsDimension x="0" y="-2"/></Offset></Anchor></Anchors>
                </FontString>
                <FontString name="UIErrorsFrameLine3" inherits="GameFontNormalLarge" justifyH="CENTER">
                    <Size><AbsDimension x="512" y="0"/></Size>
                    <Anchors><Anchor point="TOP" relativeTo="UIErrorsFrameLine2" relativePoint="BOTTOM"><Offset><AbsDimension x="0" y="-2"/></Offset></Anchor></Anchors>
                </FontString>
            </Layer>
        </Layers>
        <Scripts>
            <OnLoad>UIErrorsFrame_OnLoad()</OnLoad>
            <OnEvent>UIErrorsFrame_OnEvent(event, arg1)</OnEvent>
            <OnUpdate>BenillaErrorsFrame_OnUpdate(self, arg1)</OnUpdate>
        </Scripts>
    </Frame>
</Ui>