moon-well-ui/data/addon/ForeverUI/Layout.lua

-- ForeverUI: movable positions.
-- Every frame ForeverUI builds registers here with a default position; this table places it
-- on load and remembers where the player moves it. Everything is anchored to UIParent, never
-- to another ForeverUI frame, so moving one element never drags another.

ForeverUI = ForeverUI or {}

-- Disable a client frame. Hiding is not enough: its own code shows it again (page change,
-- vehicle exit, rune update). So we unregister its events, hide it, and hide it again on
-- OnShow.
function ForeverUI.Suppress(frame)
	if not frame or frame.foreverSuppressed then
		return
	end

	if frame.UnregisterAllEvents then
		frame:UnregisterAllEvents()
	end
	frame:Hide()

	if frame.HookScript then
		frame:HookScript("OnShow", function(self)
			self:Hide()
		end)
	end

	frame.foreverSuppressed = true
end

local Layout = {}
ForeverUI.Layout = Layout

Layout.systems = {}   -- id -> { frame, label, defaults, baseScale }
Layout.order = {}     -- ids, in registration order
Layout.editing = false
Layout.work = nil     -- working copy of the positions during a Customize UI session
Layout.onRegister = nil  -- set by Customize UI: called with an id registered while editing

local PREFIX = "|cff66ccffForeverUI|r : "
local L = ForeverUI.L

local function say(message)
	DEFAULT_CHAT_FRAME:AddMessage(PREFIX .. message)
end
Layout.Say = say

local function positions()
	ForeverUIDB = ForeverUIDB or {}
	ForeverUIDB.positions = ForeverUIDB.positions or {}
	return ForeverUIDB.positions
end

-- Positions in effect: the working copy while editing, the saved ones otherwise.
local function current()
	return Layout.work or positions()
end

-- A saved entry: an anchor (point, relativePoint, x, y), a size (scale), or both. Offsets are
-- in the frame's units at 100 %; an entry without anchor keeps the default one.
local function copy(p)
	return { point = p.point, relativePoint = p.relativePoint, x = p.x, y = p.y, scale = p.scale }
end

-- Anchor in effect: the saved one, or the default one.
function Layout.Anchor(id)
	local system = Layout.systems[id]
	local p = current()[id]
	if p and p.point then
		return p
	end
	return system and system.defaults
end

-- True while the element keeps its default anchor (the player has not moved it).
function Layout.IsDefault(id)
	local p = current()[id]
	return not (p and p.point)
end

-- Size the element has at 100 %, set by its own code (an automatic fit); the player's size
-- applies on top of it.
function Layout.SetBaseScale(id, scale)
	local system = Layout.systems[id]
	if not system then
		return false
	end
	system.baseScale = scale
	Layout.Apply(id)
	return true
end

-- Size in effect, 1 for 100 %.
function Layout.Scale(id)
	local p = current()[id]
	return p and p.scale or 1
end

-- Ratio of the frame's units at 100 % to UIParent's.
local function unit(system, scale)
	return system.frame:GetEffectiveScale() / UIParent:GetEffectiveScale() / scale
end

-- Place the frame at its saved position and size, or at the default ones. The offsets shrink
-- with the size, so the anchor stays at the same place on screen.
function Layout.Apply(id)
	local system = Layout.systems[id]
	if not system then
		return false
	end

	local p = Layout.Anchor(id)
	local scale = Layout.Scale(id)
	system.frame:SetScale(system.baseScale * scale)
	system.frame:ClearAllPoints()
	system.frame:SetPoint(p.point, UIParent, p.relativePoint, p.x / scale, p.y / scale)
	return true
end

-- Records the frame's current anchor (in the working copy while editing).
function Layout.Save(id)
	local system = Layout.systems[id]
	if not system then
		return false
	end

	local point, _, relativePoint, x, y = system.frame:GetPoint(1)
	if not point then
		return false
	end

	local scale = Layout.Scale(id)
	current()[id] = {
		point = point,
		relativePoint = relativePoint or point,
		x = (x or 0) * scale,
		y = (y or 0) * scale,
		scale = current()[id] and current()[id].scale,
	}
	return true
end

-- Moves the element. x, y: offsets in UIParent units; point: new anchor, the same point of
-- the element and of the screen (nil keeps the current anchor).
function Layout.SetPosition(id, x, y, point)
	local system = Layout.systems[id]
	if not system then
		return false
	end
	local anchor = Layout.Anchor(id)
	local k = unit(system, Layout.Scale(id))
	local p = current()[id] or {}
	p.point, p.relativePoint = point or anchor.point, point or anchor.relativePoint
	p.x, p.y = x / k, y / k
	current()[id] = p
	Layout.Apply(id)
	return true
end

-- Resizes the element around its anchor; scale: 1 for 100 %.
function Layout.SetScale(id, scale)
	if not Layout.systems[id] then
		return false
	end
	local p = current()[id] or {}
	p.scale = (scale ~= 1) and scale or nil
	current()[id] = next(p) and p or nil
	Layout.Apply(id)
	return true
end

-- Back to the default position: one element, or all of them when id is nil.
function Layout.Reset(id)
	if id then
		if not Layout.systems[id] then
			return false
		end
		current()[id] = nil
		Layout.Apply(id)
		return true
	end

	for _, systemID in ipairs(Layout.order) do
		current()[systemID] = nil
		Layout.Apply(systemID)
	end
	return true
end

-- Customize UI session: moves go to a working copy; Commit saves it, Revert drops it and
-- puts every element back where it was.
-- The working copy holds every entry, so an element registered during the session finds its
-- own; only the elements' entries go back (windows keep theirs, even moved meanwhile).
function Layout.BeginEdit()
	local work = {}
	for id, p in pairs(positions()) do
		work[id] = copy(p)
	end
	Layout.work = work
	Layout.editing = true
end

function Layout.Commit()
	local work = Layout.work
	if work then
		local saved = positions()
		for id in pairs(Layout.systems) do
			saved[id] = work[id]
		end
	end
	Layout.work = nil
	Layout.editing = false
end

function Layout.Revert()
	Layout.work = nil
	Layout.editing = false
	for _, id in ipairs(Layout.order) do
		Layout.Apply(id)
	end
end

-- Make the frame movable and place it.
-- id: saved-position key; label: edit mode label; point..y: default anchor on UIParent
function Layout.Register(frame, id, label, point, relativePoint, x, y)
	Layout.systems[id] = {
		frame = frame,
		label = label,
		defaults = { point = point, relativePoint = relativePoint, x = x, y = y },
		baseScale = frame:GetScale(),
	}
	table.insert(Layout.order, id)

	frame:SetMovable(true)
	frame:SetClampedToScreen(true)
	if frame:GetFrameStrata() ~= Layout.STRATA then frame:SetFrameStrata(Layout.STRATA) end
	Layout.Apply(id)

	if Layout.editing and Layout.onRegister then
		Layout.onRegister(id)
	end
	return frame
end

-- Change the default position of a registered element. The bottom of the screen is a chain:
-- the action bar and the bags sit on each side of the micro menu, whose width is known only
-- once its buttons are counted. An element the player has moved keeps its position.
function Layout.SetDefaults(id, point, relativePoint, x, y)
	local system = Layout.systems[id]
	if not system then
		return false
	end

	system.defaults = { point = point, relativePoint = relativePoint, x = x, y = y }
	local p = current()[id]
	if not (p and p.point) then
		Layout.Apply(id)
	end
	return true
end

-- Fractions of a box for an anchor point: x from the left, y from the bottom.
local function fractions(point)
	local fx = (string.find(point, "LEFT") and 0) or (string.find(point, "RIGHT") and 1) or 0.5
	local fy = (string.find(point, "BOTTOM") and 0) or (string.find(point, "TOP") and 1) or 0.5
	return fx, fy
end
Layout.Fractions = fractions

-- The frame an anchor refers to; relativeTo: a frame or its name, as SetPoint takes it.
local function frameOf(relativeTo)
	return type(relativeTo) == "string" and _G[relativeTo] or relativeTo
end

-- An anchor of the element on another frame, as the same place given from the screen: offsets
-- of point from the same point of UIParent, in the element's units at 100 %; nil while that
-- frame is not laid out. The other arguments as SetPoint's (no relativeTo: the parent).
local function onScreen(id, point, relativeTo, relativePoint, x, y)
	local system = Layout.systems[id]
	local other = frameOf(relativeTo) or system.frame:GetParent()
	local left, bottom = other and other:GetLeft(), other and other:GetBottom()
	if not (left and bottom) then
		return nil
	end
	local scale = Layout.Scale(id)
	local k = unit(system, scale)              -- element's units at 100 %, in UIParent's
	local ko = other:GetEffectiveScale() / UIParent:GetEffectiveScale()
	local fx, fy = fractions(relativePoint or point)
	local px = (left + other:GetWidth() * fx) * ko + (x or 0) * k * scale
	local py = (bottom + other:GetHeight() * fy) * ko + (y or 0) * k * scale
	local gx, gy = fractions(point)
	return (px - gx * UIParent:GetWidth()) / k, (py - gy * UIParent:GetHeight()) / k
end

-- A client frame that the client itself keeps anchoring elsewhere (UIParent_ManageFramePositions),
-- made movable like ForeverUI's elements. Its default is the client's last anchor, given from the
-- screen, and follows the frame that anchor refers to when that one moves; once the player has
-- moved it, its own anchor comes back after each of the client's. Anchors on the screen (its own,
-- Customize UI's while dragging) are left alone. id, label: as Register's.
function Layout.RegisterClientFrame(frame, id, label)
	local last = {}                         -- the client's last anchor
	-- kept up to date even while moved, so that a reset finds the client's place of the moment
	local function placeDefault()
		local dx, dy = onScreen(id, last.point, last.relativeTo, last.relativePoint, last.x, last.y)
		if dx then
			Layout.SetDefaults(id, last.point, last.point, dx, dy)
		end
	end
	-- point..y: an anchor as SetPoint takes it
	local function follow(point, relativeTo, relativePoint, x, y)
		if not point or relativeTo == UIParent or relativeTo == "UIParent" then
			return
		end
		last = { point = point, relativeTo = relativeTo, relativePoint = relativePoint, x = x, y = y }
		placeDefault()
		if not Layout.IsDefault(id) then
			Layout.Apply(id)
		end
	end
	local point, relativeTo, relativePoint, x, y = frame:GetPoint(1)
	Layout.Register(frame, id, label, "TOPRIGHT", "TOPRIGHT", 0, 0)
	follow(point, relativeTo, relativePoint, x, y)
	hooksecurefunc(frame, "SetPoint", function(_, ...) follow(...) end)
	-- the frame the client's anchor refers to moved (the minimap, by the player)
	hooksecurefunc(Layout, "Apply", function(other)
		local moved = other ~= id and Layout.systems[other] and Layout.systems[other].frame
		if moved and moved == frameOf(last.relativeTo) then
			placeDefault()
		end
	end)
	return frame
end

-- ---------- Draw order
-- camelot keeps the playing screen in LOW (unit frames, minimap, objectives) and MEDIUM (action
-- bars, menu, bags bar) and raises each window above the whole MEDIUM strata (toplevel, Raise).
-- 3.3.5 does not raise our windows above the bars, so every element of the playing screen
-- goes to LOW, keeping its levels, and MEDIUM holds only the windows and bags: any of them is
-- drawn over any element of the playing screen. The client's buttons we anchor elsewhere (main
-- bar, micro-menu, bag slots, bonus, stance, pet, totem and possess bars) are children of
-- MainMenuBar; the vehicle bar and the durability figure belong to the playing screen too.
-- The pet buttons carry their own MEDIUM and do not follow their bar.
Layout.STRATA = "LOW"
local CLIENT_FRAMES = { "MainMenuBar", "VehicleMenuBar", "DurabilityFrame" }
for i = 1, NUM_PET_ACTION_SLOTS or 10 do
	CLIENT_FRAMES[#CLIENT_FRAMES + 1] = "PetActionButton" .. i
end

-- MainMenuBar holds secure buttons: out of combat only
local function lowerClientFrames()
	if InCombatLockdown() then
		return false
	end
	for _, name in ipairs(CLIENT_FRAMES) do
		local f = _G[name]
		if f and f:GetFrameStrata() ~= Layout.STRATA then f:SetFrameStrata(Layout.STRATA) end
	end
	return true
end
local lowered = lowerClientFrames()

-- The durability figure, stacked by the client under the minimap, moves like the elements. Its
-- weapon, shield and ranged pieces reach past its 60 x 65 frame (DurabilityFrame.xml): kept on
-- screen with it.
if DurabilityFrame then
	Layout.RegisterClientFrame(DurabilityFrame, "durability", DURABILITY)
	DurabilityFrame:SetClampRectInsets(-12, 19, 0, -11)
end

-- Places every element once saved variables are loaded.
local watcher = CreateFrame("Frame")
watcher:RegisterEvent("PLAYER_LOGIN")
watcher:RegisterEvent("PLAYER_REGEN_ENABLED")
watcher:SetScript("OnEvent", function(_, event)
	if not lowered then lowered = lowerClientFrames() end
	if event ~= "PLAYER_LOGIN" then return end
	for _, id in ipairs(Layout.order) do
		Layout.Apply(id)
	end
end)

SLASH_FOREVERUI1 = "/fui"
SLASH_FOREVERUI2 = "/foreverui"

SlashCmdList["FOREVERUI"] = function(message)
	local command, argument = string.match(message or "", "^(%S*)%s*(.*)$")
	argument = argument or ""
	command = string.lower(command or "")

	if command == "" or command == "edit" then
		ForeverUI.CustomizeUI.Toggle()
	elseif command == "reset" then
		if InCombatLockdown() then
			-- secure frames (unit frames, action bars) cannot move in combat: the saved positions
			-- would be erased and the frames left where they are
			say(ERR_NOT_IN_COMBAT)
		elseif argument ~= "" then
			if Layout.Reset(argument) then
				say(L.LAYOUT_RESET_ONE .. argument)
			else
				say(L.LAYOUT_UNKNOWN_ELEMENT .. argument)
			end
		else
			Layout.Reset()
			say(L.LAYOUT_RESET_ALL)
		end
	elseif command == "list" then
		say(L.LAYOUT_LIST_HEADER)
		for _, id in ipairs(Layout.order) do
			local system = Layout.systems[id]
			local saved = positions()[id]
			DEFAULT_CHAT_FRAME:AddMessage(string.format("   %s (%s)%s", id, system.label,
				saved and L.LAYOUT_LIST_MOVED or ""))
		end
	else
		say(L.LAYOUT_HELP)
	end
end