EllesmereUI_Glows.lua

if EUI_CLIENT_BLOCKED then return end -- pre-12.1 client failsafe (EllesmereUI_ClientGate.lua)
-------------------------------------------------------------------------------
--  EllesmereUI_Glows.lua
--  Shared glow rendering engine for the EllesmereUI addon suite.
--  Provides: Pixel Glow (procedural ants), Action Button Glow, Auto-Cast
--  Shine, Shape Glow, and FlipBook-based glows (GCD, Modern WoW, Classic WoW).
--  Each addon attaches to EllesmereUI.Glows.* instead of duplicating engines.
-------------------------------------------------------------------------------
if not EllesmereUI then return end
if EllesmereUI.Glows then return end  -- already loaded by another addon

local floor = math.floor
local min   = math.min
local ceil  = math.ceil
local sin   = math.sin

-------------------------------------------------------------------------------
--  Style Definitions (superset of all addons)
--  Each addon picks from this table by index or iterates for its dropdown.
--  Fields: name, procedural, buttonGlow, autocast, shapeGlow, atlas, texture,
--          rows, columns, frames, duration, frameW, frameH, scale, previewScale
-------------------------------------------------------------------------------
local GLOW_STYLES = {
    { name = "Pixel Glow",         procedural = true },
    { name = "Action Button Glow", buttonGlow = true },
    { name = "Auto-Cast Shine",    autocast   = true },
    { name = "Shape Glow",         shapeGlow  = true },
    { name = "GCD",
      atlas = "RotationHelper_Ants_Flipbook", texPadding = 1.6 },
    { name = "Modern WoW Glow",
      atlas = "UI-HUD-ActionBar-Proc-Loop-Flipbook", texPadding = 1.4 },
    { name = "Classic WoW Glow",
      texture = "Interface\\SpellActivationOverlay\\IconAlertAnts",
      -- 5x5 grid = 25 cells, but only the first 22 are real ant frames; the last
      -- 3 are blank. Playing all 25 flashed an empty gap each loop that read as a
      -- backwards stutter. 22 matches what the Action Button Glow uses.
      rows = 5, columns = 5, frames = 22, duration = 0.3,
      frameW = 48, frameH = 48, texPadding = 1.25 },
}

-------------------------------------------------------------------------------
--  Texture constants
-------------------------------------------------------------------------------
local ANTS_TEX      = [[Interface\SpellActivationOverlay\IconAlertAnts]]
local ICON_ALERT_TEX = [[Interface\SpellActivationOverlay\IconAlert]]
local BG_GLOW_L, BG_GLOW_R = 0.00781250, 0.50781250
local BG_GLOW_T, BG_GLOW_B = 0.27734375, 0.52734375
local SHINE_TEX    = [[Interface\Artifacts\Artifacts]]
local SHINE_COORDS = { 0.8115234375, 0.9169921875, 0.8798828125, 0.9853515625 }
local SPARKLE_LAYER_SIZES = { 7, 6, 5, 4 }

-------------------------------------------------------------------------------
--  Central Glow Driver
--  One OnUpdate (on a frame we own) animates every active glow. Each animated
--  engine registers its wrapper tagged by kind; this driver gates the WHOLE
--  dispatch loop at ~60fps and routes each registered wrapper to its update
--  function. FlipBook glows are C-driven (AnimationGroup) and never register
--  here. The driver hides itself when no glow is registered (zero idle cost)
--  and re-arms when the first glow registers.
-------------------------------------------------------------------------------
local DRIVER_GATE = 0.016  -- ~60fps ceiling for the entire dispatch loop

-- Array-based registry for cheap churn. _reg is a dense 1..N array of wrapper frames;
-- _regFn the parallel array of their engine update functions (called directly in the
-- hot loop, so dispatch is pure array access with no kind->fn lookup); _regIndex maps
-- wrapper -> its slot in _reg (for O(1) swap-remove); _regKind maps wrapper -> its kind
-- tag, read only by Unregister (cold path). _regCount is the live entry count.
local _reg      = {}
local _regFn    = {}
local _regIndex = {}
local _regKind  = {}
local _regCount = 0
local _driver
local _driverAccum = 0

-- Unregister a wrapper. Safe no-op when the wrapper was never registered (Stop
-- without Start), so calling every Stop* in StopAllGlows is fine. When a kind is
-- passed it must match the wrapper's current registration: this makes a lone
-- cross-kind Stop* (e.g. StopButtonGlow on an "ants"-registered wrapper) a no-op
-- instead of tearing down the still-active engine. A nil kind stays kind-agnostic.
-- Swap-removes the entry so churn stays O(1); hides the driver when empty.
-- (Defined above the driver loop: the loop drops forbidden wrappers itself.)
local function _Unregister(wrapper, kind)
    local idx = _regIndex[wrapper]
    if not idx then return end
    if kind and _regKind[wrapper] ~= kind then return end
    local last = _reg[_regCount]
    _reg[idx] = last
    _regFn[idx] = _regFn[_regCount]
    _regIndex[last] = idx
    _reg[_regCount] = nil
    _regFn[_regCount] = nil
    _regCount = _regCount - 1
    _regIndex[wrapper] = nil
    _regKind[wrapper] = nil
    if _regCount == 0 and _driver then _driver:Hide() end
end

local function _VisProbe(w) return w:IsVisible() end

local function _DriverOnUpdate(self, elapsed)
    -- Gate the WHOLE loop at ~60fps: accumulate raw elapsed and only run a
    -- dispatch pass once the accumulator reaches the gate. The accumulated dt
    -- is handed to every engine and the accumulator resets to 0 (not minus the
    -- gate), so the sum of dispatched dt equals real elapsed exactly --
    -- animation speed is identical to a per-frame OnUpdate.
    local dt = _driverAccum + elapsed
    if dt < DRIVER_GATE then
        _driverAccum = dt
        return
    end
    _driverAccum = 0
    -- Walk the dense array by index. An engine may unregister itself (or
    -- another wrapper) from inside its own update via Stop*, which swap-removes
    -- and shrinks _regCount; re-read _regCount each step and, when the current
    -- slot was swapped, re-test the same slot instead of advancing.
    local i = 1
    while i <= _regCount do
        local wrapper = _reg[i]
        -- Visibility gate: a per-wrapper OnUpdate used to stop for free when
        -- the frame OR any ancestor was hidden. IsVisible() reproduces that
        -- (own shown flag AND every ancestor shown). It reads only boolean
        -- shown flags, never alpha, so it is safe on the secret-alpha overlays
        -- (important-cast, RaidFrames threshold) whose alpha is a secret value.
        -- A wrapper that is shown but alpha-0 stays IsVisible()==true and keeps
        -- animating exactly as it did under its own OnUpdate; only Hide()-d or
        -- hidden-ancestor wrappers are skipped, and they resume automatically.
        -- 12.1: a wrapper inside an ENGINE aura-button subtree has a SECRET
        -- visibility (the engine drives the button's shown state); a boolean test on it
        -- errors. Treat secret as hidden: the animation freezes for those wrappers
        -- while restricted (the glow still renders when its parent is actually shown)
        -- instead of ticking on the engine's 10x hidden pool buttons. Since PTR build
        -- 68914 the aura-button subtree is FORBIDDEN to addon code outside sanctioned
        -- windows: the IsVisible call itself throws instead of returning a secret, and
        -- one throwing wrapper would error every driver pass and freeze every other
        -- registered glow behind it. Probe under pcall and drop a throwing wrapper
        -- permanently -- forbidden-partition membership never recovers. (Driver styles
        -- should not be hosted there at all; StartEngineGlow is the sanctioned path.
        -- This guard makes a mistake non-fatal.)
        local vis = true
        if wrapper.IsVisible then
            local okv
            okv, vis = pcall(_VisProbe, wrapper)
            if not okv then
                _Unregister(wrapper)
                vis = false
            elseif issecretvalue and issecretvalue(vis) then
                vis = false
            end
        end
        if vis then
            local fn = _regFn[i]
            if fn then fn(wrapper, dt) end
        end
        if _reg[i] == wrapper then
            i = i + 1
        end
    end
    if _regCount == 0 then
        self:Hide()
    end
end

local function _Arm()
    if not _driver then
        _driver = CreateFrame("Frame")
        _driver:Hide()
        _driver:SetScript("OnUpdate", _DriverOnUpdate)
    end
    _driverAccum = 0          -- avoid a stale-dt spike after an idle period
    _driver:Show()
end

-- Register a wrapper under the given kind. Idempotent: a second Start on the
-- same wrapper does not duplicate the entry or move the count; it only refreshes
-- the kind tag (so a style switch is robust even without a Stop first). Arms the
-- driver on the 0 -> 1 transition.
local function _Register(wrapper, fn, kind)
    local i = _regIndex[wrapper]
    if i then
        _regFn[i] = fn
        _regKind[wrapper] = kind
        return
    end
    _regCount = _regCount + 1
    _reg[_regCount] = wrapper
    _regFn[_regCount] = fn
    _regIndex[wrapper] = _regCount
    _regKind[wrapper] = kind
    if _regCount == 1 then _Arm() end
end

-------------------------------------------------------------------------------
--  Procedural Ants Engine (texcoord-scroll)
--  4 fixed edge textures whose dashes march by scrolling a tileable strip via
--  SetTexCoord -- no per-frame SetPoint/SetSize, so it is FlipBook-cheap. The
--  N (line count) / thickness / speed / color are all configurable; the dash
--  LENGTH is the texture's duty cycle rather than a runtime segment length.
-------------------------------------------------------------------------------
local DASH_H = [[Interface\AddOns\EllesmereUI\media\glow-dash-h.tga]]
local DASH_V = [[Interface\AddOns\EllesmereUI\media\glow-dash-v.tga]]

-- Resolve the wrapper's pixel-snapped size and precompute the per-edge phase endpoints
-- (invariant until the next resize). Returns false while the size is still 0, the scale
-- chain is degenerate, or the pixel grid is unusable, so the caller retries on a later
-- tick. Shared by the animated (_AntsOnUpdate) and static (_AntsStaticSettle) paths.
local function _AntsResolveSize(self, d)
    local w, h = self:GetSize()
    -- Taint-strip (reparented frames can return secret-number sizes).
    w = tonumber(tostring(w)) or 0
    h = tonumber(tostring(h)) or 0
    if w * h == 0 and d.fallbackW and d.fallbackW > 0 then
        w = d.fallbackW; h = d.fallbackH or d.fallbackW
    end
    if w * h == 0 then return false end
    -- Snap dimensions AND thickness to physical pixels so every edge renders
    -- the same whole-pixel thickness (unsnapped SetHeight/SetWidth lets some
    -- sides round thicker than others at fractional effective scale).
    local PP = EllesmereUI.PP
    -- A degenerate scale chain (0 while layout is unresolved, or the
    -- SetScale(0.001) hide path) makes onePixel enormous, which collapses the
    -- snap below to w = h = 0 and turns the k divide into N/0. Every phase
    -- endpoint then goes non-finite and SetTexCoord rejects it on every driver
    -- tick. Stay unresolved instead and retry once the scale is real.
    local es = self:GetEffectiveScale()
    -- Same subtree class the GetSize taint-strip above exists for: a secret
    -- effective scale would hard-error on the comparison below, so take the
    -- retry path instead. No-op for normal values.
    if not es or (issecretvalue and issecretvalue(es)) or es < 0.1 then return false end
    local onePixel = PP.perfect / es
    w = floor(w / onePixel + 0.5) * onePixel
    h = floor(h / onePixel + 0.5) * onePixel
    -- A genuinely sub-pixel wrapper passes the size test above but snaps to 0;
    -- floor both dimensions at one pixel so (w + h) is always a real divisor.
    if w < onePixel then w = onePixel end
    if h < onePixel then h = onePixel end
    -- Total sanity gate before anything is cached. An infinite onePixel (a
    -- bogus PP.physicalHeight makes PP.perfect infinite) snaps w and h to NaN,
    -- which slips past every comparison above and then poisons the k divide
    -- below. NaN and inf both fail this test, so the phase endpoints are always
    -- real numbers and SetTexCoord can never be handed a value it rejects.
    if not (w > 0 and h > 0 and w + h < math.huge) then return false end
    local sTh = floor(d.th / onePixel + 0.5) * onePixel
    if sTh < onePixel then sTh = onePixel end
    d.top:SetHeight(sTh); d.bottom:SetHeight(sTh)
    d.left:SetWidth(sTh); d.right:SetWidth(sTh)
    d.w = w; d.h = h
    -- Precompute the per-edge phase endpoints; they are invariant until the
    -- next resize/restart, so only the scroll offset o changes per tick.
    -- ph(P) = P * N / perim is the perimeter position in dash-period units;
    -- the four edges share it so dashes stay continuous around every corner.
    local k = d.N / (2 * (w + h))
    d.wk   = w * k
    d.whk  = (w + h) * k
    d.wwhk = (2 * w + h) * k
    return true
end

local function _AntsOnUpdate(self, elapsed)
    local d = self._euiScrollData
    if not d then return end
    d.timer = d.timer + elapsed
    if d.timer >= d.period then d.timer = d.timer - d.period end
    -- Positive-test rather than == 0 so a non-finite cached size fails it too
    -- and re-resolves, instead of feeding bad texcoords in forever.
    if not (d.w > 0 and d.h > 0) then
        if not _AntsResolveSize(self, d) then return end
    end
    local N = d.N
    local o = (d.timer / d.period) * N   -- scroll offset (N integer -> seamless wrap)
    -- Direction is clockwise; the bottom/left edges flip their coords to match.
    local wk, whk, wwhk = d.wk, d.whk, d.wwhk
    d.top:SetTexCoord(-o, wk - o, 0, 1)
    d.right:SetTexCoord(0, 1, wk - o, whk - o)
    d.bottom:SetTexCoord(wwhk - o, whk - o, 0, 1)
    d.left:SetTexCoord(0, 1, N - o, wwhk - o)
end

-- Static (non-marching) dashes: draw once at the frozen base phase (scroll
-- offset 0). These are exactly the animated coords evaluated at o = 0, so the
-- dashes stay corner-continuous -- a dashed border rather than marching ants.
local function _AntsDrawStatic(self, d)
    local N = d.N
    local wk, whk, wwhk = d.wk, d.whk, d.wwhk
    d.top:SetTexCoord(0, wk, 0, 1)
    d.right:SetTexCoord(0, 1, wk, whk)
    d.bottom:SetTexCoord(wwhk, whk, 0, 1)
    d.left:SetTexCoord(0, 1, N, wwhk)
end

-- One-shot settler for static mode when the size was not resolved at Start time
-- (SetAllPoints wrappers can read 0 before layout resolves). Resolves, draws
-- once, then unregisters so a static border costs nothing per frame thereafter.
local function _AntsStaticSettle(self, elapsed)
    local d = self._euiScrollData
    if not d then _Unregister(self, "ants"); return end
    if not (d.w > 0 and d.h > 0) then
        if not _AntsResolveSize(self, d) then return end
    end
    _AntsDrawStatic(self, d)
    _Unregister(self, "ants")
end

-- lineLen is accepted for call-signature compatibility but unused: the dash
-- length is the texture's duty cycle, not a runtime segment length.
local function StartProceduralAnts(wrapper, N, th, period, lineLen, cr, cg, cb, szOrW, szH, bgR, bgG, bgB, bgA, static)
    if not wrapper._euiScrollData then
        local function mk(p1, p1f, p2, p2f)
            local t = wrapper:CreateTexture(nil, "OVERLAY", nil, 7)
            t:SetPoint(p1, wrapper, p1f)
            t:SetPoint(p2, wrapper, p2f)
            return t
        end
        wrapper._euiScrollData = {
            top    = mk("TOPLEFT", "TOPLEFT", "TOPRIGHT", "TOPRIGHT"),
            bottom = mk("BOTTOMLEFT", "BOTTOMLEFT", "BOTTOMRIGHT", "BOTTOMRIGHT"),
            left   = mk("TOPLEFT", "TOPLEFT", "BOTTOMLEFT", "BOTTOMLEFT"),
            right  = mk("TOPRIGHT", "TOPRIGHT", "BOTTOMRIGHT", "BOTTOMRIGHT"),
            timer = 0, w = 0, h = 0,
        }
    end
    local d = wrapper._euiScrollData
    d.N = (N and N > 0) and N or 8
    d.period = period or 4
    d.w = 0; d.h = 0
    d.fallbackW = szOrW or 0; d.fallbackH = szH or szOrW or 0
    th = th or 2
    d.th = th
    d.top:SetTexture(DASH_H, "REPEAT", "REPEAT");    d.top:SetHeight(th)
    d.bottom:SetTexture(DASH_H, "REPEAT", "REPEAT"); d.bottom:SetHeight(th)
    d.left:SetTexture(DASH_V, "REPEAT", "REPEAT");   d.left:SetWidth(th)
    d.right:SetTexture(DASH_V, "REPEAT", "REPEAT");  d.right:SetWidth(th)
    -- bgR being non-nil is the "background on" signal; callers pass nil to
    -- disable. Do NOT change this to `bgR > 0`: a fully black background is
    -- r=0, which is a valid enabled color and must still draw.
    if bgR then
        if not d.bgTop then
            local function mkBg(p1, p1f, p2, p2f)
                local t = wrapper:CreateTexture(nil, "OVERLAY", nil, 6)
                t:SetPoint(p1, wrapper, p1f)
                t:SetPoint(p2, wrapper, p2f)
                return t
            end
            d.bgTop    = mkBg("TOPLEFT", "TOPLEFT", "TOPRIGHT", "TOPRIGHT")
            d.bgBottom = mkBg("BOTTOMLEFT", "BOTTOMLEFT", "BOTTOMRIGHT", "BOTTOMRIGHT")
            d.bgLeft   = mkBg("TOPLEFT", "TOPLEFT", "BOTTOMLEFT", "BOTTOMLEFT")
            d.bgRight  = mkBg("TOPRIGHT", "TOPRIGHT", "BOTTOMRIGHT", "BOTTOMRIGHT")
        end
        bgA = bgA or 1
        d.bgTop:SetHeight(th); d.bgBottom:SetHeight(th)
        d.bgLeft:SetWidth(th); d.bgRight:SetWidth(th)
        d.bgTop:SetColorTexture(bgR, bgG or 0, bgB or 0, bgA);       d.bgTop:Show()
        d.bgBottom:SetColorTexture(bgR, bgG or 0, bgB or 0, bgA);    d.bgBottom:Show()
        d.bgLeft:SetColorTexture(bgR, bgG or 0, bgB or 0, bgA);      d.bgLeft:Show()
        d.bgRight:SetColorTexture(bgR, bgG or 0, bgB or 0, bgA);     d.bgRight:Show()
    elseif d.bgTop then
        d.bgTop:Hide(); d.bgBottom:Hide(); d.bgLeft:Hide(); d.bgRight:Hide()
    end
    d.top:SetVertexColor(cr, cg, cb, 1);    d.top:Show()
    d.bottom:SetVertexColor(cr, cg, cb, 1); d.bottom:Show()
    d.left:SetVertexColor(cr, cg, cb, 1);   d.left:Show()
    d.right:SetVertexColor(cr, cg, cb, 1);  d.right:Show()
    if static then
        -- Frozen dashes: draw once now (size permitting) and stay off the
        -- animation driver. If layout has not resolved yet, a one-shot settler
        -- draws on the first tick that reads a real size, then unregisters.
        if _AntsResolveSize(wrapper, d) then
            _AntsDrawStatic(wrapper, d)
            _Unregister(wrapper, "ants")   -- clear any prior animated registration
        else
            _Register(wrapper, _AntsStaticSettle, "ants")
        end
    else
        _Register(wrapper, _AntsOnUpdate, "ants")
    end
end

local function StopProceduralAnts(wrapper)
    _Unregister(wrapper, "ants")
    local d = wrapper._euiScrollData
    if d then
        d.top:Hide(); d.bottom:Hide(); d.left:Hide(); d.right:Hide()
        if d.bgTop then d.bgTop:Hide(); d.bgBottom:Hide(); d.bgLeft:Hide(); d.bgRight:Hide() end
    end
end

-- Recolor active dashes in place. Secret-safe: r,g,b,a flow straight into
-- SetVertexColor with no arithmetic, so a secret (restricted) color is fine.
-- Used by the Raid Frames Frame-Border threshold recolor.
local function SetProceduralAntsColor(wrapper, r, g, b, a)
    local d = wrapper._euiScrollData
    if not d then return end
    a = a or 1
    d.top:SetVertexColor(r, g, b, a)
    d.bottom:SetVertexColor(r, g, b, a)
    d.left:SetVertexColor(r, g, b, a)
    d.right:SetVertexColor(r, g, b, a)
end

-------------------------------------------------------------------------------
--  Action Button Glow Engine
--  Outer glow (soft border from IconAlert) + animated marching ants.
-------------------------------------------------------------------------------
-- Marching-ants sprite cycler. Replaces a Blizzard SharedXML global that was
-- removed in 12.0 (present on live, nil on the PTR -> the glow OnUpdate erroring
-- out). Framerate-independent: it advances by however many cells the elapsed
-- time covers and carries the remainder, so the march speed is identical whether
-- the glow driver ticks at 60fps or faster, and it does not inherit the original
-- global's framerate-dependent quirks. ANTS_FRAME_TIME (seconds per cell) is the
-- single knob for the speed. State lives on our own ants texture.
local ANTS_FRAME_TIME = 0.017  -- ~59 cells/sec -> ~0.37s per 22-frame loop
local function _AnimateTexCoords(tex, sheetW, sheetH, cellW, cellH, numFrames, elapsed)
    if not tex._euiAnimCols then
        tex._euiAnimCols  = floor(sheetW / cellW)
        tex._euiAnimColW  = cellW / sheetW
        tex._euiAnimRowH  = cellH / sheetH
        tex._euiAnimFrame = 0
        tex._euiAnimAccum = 0
    end
    tex._euiAnimAccum = tex._euiAnimAccum + elapsed
    if tex._euiAnimAccum < ANTS_FRAME_TIME then return end

    local advance = floor(tex._euiAnimAccum / ANTS_FRAME_TIME)
    tex._euiAnimAccum = tex._euiAnimAccum - advance * ANTS_FRAME_TIME
    local frame = (tex._euiAnimFrame + advance) % numFrames
    tex._euiAnimFrame = frame

    local cols = tex._euiAnimCols
    local colW = tex._euiAnimColW
    local rowH = tex._euiAnimRowH
    local left = (frame % cols) * colW
    local top  = floor(frame / cols) * rowH
    tex:SetTexCoord(left, left + colW, top, top + rowH)
end

local function _ButtonGlowOnUpdate(self, elapsed)
    local d = self._euiBgData
    if not d then return end
    _AnimateTexCoords(d.ants, 256, 256, 48, 48, 22, elapsed)
end

local function StartButtonGlow(wrapper, szOrW, cr, cg, cb, scale, szH)
    scale = scale or 1.0
    local w = szOrW or 36
    local h = szH or w
    if not wrapper._euiBgData then
        local glow = wrapper:CreateTexture(nil, "OVERLAY", nil, 7)
        glow:SetTexture(ICON_ALERT_TEX)
        glow:SetTexCoord(BG_GLOW_L, BG_GLOW_R, BG_GLOW_T, BG_GLOW_B)
        glow:SetBlendMode("ADD")
        glow:SetPoint("CENTER")
        local ants = wrapper:CreateTexture(nil, "OVERLAY", nil, 7)
        ants:SetTexture(ANTS_TEX)
        ants:SetBlendMode("ADD")
        ants:SetPoint("CENTER")
        wrapper._euiBgData = { glow = glow, ants = ants }
    end
    local d = wrapper._euiBgData
    -- The ants texture has transparent padding baked into its frames,
    -- so we scale up to compensate and match the button edge visually.
    local antsW, antsH = w * 1.35, h * 1.35
    local glowW, glowH = antsW * 1.3, antsH * 1.3
    d.glow:SetSize(glowW, glowH)
    d.glow:SetDesaturated(true); d.glow:SetVertexColor(cr, cg, cb, 1)
    d.glow:SetAlpha(1); d.glow:Show()
    d.ants:SetSize(antsW, antsH)
    d.ants:SetDesaturated(true); d.ants:SetVertexColor(cr, cg, cb, 1)
    d.ants:SetAlpha(1); d.ants:Show()
    _Register(wrapper, _ButtonGlowOnUpdate, "button")
end

local function StopButtonGlow(wrapper)
    _Unregister(wrapper, "button")
    if wrapper._euiBgData then
        wrapper._euiBgData.ants:Hide()
        wrapper._euiBgData.glow:Hide()
    end
end

-------------------------------------------------------------------------------
--  Auto-Cast Shine Engine
--  4 layers of sparkle dots orbit the perimeter at staggered speeds.
--  Each layer has dotsPerLayer dots evenly spaced. Layer k orbits k times
--  slower than layer 1, creating a cascading sparkle effect.
-------------------------------------------------------------------------------

-- Compute x,y offset from TOPLEFT for a point at distance `dist`
-- around the perimeter (clockwise from top-left corner).
local function _OrbitXY(dist, w, h)
    if dist < w then
        return dist, 0
    end
    dist = dist - w
    if dist < h then
        return w, -dist
    end
    dist = dist - h
    if dist < w then
        return w - dist, -h
    end
    return 0, -(h - (dist - w))
end

local function _AutoCastOnUpdate(self, elapsed)
    local d = self._euiAcData
    if not d then return end
    local layerPhase = d.layerPhase
    local basePeriod = d.period
    for layer = 1, 4 do
        layerPhase[layer] = layerPhase[layer] + elapsed / (basePeriod * layer)
        if layerPhase[layer] > 1 then layerPhase[layer] = layerPhase[layer] - 1 end
    end
    d._accum = (d._accum or 0) + elapsed
    if d._accum < 0.016 then return end
    d._accum = 0
    local w, h = d.w, d.h
    if w * h == 0 then
        w, h = self:GetSize()
        -- Strip taint from size values (reparented buttons can return
        -- "secret number" tainted dimensions from GetSize).
        w = tonumber(tostring(w)) or 0
        h = tonumber(tostring(h)) or 0
        -- Fallback to the w/h passed at start time (SetAllPoints wrappers
        -- may return 0 before layout resolves)
        if w * h == 0 and d.fallbackW and d.fallbackW > 0 then
            w = d.fallbackW; h = d.fallbackH or d.fallbackW
        end
        if w * h == 0 then return end
        d.w = w; d.h = h
        d.perim = 2 * (w + h)
        d.spacing = d.perim / d.dotsPerLayer
    end
    local perim = d.perim
    local spacing = d.spacing
    local sparkles = d.sparkles
    local dotsPerLayer = d.dotsPerLayer
    local idx = 0
    for layer = 1, 4 do
        local phase = layerPhase[layer] * perim
        for i = 1, dotsPerLayer do
            idx = idx + 1
            local dist = (spacing * i + phase) % perim
            local px, py = _OrbitXY(dist, w, h)
            local dot = sparkles[idx]
            dot:ClearAllPoints()
            dot:SetPoint("CENTER", self, "TOPLEFT", px, py)
        end
    end
end

local function StartAutoCastShine(wrapper, szOrW, cr, cg, cb, scale, szH)
    scale = scale or 1.0
    local dotsPerLayer = 4
    local totalDots = dotsPerLayer * 4
    if not wrapper._euiAcData then
        wrapper._euiAcData = {
            sparkles = {},
            layerPhase = { 0, 0.25, 0.5, 0.75 },
            dotsPerLayer = dotsPerLayer,
            period = 2,
            w = 0, h = 0,
        }
    end
    local d = wrapper._euiAcData
    d.dotsPerLayer = dotsPerLayer
    d.layerPhase[1] = 0; d.layerPhase[2] = 0.25; d.layerPhase[3] = 0.5; d.layerPhase[4] = 0.75
    for idx = 1, totalDots do
        if not d.sparkles[idx] then
            local dot = wrapper:CreateTexture(nil, "OVERLAY", nil, 7)
            dot:SetTexture(SHINE_TEX)
            dot:SetTexCoord(SHINE_COORDS[1], SHINE_COORDS[2], SHINE_COORDS[3], SHINE_COORDS[4])
            dot:SetDesaturated(true); dot:SetBlendMode("ADD")
            d.sparkles[idx] = dot
        end
        local layer = ceil(idx / dotsPerLayer)
        local baseSz = (SPARKLE_LAYER_SIZES[layer] or 4) * scale
        d.sparkles[idx]:SetSize(baseSz, baseSz)
        d.sparkles[idx]:SetVertexColor(cr, cg, cb, 1)
        d.sparkles[idx]:Show()
    end
    for idx = totalDots + 1, #d.sparkles do d.sparkles[idx]:Hide() end
    d.w = 0; d.h = 0; d.fallbackW = szOrW or 0; d.fallbackH = szH or szOrW or 0
    _Register(wrapper, _AutoCastOnUpdate, "autocast")
end

local function StopAutoCastShine(wrapper)
    _Unregister(wrapper, "autocast")
    if wrapper._euiAcData then
        for _, dot in ipairs(wrapper._euiAcData.sparkles) do dot:Hide() end
    end
end

-------------------------------------------------------------------------------
--  Shape Glow Engine
--  Pulsing additive glow using the icon's shape mask texture.
--  Used by ActionBars (custom shapes) and CDM (custom icon shapes).
--  opts.maskPath   — path to the shape mask texture
--  opts.borderPath — path to the shape border texture
--  opts.shapeMask  — MaskTexture object for AddMaskTexture
-------------------------------------------------------------------------------
local function _ShapeGlowOnUpdate(self, elapsed)
    local d = self._euiSgData
    if not d then return end
    local timer = d.timer + elapsed * d.speed
    if timer > 6.2832 then timer = timer - 6.2832 end
    d.timer = timer
    d.glow:SetAlpha(0.25 + 0.25 * (0.5 + 0.5 * sin(timer)))
    local bright = d.bright
    if bright then
        local bTimer = (d.bTimer or 0) + elapsed * d.speed * 0.50
        if bTimer > 6.2832 then bTimer = bTimer - 6.2832 end
        d.bTimer = bTimer
        bright:SetAlpha(0.35 + 0.10 * (0.5 + 0.5 * sin(bTimer)))
    end
end

local function StartShapeGlow(wrapper, sz, cr, cg, cb, scale, opts)
    scale = scale or 1.20
    opts = opts or {}
    -- anchorFrame overrides GetParent() for cases where the wrapper is
    -- parented to a different frame (e.g. action bar wrappers use
    -- btn:GetParent() to escape mask clipping).
    local btn = opts.anchorFrame or wrapper:GetParent()
    if not btn then return end
    if not wrapper._euiSgData then
        local glow   = btn:CreateTexture(nil, "OVERLAY", nil, 5)
        glow:SetBlendMode("ADD")
        local edge   = btn:CreateTexture(nil, "OVERLAY", nil, 5)
        edge:SetBlendMode("ADD")
        local bright = btn:CreateTexture(nil, "OVERLAY", nil, 7)
        bright:SetBlendMode("ADD")
        wrapper._euiSgData = { glow = glow, edge = edge, bright = bright, timer = 0, speed = 10.0 }
    end
    local d = wrapper._euiSgData
    d.timer = 0

    -- Glow extends slightly past the button edge for the pulsing effect
    local extend = sz * 0.10
    d.glow:ClearAllPoints()
    d.glow:SetPoint("TOPLEFT",     btn, "TOPLEFT",     -extend,  extend)
    d.glow:SetPoint("BOTTOMRIGHT", btn, "BOTTOMRIGHT",  extend, -extend)
    local maskPath   = opts.maskPath
    local borderPath = opts.borderPath
    if maskPath then
        d.glow:SetTexture(maskPath, "CLAMPTOBLACKADDITIVE", "CLAMPTOBLACKADDITIVE")
    else
        d.glow:SetColorTexture(1, 1, 1, 1)
    end
    d.glow:SetVertexColor(cr, cg, cb, 1)
    d.glow:SetAlpha(1); d.glow:Show()

    -- Edge: not used (created an ugly inset inner border ring)
    d.edge:Hide()

    -- Bright border overlay
    d.bright:ClearAllPoints(); d.bright:SetAllPoints(btn)
    if borderPath then
        d.bright:SetTexture(borderPath)
    else
        d.bright:SetColorTexture(0, 0, 0, 0)
    end
    d.bright:SetVertexColor(cr, cg, cb, 1)
    d.bright:SetAlpha(0.5); d.bright:Show()

    -- Mask the pulsing glow with the shape mask texture
    local shapeMask = opts.shapeMask
    if shapeMask then
        pcall(d.glow.RemoveMaskTexture, d.glow, shapeMask)
        pcall(d.glow.AddMaskTexture, d.glow, shapeMask)
    end
    _Register(wrapper, _ShapeGlowOnUpdate, "shape")
end

local function StopShapeGlow(wrapper)
    _Unregister(wrapper, "shape")
    if wrapper._euiSgData then
        wrapper._euiSgData.glow:Hide()
        wrapper._euiSgData.edge:Hide()
        wrapper._euiSgData.bright:Hide()
    end
end

-------------------------------------------------------------------------------
--  FlipBook Glow Engine
--  Handles atlas-based and raw-texture FlipBook animations (GCD, Modern WoW
--  Glow, Classic WoW Glow, and any future FlipBook styles).
-------------------------------------------------------------------------------
local function StartFlipBookGlow(wrapper, szOrW, entry, cr, cg, cb, szH)
    -- FlipBook frames have transparent padding baked in. Each atlas
    -- has a different amount, so the style entry carries a texPadding
    -- multiplier (defaults to 1 = no compensation).
    local w = szOrW or 36
    local h = szH or w
    local texW = w * (entry.texPadding or 1)
    local texH = h * (entry.texPadding or 1)

    if not wrapper._euiFlipData then
        local tex = wrapper:CreateTexture(nil, "OVERLAY", nil, 7)
        tex:SetPoint("CENTER")
        local ag = tex:CreateAnimationGroup()
        ag:SetLooping("REPEAT")
        local anim = ag:CreateAnimation("FlipBook")
        wrapper._euiFlipData = { tex = tex, ag = ag, anim = anim }
    end
    local d = wrapper._euiFlipData
    d.tex:SetSize(texW, texH)
    if entry.atlas then
        d.tex:SetAtlas(entry.atlas)
    elseif entry.texture then
        d.tex:SetTexture(entry.texture)
    end
    if cr then
        d.tex:SetDesaturated(true)
        d.tex:SetVertexColor(cr, cg, cb)
    else
        -- no color requested - just show atlas untinted
        d.tex:SetDesaturated(false)
        d.tex:SetVertexColor(1, 1, 1)
    end
    d.tex:Show()
    d.anim:SetFlipBookRows(entry.rows or 6)
    d.anim:SetFlipBookColumns(entry.columns or 5)
    d.anim:SetFlipBookFrames(entry.frames or 30)
    d.anim:SetDuration(entry.duration or 1.0)
    d.anim:SetFlipBookFrameWidth(entry.frameW or 0)
    d.anim:SetFlipBookFrameHeight(entry.frameH or 0)
    if d.ag:IsPlaying() then d.ag:Stop() end
    d.ag:Play()

    -- Ants overlay: a non-desaturated duplicate at low alpha for atlas styles
    if entry.atlas then
        if not d.ants then
            local aTex = wrapper:CreateTexture(nil, "OVERLAY", nil, 7)
            aTex:SetPoint("CENTER")
            aTex:SetBlendMode("ADD")
            local aAg = aTex:CreateAnimationGroup()
            aAg:SetLooping("REPEAT")
            local aAnim = aAg:CreateAnimation("FlipBook")
            d.ants = aTex; d.antsAg = aAg; d.antsAnim = aAnim
        end
        d.ants:SetSize(texW, texH)
        d.ants:SetAtlas(entry.atlas)
        d.ants:SetDesaturated(false)
        d.ants:SetVertexColor(1, 1, 1)
        d.ants:SetAlpha(0.35)
        d.antsAnim:SetFlipBookRows(entry.rows or 6)
        d.antsAnim:SetFlipBookColumns(entry.columns or 5)
        d.antsAnim:SetFlipBookFrames(entry.frames or 30)
        d.antsAnim:SetDuration(entry.duration or 1.0)
        d.antsAnim:SetFlipBookFrameWidth(entry.frameW or 0)
        d.antsAnim:SetFlipBookFrameHeight(entry.frameH or 0)
        d.ants:Show()
        if d.antsAg:IsPlaying() then d.antsAg:Stop() end
        d.antsAg:Play()
    elseif d.ants then
        d.ants:Hide()
        if d.antsAg then d.antsAg:Stop() end
    end

    wrapper:SetScript("OnUpdate", nil)
end

local function StopFlipBookGlow(wrapper)
    if wrapper._euiFlipData then
        wrapper._euiFlipData.tex:Hide()
        if wrapper._euiFlipData.ag then wrapper._euiFlipData.ag:Stop() end
        if wrapper._euiFlipData.ants then wrapper._euiFlipData.ants:Hide() end
        if wrapper._euiFlipData.antsAg then wrapper._euiFlipData.antsAg:Stop() end
    end
end

-- Defined above StopAllGlows so engine-hosted ants (StartEngineGlow /
-- StartAnimatedAnts) tear down through the same unified stop path.
local function StopAnimatedAnts(wrapper)
    local d = wrapper._euiAnimAnts
    if not d then return end
    for i = 1, 4 do
        d.groups[i]:Stop()
        d.strips[i]:Hide()
    end
end

-------------------------------------------------------------------------------
--  StopAllGlows — clears any active glow engine on a wrapper frame
-------------------------------------------------------------------------------
local function StopAllGlows(wrapper)
    if not wrapper then return end
    StopProceduralAnts(wrapper)
    StopButtonGlow(wrapper)
    StopAutoCastShine(wrapper)
    StopShapeGlow(wrapper)
    StopFlipBookGlow(wrapper)
    StopAnimatedAnts(wrapper)
    -- Defensive scrub: the central driver owns the only OnUpdate now, so the
    -- five Stop* calls above already unregistered this wrapper from the driver.
    -- This clears any stale OnUpdate a pre-migration build may have left on the
    -- wrapper itself (harmless on our own frame; never touches the driver).
    wrapper:SetScript("OnUpdate", nil)
end

-------------------------------------------------------------------------------
--  StartGlow — unified entry point
--  wrapper  : Frame to render the glow on
--  styleIdx : index into GLOW_STYLES (1-based)
--  sz       : icon/frame size in pixels
--  cr,cg,cb : glow color (0-1)
--  opts     : optional table with overrides:
--    .scale       — override entry.scale
    --    .N, .th, .period, .bg — pixel glow tuning/background
--    .maskPath, .borderPath, .shapeMask — shape glow textures
-------------------------------------------------------------------------------
local function StartGlow(wrapper, styleIdx, szOrW, cr, cg, cb, opts, szH)
    if not wrapper then return end
    styleIdx = tonumber(styleIdx) or 1
    if styleIdx < 1 or styleIdx > #GLOW_STYLES then styleIdx = 1 end
    local entry = GLOW_STYLES[styleIdx]
    opts = opts or {}
    local w = szOrW or 36
    local h = szH or w
    cr = cr or 1; cg = cg or 1; cb = cb or 1

    -- Stop any previous glow
    StopAllGlows(wrapper)

    if entry.procedural then
        local N       = opts.N or 8
        local th      = opts.th or 2
        local period  = opts.period or 4
        local lineLen = floor((w + h) * (2 / N - 0.1))
        lineLen = min(lineLen, min(w, h))
        if lineLen < 1 then lineLen = 1 end
        local bg = opts.bg
        StartProceduralAnts(wrapper, N, th, period, lineLen, cr, cg, cb, w, h,
            bg and (bg.r or 0) or nil, bg and (bg.g or 0) or nil, bg and (bg.b or 0) or nil, bg and (bg.a or 1) or nil)

    elseif entry.buttonGlow then
        StartButtonGlow(wrapper, w, cr, cg, cb, nil, h)

    elseif entry.autocast then
        StartAutoCastShine(wrapper, w, cr, cg, cb, 1.0, h)

    elseif entry.shapeGlow then
        StartShapeGlow(wrapper, w, cr, cg, cb, 1.20, opts)

    else
        -- FlipBook mode (GCD, Modern WoW Glow, Classic WoW Glow, etc.)
        StartFlipBookGlow(wrapper, w, entry, cr, cg, cb, h)
    end

    wrapper._euiGlowActive = true
    wrapper:SetAlpha(1)
    -- No Show() — wrapper should already be shown. Toggling visibility
    -- on children of Blizzard viewer frames triggers Layout cascades.
end

local function StopGlow(wrapper)
    if not wrapper then return end
    StopAllGlows(wrapper)
    wrapper._euiGlowActive = false
    wrapper:SetAlpha(0)
end

-------------------------------------------------------------------------------
--  Animation-driven glow (engine aura buttons)
--  The 12.1 slot-button subtree is forbidden to addon code outside its
--  creation window, so the driver-ticked engines above (Lua OnUpdate)
--  freeze there. This variant reproduces the Pixel Glow march with C-side
--  AnimationGroups: created and started once in the creation window, it
--  animates forever with zero per-frame Lua -- identically in and out of
--  secret contexts.
-------------------------------------------------------------------------------
local ANIM_MASK_TEX = [[Interface\Buttons\WHITE8X8]]

-- Marching dashes: per edge, a dash strip one pattern-cycle longer than the edge slides
-- by exactly one cycle and loops; a rect mask clips it to the edge, so the snap-back is
-- invisible and the march is seamless. Strip texcoords carry the cumulative perimeter
-- phase, keeping dashes corner-continuous exactly like the driver-ticked ants (phase
-- matters modulo one cycle, so the one-cycle anchor offsets cancel out).
local function StartAnimatedAnts(wrapper, N, th, period, cr, cg, cb, w, h, ca)
    N = (N and N > 0) and N or 8
    th = th or 2
    period = period or 4
    w = w or 36; h = h or w
    local perim = 2 * (w + h)
    local P = perim / N              -- pixels per dash cycle
    local step = period / N          -- seconds per dash cycle
    local d = wrapper._euiAnimAnts
    if not d then
        d = { strips = {}, masks = {}, groups = {}, trs = {} }
        wrapper._euiAnimAnts = d
        for i = 1, 4 do
            local mask = wrapper:CreateMaskTexture()
            mask:SetTexture(ANIM_MASK_TEX, "CLAMPTOBLACKADDITIVE", "CLAMPTOBLACKADDITIVE")
            local strip = wrapper:CreateTexture(nil, "OVERLAY", nil, 7)
            strip:AddMaskTexture(mask)
            local ag = strip:CreateAnimationGroup()
            ag:SetLooping("REPEAT")
            local tr = ag:CreateAnimation("Translation")
            tr:SetSmoothing("NONE")
            d.masks[i], d.strips[i], d.groups[i], d.trs[i] = mask, strip, ag, tr
        end
    end
    -- Edge order (clockwise): 1 top scrolls right, 2 right scrolls down,
    -- 3 bottom scrolls left, 4 left scrolls up. base = cumulative
    -- perimeter phase in cycles at the edge's visual start.
    local edges = {
        { tex = DASH_H, len = w, dx = P,  dy = 0,  vert = false, base = 0 },
        { tex = DASH_V, len = h, dx = 0,  dy = -P, vert = true,  base = w / P },
        { tex = DASH_H, len = w, dx = -P, dy = 0,  vert = false, base = (w + h) / P },
        { tex = DASH_V, len = h, dx = 0,  dy = P,  vert = true,  base = (w + h + w) / P },
    }
    for i = 1, 4 do
        local e = edges[i]
        local mask, strip, ag, tr = d.masks[i], d.strips[i], d.groups[i], d.trs[i]
        ag:Stop()
        strip:SetTexture(e.tex, "REPEAT", "REPEAT")
        strip:SetVertexColor(cr or 1, cg or 1, cb or 1, ca or 1)
        mask:ClearAllPoints()
        strip:ClearAllPoints()
        local cyc = (e.len + P) / P
        if not e.vert then
            mask:SetSize(e.len, th)
            strip:SetSize(e.len + P, th)
            if i == 1 then
                mask:SetPoint("TOPLEFT", wrapper, "TOPLEFT", 0, 0)
                strip:SetPoint("TOPLEFT", wrapper, "TOPLEFT", -P, 0)
            else
                mask:SetPoint("BOTTOMLEFT", wrapper, "BOTTOMLEFT", 0, 0)
                strip:SetPoint("BOTTOMLEFT", wrapper, "BOTTOMLEFT", 0, 0)
            end
            strip:SetTexCoord(e.base, e.base + cyc, 0, 1)
        else
            mask:SetSize(th, e.len)
            strip:SetSize(th, e.len + P)
            if i == 2 then
                mask:SetPoint("TOPRIGHT", wrapper, "TOPRIGHT", 0, 0)
                strip:SetPoint("TOPRIGHT", wrapper, "TOPRIGHT", 0, P)
            else
                mask:SetPoint("BOTTOMLEFT", wrapper, "BOTTOMLEFT", 0, 0)
                strip:SetPoint("BOTTOMLEFT", wrapper, "BOTTOMLEFT", 0, -P)
            end
            strip:SetTexCoord(0, 1, e.base, e.base + cyc)
        end
        strip:Show()
        tr:SetOffset(e.dx, e.dy)
        tr:SetDuration(step)
        ag:Play()
    end
end

-------------------------------------------------------------------------------
--  StartEngineGlow — StartGlow for wrappers on ENGINE aura-button subtrees
--  (12.1 forbidden partition: NP purge, RF DM fx, RF BM icon glow, ...).
--  Driver-ticked engines cannot run there -- the driver's Lua reads on the
--  wrapper throw outside sanctioned windows -- so every driver style routes
--  to its C-side equivalent and animates identically in and out of secret
--  contexts: Pixel Glow renders its GENUINE dash march through the animated
--  ants engine (not a lookalike remap), Action Button Glow plays its
--  flipbook twin (the same IconAlertAnts sheet the driver version scrolls),
--  and Auto-Cast Shine / Shape Glow -- no C-side equivalent built -- fall
--  back to the Modern WoW Glow loop (options on engine-hosted pickers hide
--  those two; the fallback only covers stale saved values). FlipBook picks
--  pass through untouched. Never registers with the central driver.
-------------------------------------------------------------------------------
local function StartEngineGlow(wrapper, styleIdx, szOrW, cr, cg, cb, opts, szH)
    if not wrapper then return end
    styleIdx = tonumber(styleIdx) or 1
    if styleIdx < 1 or styleIdx > #GLOW_STYLES then styleIdx = 1 end
    local entry = GLOW_STYLES[styleIdx]
    if entry.procedural then
        opts = opts or {}
        local w = szOrW or 36
        StopAllGlows(wrapper)
        StartAnimatedAnts(wrapper, opts.N or 8, opts.th or 2, opts.period or 4,
            cr or 1, cg or 1, cb or 1, w, szH or w)
        wrapper._euiGlowActive = true
        wrapper:SetAlpha(1)
        return
    end
    if entry.buttonGlow then
        styleIdx = 7
    elseif entry.autocast or entry.shapeGlow then
        styleIdx = 6
    end
    StartGlow(wrapper, styleIdx, szOrW, cr, cg, cb, opts, szH)
end

-------------------------------------------------------------------------------
--  Public API — attached to EllesmereUI.Glows
-------------------------------------------------------------------------------
-- Styles that render through C-side FlipBook AnimationGroups (GCD, Modern WoW Glow,
-- Classic WoW Glow) animate IDENTICALLY under 12.1 aura restrictions; driver-ticked
-- styles (Pixel, Action Button, Auto-Cast, Shape) cannot -- secret visibility blocks
-- their Lua ticks, leaving a frozen artifact. Kept for external callers that want a
-- plain style REMAP (in-tree engine-button hosts use StartEngineGlow instead, which
-- renders Pixel genuinely): Pixel -> Classic WoW Glow (ants), everything else
-- driver-based -> Modern WoW Glow (the standard proc loop).
local SAFE_STYLE_MAP = { [1] = 7, [2] = 6, [3] = 6, [4] = 6 }
local function RestrictionSafeStyle(idx)
    local entry = GLOW_STYLES[idx]
    if entry and (entry.procedural or entry.buttonGlow or entry.autocast or entry.shapeGlow) then
        return SAFE_STYLE_MAP[idx] or 6
    end
    return idx
end

EllesmereUI.Glows = {
    STYLES              = GLOW_STYLES,

    -- High-level API (recommended)
    StartGlow           = StartGlow,
    StartEngineGlow     = StartEngineGlow,
    StopGlow            = StopGlow,
    RestrictionSafeStyle = RestrictionSafeStyle,

    -- Low-level engines (for addons that need direct control)
    StartProceduralAnts = StartProceduralAnts,
    StopProceduralAnts  = StopProceduralAnts,
    SetProceduralAntsColor = SetProceduralAntsColor,
    StartButtonGlow     = StartButtonGlow,
    StopButtonGlow      = StopButtonGlow,
    StartAutoCastShine  = StartAutoCastShine,
    StopAutoCastShine   = StopAutoCastShine,
    StartAnimatedAnts   = StartAnimatedAnts,
    StopAnimatedAnts    = StopAnimatedAnts,
    StartShapeGlow      = StartShapeGlow,
    StopShapeGlow       = StopShapeGlow,
    StartFlipBookGlow   = StartFlipBookGlow,
    StopFlipBookGlow    = StopFlipBookGlow,
    StopAllGlows        = StopAllGlows,
}