---------------------------------------------------------------------------
-- Options - the app window.
--
-- Three columns, fixed:
--
--   left    the functions. Cooldowns, Edit mode, settings, and the three
--           read-only pages. It does NOT list your bars - that was the
--           mistake in the last shape, because it made you pick a bar before
--           you could see any of them.
--   middle  what you are working on. For Cooldowns that is every bar you own,
--           under each other, scrollable, with "Add new bar" at the bottom of
--           the stack where the next one appears.
--   right   the spells, in full, all the time. It becomes the settings for
--           one bar while you have its Options open, and goes back after.
--
-- The secondary pages take the middle AND the right, because they have no
-- spell list to show and a narrow column of text next to an empty panel is
-- the wasted space this rebuild set out to remove.
---------------------------------------------------------------------------
local _, ns = ...

local Options = {}
ns.Options = Options

local UI = ns.UI
local C = UI.C

-- The left column holds six words and a button; it does not need to be as
-- wide as the thing you are working on. The right one holds a settings label
-- AND its control on the same line, and it was clipping labels to "T..." to
-- fit. So: take the width from the one that has nothing to say and give it to
-- the one that ran out.
-- TAKEN FROM THE DESIGN SYSTEM, NOT TYPED AGAIN.
--
-- These were four literals here and four more in Widgets, for the same four
-- measurements - and the inspector reads its own copy in order to decide what
-- fits on a row. Two numbers for one distance is a number that will disagree
-- with itself, and it did the moment the rail was widened.
--
-- The rail carries a state light per feature now, so it needed the room for
-- one; the window grew by the same amount rather than taking it out of the
-- work area, which is the column that was short in the first place.
local WINDOW_W, WINDOW_H = UI.WINDOW_W, UI.WINDOW_H
local SIDEBAR_W = UI.RAIL_W
local SIDE_W    = UI.INSPECTOR_W
local PAD       = 20

-- Shared with Widgets, so the rule under the brand, the rule under the page
-- title and the rule under the right column's heading are the same line.
local HEADER_H  = UI.HEADER_H

-- The strip at the bottom of the rail that carries the version and the client
-- build. Named because the sum that decides whether the list of entries fits
-- has to subtract it, and a number typed in two places is a number that
-- drifts - which is exactly how an entry ends up behind it.
local RAIL_FOOT_H = 38

-- The block of outward links between the nav and that foot: one row per store
-- plus Discord. SHORTER THAN A NAV ROW, and the number is measured, not
-- preferred - see where they are built. It is also the right look: these are
-- references, not pages, and a reference as tall as a destination claims to be
-- one.
local RAIL_LINK_H = 22

-- What that block costs the nav, published so the check and the layout read
-- ONE number. They were two for a version - the check still subtracted a
-- single row while three were being drawn - which is a check quietly agreeing
-- with a window that had already changed.
function Options.RailTail()
    return #ns.LINKS * RAIL_LINK_H + 12
end

-- THE CLOSE CROSS, AND WHY ITS SIZE IS A SHARED NUMBER.
--
-- The cross sits in the window's top-right corner. The page's header actions
-- sit at the right edge of the MIDDLE column. On a page with a third column
-- those are 400 pixels apart and nothing touches; on a page without one they
-- are the same corner, and the cross was drawn straight through the last
-- button's label. Owner, with a picture of the answer page: "das X oben
-- rechts fixen".
--
-- So the actions have to know how much room to leave, which means the cross's
-- width cannot be typed at the one place that draws it.
local CLOSE_W = 24
local CLOSE_ROOM = CLOSE_W + 10

---------------------------------------------------------------------------
-- Diagnostics
---------------------------------------------------------------------------
-- THE FOUR READINGS AT THE TOP OF DIAGNOSTICS.
--
-- Every one of them is measured on this machine. Nothing here is a number
-- somebody typed in once, and nothing that has no live source is drawn: the
-- design sketch also showed a "secret values" count and a timing chart, and
-- neither exists to be read - the secret-value figure in About is a
-- measurement taken by hand, not a counter, and there is no timing series at
-- all. A dashboard that invents its own numbers is worse than one with four.
-- MEMORY IS A READING LIKE THE OTHERS, and it is here because the owner had
-- to ask: "warum ist unser addon im spiel 13 mb gross". Nothing in the window
-- could answer him, so the answer took a desktop measurement. It is one call
-- and it belongs on the page whose whole job is what this addon is doing to
-- your client.
--
-- No good/warn colour on it. A threshold would be invented - what is "too
-- much" depends on what you have open - and a tile that turns orange at a
-- number somebody guessed teaches people to distrust the other four.
local DIAG_STATS = { "Cooldowns tracked", "Pixels per unit", "Memory" }

-- HOW MUCH OF THE CLIENT'S LUA HEAP IS OURS, in a form a tile can show.
--
-- Two facts, both checked against addons installed on this machine rather
-- than assumed:
--
--   * The memory pair is still GLOBAL - only the addon INFO calls moved into
--     C_AddOns - and GetAddOnMemoryUsage takes a NAME as well as an index.
--   * UpdateAddOnMemoryUsage walks every loaded addon and is a spike you can
--     see. EllesmereUI, which puts the same number on a data bar, rescans
--     once every thirty seconds and says why in its own comment.
--
-- This page repaints on every keystroke in a settings box, so the reading is
-- taken at most once every five seconds and the tile shows the last one in
-- between. A number five seconds old is the truth about an addon's memory;
-- a scan per keystroke is a stutter while you type.
local MEM_EVERY = 5
local memTaken, memText = 0, "-"

-- The client counts in KB. Pure, and exported, so the one thing here that can
-- be wrong without anybody noticing - a tile reading "13312 KB" - has a test.
function Options.MemoryText(kb)
    kb = tonumber(kb) or 0
    if kb >= 1024 then return string.format("%.1f MB", kb / 1024) end
    return string.format("%d KB", kb)
end

local function MemoryReading()
    if not (UpdateAddOnMemoryUsage and GetAddOnMemoryUsage) then return "-" end

    local now = GetTime and GetTime() or 0
    if memText ~= "-" and now - memTaken < MEM_EVERY then return memText end
    memTaken = now

    UpdateAddOnMemoryUsage()
    memText = Options.MemoryText(GetAddOnMemoryUsage("ZwoelfStuff"))
    return memText
end

local function BuildDiagnosticsPage(page, width)
    local grid = UI.Page(page, width)

    ---------------------------------------------------------------------
    -- The readings
    ---------------------------------------------------------------------
    local statHost = CreateFrame("Frame", nil, grid.content)
    statHost:SetHeight(UI.STAT_H)

    local STAT_GAP = 10
    local tileWidth = math.floor(
        (grid.width - STAT_GAP * (#DIAG_STATS - 1)) / #DIAG_STATS)

    local stats = {}
    for index, caption in ipairs(DIAG_STATS) do
        local stat = UI.Stat(statHost, caption)
        stat:SetTileWidth(tileWidth)
        stat:SetPoint("TOPLEFT", statHost, "TOPLEFT",
            (index - 1) * (tileWidth + STAT_GAP), 0)
        stats[index] = stat
    end
    grid:Wide(statHost, UI.STAT_H, 0, 12)

    grid:Section("Cooldown Manager")
    grid:Note("Everything on your bars comes from Blizzard's Cooldown Manager - it "
        .. "already knows the spells, binds the auras and has the timing, none of "
        .. "which an addon can do for itself on this patch.")

    grid:Buttons({
        { text = "What it holds", onClick = function()
            ns.CDM:Dump()
        end },
    })

    grid:Section("Auras")
    grid:Note("Procs are recorded while you play, per class and spec, and their "
        .. "duration is measured rather than assumed. Output goes to your chat frame.")

    grid:Buttons({
        { text = "What was seen", onClick = function()
            ns.Auras:Dump()
        end },
        { text = "Export this spec", onClick = function()
            ns.Auras:Export()
        end },
    })


    grid:Section("This client")

    -- HOW SHARP THE MARKS IN THIS WINDOW ARE, and it is a measurement rather
    -- than an opinion. Every icon here was soft for months because the rule
    -- that picks a file guessed at this number instead of reading it, and
    -- "sieht matschig aus" is not something a screenshot can settle. Now it
    -- says which file it loaded and why.
    -- The caveat belongs ON the row: a cut is chosen when a mark is BUILT, so
    -- this line can be right while the window in front of you was drawn under
    -- the old setting.
    local sharpRow = grid:FullRow("Icon sharpness", { controlWidth = 300,
        sublabel = "Chosen when the window is built - a UI scale change needs a /reload" })
    local sharpState = UI.Label(sharpRow.slot, "", 12, C.text)
    sharpState:SetPoint("RIGHT", sharpRow.slot, "RIGHT", 0, 0)
    sharpState:SetJustifyH("RIGHT")

    local engineRow = grid:FullRow("Aura engine (12.1)", { controlWidth = 260 })
    local engineState = UI.Label(engineRow.slot, "", 12, C.text)
    engineState:SetPoint("RIGHT", engineRow.slot, "RIGHT", 0, 0)
    engineState:SetJustifyH("RIGHT")

    grid:Note("Procs are recognised by their spell overlay, and their length "
        .. "is measured while you play.")

    grid:Layout()

    page.Refresh = function()
        local perUnit = UI.PixelsPerUnit()

        ---------------------------------------------------------------
        -- The four readings
        ---------------------------------------------------------------
        -- COUNTED, not asked for: there is no items-held call on CDM, and
        -- walking what it hands out is the only honest answer. Guarded,
        -- because on a client where the Cooldown Manager is not up
        -- ForEachItemEverywhere walks nothing and the answer is nought
        -- rather than an error.
        local held = 0
        if ns.CDM:IsAvailable() then
            ns.CDM:ForEachItemEverywhere(function() held = held + 1 end)
        end
        -- What the Cooldown Manager is holding. Nothing of ours displays
        -- it any more; the catalogue behind the death log's defensives and
        -- the reminders is built out of exactly these items, so nought here
        -- is why those two come up empty.
        stats[1]:Set(tostring(held), held > 0 and "good" or "warn")
        stats[2]:Set(string.format("%.2f", perUnit))
        stats[3]:Set(MemoryReading())

        sharpState:SetText(string.format(
            "%.2f px per unit - %dpx and %dpx files",
            perUnit, UI.IconCutFor(16, perUnit), UI.IconCutFor(32, perUnit)))

        -- THIS COMMENT SAID "Engine.lua is parked on a 12.0 client, so
        -- ns.Engine is nil here" AND IT HAD BEEN FALSE FOR FIVE DAYS. It was
        -- written 2026-08-06, when the file really was out of the TOC; the
        -- co-tank wave put Core\Engine.lua back in on 2026-08-08 and this line
        -- was never revisited. ns.Engine has existed on every client since -
        -- the file assigns it at file scope - and the only thing 12.1 changed
        -- is that Engine:IsAvailable() now answers true.
        --
        -- The guard stays, because a file CAN be parked again and reading
        -- through a nil is a crash rather than a missing feature. What went is
        -- the sentence that promised a patch which has since arrived.
        if not ns.Engine then
            engineState:SetText("|cff888888not loaded on this client|r")
        elseif ns.Engine:IsAvailable() then
            engineState:SetText("|cff40ff40available|r")
        else
            engineState:SetText("|cffff4040"
                .. (ns.Engine:UnavailableReason() or "unavailable") .. "|r")
        end

        grid:Refresh()
    end
end

---------------------------------------------------------------------------
-- About
---------------------------------------------------------------------------
-- THE BLOCK AT THE TOP OF ABOUT: the mark, the name, why it exists, and the
-- three facts anybody is asked for the moment something goes wrong.
--
-- Its own function because it is the one piece of this page that is a LAYOUT
-- rather than a paragraph, and the page below it is built by the grid.
local ABOUT_LOGO = 56
local ABOUT_META = { "Author", "Version", "Client" }

local function BuildAboutHead(parent, width, intro)
    local head = CreateFrame("Frame", nil, parent)

    local logo = head:CreateTexture(nil, "ARTWORK")
    logo:SetSize(ABOUT_LOGO, ABOUT_LOGO)
    logo:SetPoint("TOPLEFT", head, "TOPLEFT", 0, 0)
    logo:SetTexture(ns.ICON_TEXTURE)

    local column = ABOUT_LOGO + 18

    local name = UI.Label(head, "ZwoelfStuff", UI.FS.title, C.text)
    name:SetPoint("TOPLEFT", head, "TOPLEFT", column, -2)

    local blurb = UI.Label(head, intro, UI.FS.row, C.textBody)
    blurb:SetPoint("TOPLEFT", name, "BOTTOMLEFT", 0, -10)
    blurb:SetJustifyH("LEFT")
    blurb:SetJustifyV("TOP")
    blurb:SetWidth(width - column)

    -- Author, version, client - caption over value, side by side. The same
    -- three the rail's foot carries, which is not a duplication: the foot is
    -- glanceable and this is the page you are sent to when somebody asks.
    --
    -- Zwoelf with the umlaut: this VALUE names the person. The addon keeps
    -- the transliteration everywhere it is an identifier. Owner: "der
    -- charakter heisst Zwölf! das addon zwoelf, wichtig!"
    local values = {
        "Zwölf  -  EU Destromath",
        ns.version,
        (GetBuildInfo()) or "",
    }

    local FIELD_GAP = 34
    local x, fieldTop = 0, nil
    for index, caption in ipairs(ABOUT_META) do
        local label = UI.Eyebrow(head, caption)
        local value = UI.Label(head, values[index], UI.FS.row, C.text)

        if fieldTop then
            label:SetPoint("TOPLEFT", fieldTop, "TOPLEFT", x, 0)
        else
            label:SetPoint("TOPLEFT", blurb, "BOTTOMLEFT", 0, -18)
            fieldTop = label
        end
        value:SetPoint("TOPLEFT", label, "BOTTOMLEFT", 0, -4)

        x = x + math.max(label:GetStringWidth(), value:GetStringWidth())
            + FIELD_GAP
    end

    -- IT SETS ITS OWN SIZE, and that is not a detail.
    --
    -- Grid:Layout gives a wide block a POINT and nothing else - it never sets
    -- a height. A frame left at its default 0 reserves the room the grid was
    -- told about and draws none of it, which is exactly what this block did on
    -- its first outing: owner, with a picture, "about hat ein riesen gap
    -- oben." Every other frame block in this window sets its own rectangle -
    -- Grid:Buttons does, the chip host does, the stat strip does - and this
    -- one had been written as if the grid would do it.
    --
    -- Measured, not typed: the blurb wraps, and how many lines that takes
    -- depends on the panel font the user chose.
    local NAME_H, EYEBROW_H, VALUE_H = 22, 11, 15
    local height = math.max(ABOUT_LOGO,
        NAME_H + 10 + blurb:GetStringHeight() + 18 + EYEBROW_H + 4 + VALUE_H)

    head:SetSize(width, height)
    head.Measure = function() return height end
    return head
end

-- WHY THIS ADDON EXISTS, IN HIS OWN WORDS, and the same words the README
-- opens with. Owner: "der text sollte auch ins about!" - and he is right that
-- it belongs here rather than only on a page nobody reads from inside the
-- game.
--
-- One paragraph up top rather than nine lines: the block beside the mark is
-- what somebody reads, and everything colder than that has its own heading
-- under it.
local ABOUT_INTRO =
    "After many years I have built a new addon again, one that serves my own "
    .. "needs as a tank first, and those of my M+ groups and friends. You will "
    .. "find a lot of these features in other addons too - but like everybody, "
    .. "I have my own ideas about what I want in the game. Hence this addon. I "
    .. "hope it is as useful to you as it is to me."

-- THE CREDIT, WORD FOR WORD FROM THE README. Owner: "in about muss unter
-- meinen text noch der info text aus der readme rein." It belongs in both
-- places for the same reason it exists at all: the people who would recognise
-- these names are players, and a player never opens a repository.
local ABOUT_CREDIT = {
    "This addon is no replacement for EllesmereUI or ElvUI. I love both of "
    .. "them and use them for my own UI. This is a collection of the features "
    .. "I like, done my way. And of course - feature requests and feedback are "
    .. "welcome!",

    "It was written by reading other addons - EllesmereUI, ElvUI, BigWigs, "
    .. "Method Raid Tools, Mythic Dungeon Tools, Details!, WeakAuras, Plater, "
    .. "LibOpenRaid and a few more. Their authors have our thanks.",

    "No code was copied from any of them. What we took is a different thing: "
    .. "facts about the game's API. Which field a table actually carries, "
    .. "which event fires first, which call answers on a fresh login and which "
    .. "one returns nothing until a frame later, which values the client "
    .. "withholds in a dungeon. None of that is documented anywhere, and on a "
    .. "patch that keeps closing doors it is often not discoverable at all "
    .. "except by reading code that already works.",

    "So the comments in Core/ cite those addons by name and by line, and they "
    .. "say 'read off working code on this machine' rather than pretending we "
    .. "knew. A number nobody can re-check is a number that quietly goes wrong "
    .. "two patches later - see Core/CDM.lua, which is mostly a record of "
    .. "where each fact came from.",

    "If you are one of those authors and you would rather not be named here, "
    .. "say so and we will take the citation out.",
}

-- One command row: the command on the left in the accent, what it does beside
-- it. NOT a Grid row - a row right-aligns its control against a slot, and
-- these two are a pair read left to right.
--
-- There is no monospace face to set the command in. The client ships none and
-- the panel font is whatever LibSharedMedia handed over, so the column is held
-- by a MEASURED indent instead and the colour does the separating.
local COMMAND_H = 20
local COMMAND_GAP = 14

local function BuildCommandColumn(parent, entries, columnWidth, cmdWidth)
    local block = CreateFrame("Frame", nil, parent)
    block:SetWidth(columnWidth)

    local y = 0
    for _, entry in ipairs(entries) do
        if entry.group then
            local caption = UI.Eyebrow(block, entry.group)
            caption:SetPoint("TOPLEFT", block, "TOPLEFT", 0, -(y + 10))
            y = y + 10 + 18
        else
            local cmd = UI.Label(block, entry.cmd, UI.FS.meta, C.accent)
            cmd:SetPoint("TOPLEFT", block, "TOPLEFT", 0, -y)
            cmd:SetWidth(cmdWidth)
            cmd:SetJustifyH("LEFT")

            local what = UI.Label(block, entry.text, UI.FS.meta, C.textDim)
            what:SetPoint("TOPLEFT", block, "TOPLEFT",
                cmdWidth + COMMAND_GAP, -y)
            what:SetWidth(columnWidth - cmdWidth - COMMAND_GAP)
            what:SetJustifyH("LEFT")
            what:SetJustifyV("TOP")

            -- A description can wrap, and the next row has to start under the
            -- taller of the two rather than under a number typed here.
            y = y + math.max(COMMAND_H, what:GetStringHeight() + 6)
        end
    end

    block:SetHeight(math.max(1, y))
    return block
end

-- Where to cut the command list into two columns, counting the HEIGHT each
-- entry costs rather than the entries - a heading is not a command and a
-- wrapped description is worth two rows.
--
-- Pure, and exported, because the harness cannot measure a string: it is the
-- balance rule that is worth checking, not the pixels.
function Options.SplitCommands(entries)
    local weight = 0
    for _, entry in ipairs(entries) do
        weight = weight + (entry.group and 1.4 or 1)
    end

    local half, running = weight / 2, 0
    for index, entry in ipairs(entries) do
        running = running + (entry.group and 1.4 or 1)
        -- Never cut so that a heading is the last thing in the left column.
        if running >= half and not entry.group then return index end
    end
    return #entries
end

local function BuildAboutPage(page, width)
    local grid = UI.Page(page, width)

    local head = BuildAboutHead(grid.content, grid.width, ABOUT_INTRO)
    grid:Wide(head, head.Measure(), 0, 10)

    ---------------------------------------------------------------------
    -- Where to get it
    --
    -- FROM ns.STORES, not typed here: the same list the release announcement
    -- prints from, so a third store appears on this page by existing rather
    -- than by somebody remembering.
    --
    -- A click cannot open a browser - no addon may hand a URL to one, by
    -- design - so it opens a box with the address selected. That is the
    -- honest version of a link inside a game: one Ctrl+C and it is in the
    -- address bar. A row that looked like a link and did nothing would be
    -- worse than no row.
    ---------------------------------------------------------------------
    grid:Section("Where to get it")

    for _, store in ipairs(ns.STORES) do
        local row = grid:Row(store.name, { icon = store.icon })
        local button = UI.Button(row.slot, "Copy the address",
            UI.ButtonWidth("Copy the address"), function()
                UI.CopyBox(store.name, store.url,
                    "Ctrl+C copies it, then paste it into your browser. Esc "
                    .. "closes. An addon cannot open a browser itself - the "
                    .. "client has no call for it, by design.")
            end)
        button:SetPoint("RIGHT", row.slot, "RIGHT", 0, 0)
    end

    grid:Note("Both stores get the same build from the same release, so it "
        .. "makes no difference which one you use.")

    grid:Section("Standing on other people's shoulders")
    for _, paragraph in ipairs(ABOUT_CREDIT) do grid:Note(paragraph) end

    ---------------------------------------------------------------------
    -- WHO OWNS THIS, said in the addon rather than only in a file nobody
    -- opens. The store page has always said All Rights Reserved; the folder
    -- that ships shipped an MIT LICENSE beside it until 4.83.0, which is the
    -- kind of contradiction that only ever gets found by somebody acting on
    -- the wrong half of it.
    --
    -- The libraries are named separately on purpose: their terms are theirs,
    -- they travel with the files, and claiming them under ours would be
    -- exactly the mistake the LibDeflate note in the README is about.
    ---------------------------------------------------------------------
    grid:Section("Licence")

    grid:Note("ZwoelfStuff is |cffffd100All Rights Reserved|r, "
        .. "\194\169 2026 Christian McCain. Download it, install it, play "
        .. "with it, keep your own backup. Republishing it, selling it or "
        .. "handing out a changed copy needs written permission first.")

    grid:Note("The libraries under Libs/ keep their own terms and are not "
        .. "covered by that: LibStub is public domain, CallbackHandler is "
        .. "BSD, LibSharedMedia is LGPL 2.1, LibSerialize is MIT and "
        .. "LibDeflate is zlib.")

    grid:Note("Releases up to 4.82.0 went out under the MIT License. That "
        .. "was given and is not being taken back - it still applies to "
        .. "those versions. These terms start at 4.83.0.")

    ---------------------------------------------------------------------
    -- Commands
    --
    -- FROM ns.COMMANDS, which the chat help prints from as well. This page
    -- used to carry a second list, typed by hand, and it had gone stale: it
    -- advertised `/zs text` and knew nothing of build, modules, report, skin,
    -- test, taunt or death.
    ---------------------------------------------------------------------
    grid:Section("Commands")

    local cut = Options.SplitCommands(ns.COMMANDS)
    local left, right = {}, {}
    for index, entry in ipairs(ns.COMMANDS) do
        local into = (index <= cut) and left or right
        into[#into + 1] = entry
    end

    -- The widest command there is, measured once and used by both columns, so
    -- the two lists have one indent between them rather than two.
    local cmdWidth = 0
    local ruler = UI.Label(grid.content, "", UI.FS.meta, C.accent)
    for _, entry in ipairs(ns.COMMANDS) do
        if entry.cmd then
            ruler:SetText(entry.cmd)
            cmdWidth = math.max(cmdWidth, ruler:GetStringWidth() or 0)
        end
    end
    ruler:Hide()
    cmdWidth = math.ceil(cmdWidth) + 6

    local columnWidth = grid.colWidth
    local host = CreateFrame("Frame", nil, grid.content)

    local leftBlock = BuildCommandColumn(host, left, columnWidth, cmdWidth)
    leftBlock:SetPoint("TOPLEFT", host, "TOPLEFT", 0, 0)

    local rightBlock = BuildCommandColumn(host, right, columnWidth, cmdWidth)
    rightBlock:SetPoint("TOPLEFT", host, "TOPLEFT",
        columnWidth + UI.COL_GAP, 0)

    local tallest = math.max(leftBlock:GetHeight(), rightBlock:GetHeight())
    host:SetHeight(tallest)
    grid:Wide(host, tallest, 0, 10)

    grid:Layout()
end

---------------------------------------------------------------------------
-- Changelog
---------------------------------------------------------------------------
-- ONE RELEASE IS ONE THING TO READ, so it is drawn as one.
--
-- It was a version, a date and a column of hyphens, and forty-six of those
-- run together into a wall you scroll past rather than read. What separates
-- them now is the same thing that separates two sections anywhere else in
-- this window: a rule across, air above it, and the eye's own idea of a
-- block. No boxes - a card border around every release would be forty-six
-- rectangles and louder than the words in them.
--
-- THE ONE YOU ARE RUNNING SAYS SO. Opening this page after an update, the
-- first question is "is this the one I just got", and a date does not answer
-- it - "installed" beside the number does.
local function BuildChangelogPage(page, width)
    local textWidth = width - 20
    local scroll, content = UI.ScrollArea(page, textWidth)

    local y = 0
    for index, entry in ipairs(ns.CHANGELOG) do
        -- A hairline over every release but the first: it belongs to the gap
        -- BETWEEN two of them, so the top of the page does not get one.
        if index > 1 then
            y = y - 20
            local rule = content:CreateTexture(nil, "ARTWORK")
            rule:SetColorTexture(C.edge[1], C.edge[2], C.edge[3], 1)
            rule:SetHeight(1)
            rule:SetPoint("TOPLEFT", content, "TOPLEFT", 0, y)
            rule:SetPoint("TOPRIGHT", content, "TOPRIGHT", 0, y)
            y = y - 20
        end

        local heading = UI.Label(content, entry.version, 15, C.accent)
        heading:SetPoint("TOPLEFT", content, "TOPLEFT", 0, y)

        local date = UI.Label(content, entry.date, 11, C.textFaint)
        date:SetPoint("LEFT", heading, "RIGHT", 10, -1)

        if entry.version == ns.version then
            local mark = UI.Label(content, "INSTALLED", 10, C.textDim)
            mark:SetPoint("TOPRIGHT", content, "TOPRIGHT", 0, y - 2)
        end

        y = y - 26

        for _, line in ipairs(entry.lines) do
            -- A DOT, not a hyphen: a hyphen sits on the baseline of a line
            -- whose first row is what it belongs to, and at three lines of
            -- wrapped text it reads as punctuation. Four pixels, faint, on
            -- the cap height of the first row.
            local dot = content:CreateTexture(nil, "ARTWORK")
            dot:SetColorTexture(C.accent[1], C.accent[2], C.accent[3], 0.55)
            dot:SetSize(3, 3)
            dot:SetPoint("TOPLEFT", content, "TOPLEFT", 3, y - 7)

            -- THROUGH THE SAME READER AS THE NEWS WINDOW. A line may be a
            -- string or a table carrying an icon and a link, and this page
            -- passed it straight to SetText - so the first entry with an
            -- icon in it emptied the whole page. One list with two readers
            -- is one reader too many; there is a shared one for this.
            local bullet = UI.Label(content, ns.ChangelogText(line), 12,
                C.text)
            bullet:SetPoint("TOPLEFT", content, "TOPLEFT", 14, y)
            bullet:SetWidth(textWidth - 14)
            bullet:SetJustifyV("TOP")
            -- Width is set, so GetStringHeight reports the wrapped height.
            -- Ten between two entries rather than six: these are sentences,
            -- not a list of names, and they need to come apart.
            y = y - (bullet:GetStringHeight() + 10)
        end
    end

    content:SetHeight(math.max(1, -y + 10))
    if scroll.Update then scroll.Update() end
end

---------------------------------------------------------------------------
-- The functions in the left column
--
-- "cooldowns" is the addon; the rest are secondary and look it. Only the
-- first one uses the right column, which is why it carries the flag rather
-- than the shell hardcoding an index.
---------------------------------------------------------------------------
-- THE FIRST ENTRY IS THE PAGE THE WINDOW OPENS ON, and that is not merely an
-- order: Create() runs its builder before anything is shown. Whatever stands
-- here has to survive being built before the window has ever been on screen.
--
-- (The ten lines that used to sit here belonged to the Cooldowns page, which
-- was the first entry until the bars went. The comment stayed behind and read
-- as if it were about Settings - "its two actions carry their marks" over a
-- page that has no actions.)
local PAGES = {
    -- Through the namespace like the pages below it: the builder lives in
    -- Core/OptionsSettings.lua. What this page holds is the split its own
    -- header comment explains - every bar, this window, the ways in - and
    -- nothing that changes WHICH settings you have. That is Profiles.
    -- NO THIRD COLUMN. It had the explain panel - a column that shows the
    -- paragraph belonging to whichever row you point at - and the owner threw
    -- it out on sight: "die settings seite braucht keine rechte leiste."
    --
    -- He is right, and the reason is that this page is the one where the
    -- paragraphs are SHORT. A panel 400 wide standing empty until you hover
    -- something, to hold two lines that fit under the row perfectly well, is
    -- 400 pixels spent on a hover state. The notes are drawn on the page now,
    -- which is what every other page without a third column does.
    { key = "settings", title = "Settings", glyph = "sliders",
      subtitle = "Every bar, this window, and the ways in.",
      build = function(page, width) return ns.OptionsSettings:BuildPage(page, width) end },

    -- The one page that is about somebody ELSE. It carries its own right-hand
    -- column - not the bar inspector and not the explain panel - because what
    -- belongs beside a co-tank preview is the co-tank settings and nothing in
    -- the other two is about this page at all.
    -- NO HEADER ACTIONS. Owner, 2026-08-16: the macro button belongs with
    -- the taunt settings it writes for - it sits under "Asking for a taunt"
    -- on the page now - and "What a taunt would say" was a report for the
    -- desk, not a thing a player goes looking for. `/zs tanks` still prints
    -- it.
    { key = "cotanks", title = "Tank Unitframes", glyph = "tanks", tanks = true,
      module = "cotanks",
      subtitle = "Every tank in the group, with their health and their auras.",
      -- Through the namespace, not a local: the builder lives in
      -- Core/OptionsCoTanks.lua, which loads BEFORE this file but after this
      -- table would have captured a local upvalue that was still nil.
      build = function(page, width) return ns.OptionsCoTanks:BuildPage(page, width) end },

    -- The other page about the fight rather than about the bars. It carries
    -- the SPELL LIST as its third column - the same list the bars page uses -
    -- because the whole gesture is dragging a spell onto the reminder.
    { key = "reminders", title = "Reminders", glyph = "bell", reminders = true,
      module = "reminders",
      subtitle = "Text on your screen when a buff has fallen off.",
      build = function(page, width) return ns.OptionsReminders:BuildPage(page, width) end },

    -- The cooldowns SOMEBODY ELSE presses on you. Its third column is our own
    -- own short list rather than the Cooldown Manager's catalogue - that
    -- list is YOUR spells, and every spell on this page belongs to another
    -- player.
    { key = "externals", title = "External CD request", glyph = "tanks",
      externals = true, module = "externals",
      subtitle = "Somebody else's cooldown, and one click to ask for it.",
      actions = {
          { text = "Set keys",
            onClick = function() ns.Keys:SetActive(true) end },
          { text = "Test mode", widest = "Test mode: on",
            label = function()
                return ns.Externals.testing and "Test mode: on" or "Test mode"
            end,
            onClick = function()
                ns.Externals:SetTestMode(not ns.Externals.testing)
                ns.Options:Refresh()
            end },
      },
      build = function(page, width) return ns.OptionsExternals:BuildPage(page, width) end },

    -- THE MIRROR OF THE PAGE ABOVE. That one asks; this one is asked. Two
    -- pages rather than two halves of one, because they belong to different
    -- people on different evenings - a tank sets the first up, a healer the
    -- second - and they are separate modules for the same reason.
    { key = "answers", title = "External CD answer", glyph = "tanks",
      module = "answers",
      subtitle = "When somebody asks for one of yours, a button lights up.",
      -- ONE ACTION. "What every cell would cast" was the report that says
      -- whether this works at all - and it is a report for the desk, so it
      -- left the header on the owner's word (2026-08-16). ns.Answers:Dump()
      -- is still there behind `/zs answers`.
      actions = {
          { text = "Set keys",
            onClick = function() ns.Keys:SetActive(true) end },
      },
      build = function(page, width) return ns.OptionsAnswers:BuildPage(page, width) end },

    -- THE RAID LEADER'S PAGE. Its third column is the list of buttons there
    -- are, which is the externals page's shape and deliberately so - the
    -- owner asked for "das bewaehrte layout wo ich mir die bar zusammen
    -- stellen kann", and two pages that assemble a lattice must not be two
    -- different pictures.
    { key = "raidbar", title = "Raid Bar", glyph = "grid", raidbar = true,
      module = "raidbar",
      subtitle = "Markers, pings, a ready check and a pull timer.",
      actions = {
          { text = "Raid check",
            onClick = function() ns.RaidCheck:Toggle() end },
          { text = "Move it",
            onClick = function() ns.EditMode:SetUnlocked(true) end },
      },
      build = function(page, width) return ns.OptionsRaidBar:BuildPage(page, width) end },

    -- THE COOLDOWN MANAGER PAGE IS GONE FROM THIS LIST, on the owner's word
    -- (2026-08-16): "das modul komplett aus der uebersicht links rausnehmen
    -- ... als wenn es nicht drin waere." The page builder
    -- (OptionsCooldowns) still loads and the module entry still exists,
    -- hidden - see Core/Modules.lua - so `/zs modules cooldowns` can
    -- resurrect the feature without an install. Putting the page back is
    -- one entry here and one NAV row below.

    -- NO THIRD COLUMN. Everything on it is a yes-or-no about something that
    -- happens without you, and there is no list to pick from - the two boxes
    -- are typed into.
    { key = "invites", title = "Invites", glyph = "tanks", module = "invites",
      subtitle = "Somebody whispers a word and they are in the group.",
      -- THE THREE THINGS THIS PAGE DOES RIGHT NOW are its header, on the
      -- owner's word (2026-08-16): they used to sit at the bottom of the
      -- page under the rank filter, and "What is listening" - a report for
      -- the desk - sat up here instead. The rank filter stays on the page,
      -- beside the note that says what it filters.
      actions = {
          { text = "Invite the guild",
            onClick = function() ns.Invites.InviteGuild() end },
          { text = "Invite everyone back",
            onClick = function() ns.Invites.InviteBack() end },
          { text = "Disband",
            onClick = function() ns.Invites.Disband() end },
      },
      build = function(page, width) return ns.OptionsInvites:BuildPage(page, width) end },

    -- The death log, and with it the DEFENSIVES LIST that used to live on a
    -- Timeline page of its own. That page is gone: what it drew live was the
    -- fight's next scheduled hit, and the replay answers the same question
    -- afterwards with everything the panel could never show. The list it
    -- carried was always read by this window anyway.
    --
    -- It carries the spell palette as its third column, because picking your
    -- defensives out of a dropdown of forty names was the worst part of it.
    { key = "deaths", title = "Death-log", glyph = "skull", deaths = true,
      module = "deaths",
      subtitle = "What killed you, and what could have prevented it.",
      actions = {
          { text = "Open it", onClick = function() ns.Death:Show() end },
          { text = "Share in chat", onClick = function() ns.Death:Share() end },
      },
      build = function(page, width) return ns.OptionsDeaths:BuildPage(page, width) end },

    -- The third page about the fight. No third column: what it shows is the
    -- state of a route, and there is no list to pick from.
    -- Its own page rather than a section of Settings. Everything on Settings
    -- changes how something LOOKS; everything here changes which settings are
    -- in use at all, and one of the buttons deletes them. Those two do not
    -- belong on one page under two headings.
    { key = "profiles", title = "Profiles", glyph = "sliders",
      subtitle = "Name a set of settings, share it, or use somebody else's.",
      build = function(page, width) return ns.OptionsProfiles:BuildPage(page, width) end },

    { key = "diagnostics", title = "Diagnostics", glyph = "pulse",
      subtitle = "What the Cooldown Manager holds, and what the client refuses to show.",
      build = BuildDiagnosticsPage },

    -- ONE ACTION, AND THE STORES ARE NOT IT.
    --
    -- CurseForge was up here for a version. Then Wago arrived, and three
    -- addresses do not fit a band with a measured ceiling of two - which is
    -- the right answer, because it exposed the real mistake: a download
    -- address is not something you DO on this page, it is something the page
    -- SAYS. The stores are a section in the body now, built from ns.STORES,
    -- so a third one appears by existing.
    --
    -- Discord stays, because "ask somebody" is an action.
    { key = "about", title = "About", glyph = "info",
      subtitle = "Why this addon exists, and every command.",
      actions = {
          { text = "Discord", icon = "brand-discord", onClick = function()
              UI.CopyBox("Discord", ns.DISCORD_URL,
                  "Ctrl+C copies it, then paste it into your browser. Esc "
                  .. "closes. An addon cannot open a browser itself - the "
                  .. "client has no call for it, by design.")
          end },
      },
      build = BuildAboutPage },

    { key = "changelog", title = "Changelog", glyph = "log",
      subtitle = "What changed, and why.",
      build = BuildChangelogPage },
}

-- The three pages that carry a THIRD COLUMN, published so the rule below can
-- be checked without building a window.
Options.PAGES = PAGES

---------------------------------------------------------------------------
-- The rail, in the order it reads
--
-- AT FILE SCOPE SO IT CAN BE CHECKED. It was built inside the window, where
-- nothing could look at it, and a `page` naming a key PAGES no longer has
-- costs a blank row: the lookup answers nil, the label falls back to the
-- empty string and the click calls ShowPage(nil). A dead row in the rail
-- that says nothing about itself - which is what "the Bars entry can go" was
-- one bad edit away from leaving behind.
--
-- Every entry is an `eyebrow` heading, a `page`, or a bare `gap`. The one row
-- that is none of those - Edit mode, which CLOSES this window rather than
-- opening a page - is added by the builder, because its action needs the
-- frame it closes. It goes at the head: it is the entry used most often, and
-- a door belongs at the top.
--
-- THE FIRST GROUP HAS NO HEADING, at the owner's word 2026-08-15: "entferne
-- M+ and raid stuff". It never earned one - "System" and "Info" name a
-- handful of rows each and are worth a caption, while the first group was
-- everything the addon does and got a label that only said so at length.
--
-- The `gap` in its place is not decoration and is the reason this is not a
-- plain deletion. That heading carried the ONLY air between the door and the
-- list (see `position > 1` in the painter), and glueing Edit mode to
-- Cooldowns turns a door into the first item of a menu.
---------------------------------------------------------------------------
local NAV = {
    { gap = true },
    -- Cooldowns stood here, above co-tanks, until the owner benched the
    -- feature (2026-08-16): "komplett aus der uebersicht links rausnehmen".
    { page = "cotanks" },
    { page = "reminders" },
    { page = "externals" },
    { page = "answers" },
    { page = "deaths" },
    -- THE TWO NEWEST GO AT THE END, at the owner's word: "raid bar bitte
    -- unter death log stellen".
    --
    -- The first draft put the raid bar at the head of this group on the
    -- argument that it is the entry about the whole group rather than about
    -- you. That argument is fine and it loses to a better one: the five above
    -- it have not moved since they were added, and a rail somebody has been
    -- reading for weeks is a list they no longer read - they go to the place.
    -- Inserting a row at the top moves every one of those places by one, to
    -- save one row of travel on a page that is new to everybody anyway.
    { page = "raidbar" },
    { page = "invites" },
    { eyebrow = "System" },
    { page = "settings" },
    { page = "profiles" },
    { page = "diagnostics" },
    { eyebrow = "Info" },
    { page = "about" },
    { page = "changelog" },
}
Options.NAV = NAV

-- A PAGE IS BUILT AT THE WIDTH IT WILL BE SHOWN AT, not at the widest one
-- there is.
--
-- Every page used to be built at the WIDE middle column - the one you get when
-- there is no third column. A page that DECLARES a third column is shown in
-- the NARROW middle instead, so its rows were 1136 units wide inside 750: the
-- labels showed, the rule lines ran to the edge and were clipped, and every
-- control - which sits at the RIGHT end of its row - was four hundred units
-- off the side of the window.
--
-- The whole Co-Tanks page looked like a list of headings with nothing to set,
-- and Settings has had the same hole in it since the explain column was added:
-- its font pickers are full-width rows and have never been on screen.
-- Half-width rows fit either way, which is why it survived so long and why it
-- was invisible - the page was half working, which reads as a design.
--
-- Pure and exported for the same reason SnapAxis and SparkEdge are: the whole
-- rule is one table entry in and one number out, and the desktop harness
-- CANNOT see the bug it prevents - its frame stub answers GetWidth with a
-- fixed number whatever was set, so a page built at the wrong width looks
-- exactly like one built at the right one.
-- DOES THIS PAGE CARRY A THIRD COLUMN AT ALL?
--
-- One function, because the answer is needed in three places - the width
-- above, the painter below, and the check in SelfTest - and the check used to
-- carry its own copy of the list. A page flag added to PAGES and to PageWidth
-- but not to the check would then be asserted against the OLD rule and fail
-- while being correct, which is precisely what a new page did.
--
-- WHICH column it is stays a separate question, asked only by the painter.
---------------------------------------------------------------------------
-- THE OFF STATE, drawn once and reused by every page that has a module.
--
-- Owner's choice, 2026-08-09: a switched-off module keeps its row in the rail
-- and keeps its page. So the page is still built and still shown, and this
-- sits over it, greying it and swallowing the clicks.
--
-- ONE of these, not one per page. Four copies of "this is switched off" is
-- four things to keep in step, and it is always the fourth that drifts - the
-- same reason the death window has one renderer and not a preview beside it.
--
-- It is deliberately not a full curtain: what shows through underneath is the
-- page you would get, which is the best argument the switch has.
---------------------------------------------------------------------------
local function BuildModuleGate(parent)
    local gate = CreateFrame("Frame", nil, parent)
    gate:SetAllPoints(parent)
    -- Well above the page it covers. A page builds cards, scroll areas and
    -- popups at levels of their own, and a curtain a card can poke through is
    -- worse than none.
    gate:SetFrameLevel(parent:GetFrameLevel() + 30)
    -- Swallows what is meant for the page beneath. Without this the greyed
    -- page is still fully clickable, which is the one thing greying promises
    -- it is not.
    gate:EnableMouse(true)
    gate:Hide()
    UI.Fill(gate, "BACKGROUND", C.windowBg, 0.86)

    local card = UI.Card(gate, 460)
    card:SetPoint("TOP", gate, "TOP", 0, -120)

    local title = UI.Label(card, "", UI.FS.card, C.text)
    title:SetPoint("TOPLEFT", card, "TOPLEFT", UI.PAD, -UI.PAD)

    local blurb = UI.Label(card, "", UI.FS.meta, C.textBody)
    blurb:SetPoint("TOPLEFT", title, "BOTTOMLEFT", 0, -8)
    blurb:SetWidth(460 - UI.PAD * 2)
    blurb:SetJustifyH("LEFT")

    local detail = UI.Label(card, "", UI.FS.meta, C.textFaint)
    detail:SetPoint("TOPLEFT", blurb, "BOTTOMLEFT", 0, -6)
    detail:SetWidth(460 - UI.PAD * 2)
    detail:SetJustifyH("LEFT")

    local button = UI.Button(card, ns.L["Switch it on"], 140, function()
        if gate.key then
            ns.Modules:Set(gate.key, true)
            ns.Options:Refresh()
        end
    end, "primary")
    button:SetPoint("TOPLEFT", detail, "BOTTOMLEFT", 0, -UI.PAD)

    -- The card is as tall as what is in it, measured after the text has been
    -- set rather than guessed at - two wrapped lines and one are 14 pixels
    -- apart, and a fixed height is wrong for one of them.
    function gate:Update(key)
        self.key = key
        local entry = key and ns.Modules:Get(key)
        if not entry then
            self:Hide()
            return
        end
        title:SetText(ns.L("%s is switched off", ns.L[entry.title]))
        blurb:SetText(ns.L[entry.blurb])
        detail:SetText(entry.detail and ns.L[entry.detail] or "")
        detail:SetShown((entry.detail or "") ~= "")
        card:SetHeight(UI.PAD + title:GetStringHeight() + 8
            + blurb:GetStringHeight() + (detail:IsShown() and (6 + detail:GetStringHeight()) or 0)
            + UI.PAD + UI.BUTTON_H + UI.PAD)
        self:Show()
    end

    return gate
end

function Options.HasThirdColumn(entry)
    return (entry.side or entry.explain or entry.tanks or entry.reminders
        or entry.deaths or entry.externals or entry.raidbar
        or entry.cooldowns) and true or false
end

-- WHICH PAGE THE WINDOW OPENS ON, as a pure function of the page list and
-- what was last remembered.
--
--   the remembered key, if that page still exists and its module is on
--   else the first page there is, which is Settings and always exists
--
-- (The middle preference - "else Cooldowns, where a fresh install lands" -
-- went with the Cooldowns page when the owner benched the feature.)
--
-- Pure so the desk can ask it every one of those ways without a window.
function Options.Landing(pages, remembered)
    local firstLive
    for index, entry in ipairs(pages or {}) do
        local live = not entry.module or ns.Modules:IsOn(entry.module)
        if live then
            if entry.key == remembered then return index end
            firstLive = firstLive or index
        end
    end

    return firstLive or 1
end

function Options.PageWidth(entry, narrow, wide)
    if Options.HasThirdColumn(entry) then return narrow end
    return wide
end

-- The one place the window's scale is applied, so the row on Settings and
-- the boot path cannot drift apart about what the setting means.
function Options:ApplyScale()
    if self.frame then self.frame:SetScale(ns.db.windowScale or 1) end
end

-- HOW SOLID THE WINDOW IS, and there is exactly ONE alpha - on the outermost
-- frame, where it fades the whole thing at once.
--
-- Not per layer. Card 90, row 80, field 70 sounds like depth and is not: the
-- values MULTIPLY wherever two of them overlap, so no surface has a colour you
-- can predict from its own setting, and the darkest tone in the design stops
-- being the darkest one.
--
-- 94% by default. That is enough to see that something is behind the window
-- and little enough that no 13px label goes soft; below about 85 it stops
-- being reliable over a bright scene. The file header in Widgets.lua used to
-- say every colour here is opaque - the owner asked for this, so that block
-- says what it says now.
--
-- Like windowScale, it is read with a fallback rather than seeded into
-- DEFAULTS: a profile that predates the setting resolves to the same number
-- as a new one, and nothing has to migrate.
function Options:ApplyAlpha()
    if self.frame then self.frame:SetAlpha(ns.db.windowAlpha or 0.94) end
end

function Options:Create()
    if self.frame then return end

    local frame = CreateFrame("Frame", "ZwoelfStuffOptionsFrame", UIParent)
    frame:SetSize(WINDOW_W, WINDOW_H)
    frame:SetPoint("CENTER", UIParent, "CENTER", 0, 0)
    frame:SetFrameStrata("HIGH")
    frame:SetClampedToScreen(true)
    frame:SetMovable(true)
    frame:EnableMouse(true)
    frame:RegisterForDrag("LeftButton")
    frame:SetScript("OnDragStart", frame.StartMoving)
    frame:SetScript("OnDragStop", frame.StopMovingOrSizing)
    frame:SetScript("OnHide", function()
        -- The menu lives on UIParent so it can escape the window bounds; it
        -- may not outlive the window.
        UI.ClosePopup()
    end)
    frame:Hide()

    UI.Fill(frame, "BACKGROUND", C.windowBg)

    -- THE GROUND GETS AN UP AND A DOWN.
    --
    -- It was one flat colour, and three columns of three flat colours have no
    -- direction at all - the window read as a wall rather than as a surface.
    -- A single vertical gradient over the whole frame fixes that for the price
    -- of one texture: lighter at the top, gone by the middle, so nothing sits
    -- on a ground that is brighter than the row above it.
    --
    -- NO TILED WEAVE. It was drawn in the mockup and measured out again: a
    -- pattern under 12px text needs to sit on the interface grid to stay
    -- still, WoW does not put it there, and 4% of a texture that shimmers is
    -- worse than no texture. The gradient carries the whole effect anyway.
    if type(CreateColor) == "function" then
        local lift = frame:CreateTexture(nil, "BACKGROUND", nil, 1)
        lift:SetColorTexture(1, 1, 1, 1)
        lift:SetPoint("TOPLEFT", frame, "TOPLEFT", 1, -1)
        lift:SetPoint("TOPRIGHT", frame, "TOPRIGHT", -1, -1)
        lift:SetHeight(math.floor(WINDOW_H * 0.55))
        lift:SetGradient("VERTICAL",
            CreateColor(C.windowBg[1], C.windowBg[2], C.windowBg[3], 0),
            CreateColor(0.106, 0.118, 0.145, 1))
    end
    local outer = ns.CreateBorder(frame, 1, "BORDER")
    outer:SetColor(C.edge[1], C.edge[2], C.edge[3], 1)

    ---------------------------------------------------------------------
    -- Left column
    ---------------------------------------------------------------------
    local rail = CreateFrame("Frame", nil, frame)
    rail:SetPoint("TOPLEFT", frame, "TOPLEFT", 1, -1)
    rail:SetPoint("BOTTOMLEFT", frame, "BOTTOMLEFT", 1, 1)
    rail:SetWidth(SIDEBAR_W)
    UI.Fill(rail, "BACKGROUND", C.sidebarBg)

    local railEdge = UI.Separator(rail, false)
    railEdge:SetPoint("TOPRIGHT", rail, "TOPRIGHT", 0, 0)
    railEdge:SetPoint("BOTTOMRIGHT", rail, "BOTTOMRIGHT", 0, 0)

    -- NO LIT CAP OVER THE RAIL, AND IT IS NOT TO COME BACK.
    --
    -- 4.76.0 put a four-layer gradient here and 160 pixels of dark red stood
    -- over the wordmark. Owner, with a picture of it: "lass den verlauf weg,
    -- das sieht unmoeglich aus und raum das menue wieder auf."
    --
    -- The gesture it was copying - a wordmark standing on artwork, the way a
    -- launcher does it - needs artwork worth standing on. A gradient is not
    -- that. What it actually bought was a third of the column spent on
    -- nothing, above a list that then had to fight for the rest.
    --
    -- The head starts at the top of the rail now, where it started before.

    -- The rail head, on the same 62 as every other column's header band.
    --
    -- A FRAME of its own now, rather than offsets from the rail's top corner.
    -- Everything below it is anchored to it, so setting the art's height at
    -- the end re-flows the head and the nav with it - and a hardcoded offset
    -- here would have to be corrected in three more places every time the cap
    -- changes.
    local head = CreateFrame("Frame", nil, rail)
    head:SetHeight(HEADER_H)
    head:SetPoint("TOPLEFT", rail, "TOPLEFT", 0, 0)
    head:SetPoint("TOPRIGHT", rail, "TOPRIGHT", 0, 0)

    -- The mark is the addon's own icon, at 26. The wordmark is lower case and
    -- carries the split in COLOUR rather than in weight: `zwoelf` in text and
    -- `stuff` a step back. There is no weight axis on a FontString - the panel
    -- font is whatever LibSharedMedia handed over and it may ship one cut - so
    -- a design that asks for 600 against 400 gets contrast it can actually
    -- have.
    local mark = head:CreateTexture(nil, "ARTWORK")
    mark:SetSize(26, 26)
    mark:SetPoint("TOPLEFT", head, "TOPLEFT", UI.PAD, -18)
    mark:SetTexture(ns.ICON_TEXTURE)

    local brand = UI.Label(head, "zwoelf", UI.FS.card, C.text)
    brand:SetPoint("TOPLEFT", mark, "TOPRIGHT", 10, -1)

    local brandTail = UI.Label(head, "stuff", UI.FS.card, C.textFaint)
    brandTail:SetPoint("LEFT", brand, "RIGHT", 0, 0)

    local brandSub = UI.Eyebrow(head, "EU Destromath")
    brandSub:SetPoint("TOPLEFT", brand, "BOTTOMLEFT", 0, -3)

    -- The foot: what version this is, and what it is running on. Both are the
    -- first thing anybody is asked for when something is wrong, and neither
    -- belongs anywhere the eye goes while working.
    local foot = CreateFrame("Frame", nil, rail)
    foot:SetHeight(RAIL_FOOT_H)
    foot:SetPoint("BOTTOMLEFT", rail, "BOTTOMLEFT", 0, 0)
    foot:SetPoint("BOTTOMRIGHT", rail, "BOTTOMRIGHT", 0, 0)

    local footLine = UI.Separator(foot, true)
    footLine:SetPoint("TOPLEFT", foot, "TOPLEFT", 0, 0)
    footLine:SetPoint("TOPRIGHT", foot, "TOPRIGHT", 0, 0)

    local versionLabel = UI.Label(rail, "v" .. ns.version, UI.FS.eyebrow, C.textGhost)
    versionLabel:SetPoint("LEFT", foot, "LEFT", UI.PAD, 0)

    -- GetBuildInfo returns version, build, date, tocversion. The first is the
    -- one people quote.
    local clientVersion = UI.Label(rail, (GetBuildInfo()) or "", UI.FS.eyebrow,
        C.textGhost)
    clientVersion:SetPoint("RIGHT", foot, "RIGHT", -UI.PAD, 0)

    -- THE THREE ADDRESSES, above the foot rule.
    --
    -- Where to get it, and where to ask. None of these can open a browser - no
    -- addon can, the client has no call for it - so a click opens the copy box
    -- with the address already selected. That is the honest version of a link
    -- inside a game: one Ctrl+C and it is in the address bar. A row that looked
    -- like a link and did nothing would be worse than no row.
    --
    -- SHORTER THAN A NAV ROW, and the number is not a preference. The rail is
    -- 758 tall; head 62 and foot 38 come off it, and the nav needs 512 today.
    -- Three rows at the nav's own 30 plus their air would leave 44 - less than
    -- the two spare pages the checks insist on. At 22 they leave 68. That is
    -- also the right LOOK: these are references, not pages, and a reference
    -- that stands as tall as a destination claims to be one.
    --
    -- Built from ns.STORES plus Discord rather than typed out, so a third
    -- store appears here by existing. The addresses live in Init.lua, so this
    -- column and the About page cannot end up pointing at different places.
    local LINK_H = RAIL_LINK_H
    local LINKS = {}
    for _, entry in ipairs(ns.LINKS) do
        LINKS[#LINKS + 1] = { text = entry.name, url = entry.url,
            icon = entry.icon }
    end

    -- Laid out from the foot upwards, so the LAST one written sits nearest the
    -- version line and adding a fourth pushes the block up rather than into
    -- the foot.
    local previousLink
    for position = #LINKS, 1, -1 do
        local entry = LINKS[position]

        local link = CreateFrame("Button", nil, rail)
        link:SetHeight(LINK_H)
        if previousLink then
            link:SetPoint("BOTTOMLEFT", previousLink, "TOPLEFT", 0, 0)
            link:SetPoint("BOTTOMRIGHT", previousLink, "TOPRIGHT", 0, 0)
        else
            -- Air above the block. At 6 the first of these sat against
            -- Changelog and read as the last entry of the Info group, which
            -- it is not - all three leave the addon.
            link:SetPoint("BOTTOMLEFT", foot, "TOPLEFT", 0, 12)
            link:SetPoint("BOTTOMRIGHT", foot, "TOPRIGHT", 0, 12)
        end
        previousLink = link

        -- The same hover ground a nav row has. Without it these are the only
        -- rows in the column that answer the mouse with nothing but a colour,
        -- and a row that behaves differently reads as a row of another kind.
        local background = UI.Fill(link, "BACKGROUND", C.surface)
        background:Hide()

        -- NO MARKS. There was one here for Discord for a version and it was
        -- not Discord's - traced from memory, and a brand mark you have drawn
        -- yourself is worse than none, because it claims to be the real thing.
        -- The words say it exactly, and two of the three have no mark that
        -- could be drawn at all.
        --
        -- ON THE NAV'S OWN INDENT, not the headings'. See UI.NAV_LABEL_X: at
        -- 16 this lined up with "INFO" rather than with "Changelog" right
        -- above it, and the whole foot of the column looked broken for it.
        -- A MARK ON EACH, on the nav's own 16 so the three line up with the
        -- entries above them rather than starting a second left edge.
        --
        -- It is the SAME mark on all three, and it is not a brand. It says
        -- "this leaves the game", which is the one thing all three have in
        -- common and the only thing about them this addon can honestly draw.
        -- Real logos are image files, and the two ways to get them are to
        -- ship the official ones or to trace them from memory; the second is
        -- worse than none, because a traced mark claims to be the real thing.
        -- Drop the official files into Media/icons and this line takes them.
        -- THEY ARE ON THE DISK NOW (2026-08-16) - the real marks, see
        -- ns.LINKS - so each row wears its own, and the arrow that stood in
        -- for all of them stays the fallback for a link without one.
        local outward = UI.Glyph(link, entry.icon or "menu-export", 12,
            C.textGhost)
        outward:SetPoint("LEFT", link, "LEFT", UI.PAD, 0)

        local label = UI.Label(link, entry.text, UI.FS.meta, C.textDim)
        label:SetPoint("LEFT", link, "LEFT", UI.NAV_LABEL_X, 0)

        link:SetScript("OnEnter", function()
            background:Show()
            label:SetTextColor(C.text[1], C.text[2], C.text[3])
        end)
        link:SetScript("OnLeave", function()
            background:Hide()
            label:SetTextColor(C.textDim[1], C.textDim[2], C.textDim[3])
        end)
        link:SetScript("OnClick", function()
            UI.CopyBox(entry.text, entry.url,
                "Ctrl+C copies it, then paste it into your browser. Esc "
                .. "closes. An addon cannot open a browser itself - the "
                .. "client has no call for it, by design.")
        end)
    end


    -- ONE rule, across the whole window. Three separate lines with three sets
    -- of padding never quite agree, and the eye reads the disagreement as
    -- sloppiness even when the heights match.
    --
    -- Window chrome: the one header rule and the close button. Both have to
    -- sit ABOVE the three column backgrounds, and a texture on the window
    -- itself would be painted under its own child frames no matter which
    -- layer it claims. So they get a frame of their own, with a level that
    -- settles the question rather than relying on creation order.
    local chrome = CreateFrame("Frame", nil, frame)
    chrome:SetAllPoints(frame)
    chrome:SetFrameLevel(frame:GetFrameLevel() + 20)

    local headerLine = chrome:CreateTexture(nil, "OVERLAY")
    headerLine:SetPoint("TOPLEFT", frame, "TOPLEFT", 1, -HEADER_H)
    headerLine:SetPoint("TOPRIGHT", frame, "TOPRIGHT", -1, -HEADER_H)
    headerLine:SetHeight(1)
    headerLine:SetColorTexture(C.separator[1], C.separator[2], C.separator[3], 1)

    -- The one close cross, in the window's top-right corner - which is also
    -- the top right of the inspector, which is where the design draws it.
    local close = CreateFrame("Button", nil, chrome)
    close:SetSize(CLOSE_W, CLOSE_W)
    close:SetPoint("TOPRIGHT", frame, "TOPRIGHT", -PAD, -19)
    -- The design's cross, not the letter X. At 12 the two are hard to tell
    -- apart until you look, and then the letter is unmistakable: it has serif
    -- weight on one stroke and none on the other.
    local closeMark = UI.Glyph(close, "ui-close", 12, C.textDim)
    closeMark:SetPoint("CENTER", close, "CENTER", 0, 0)
    close:SetScript("OnEnter", function()
        closeMark:SetColor(C.danger[1], C.danger[2], C.danger[3])
    end)
    close:SetScript("OnLeave", function()
        closeMark:SetColor(C.textDim[1], C.textDim[2], C.textDim[3])
    end)
    close:SetScript("OnClick", function() frame:Hide() end)

    ---------------------------------------------------------------------
    -- Right column
    ---------------------------------------------------------------------
    local sideHost = CreateFrame("Frame", nil, frame)
    sideHost:SetPoint("TOPRIGHT", frame, "TOPRIGHT", -1, -1)
    sideHost:SetPoint("BOTTOMRIGHT", frame, "BOTTOMRIGHT", -1, 1)
    sideHost:SetWidth(SIDE_W)
    UI.Fill(sideHost, "BACKGROUND", C.sidebarBg)

    local sideEdge = UI.Separator(sideHost, false)
    sideEdge:SetPoint("TOPLEFT", sideHost, "TOPLEFT", 0, 0)
    sideEdge:SetPoint("BOTTOMLEFT", sideHost, "BOTTOMLEFT", 0, 0)

    ---------------------------------------------------------------------
    -- The third column on a page that has no bar list: what the row you
    -- are pointing at actually does.
    --
    -- THE COLUMN IS NEVER EMPTY, and that is the point of it. Every setting
    -- used to carry its explanation on a wrapped grey line underneath, which
    -- was the single largest consumer of vertical space on the page - forty
    -- rows, forty paragraphs, and a page you scroll past the thing you came
    -- for. The text is the same text; it has moved to the one place that had
    -- nothing in it.
    ---------------------------------------------------------------------
    local explain = CreateFrame("Frame", nil, sideHost)
    explain:SetAllPoints(sideHost)
    explain:Hide()

    local explainTitle = UI.Label(explain, "", UI.FS.card, C.text)
    explainTitle:SetPoint("TOPLEFT", explain, "TOPLEFT", PAD, -16)
    explainTitle:SetWidth(SIDE_W - PAD * 2)
    explainTitle:SetWordWrap(false)

    local explainWhere = UI.Eyebrow(explain, "")
    explainWhere:SetPoint("TOPLEFT", explainTitle, "BOTTOMLEFT", 0, -5)
    explainWhere:SetWidth(SIDE_W - PAD * 2)
    explainWhere:SetWordWrap(false)

    local explainBody = UI.Label(explain, "", UI.FS.meta, C.textBody)
    explainBody:SetPoint("TOPLEFT", explain, "TOPLEFT", PAD, -(HEADER_H + 20))
    explainBody:SetWidth(SIDE_W - PAD * 2)
    explainBody:SetJustifyH("LEFT")
    explainBody:SetJustifyV("TOP")

    -- Nothing pointed at yet. A column that starts blank looks unloaded, so
    -- it says what it is for instead.
    local explainIdle = UI.Label(explain, "Point at a setting and this is where "
        .. "it says what it does.", UI.FS.meta, C.textGhost)
    explainIdle:SetPoint("TOPLEFT", explain, "TOPLEFT", PAD, -(HEADER_H + 20))
    explainIdle:SetWidth(SIDE_W - PAD * 2)
    explainIdle:SetJustifyH("LEFT")

    function self:SetExplain(title, section, body)
        explainTitle:SetText(title or "")
        explainWhere:SetText((section or ""):upper())
        explainBody:SetText(body or "")
        -- A setting with no note of its own is not a failure - most of them
        -- are named well enough not to need one. The heading still changes,
        -- so the column tracks the pointer either way.
        explainBody:SetShown(body ~= nil and body ~= "")
        explainIdle:Hide()
    end

    ---------------------------------------------------------------------
    -- Middle
    ---------------------------------------------------------------------
    local stageHost = CreateFrame("Frame", nil, frame)
    stageHost:SetPoint("TOPLEFT", rail, "TOPRIGHT", 0, 0)
    stageHost:SetPoint("BOTTOMLEFT", rail, "BOTTOMRIGHT", 0, 0)
    -- windowBg, not canvasBg. The rail and the inspector are DARKER than this
    -- in the new palette, which is the whole trick: the content is the top
    -- level of the window rather than a trench between two raised sides.
    UI.Fill(stageHost, "BACKGROUND", C.windowBg)

    -- NO LIT SURFACE ON THIS BAND, and it was tried. The run-out closed in
    -- from the RIGHT, so the open, brightest part sat at x=20 - which is
    -- exactly where the page title and its subline start. In game the title
    -- was dark red on red and could not be read at all.
    --
    -- It is the same rule this design already writes down for settings rows,
    -- and the band breaks it harder: a 20px title, a 12px subline AND two
    -- buttons all stand on these 62 pixels. There is nowhere on it that is
    -- free. The rail cap and the welcome window are where the surface earns
    -- its place - both have room above the words.

    local pageTitle = UI.Label(stageHost, "", UI.FS.title, C.text)
    pageTitle:SetPoint("TOPLEFT", stageHost, "TOPLEFT", PAD, -16)

    -- Width, not a second anchor: a font string given both TOPLEFT and RIGHT
    -- is told two different vertical positions and lands somewhere else.
    local pageSubtitle = UI.Label(stageHost, "", UI.FS.meta, C.textFaint)
    pageSubtitle:SetPoint("TOPLEFT", pageTitle, "BOTTOMLEFT", 0, -6)
    pageSubtitle:SetJustifyH("LEFT")
    pageSubtitle:SetWordWrap(false)

    -- THE PAGE'S OWN ACTIONS, IN THE BAND BESIDE ITS TITLE.
    --
    -- Every page names its own in the PAGES table above and this draws
    -- whichever pair the page in front of you asked for. They used to be a
    -- COLUMN OF BUTTONS INSIDE the page, beside that page's preview - so the
    -- same kind of thing lived in two different places depending on which
    -- entry in the rail you had clicked, and on the pages that had them they
    -- ate the width the preview needed.
    --
    -- TWO IS A MEASURED CEILING, not a preference. A page with a third column
    -- gets a 790 middle, 750 of it inside the padding. A 20px title takes
    -- some 190 of that, so the actions may have about 540 - and the SUBLINE
    -- has to live in what is left of the line under them, without wrapping.
    -- Four buttons at the width their own words ask for come to about 470 and
    -- leave the sentence 260, cut off mid-word. Two leave it 400.
    --
    -- A page WITHOUT a third column has the inspector's 400 as well, and
    -- that is where a third button fits: the Invites page carries its three
    -- "right now" actions up here (owner, 2026-08-16), some 400 of buttons
    -- against a middle 400 wider than the one the ceiling was measured on.
    -- The ceiling is asked per page, from the same predicate that decides
    -- the width, so the two cannot disagree.
    local ACTION_GAP = 6
    local MAX_ACTIONS = 2
    local MAX_ACTIONS_WIDE = 3

    -- A button with a mark in front of it needs room for the mark as well as
    -- for its words, and UI.ButtonWidth measures the WORDS: twelve for the
    -- glyph, four for the gap after it, four so the pair keeps its padding.
    local ICON_ROOM = 20

    local actionsByPage = {}
    for index, entry in ipairs(PAGES) do
        if entry.actions then
            local built, span = {}, 0
            local ceiling = Options.HasThirdColumn(entry) and MAX_ACTIONS
                or MAX_ACTIONS_WIDE
            for slot, spec in ipairs(entry.actions) do
                if slot > ceiling then break end

                -- CUT FOR THE WIDEST IT WILL EVER SAY, not for what it says
                -- while the window is being built. "Test mode" grows to
                -- "Test mode: on" the moment it is running, and a button
                -- measured for the short one clips the long one.
                local room = UI.ButtonWidth(spec.widest or spec.text)
                    + (spec.icon and ICON_ROOM or 0)

                local button = UI.Button(stageHost, spec.text, room,
                    spec.onClick)
                if spec.icon then button:SetIcon(spec.icon) end
                button:Hide()

                built[#built + 1] = { button = button, spec = spec }
                span = span + room + (slot > 1 and ACTION_GAP or 0)
            end

            -- Laid out from the right edge inwards, so the page reads
            -- title -> air -> first action -> second action the way it is
            -- written in the table. Only the LAST one touches the column
            -- edge; the rest hang off it, which is why re-anchoring for the
            -- close cross below is one call and not a loop.
            local previous
            for position = #built, 1, -1 do
                local button = built[position].button
                if previous then
                    button:SetPoint("TOPRIGHT", previous, "TOPLEFT",
                        -ACTION_GAP, 0)
                end
                previous = button
            end

            built.last = previous and built[#built].button or nil
            built.span = span
            actionsByPage[index] = built
        end
    end

    local body = CreateFrame("Frame", nil, stageHost)
    body:SetPoint("TOPLEFT", stageHost, "TOPLEFT", PAD, -(HEADER_H + 16))
    body:SetPoint("BOTTOMRIGHT", stageHost, "BOTTOMRIGHT", -PAD, PAD)

    -- The middle is as wide as whatever is not the two side columns. It is
    -- re-anchored per view rather than fixed, because the pages that have no
    -- spell list get the right column's space instead of leaving it blank.
    local NARROW_W = WINDOW_W - SIDEBAR_W - SIDE_W - 2
    local WIDE_W   = WINDOW_W - SIDEBAR_W - 2

    local function SetStageWidth(withSide)
        stageHost:SetWidth(withSide and NARROW_W or WIDE_W)
    end

    local listWidth = NARROW_W - PAD * 2
    local pageWidth = WIDE_W - PAD * 2




    -- THE THIRD COLUMN IS BUILT WHEN A PAGE FIRST ASKS FOR IT.
    --
    -- All five used to be built right here, the moment the window opened,
    -- whichever page you were on - and the co-tank one even with its module
    -- switched off. MEASURED, because the owner asked why this addon holds
    -- 13 MB while a whole UI replacement holds 15:
    --
    --   Options:Create                    4.6 MB
    --     OptionsBars:BuildSide           2.4 MB   796 frames
    --     OptionsCoTanks:BuildSide        1.7 MB   595 frames
    --     the other three                 0.25 MB   80 frames
    --
    -- Two panes, 1391 frames, and on a normal evening you open one of them.
    -- The PAGES have been lazy for versions - `entry.build and not
    -- entry.built` a few lines down is this same idea - the panes were just
    -- never brought over.
    --
    -- Built on first SHOW rather than on first page-visit, because that is
    -- the same question: a pane is shown by exactly one page.
    local SIDES = {
        tanks     = function() return ns.OptionsCoTanks:BuildSide(sideHost, PAD) end,
        reminders = function() return ns.OptionsReminders:BuildSide(sideHost, PAD) end,
        deaths    = function() return ns.OptionsDeaths:BuildSide(sideHost, PAD) end,
        externals = function() return ns.OptionsExternals:BuildSide(sideHost, PAD) end,
        raidbar   = function() return ns.OptionsRaidBar:BuildSide(sideHost, PAD) end,
        cooldowns = function() return ns.OptionsCooldowns:BuildSide(sideHost, PAD) end,
    }
    local panes = {}

    local function Pane(key)
        local pane = panes[key]
        if not pane then
            pane = SIDES[key]()
            panes[key] = pane
        end
        return pane
    end

    -- Hiding one that was never built is not a thing that has to happen: a
    -- pane nobody has asked for is not on screen.
    local function ShowPane(key, wanted)
        if wanted then
            Pane(key):Show()
        elseif panes[key] then
            panes[key]:Hide()
        end
    end

    -- Over the middle column, and built here so it is above every page frame
    -- created below it.
    local moduleGate = BuildModuleGate(body)

    local pageFrames = {}
    for index, entry in ipairs(PAGES) do
        if entry.build then
            local page = CreateFrame("Frame", nil, body)
            page:SetAllPoints(body)
            page:Hide()
            pageFrames[index] = page
        end
    end

    self.frame = frame
    self.pageIndex = 1
    self:ApplyScale()
    self:ApplyAlpha()

    ---------------------------------------------------------------------
    -- Left column entries
    ---------------------------------------------------------------------
    local navItems = {}

    local function ShowPage(index)
        self.pageIndex = index

        local entry = PAGES[index]

        -- REMEMBERED BY KEY, NEVER BY INDEX. Owner, 2026-08-15: "das
        -- speichern des letzten offenen modules fehlt immer noch, ich lande
        -- beim oeffnen immer in den settings."
        --
        -- The key and not the number: PAGES is reordered whenever a page is
        -- added or a group is rearranged, so a stored 4 is "whichever page is
        -- fourth in the version you are running" - it would silently point
        -- somewhere else after every release, which is worse than not
        -- remembering at all because it looks like it worked.
        if ns.db and entry and entry.key then ns.db.lastPage = entry.key end
        if entry.build and not entry.built then
            entry.built = true
            entry.build(pageFrames[index], Options.PageWidth(entry, listWidth, pageWidth))
        end
        self:Refresh()
    end

    -- THE RAIL IS GROUPED, and its order is not the page list's order.
    --
    -- Seven flat entries is a list you read from the top every time, because
    -- nothing in it says where the thing you want is likely to be. Three
    -- headed groups is three places to look, and the heading answers "is what
    -- I want even in here" before any of the labels are read.
    --
    -- EDIT MODE STANDS ABOVE THE GROUPS, on its own, with no heading over it.
    --
    -- It was filed under Bars, which reads as "one of the bar pages" - and it
    -- is not a page at all. Every other entry opens something inside this
    -- window; this one CLOSES the window and puts you on the screen with your
    -- panels in your hands. That is a different kind of thing, and a heading
    -- over it would be a promise that the entries under it behave alike.
    --
    -- It is also the entry that gets used most often and it was five rows
    -- down. A door belongs at the top.
    --
    -- The rest of the rail is the NAV table at the top of this file, where the
    -- self test can read it. Only this one row is built here, because closing
    -- the window needs the window.
    local rail_entries = {
        { title = "Edit mode", glyph = "move", onClick = function()
            frame:Hide()
            ns.EditMode:SetUnlocked(true)
        end },
    }
    for _, entry in ipairs(NAV) do
        rail_entries[#rail_entries + 1] = entry
    end

    local pageByKey = {}
    for index, entry in ipairs(PAGES) do pageByKey[entry.key] = index end

    -- Measured from the HEAD's bottom edge, not the rail's top corner. The lit
    -- cap above the head has no height yet - it gets one at the end of this
    -- function, from what the loop below turns out to need - and an offset
    -- from the rail's top would have to be recomputed then.
    local y = UI.PAD
    for position, entry in ipairs(rail_entries) do
        if entry.gap then
            -- The same air a heading brings, without the words. Only between
            -- rows: leading air at the very top would push the list off its
            -- own head.
            if position > 1 then y = y + 18 end
        elseif entry.eyebrow then
            -- Air ABOVE the heading, and none under it. A heading belongs to
            -- what follows; spaced evenly it belongs to neither side.
            if position > 1 then y = y + 18 end
            local caption = UI.Eyebrow(rail, ns.L[entry.eyebrow])
            caption:SetPoint("TOPLEFT", head, "BOTTOMLEFT", UI.PAD, -y - 6)
            y = y + 20
        else
            local index = entry.page and pageByKey[entry.page]
            local pageEntry = index and PAGES[index]
            local item = UI.NavItem(rail,
                ns.L[entry.title or (pageEntry and pageEntry.title) or ""],
                entry.glyph or (pageEntry and pageEntry.glyph),
                entry.onClick or function() ShowPage(index) end)
            -- FLUSH WITH BOTH EDGES of the rail, not inset.
            --
            -- Inset by 8, the active row's fill is a floating box with a gap
            -- down its right-hand side, and the accent bar sits 8 pixels in
            -- from the column edge instead of ON it. The design runs the row
            -- from edge to edge; the padding belongs INSIDE the row, which is
            -- where the icon's own 8 already is.
            item:SetPoint("TOPLEFT", head, "BOTTOMLEFT", 0, -y)
            item:SetPoint("TOPRIGHT", head, "BOTTOMRIGHT", 0, -y)
            if index then navItems[index] = item end
            y = y + UI.NAV_ITEM_H
        end
    end

    -- WHAT THE LIST ACTUALLY NEEDS, checked rather than hoped for. `y` is the
    -- nav's real height, counted as it was built. There is no artwork to take
    -- the room from any more, but the sum still has to hold: rail less head
    -- less foot less the Discord row is what the entries may use, and going
    -- over it does not clip - it pushes the last entry behind the foot. That
    -- is not hypothetical. It happened while this column was being designed,
    -- and the one that vanished was Changelog.
    -- The sum itself is UI.RailFits, and it is checked by the self test
    -- against the real page count rather than here - a rail that does not fit
    -- is a mistake made while editing this file, not a state a player can get
    -- into, so it belongs in the checks and not in everybody's login.

    ---------------------------------------------------------------------
    -- Painting
    ---------------------------------------------------------------------
    local function PaintView()
        local entry = PAGES[self.pageIndex] or PAGES[1]

        -- IS THE FEATURE THIS PAGE BELONGS TO RUNNING AT ALL. Asked before
        -- anything else, because the answer decides how much of the window
        -- this page gets to use.
        local moduleOn = not entry.module or ns.Modules:IsOn(entry.module)
        moduleGate:Update(not moduleOn and entry.module or nil)

        local withExplain = entry.explain and true or false
        local withTanks = entry.tanks and moduleOn or false
        local withReminders = entry.reminders and moduleOn or false
        local withDeaths = entry.deaths and moduleOn or false
        local withExternals = entry.externals and moduleOn or false
        local withRaidBar = entry.raidbar and moduleOn or false

        -- The middle column narrows for any of them: the third column is
        -- there or it is not, and what is IN it is a separate question.
        --
        -- A switched-off module has no third column. Greying the page but
        -- leaving its spell palette live beside it would be half a state, and
        -- the half that is still live is the half that edits settings for
        -- something that is not running.
        local third = withExplain or withTanks or withReminders
            or withDeaths or withExternals or withRaidBar
        SetStageWidth(third)
        sideHost:SetShown(third)
        explain:SetShown(withExplain)
        ShowPane("tanks", withTanks)
        ShowPane("reminders", withReminders)
        ShowPane("deaths", withDeaths)
        ShowPane("externals", withExternals)
        ShowPane("raidbar", withRaidBar)
        if withTanks then ns.OptionsCoTanks:Refresh() end
        if withReminders then ns.OptionsReminders:Refresh() end
        if withDeaths then ns.OptionsDeaths:Refresh() end
        if withExternals then panes.externals.Refresh() end
        if withRaidBar then panes.raidbar.Refresh() end

        -- THROUGH L, and the fallback is what makes this free: a page whose
        -- title has no translation gets its own English word back, which is
        -- the string that was there before this line existed.
        pageTitle:SetText(ns.L[entry.title])
        pageSubtitle:SetText(entry.subtitle and ns.L[entry.subtitle] or nil)

        -- WHATEVER THE LAST PAGE PUT IN THE BAND COMES OUT OF IT. Every
        -- page's pair is walked, not only this one's: the band is one strip
        -- of window shared by eleven pages, and a button left showing is a
        -- button that acts on the page you just left.
        --
        -- A switched-off module takes its actions with it. "Move bars" over a
        -- page that is greyed out is an offer to go and arrange nothing.
        for pageIndex, built in pairs(actionsByPage) do
            local mine = pageIndex == self.pageIndex and moduleOn
            for _, item in ipairs(built) do
                item.button:SetShown(mine)

                -- A LABEL THAT REPORTS A STATE IS RE-READ HERE. "Test mode"
                -- says "Test mode: on" while it is running, and what changed
                -- is the state, not which page you are standing on - so it
                -- cannot be set once when the button is made.
                if mine and item.spec.label then
                    item.button:SetText(item.spec.label())
                end
            end
        end

        -- WHERE THE LAST ACTION STOPS, and it is not the same edge on every
        -- page. With a third column the close cross is 400 pixels away over
        -- that column and the buttons may have the whole middle; without one
        -- the middle runs to the window's edge and the cross is standing in
        -- the last button's label.
        --
        -- Set on every repaint rather than at build time: whether a page has
        -- its third column is not fixed - switching its module off takes the
        -- column away and hands the middle those 400 pixels.
        local crossRoom = third and 0 or CLOSE_ROOM
        local mineActions = moduleOn and actionsByPage[self.pageIndex]
        if mineActions and mineActions.last then
            mineActions.last:ClearAllPoints()
            mineActions.last:SetPoint("TOPRIGHT", stageHost, "TOPRIGHT",
                -(PAD + crossRoom), -18)
        end

        -- The subtitle stops at the buttons rather than at the column edge,
        -- or a long one runs underneath them.
        local room = (third and NARROW_W or WIDE_W) - PAD * 2
        if mineActions then
            room = room - (mineActions.span + crossRoom + UI.PAD)
        end
        pageSubtitle:SetWidth(room)

        for index, page in pairs(pageFrames) do
            page:SetShown(index == self.pageIndex)
        end

        -- Every row, not just this one: switching a module changes a row that
        -- is not the row you are standing on.
        for index, item in ipairs(navItems) do
            local rowEntry = PAGES[index]
            local rowModule = rowEntry and rowEntry.module
            item:SetModuleState(rowModule ~= nil,
                rowModule ~= nil and ns.Modules:IsOn(rowModule))
            item:SetActive(index == self.pageIndex)
        end

        do
            local page = pageFrames[self.pageIndex]
            if page and page.Refresh then page.Refresh() end
        end
    end

    self.PaintView = PaintView
    self.ShowPage = ShowPage

    SetStageWidth(true)

    -- THROUGH THE SAME DOOR AS EVERY OTHER PAGE, and this line is a bug fix.
    --
    -- It used to be a bare self:Refresh(), which PAINTS the window and shows
    -- page one - and never runs its builder, because building happens in
    -- ShowPage and nothing had called it yet. That was harmless for exactly
    -- as long as page one was the Cooldowns page: that page had NO builder at
    -- all, it was drawn entirely by the frame, its status line and its two
    -- action buttons.
    --
    -- The bars went and Settings moved up into the first slot. Settings has a
    -- builder. So the window opened on a page that had never been built - an
    -- empty stage with its rail row lit - and clicking any other row and back
    -- filled it in, because THAT goes through ShowPage. Owner, 2026-08-15:
    -- "immer wenn ich das addon oeffne, lande ich auf einer leeren settings
    -- seite, erst beim hin und her klicken wird der inhalt geladen."
    --
    -- The desk could not see it: the harness walks ShowPage over every page
    -- deliberately, so out here page one was always built a moment later.
    -- WHERE THE WINDOW OPENS.
    --
    -- Cooldowns on the very first open - owner, 2026-08-15: "bitte cooldowns
    -- als standard open fenster einstellen wenn das erste mal geoeffnet wird
    -- ansonsten bitte last modul merken" - and after that wherever he was.
    --
    -- FALLS BACK TWICE, and both fallbacks matter: a remembered page whose
    -- MODULE has since been switched off is a page the rail no longer shows,
    -- and opening onto it would be a blank window with nothing selected.
    self.pageIndex = Options.Landing(PAGES, ns.db and ns.db.lastPage)
    ShowPage(self.pageIndex)

    table.insert(UISpecialFrames, "ZwoelfStuffOptionsFrame")   -- close with ESC
end

function Options:Refresh()
    if not self.frame then return end
    if self.PaintView then self.PaintView() end
end

-- Called by CDM when the Cooldown Manager's contents change: the spell list
-- is a view of it, so it must not go stale while it is open.
function Options:OnCatalogChanged()
    if self.frame and self.frame:IsShown() then
        self:Refresh()
    end
end

-- Opens on a named page. Separate from Toggle on purpose: something that
-- WANTS the window open must not close it because it happened to be open
-- already, which is exactly what "Bar options" in the unlock overlay did.
function Options:Open(pageKey)
    self:Create()

    if pageKey and self.ShowPage then
        for index, entry in ipairs(PAGES) do
            if entry.key == pageKey then
                self.ShowPage(index)
                break
            end
        end
    end

    self:Refresh()
    self.frame:Show()
end

function Options:Toggle()
    self:Create()
    if self.frame:IsShown() then
        self.frame:Hide()
    else
        self:Open()
    end
end
