-- Aurora Speed Kit (unofficial) - Main.lua - kit version 1
--
-- Puts Marcus's faster-starting "speed build" of Aurora.xex (Aurora 0.7b.2 r1655; console test 2026-11-04:
-- game list in 17 s instead of 96 s) into every Aurora instance it finds. Undo puts the original back.
-- Nothing else changes: no databases, settings, skins or plugins.
--
-- Safety rules
--  * Files are recognised by size and SHA-1 only (pinned below). A file the kit does not recognise is never
--    changed or deleted; the only exception is Repair, which you must pick and which only renames it to .bad.
--  * The speed build is made on the console from your own original Aurora.xex plus a patch that is useless
--    without it. Every file the kit writes is checked before it is used.
--  * The original is copied to Aurora.xex.r1655.bak and checked before an instance changes.
--  * All downloading and building happens first, in this kit's tmp folder. Then instances change one at a
--    time, the one you are running last. Aurora.xex and .bad files are never deleted.
--  * The kit deletes only files with its own names: Aurora.xex.r1655.bak, Aurora.xex.sk-new, Aurora.xex.sk-old*
--    and SpeedKit folders. Your own copies (for example Aurora.xex.new or Aurora.xex.old) are only read.
--  * Files it may add next to Aurora.xex: Aurora.xex.r1655.bak; Aurora.xex.sk-new (while it switches);
--    Aurora.xex.sk-old (only if a plain switch is refused); Aurora.xex.bad (Repair). In each instance:
--    User\Scripts\Utility\SpeedKit\ with Main.lua and the patch. In this folder: the patch, tmp\ (while it
--    works), speedkit.log and speedkit.marker.
--
-- If an instance will not start, see HELP below. Never turn the console off while the kit says so.
--
-- For editors: the top level must hold only plain values and function definitions. Aurora runs it while it
-- builds the Scripts list, without the string, table or Aurora libraries; a library call there hides the kit.

scriptTitle = "Aurora Speed Kit (unofficial)"
scriptAuthor = "Marcus"
scriptVersion = 1
scriptDescription = "Unofficial: makes Aurora 0.7b.2 (r1655) start faster by putting a checked speed build in each instance, with backups and Undo."
scriptPermissions = { "http", "filesystem" }

-- ----- Pinned values (computed on the PC from the lab files; do not edit) ----------------------------------
local KIT_VERSION = 1
local KIT_TITLE = "Aurora Speed Kit (unofficial)"
local BASEURL = "http://thatoneconsolemodder.app/"            -- set by the release builder, for example http://thevault.example/
local PATCH_URL = "sk/v1/r1655-b1.xdp"   -- added to BASEURL; the builder checks it against the kit version

-- Stock Aurora 0.7b.2 r1655. Also CRC32 590CA44F, MD5 20638912B5685327460AB37529DC9638.
local STOCK = { key = "original", text = "original Aurora.xex", size = 12333056, sha1 = "347613582AA0210C8B723A35D4658E91A4A90808" }
-- Speed build ("Build B"). Also CRC32 8AA7B6B3, MD5 F7E7E558B163CF26FE94A9FC26B34F30.
local SPEED = { key = "speed", text = "speed build", size = 12333056, sha1 = "1621A9DAF492682254A048E7C41967659629F127" }
-- Patch = stock XOR speed build over RANGES, one range after the other. Also CRC32 5DBCD54D,
-- MD5 76392B636236F3EEB6BDD8496D7424BF. It works both ways: stock XOR patch = speed, speed XOR patch = stock.
local PATCH = { key = "patch", text = "speed patch", size = 9088864, sha1 = "655BA302B9C911065FD5A5D8D9E26942E47DFB70" }
-- The only bytes that differ between the two builds: { file offset, length }; both lengths are multiples of 4.
local RANGES = { { 0x20C, 4480 }, { 0x319220, 9084384 } }

-- R2: the kit's working copies have names only the kit uses, so it never deletes a copy you made yourself.
local XEX, BAK, NEW, OLD, BAD = "Aurora.xex", "Aurora.xex.r1655.bak", "Aurora.xex.sk-new", "Aurora.xex.sk-old", "Aurora.xex.bad"
local MAIN_FILE, PATCH_FILE, TMP = "Main.lua", "r1655-b1.xdp", "tmp"
local LOG_FILE, MARKER_FILE = "speedkit.log", "speedkit.marker"
local KIT_REL = "User\\Scripts\\Utility\\SpeedKit"    -- the kit's folder inside an instance
local DEBUG_LOG = "Game:\\Data\\Logs\\debug.log"
local CHUNK, WORDS = 65536, 1024                       -- bytes per read; 32-bit words per pack/unpack call
local LOW_SPACE = 157286400                            -- warn below 150 MB free (advice only)
local WRAP, PAGE = 60, 8                               -- one-button message box: characters per line, lines per box
local BOX_WRAP, BOX_LINES = 68, 11                     -- two-button box: wraps by itself (about 72), shows about 12 lines
local SKIP_DRIVES = { ["game:"] = true, ["system:"] = true, ["hdd0:"] = true, ["hddx:"] = true, ["sysext:"] = true,
	["flash:"] = true, ["dvd:"] = true, ["hddvdplayer:"] = true, ["hddvdstorage:"] = true, ["transfercable:"] = true,
	["transfercablexbox1:"] = true, ["connx:"] = true }
local STATE_TEXT = { original = "original", speed = "speed build", missing = "missing" }
local HELP = "1. Start another Aurora instance from your boot menu (for example qLoader) and run Scripts > Aurora Speed Kit there. Install or Undo repairs the broken instance.\n\n2. Or, in a working instance, open File Manager and go to the broken instance's Aurora folder. Rename the broken Aurora.xex to Aurora.xex.broken. Then rename Aurora.xex.r1655.bak (or Aurora.xex.sk-new or Aurora.xex.sk-old) to Aurora.xex. The next Install makes a new backup.\n\n3. If no Aurora starts at all, put the drive on a PC (FATXplorer) and do the same renames there.\n\n4. Never turn the console off while the kit says 'do not turn the console off'."

local K = {}   -- run-time state set in main() and scan(): base, mainSha, mainId, drives, unsure, multi

-- ----- Small helpers (every Aurora call is protected; file results are checked by hash, never trusted) -----
local function int(x) return math.floor(tonumber(x) or 0) end
local function stateText(s) return STATE_TEXT[s] or "unknown" end
local function startsWith(s, p) return string.sub(s, 1, #p) == p end

local function stamp()
	local okd, d = pcall(Aurora.GetDate)
	local okt, t = pcall(Aurora.GetTime)
	if not okd or type(d) ~= "table" then d = {} end
	if not okt or type(t) ~= "table" then t = {} end
	return string.format("%04d-%02d-%02d %02d:%02d:%02d.%03d", int(d.Year), int(d.Month), int(d.Day),
		int(t.Hour), int(t.Minute), int(t.Second), int(t.Milliseconds))
end

-- Support log: "SpeedKit|" lines in Aurora's debug.log, plus speedkit.log in the kit folder.
local function log(msg)
	msg = tostring(msg)
	print("SpeedKit| " .. msg)
	if not K.base then return end
	pcall(function()
		local f = io.open(K.base .. LOG_FILE, "ab")
		if f then f:write(stamp(), "  ", msg, "\r\n") f:close() end
	end)
end

local function status(text, cur, total)
	pcall(Script.SetStatus, text)
	if cur and total and total > 0 then pcall(Script.SetProgress, cur, total) end
end

-- Lab fix F1: Aurora's one-button message box does not wrap text; every paragraph longer than one line is cut
-- with "..." (lab test 2026-11-05: the HELP steps were unreadable). So the kit breaks long lines itself, at a
-- space, or after a backslash inside a long path.
local function wrap(text, width)
	local out = {}
	for line in string.gmatch(tostring(text) .. "\n", "(.-)\n") do
		while #line > width do
			local cut = nil
			for i = width + 1, 2, -1 do
				if string.sub(line, i, i) == " " then cut = i break end
			end
			if cut then
				out[#out + 1] = string.sub(line, 1, cut - 1)
				line = string.sub(line, cut + 1)
			else
				local b = width
				for i = width, 2, -1 do
					if string.sub(line, i, i) == "\\" then b = i break end
				end
				out[#out + 1] = string.sub(line, 1, b)
				line = string.sub(line, b + 1)
			end
		end
		out[#out + 1] = line
	end
	return table.concat(out, "\n")
end

-- The one-button box also shows only about 8 lines (lab test: step 3 of the HELP text was cut off), so a longer
-- text is shown in parts, "(1/2)" and so on, with a Next button. Parts end between paragraphs where possible.
-- Returns false when a part was closed with B (R17: then the rest is not shown).
local function say(title, text)
	local paras, cur = {}, {}
	for l in string.gmatch(wrap(text, WRAP) .. "\n", "(.-)\n") do
		if l == "" then
			if #cur > 0 then paras[#paras + 1] = cur cur = {} end
		else
			cur[#cur + 1] = l
		end
	end
	if #cur > 0 then paras[#paras + 1] = cur end
	local pages, page = {}, {}
	for _, p in ipairs(paras) do
		if #page > 0 and #page + 1 + #p > PAGE then pages[#pages + 1] = page page = {} end
		if #page > 0 then page[#page + 1] = "" end
		for _, l in ipairs(p) do
			if #page >= PAGE then pages[#pages + 1] = page page = {} end
			page[#page + 1] = l
		end
	end
	if #page > 0 or #pages == 0 then pages[#pages + 1] = page end
	for i, pg in ipairs(pages) do
		local t = (#pages > 1) and (title .. " (" .. i .. "/" .. #pages .. ")") or title
		local ok, r = pcall(Script.ShowMessageBox, t, table.concat(pg, "\n"), (i < #pages) and "Next" or "OK")
		if ok and type(r) == "table" and r.Canceled == true then return false end
	end
	return true
end

-- Two-button box: 1 or 2 for the button picked, nil when it was closed with B. The first button has the focus.
local function choose(title, text, first, second)
	local ok, r = pcall(Script.ShowMessageBox, title, text, first, second)
	if ok and type(r) == "table" and r.Canceled ~= true and (r.Button == 1 or r.Button == 2) then return r.Button end
	return nil
end

-- true only when the first button was chosen (B counts as No)
local function ask(title, text, yes, no) return choose(title, text, yes or "Yes", no or "No") == 1 end

-- R7: the two-button box shows only about 11 lines (lab test: with four instances and a download its end was
-- cut off). A longer text is shown first with say(), in parts, and then only the short question is asked.
local function confirm(title, head, body, question, yes, no)
	local text = body .. "\n\n" .. question
	if head ~= "" then text = head .. "\n\n" .. text end
	local n = 0
	for _ in string.gmatch(wrap(text, BOX_WRAP) .. "\n", "(.-)\n") do n = n + 1 end
	if n <= BOX_LINES then return ask(title, text, yes, no) end
	if not say(title, body) then return false end
	return ask(title, ((head ~= "") and (head .. "\n\n") or "") .. question, yes, no)
end

-- number of the chosen line, or nil
local function pick(title, items)
	local ok, r = pcall(Script.ShowPopupList, title, "Nothing to show.", items)
	if not ok or type(r) ~= "table" or r.Canceled == true or type(r.Selected) ~= "table" then return nil end
	return tonumber(r.Selected.Key)
end

local function canceled() local ok, c = pcall(Script.IsCanceled) return ok and c == true end
local function isThere(p) local ok, r = pcall(FileSystem.FileExists, p) return ok and r == true end
local function copyFile(a, b, overwrite) local ok, r = pcall(FileSystem.CopyFile, a, b, overwrite == true) return ok and r == true end
local function moveFile(a, b) local ok, r = pcall(FileSystem.MoveFile, a, b, true) return ok and r == true end
local function renameFile(a, b) local ok, r = pcall(FileSystem.Rename, a, b) return ok and r == true end

-- Lab fix F5: size through io first. In the lab, FileSystem.GetFileSize returned 0 for a file CopyFile had just
-- written (and for that file after a MoveFile), while io.open and the SHA-1 read it correctly, so every backup
-- check failed. GetFileSize is only the fallback now; the SHA-1 check stays the authority.
local function fileSize(p)
	local ok, r = pcall(function()
		local f = io.open(p, "rb")
		if not f then return nil end
		local n = f:seek("end")
		f:close()
		return n
	end)
	if ok and type(r) == "number" then return r end
	local ok2, r2 = pcall(FileSystem.GetFileSize, p)
	if ok2 and type(r2) == "number" then return r2 end
	return -1
end

local function fileSha1(p)
	local ok, r = pcall(Aurora.Sha1HashFile, p)
	if ok and type(r) == "string" then return string.upper(r) end
	return ""
end

-- R10: Sha1HashFile returns "" for about 1 file in 256 (first digest byte 00), so the kit's own copies are
-- recognised by size and CRC32 (always 8 digits) instead.
local function kitId(p)
	local ok, c = pcall(Aurora.Crc32HashFile, p)
	if not ok or type(c) ~= "string" or c == "" then return "" end
	return fileSize(p) .. "/" .. string.upper(c)
end

local function matches(p, want) return isThere(p) and fileSize(p) == want.size and fileSha1(p) == want.sha1 end

local function remove(p)
	if not isThere(p) then return true end
	pcall(FileSystem.DeleteFile, p)
	return not isThere(p)
end

local function makeDir(p)
	pcall(FileSystem.CreateDirectory, p)   -- always returns true, so check afterwards
	return isThere(p)
end

local function removeDir(p)
	if isThere(p) then pcall(FileSystem.DeleteDirectory, p) end
	return not isThere(p)
end

-- first free name among stem, stem2 .. stem9 in dir
local function freeName(dir, stem)
	for i = 1, 9 do
		local n = (i == 1) and stem or (stem .. i)
		if not isThere(dir .. "\\" .. n) then return n end
	end
	return nil
end

-- What a file is, from its content only: "missing", "original", "speed" or "unknown"; also its SHA-1.
local function classify(p)
	if not isThere(p) then return "missing", "" end
	if fileSize(p) ~= STOCK.size then return "unknown", "" end
	local h = fileSha1(p)
	if h == STOCK.sha1 then return "original", h end
	if h == SPEED.sha1 then return "speed", h end
	return "unknown", h
end

-- TheVault address, or nil when the release builder did not fill it in
local function baseUrl()
	local u = BASEURL
	if type(u) ~= "string" or not string.find(u, "^https?://[%w%-%.]+") then return nil end
	if string.sub(u, -1) ~= "/" then u = u .. "/" end
	return u
end

-- How an instance is named in plans and summaries: "XBLA", "XBLA (Usb0:)" when drives differ, plus "(running)".
local function name(inst)
	local n = inst.label
	if K.multi and inst.where ~= "Game:" then n = n .. " (" .. inst.where .. ")" end
	if inst.running then n = n .. " (running)" end
	return n
end

-- R15: the drive as users know it ("Hdd1:"), not Aurora's internal drive name
local function driveText(inst)
	if inst.where == "Game:" then return "this Aurora's drive:" end
	return inst.where
end

-- ----- Finding the instances ------------------------------------------------------------------------------
local function looksLikeInstance(root)
	return isThere(root .. "\\" .. XEX) or isThere(root .. "\\" .. BAK) or isThere(root .. "\\" .. NEW) or isThere(root .. "\\" .. OLD)
end

-- Reads one instance's state from file contents only. R2: the kit's own copies have kit-only names
-- (.r1655.bak, .sk-new, .sk-old*); every other Aurora.xex.* file is yours and is only ever read.
local function readInstance(inst)
	local dir = inst.op
	inst.state, inst.sha = classify(dir .. "\\" .. XEX)
	local f = { bak = classify(dir .. "\\" .. BAK), new = classify(dir .. "\\" .. NEW), olds = {}, bads = {}, others = {}, checked = {} }
	local lbak, lnew, lold, lbad = string.lower(BAK), string.lower(NEW), string.lower(OLD), string.lower(BAD)
	local ok, items = pcall(FileSystem.GetFiles, dir .. "\\*")
	for _, e in ipairs((ok and type(items) == "table") and items or {}) do
		local n = type(e) == "table" and e.Name or nil
		local l = type(n) == "string" and string.lower(n) or ""
		local isDir = type(e) == "table" and (int(e.Attributes) // 16) % 2 == 1
		if not isDir and startsWith(l, "aurora.xex.") and l ~= lbak and l ~= lnew then
			if startsWith(l, lold) then
				f.olds[#f.olds + 1] = { name = n, state = classify(dir .. "\\" .. n) }
			elseif startsWith(l, lbad) then
				f.bads[#f.bads + 1] = n
			else
				f.others[#f.others + 1] = n   -- yours, for example Aurora.xex.new or a dated backup; hashed only when needed
			end
		end
	end
	inst.files = f
	inst.hasKit = isThere(dir .. "\\" .. KIT_REL .. "\\" .. MAIN_FILE)
	-- Repair is offered only where a good copy made by the kit sits next to Aurora.xex (m11).
	local rep = f.bak == "original" or f.new == "original" or f.new == "speed"
	for _, o in ipairs(f.olds) do rep = rep or o.state == "original" or o.state == "speed" end
	inst.repairable = rep
end

-- Which found folder is the running instance (m10)? The kit writes a fresh token into its own marker file
-- (under Game:) and reads the marker of every found folder: only an exact token match counts (R16). The
-- marker stays in this folder and gets a new token each time, so other instances' folders are only read.
local function markMine()
	local token = "SK1-" .. string.gsub(stamp(), "%D", "") .. "-" .. string.gsub(tostring({}), "%W", "")
	local mine = K.base .. MARKER_FILE
	pcall(FileSystem.WriteFile, mine, token)   -- plain text without line breaks, so text mode is fine
	local ok, back = pcall(FileSystem.ReadFile, mine)
	if ok and back == token then return token end
	return nil
end

local function hasToken(kitDir, token)   -- kitDir ends with \
	local p = kitDir .. MARKER_FILE
	if not token or not isThere(p) then return false end
	local ok, t = pcall(FileSystem.ReadFile, p)
	return ok and t == token
end

-- R8: is this kit folder (given without a \ at the end) the very folder this kit runs from?
local function sameAsMine(kitDir) return hasToken(kitDir .. "\\", markMine()) end

local function identifyRunning(found)
	local rel = string.match(K.base, "^[Gg][Aa][Mm][Ee]:\\(.+)$")   -- kit folder below Game:\, ends with \
	local hits, token = {}, nil
	if rel then token = markMine() end
	if token then
		for i, f in ipairs(found) do
			if hasToken(f.root .. "\\" .. rel, token) then hits[#hits + 1] = i end
		end
	end
	return hits
end

-- Every <drive>\AuroraInstances\<name>\Aurora and <drive>\Aurora, plus the running instance, always last.
local function scan()
	status("Looking for Aurora instances...", 0, 1)
	local found, seen = {}, {}
	K.drives = {}
	local ok, drives = pcall(FileSystem.GetDrives)
	for _, d in ipairs((ok and type(drives) == "table") and drives or {}) do
		local mp = type(d) == "table" and d.MountPoint or nil
		if type(mp) == "string" and mp ~= "" then
			local key, dname, sys = string.lower(mp), tostring(d.Name or ""), string.lower(tostring(d.SystemPath or ""))
			K.drives[key] = dname
			local skip = SKIP_DRIVES[key] or string.lower(dname) == "aurora" or string.find(key, "cache", 1, true) ~= nil
			if not skip and sys ~= "" then
				skip = seen[sys] == true   -- the same partition under a second name
				seen[sys] = true
			end
			if not skip then
				local roots = {}
				local okd, dirs = pcall(FileSystem.GetDirectories, mp .. "\\AuroraInstances\\*")
				for _, e in ipairs((okd and type(dirs) == "table") and dirs or {}) do
					local n = type(e) == "table" and e.Name or nil
					if type(n) == "string" and n ~= "." and n ~= ".." then
						roots[#roots + 1] = { label = n, root = mp .. "\\AuroraInstances\\" .. n .. "\\Aurora" }
					end
				end
				roots[#roots + 1] = { label = "Aurora", root = mp .. "\\Aurora" }
				for _, r in ipairs(roots) do
					if looksLikeInstance(r.root) then
						found[#found + 1] = { label = r.label, where = mp, root = r.root, op = r.root, drive = dname }
					end
				end
			end
		end
	end
	local hits, hit, list = identifyRunning(found), {}, {}
	for _, i in ipairs(hits) do hit[i] = true end
	for i, f in ipairs(found) do
		if not hit[i] then list[#list + 1] = f end   -- every match is the running instance under another name
	end
	local runner
	if #hits == 1 then
		runner = found[hits[1]]
		runner.op = "Game:"
	else   -- not exactly one match: Game: is its own entry, and doChange watches for doubles
		runner = { label = "This instance", where = "Game:", root = "Game:", op = "Game:", drive = K.drives["game:"] }
	end
	runner.running = true
	K.unsure = #hits ~= 1
	list[#list + 1] = runner
	local wheres, labels, nw = {}, {}, 0
	K.multi = false
	for _, inst in ipairs(list) do
		if inst.where ~= "Game:" and not wheres[inst.where] then wheres[inst.where] = true nw = nw + 1 end
		if labels[inst.label] then K.multi = true end
		labels[inst.label] = true
	end
	K.multi = K.multi or nw > 1
	for i, inst in ipairs(list) do
		status("Checking " .. inst.label .. "...", i - 1, #list)
		readInstance(inst)
	end
	log("scan: " .. #list .. " instance(s); running instance " .. (K.unsure and ("not matched (" .. #hits .. " matches)") or runner.root))
	for _, inst in ipairs(list) do log("  " .. inst.root .. ": " .. inst.state) end
	return list
end

-- Which build is running now, from this boot's debug.log (m2): the original logs "Table:  GameListSorters"
-- at start; the speed build logs "Loading User Sorts:" without it. Anything else is unknown.
local function runningNow()
	local ok, res = pcall(function()
		local f = io.open(DEBUG_LOG, "rb")
		if not f then return "unknown" end
		local loading, sorters, tail, total = false, false, "", 0
		while total < 16777216 do
			local s = f:read(CHUNK)
			if not s or #s == 0 then break end
			local buf = tail .. s
			loading = loading or string.find(buf, "Loading User Sorts:", 1, true) ~= nil
			sorters = sorters or string.find(buf, "Table:  GameListSorters", 1, true) ~= nil
			tail, total = string.sub(buf, -64), total + #s
		end
		f:close()
		if sorters then return "original" end
		return loading and "speed" or "unknown"
	end)
	return (ok and type(res) == "string") and res or "unknown"
end

-- Free space in bytes, or nil when Aurora cannot tell (m3: an unknown drive name raises an error).
local function freeBytes(dname)
	if type(dname) ~= "string" or dname == "" then return nil end
	local ok, v = pcall(FileSystem.GetPartitionFreeSpace, dname)
	return (ok and type(v) == "number") and v or nil
end

local function mb(v) return string.format("%.0f MB", v / 1048576) end

-- ----- Getting a checked source file ------------------------------------------------------------------------
-- A place on the console holding a checked copy of `want` (cheapest first), or nil. Only read, never changed.
local function findCopy(want, list)
	for _, inst in ipairs(list) do
		if inst.state == want.key then return inst.op .. "\\" .. XEX end
	end
	for _, inst in ipairs(list) do
		local f = inst.files
		if f.new == want.key then return inst.op .. "\\" .. NEW end
		if f.bak == want.key then return inst.op .. "\\" .. BAK end
		for _, o in ipairs(f.olds) do
			if o.state == want.key then return inst.op .. "\\" .. o.name end
		end
	end
	for _, inst in ipairs(list) do
		local f = inst.files
		for _, n in ipairs(f.others) do
			if f.checked[n] == nil then f.checked[n] = classify(inst.op .. "\\" .. n) end
			if f.checked[n] == want.key then return inst.op .. "\\" .. n end
		end
	end
	return nil
end

-- Downloads the patch into tmp\ and checks it. Returns its path, or nil and a message.
local function download()
	local url = baseUrl()
	if not url then return nil, "This copy of the kit has no TheVault address, so it cannot download the patch.\n\nNothing was changed." end
	local okn, online = pcall(Aurora.HasInternetConnection)
	if not (okn and online == true) and not ask(KIT_TITLE, "Aurora says this console is not online.\n\nThe kit needs to download the speed patch (about 9 MB) from TheVault. Nothing has been changed yet.\n\nTry anyway?", "Try anyway", "Cancel") then
		return nil, "Download cancelled. Nothing was changed."
	end
	local rel = TMP .. "\\" .. PATCH_FILE
	local path = K.base .. rel
	remove(path)
	remove(path .. ".dl")
	-- R12: Http.Get has no progress callback, so the bar stands still until the download ends.
	status("Downloading the speed patch (about 9 MB). The bar does not move until it ends. Nothing has been changed yet...", 0, 1)
	log("download " .. url .. PATCH_URL)
	local ok, r = pcall(Http.Get, url .. PATCH_URL, rel)   -- nil on network errors; redirects are not followed
	local problem
	if not ok or type(r) ~= "table" then
		problem = "TheVault did not answer (network error). Check the console's network and try again later."
	elseif r.Success ~= true then
		problem = (r.Canceled == true) and "The download was cancelled."
			or ("TheVault answered with an error" .. (r.ResponseCode and (" (HTTP " .. tostring(r.ResponseCode) .. ")") or "") .. ".")
	elseif not matches(path, PATCH) then
		problem = "The downloaded patch did not pass the check (" .. fileSize(path) .. " bytes, expected " .. PATCH.size .. "), so it was deleted."
	end
	if not problem then
		-- R13: keep the checked patch in the kit folder, so the kit copies spread it and Undo works offline later
		local keep = K.base .. PATCH_FILE
		if not matches(keep, PATCH) then moveFile(path, keep) end
		if matches(keep, PATCH) then
			log("download ok; patch kept as " .. keep)
			return keep
		end
		if matches(path, PATCH) then return path end
		problem = "The downloaded patch could not be kept."
	end
	log("download failed: " .. problem .. (ok and "" or (" " .. tostring(r))))
	remove(path)
	remove(path .. ".dl")
	return nil, problem .. "\n\nNothing was changed."
end

-- out = in XOR patch over RANGES; every other byte is copied unchanged. Streams 64 KB at a time.
local function xorBuild(inPath, patchPath, outPath)
	local pos, sum = 0, 0
	for _, r in ipairs(RANGES) do   -- m18: refuse a layout the loop below cannot handle
		if r[1] < pos or r[2] <= 0 or r[2] % 4 ~= 0 then return false, "Internal error: bad patch range." end
		pos, sum = r[1] + r[2], sum + r[2]
	end
	if pos > STOCK.size or sum ~= PATCH.size or fileSize(inPath) ~= STOCK.size or fileSize(patchPath) ~= PATCH.size then
		return false, "Internal error: the patch does not fit this file."
	end
	local fi, fp, fo = io.open(inPath, "rb"), io.open(patchPath, "rb"), io.open(outPath, "wb")
	local function closeAll()
		if fi then fi:close() end
		if fp then fp:close() end
		if fo then fo:close() end
	end
	if not (fi and fp and fo) then
		closeAll()
		remove(outPath)
		return false, "The kit could not open its work files.\n\nNothing was changed."
	end
	local full = "<" .. string.rep("i4", WORDS)   -- built here, never at the top level (M6)
	local total, done, stopped = STOCK.size, 0, false
	local function step(n)
		done = done + n
		status("Building the new Aurora.xex... " .. (done // (total // 100)) .. "%", done, total)
		stopped = stopped or canceled()
		return not stopped
	end
	local function pass(n)   -- copy n bytes unchanged
		while n > 0 do
			local k = math.min(n, CHUNK)
			local a = fi:read(k)
			if not a or #a ~= k or not fo:write(a) then return false end
			n = n - k
			if not step(k) then return false end
		end
		return true
	end
	local function mix(n)    -- XOR n bytes with the next n bytes of the patch, as signed 32-bit words
		while n > 0 do
			local k = math.min(n, CHUNK)
			local a, b = fi:read(k), fp:read(k)
			if not a or not b or #a ~= k or #b ~= k then return false end
			local parts, p = {}, 1
			while p <= k do
				local m = math.min(WORDS, (k - p + 1) // 4)
				if m < 1 then return false end
				local f = (m == WORDS) and full or ("<" .. string.rep("i4", m))
				local wa, wb = { string.unpack(f, a, p) }, { string.unpack(f, b, p) }
				for i = 1, m do wa[i] = wa[i] ~ wb[i] end
				parts[#parts + 1] = string.pack(f, table.unpack(wa, 1, m))
				p = p + 4 * m
			end
			if not fo:write(table.concat(parts)) then return false end
			n = n - k
			if not step(k) then return false end
		end
		return true
	end
	local ok = true
	pos = 0
	for _, r in ipairs(RANGES) do
		ok = ok and pass(r[1] - pos) and mix(r[2])
		pos = r[1] + r[2]
	end
	ok = ok and pass(total - pos) and fi:read(1) == nil and fp:read(1) == nil   -- both inputs used up exactly
	closeAll()
	if ok then return true end
	remove(outPath)
	if stopped then return false, "Stopped. Nothing was changed." end
	return false, "Building the new file failed (read or write error).\n\nNothing was changed."
end

-- Makes tmp\source.xex, a checked copy of `want`. Any download happens here, before any instance is touched.
local function prepareSource(want, other, list)
	local tmp = K.base .. TMP
	removeDir(tmp)
	if not makeDir(tmp) then return nil, "The kit could not create its work folder " .. tmp .. ".\n\nNothing was changed." end
	local out = tmp .. "\\source.xex"
	-- 1. A checked copy is already on the console (another instance, a waiting new file, a backup): no download (M3).
	local have = findCopy(want, list)
	if have then
		status("Copying the " .. want.text .. " (no download needed)...", 0, 1)
		if copyFile(have, out, true) and matches(out, want) then
			log("source: copy of " .. have)
			return out
		end
		remove(out)
		log("source: copy of " .. have .. " failed the check")
	end
	-- 2. Otherwise build it from a checked copy of the other build and the patch.
	local from = findCopy(other, list)
	if not from then return nil, "No checked copy of the " .. other.text .. " was found on this console.\n\nNothing was changed." end
	local patch = K.base .. PATCH_FILE   -- USB package (or an earlier download): the patch sits in the kit folder
	if not matches(patch, PATCH) then
		-- Lab fix F4: say so when a USB-package patch is there but damaged (lab test: only the network error showed).
		local damaged = isThere(patch)
		local msg
		patch, msg = download()
		if not patch then
			if damaged then msg = "The patch file in the kit folder (" .. PATCH_FILE .. ") is damaged, so the kit tried to download it instead.\n\n" .. tostring(msg) end
			return nil, msg
		end
	end
	status("Copying the " .. other.text .. "...", 0, 1)
	local input = tmp .. "\\input.xex"
	if not (copyFile(from, input, true) and matches(input, other)) then
		return nil, "The copy of " .. from .. " did not check out.\n\nNothing was changed."
	end
	local ok, err = xorBuild(input, patch, out)
	remove(input)
	if not ok then return nil, err end
	status("Checking the new file...", 0, 1)
	if not matches(out, want) then
		remove(out)
		return nil, "The rebuilt file is not exactly the " .. want.text .. ", so it was deleted.\n\nNothing was changed."
	end
	log("source: built from " .. from .. " and " .. patch)
	return out
end

-- ----- Changing one instance ----------------------------------------------------------------------------------
-- Aurora.xex is missing: puts a checked `want` there, from the waiting new file or as a copy of `from`.
local function putIn(dir, want, from)
	local xex, new = dir .. "\\" .. XEX, dir .. "\\" .. NEW
	if matches(new, want) and renameFile(new, xex) and matches(xex, want) then return true end
	if isThere(xex) then return false end
	return from ~= nil and matches(from, want) and copyFile(from, xex, false) and matches(xex, want)
end

-- Switches the checked Aurora.xex.sk-new in. before = what Aurora.xex was just before; from = another checked
-- copy of `want` (or nil). Returns "done", "pending" or "failed" and a message for the summary.
local function swapIn(dir, want, before, from)
	local xex, new = dir .. "\\" .. XEX, dir .. "\\" .. NEW
	local done = "now has the " .. want.text
	local moved = moveFile(new, xex)
	local now = classify(xex)
	if now == want.key then return "done", done end
	log((moved and "MoveFile said yes, but " or "MoveFile refused; ") .. xex .. " is " .. now)
	-- R4: Aurora.xex turned into something else (half written?): set it aside at once (never deleted).
	if now ~= before and now ~= "missing" then
		local bad = freeName(dir, BAD)
		if not (bad and renameFile(xex, dir .. "\\" .. bad)) then
			return "failed", "Aurora.xex did not check out after the switch and could not be set aside. Run the kit again to repair it"
		end
		log("set aside " .. xex .. " as " .. bad)
		now = "missing"
	end
	if now == "missing" then
		if putIn(dir, want, from) then return "done", done end
		return "failed", "SWAP FAILED: Aurora.xex is missing. Run the kit again now to repair it, or see Help"
	end
	-- Aurora.xex is as it was, so the switch was refused (R4: also when MoveFile said yes).
	if not matches(new, want) then
		return "failed", "the switch was refused and the checked new file is gone; Aurora.xex was not changed"
	end
	-- m13: set the current file aside, rename the new one in, and undo that if the second step fails.
	local old = freeName(dir, OLD)
	if not (old and renameFile(xex, dir .. "\\" .. old)) then
		return "pending", "could not be switched while in use; Aurora.xex was not changed. The checked new file waits as " .. NEW
	end
	local oldPath = dir .. "\\" .. old
	log("renamed " .. xex .. " to " .. old)
	if renameFile(new, xex) and matches(xex, want) then return "done", done .. " (previous file kept as " .. old .. ")" end
	if isThere(xex) then   -- renamed in, but it does not check out: set it aside, never delete it
		local bad = freeName(dir, BAD)
		if not (bad and renameFile(xex, dir .. "\\" .. bad)) then
			return "failed", "Aurora.xex did not check out after the switch; the previous file is kept as " .. old .. ". Run the kit again to repair it"
		end
	end
	if renameFile(oldPath, xex) and classify(xex) == before then
		log("put back " .. xex)
		return "pending", "could not be switched; Aurora.xex was not changed" .. (matches(new, want) and (". The checked new file waits as " .. NEW) or "")
	end
	if putIn(dir, want, from) then return "done", done .. " (previous file kept as " .. old .. ")" end
	if not isThere(xex) and copyFile(oldPath, xex, false) and classify(xex) == before then
		return "pending", "could not be switched; the previous Aurora.xex was put back (a copy of " .. old .. ")"
	end
	return "failed", "SWAP FAILED: Aurora.xex is missing; the previous file is kept as " .. old .. ". Run the kit again now to repair it, or see Help"
end

-- Puts `want` into one instance. src = checked file in tmp\ (nil when every target has its own copy).
-- Returns "done", "already", "left", "pending" or "failed" and a message.
local function replaceOne(inst, want, src)
	local dir = inst.op
	local xex, new, bak = dir .. "\\" .. XEX, dir .. "\\" .. NEW, dir .. "\\" .. BAK
	local state = classify(xex)   -- read again: never act on old information
	if state == want.key then return "already", "already has the " .. want.text end
	if (state == "unknown" or state == "missing") and not inst.repair then
		return "left", "left alone (Aurora.xex is " .. stateText(state) .. ")"
	end
	local from = src
	if want == STOCK and matches(bak, STOCK) then from = bak end   -- Undo prefers this instance's own backup
	-- 1. Install: a checked copy of the original as Aurora.xex.r1655.bak (a good existing one is kept). In a
	-- repair the original may only be in the waiting new file, which step 2 replaces, so it is backed up too.
	if want == SPEED and not matches(bak, STOCK) then
		local orig = nil
		if state == "original" then orig = xex elseif matches(new, STOCK) then orig = new end
		if orig then
			status("Backing up " .. name(inst) .. " - do not turn the console off")
			if not (copyFile(orig, bak, true) and matches(bak, STOCK)) then
				remove(bak)
				return "failed", "the backup could not be made; Aurora.xex was not changed"
			end
		end
	end
	-- 2. Aurora.xex.sk-new: keep one that already checks out (M3); otherwise copy and check
	if not matches(new, want) then
		if not from then return "failed", "no checked source file; Aurora.xex was not changed" end
		status("Copying to " .. name(inst) .. " - do not turn the console off")
		remove(new)   -- the kit's own name (R2): a leftover of an earlier run
		if not (copyFile(from, new, false) and matches(new, want)) then
			remove(new)
			return "failed", "the new file did not copy correctly; Aurora.xex was not changed"
		end
	end
	-- 3. Repair (m12): an unknown Aurora.xex is set aside as Aurora.xex.bad, never deleted
	local aside
	if state == "unknown" then
		aside = freeName(dir, BAD)
		if not aside or not renameFile(xex, dir .. "\\" .. aside) then
			return "failed", "the unknown Aurora.xex could not be set aside; it was not changed"
		end
		log("set aside " .. xex .. " as " .. aside)
	end
	-- 4. Switch
	status("Switching " .. name(inst) .. " - do not turn the console off")
	local code, msg = swapIn(dir, want, aside and "missing" or state, from)
	if aside and code == "done" then
		msg = msg .. "; the unknown file was kept as " .. aside
	elseif aside and not isThere(xex) and renameFile(dir .. "\\" .. aside, xex) then
		msg = "could not switch; the unknown Aurora.xex was put back and the checked new file waits as " .. NEW
	end
	return code, msg
end

-- R14: may this kit write its Main.lua at dst? nil = yes; "same" = it is already there; else why not.
local function otherKit(dst)
	if not isThere(dst) then return nil end
	if kitId(dst) == K.mainId then return "same" end
	local ok, txt = pcall(FileSystem.ReadFile, dst)
	if not ok or type(txt) ~= "string" or not string.find(txt, "Aurora Speed Kit", 1, true) then return "another script is there" end
	local v = tonumber(string.match(txt, "\nscriptVersion%s*=%s*(%d+)") or "")
	if v and v > KIT_VERSION then return "a newer kit (v" .. v .. ") is there" end
	return nil
end

-- Copies this kit (and a checked patch) into every other instance, so Check, Undo and finishing a waiting
-- switch work from any of them. Skips the running instance and files already in place (m9).
local function copyKit(list)
	if K.mainId == "" then return log("kit copy skipped: this kit's Main.lua could not be read") end
	local mainSrc, patchSrc = K.base .. MAIN_FILE, K.base .. PATCH_FILE
	local withPatch = matches(patchSrc, PATCH)
	for _, inst in ipairs(list) do
		if not inst.running and (inst.state == "original" or inst.state == "speed") then
			local dir = inst.op .. "\\" .. KIT_REL
			local dst, pdst = dir .. "\\" .. MAIN_FILE, dir .. "\\" .. PATCH_FILE
			local result
			if K.unsure and sameAsMine(dir) then
				result = "skipped (the kit that is running)"   -- R8
			else
				local why = otherKit(dst)
				if why and why ~= "same" then
					result = "skipped: " .. why   -- R14: never overwrite another script or a newer kit
				else
					status("Copying the kit to " .. name(inst) .. "...")
					local okMain = why == "same" or (makeDir(dir) and copyFile(mainSrc, dst, true) and kitId(dst) == K.mainId)
					if okMain and withPatch and not matches(pdst, PATCH) and not (copyFile(patchSrc, pdst, true) and matches(pdst, PATCH)) then
						remove(pdst)
					end
					result = okMain and "ok" or "FAILED"
				end
			end
			log("kit copy to " .. dir .. ": " .. result)
		end
	end
end

local function pickTargets(list, verb)
	local items = { "All instances (" .. #list .. ")" }
	for _, inst in ipairs(list) do
		items[#items + 1] = inst.label .. " (" .. inst.where .. ") - " .. stateText(inst.state) .. (inst.running and " - running now" or "")
	end
	local k = pick(verb .. ": which instances?", items)
	if k == 1 then return list end
	if k and list[k - 1] then return { list[k - 1] } end
	return nil
end

-- ----- Menu actions -----------------------------------------------------------------------------------------
local function details(inst)
	local f, xex = inst.files, inst.op .. "\\" .. XEX
	local t = { "Folder: " .. inst.root, "Aurora.xex: " .. stateText(inst.state) }
	if inst.state == "unknown" then   -- size and SHA-1 prefix, so the user can report it
		t[2] = t[2] .. " (" .. fileSize(xex) .. " bytes, SHA-1 " .. string.sub(fileSha1(xex), 1, 8) .. ")"
	end
	t[#t + 1] = "Backup " .. BAK .. ": " .. ((f.bak == "original" and "good") or (f.bak == "missing" and "none") or "damaged or unexpected")
	if f.new ~= "missing" then t[#t + 1] = "Waiting " .. NEW .. ": " .. ((f.new == "unknown" and "damaged") or stateText(f.new)) end
	for _, o in ipairs(f.olds) do t[#t + 1] = "Previous file " .. o.name .. ": " .. stateText(o.state) end
	for _, n in ipairs(f.bads) do t[#t + 1] = "Kept " .. n .. " (the kit never deletes it)" end
	for _, n in ipairs(f.others) do t[#t + 1] = "Other copy: " .. n .. " (yours; only read)" end
	t[#t + 1] = "Kit in this instance: " .. ((inst.running or inst.hasKit) and "yes" or "no")
	if inst.repairable and (inst.state == "unknown" or inst.state == "missing") then t[#t + 1] = "Install or Undo can repair this instance." end
	if inst.running and K.unsure then t[#t + 1] = "This is the Aurora you started (Game:)." end
	return table.concat(t, "\n")
end

-- Check status: reads files only, never the network (m6). It writes only in its own folder (log, marker).
local function doCheck()
	local list = scan()
	local now, runner = runningNow(), list[#list]
	local items, map = { "Running now: " .. (STATE_TEXT[now] or "unknown") .. " (from this boot's Aurora log)" }, {}
	if (now == "original" or now == "speed") and (runner.state == "original" or runner.state == "speed") and now ~= runner.state then
		items[#items + 1] = "Restart Aurora to start the " .. stateText(runner.state) .. " now on disk"   -- F3: list lines show ~70 characters
	end
	for _, inst in ipairs(list) do
		local f, notes = inst.files, ""
		if f.bak == "original" then notes = notes .. ", backup ok" end
		if f.new ~= "missing" then notes = notes .. ", new file waiting" end
		if #f.olds > 0 then notes = notes .. ", previous file kept" end
		if #f.bads > 0 then notes = notes .. ", .bad kept" end
		if inst.repairable and (inst.state == "unknown" or inst.state == "missing") then notes = notes .. ", can be repaired" end
		items[#items + 1] = inst.label .. ": " .. stateText(inst.state) .. notes .. (inst.running and ", running now" or "") .. " - " .. inst.root
		map[#items] = inst
	end
	local seen = {}
	for _, inst in ipairs(list) do
		if type(inst.drive) == "string" and inst.drive ~= "" and not seen[inst.drive] then
			seen[inst.drive] = true
			local v = freeBytes(inst.drive)
			items[#items + 1] = "Free space on " .. driveText(inst) .. " " .. (v and mb(v) or "unknown")
		end
	end
	-- Lab fix F3: popup list lines are cut after about 70 characters ("...is dama..."), so this is two short lines.
	local patchNote = "none"
	if isThere(K.base .. PATCH_FILE) then
		patchNote = matches(K.base .. PATCH_FILE, PATCH) and "good" or "damaged"
	end
	items[#items + 1] = "Kit v" .. KIT_VERSION .. ", Main.lua SHA-1 " .. (K.mainSha ~= "" and string.sub(K.mainSha, 1, 8) or "unknown")
	items[#items + 1] = "Patch file in the kit folder: " .. patchNote
	items[#items + 1] = "Help: if an instance will not start"
	local help = #items
	status("Status ready", 1, 1)
	while true do
		local k = pick(KIT_TITLE .. " - status", items)
		if not k then break end
		if map[k] then say(map[k].label, details(map[k])) elseif k == help then say("If an instance will not start", HELP) end
	end
end

-- Install (want = speed build) or Undo (want = original). Returns "restart" after the running instance changed.
local function doChange(install)
	local want, other, title, verb = SPEED, STOCK, "Install speed fix", "Install"
	if not install then want, other, title, verb = STOCK, SPEED, "Undo (restore original)", "Undo" end
	local list = scan()
	local targets = pickTargets(list, verb)
	if not targets then return end

	-- 1. Repair is asked first, so the plan shows what will really happen (R7).
	local work, repairs = {}, {}
	for _, inst in ipairs(targets) do
		if inst.state == other.key then
			work[#work + 1] = inst
		elseif inst.state ~= want.key and inst.repairable then
			repairs[#repairs + 1] = inst
		end
	end
	if #repairs > 0 then
		local names = {}
		for _, inst in ipairs(repairs) do names[#names + 1] = name(inst) .. ": Aurora.xex is " .. stateText(inst.state) end
		-- R6: the safe answer ("No") is the first, focused button; only an explicit "Repair" repairs.
		if choose("Repair?", table.concat(names, "\n") .. "\n\nA checked copy made by the kit is next to it, so the kit can repair this. An unknown Aurora.xex is not deleted: it is renamed to Aurora.xex.bad.\n\nPick No if you changed Aurora.xex yourself (for example to a newer Aurora).", "No", "Repair") == 2 then
			for _, inst in ipairs(repairs) do
				inst.repair = true
				work[#work + 1] = inst
			end
		end
	end
	local plan = {}
	for _, inst in ipairs(targets) do
		local s, line = inst.state, nil
		if s == want.key then
			line = "already has the " .. want.text
		elseif s == other.key then
			line = stateText(s) .. " -> " .. want.text .. " (backup kept)"
		elseif inst.repair then
			line = stateText(s) .. " -> " .. want.text .. ((s == "unknown") and " (old file kept as .bad)" or "")
		else
			line = "left alone (Aurora.xex is " .. stateText(s) .. ")"
		end
		plan[#plan + 1] = name(inst) .. ": " .. line
	end
	if #work == 0 then return say(title, table.concat(plan, "\n") .. "\n\nNothing to do. Nothing was changed.") end
	-- The running instance always last. R8: when it was not matched to a folder, a folder holding the same
	-- Aurora.xex as Game: may be that same instance, so such folders come just before it.
	local ordered, late = {}, {}
	local gameSha = K.unsure and list[#list].sha or ""
	for _, inst in ipairs(work) do
		if not inst.running then
			if gameSha ~= "" and inst.sha == gameSha then late[#late + 1] = inst else ordered[#ordered + 1] = inst end
		end
	end
	for _, inst in ipairs(late) do ordered[#ordered + 1] = inst end
	for _, inst in ipairs(work) do if inst.running then ordered[#ordered + 1] = inst end end

	-- 2. Is a fresh source needed, and can the kit get one?
	local needSource, needDownload = false, false
	for _, inst in ipairs(ordered) do
		local f = inst.files
		needSource = needSource or (f.new ~= want.key and not (want == STOCK and f.bak == "original"))
	end
	if needSource and not findCopy(want, list) then
		if not findCopy(other, list) then
			return say(title, "No checked copy of the " .. other.text .. " or of the " .. want.text .. " was found on this console, so the kit cannot do this.\n\nNothing was changed.")
		end
		if not matches(K.base .. PATCH_FILE, PATCH) then
			if not baseUrl() then
				return say(title, "This copy of the kit has no TheVault address, so it cannot download the patch.\n\nUse the USB package: put " .. PATCH_FILE .. " into " .. K.base .. " and try again.\n\nNothing was changed.")
			end
			needDownload = true
		end
	end

	-- 3. Confirm. Lab fix F2: the warning comes first; R7: a long plan is shown in parts before the question.
	local notes = {}
	if install then notes[#notes + 1] = "It also puts a copy of the kit (and the 9 MB patch, if it has it) in your other instances." end
	if needDownload then
		notes[#notes + 1] = "First it downloads the 9 MB patch from TheVault and checks it; nothing changes before that. The bar does not move during the download. Only if nothing happens for 10 minutes may you turn the console off."
	end
	local body = table.concat(plan, "\n")
	if #notes > 0 then body = body .. "\n\n" .. table.concat(notes, " ") end
	if not confirm(title, "Do not turn the console off until the kit says it has finished.", body, "Go ahead?", "Yes, go ahead", "No") then return end

	-- 4. Free space (advice only: every write is checked anyway)
	local low, seenDrive, onDrives = {}, {}, { list[#list] }   -- tmp\ lives on the running instance's drive
	for _, inst in ipairs(ordered) do onDrives[#onDrives + 1] = inst end
	for _, inst in ipairs(onDrives) do
		local n = inst.drive
		if type(n) == "string" and n ~= "" and not seenDrive[n] then
			seenDrive[n] = true
			local v = freeBytes(n)
			if v and v < LOW_SPACE then low[#low + 1] = driveText(inst) .. " " .. mb(v) .. " free" end
		end
	end
	if #low > 0 and not ask(title, "Free space looks low:\n" .. table.concat(low, "\n") .. "\n\nThe kit needs about 150 MB while it works. This is only a warning. Continue?", "Continue", "Stop") then
		return
	end

	-- 5. All network work and building first (m5), inside tmp\ only
	local src
	if needSource then
		pcall(Script.SetCancelEnable, true)
		local msg
		src, msg = prepareSource(want, other, list)
		pcall(Script.SetCancelEnable, false)
		if not src then return say(title, msg) end
	end
	if install then copyKit(list) end

	-- 6. Change the instances one at a time, the running one last
	local gameBefore = classify("Game:\\" .. XEX)
	local lines, restart, pending, aliasDone = {}, false, false, false
	for i, inst in ipairs(ordered) do
		local code, msg = "done", "done (same folder as above)"
		if not (inst.running and aliasDone) then
			status(verb .. ": " .. name(inst) .. " - do not turn the console off", i - 1, #ordered)
			code, msg = replaceOne(inst, want, src)
			restart = restart or (inst.running and code == "done")
			pending = pending or (inst.running and code == "pending")
			-- Running instance not matched to a folder: if changing this folder changed Game: too, it was the same one.
			if code == "done" and not inst.running and K.unsure and gameBefore ~= want.key and classify("Game:\\" .. XEX) == want.key then
				restart, aliasDone = true, true
				msg = msg .. " (this is the instance you are running)"
			end
		end
		log(verb .. " " .. inst.root .. " -> " .. code .. ": " .. msg)
		lines[#lines + 1] = name(inst) .. ": " .. msg
	end
	status(verb .. " finished", #ordered, #ordered)
	removeDir(K.base .. TMP)
	local summary = table.concat(lines, "\n")
	if pending then
		-- R3: only point to another instance when one exists that holds the kit
		local others = 0
		for _, inst in ipairs(list) do
			local s = classify(inst.op .. "\\" .. XEX)
			if not inst.running and (s == "original" or s == "speed") and isThere(inst.op .. "\\" .. KIT_REL .. "\\" .. MAIN_FILE) then others = others + 1 end
		end
		if others > 0 then
			summary = summary .. "\n\nThe instance you are running could not be switched while it runs. Nothing is broken: it keeps its Aurora.xex, and the checked new file waits next to it. To finish, start one of your other Aurora instances from your boot menu and run this kit's " .. verb .. " there. No download is needed."
		else
			summary = summary .. "\n\nYour Aurora still works and nothing is broken. This console has no other Aurora copy with the kit, so the switch cannot finish. You can delete " .. NEW .. " with File Manager."
		end
	end
	if restart then
		say(title, summary .. "\n\nThe instance you are running has been changed, so Aurora restarts now.")
		return "restart"
	end
	say(title, summary)
end

-- Removes the kit's own files from another instance's SpeedKit folder, then the folder if it is empty.
local function removeKitDir(dir)
	local main = dir .. "\\" .. MAIN_FILE
	if isThere(main) then
		local ok, txt = pcall(FileSystem.ReadFile, main)
		if kitId(main) == K.mainId or (ok and type(txt) == "string" and string.find(txt, "Aurora Speed Kit", 1, true)) then remove(main) end
	end
	for _, n in ipairs({ PATCH_FILE, LOG_FILE, MARKER_FILE, "README.txt" }) do remove(dir .. "\\" .. n) end
	removeDir(dir .. "\\" .. TMP)
	local ok, rest = pcall(FileSystem.GetFilesAndDirectories, dir .. "\\*")
	if ok and type(rest) == "table" and #rest == 0 then pcall(FileSystem.DeleteDirectory, dir) end
	return not isThere(dir)
end

-- m15: removes what the kit added, except what is still needed. R2: only files with the kit's own names;
-- Aurora.xex, .bad files and your own Aurora.xex.* copies are never deleted.
local function doRemove()
	local list = scan()
	local jobs, gone, kept, backups = {}, {}, {}, {}
	local function drop(path, isDir, what)
		jobs[#jobs + 1] = { path = path, isDir = isDir }
		gone[#gone + 1] = what
	end
	for _, inst in ipairs(list) do
		local dir, f, nm, s = inst.op, inst.files, name(inst), inst.state
		local healthy = s == "original" or s == "speed"
		local kd = dir .. "\\" .. KIT_REL
		if not inst.running and isThere(kd) then
			if K.unsure and sameAsMine(kd) then kept[#kept + 1] = nm .. ": the kit that is running"   -- R8
			else drop(kd, true, nm .. ": kit copy") end
		end
		local mine = {}
		if f.bak ~= "missing" then mine[#mine + 1] = { name = BAK, state = f.bak } end
		if f.new ~= "missing" then mine[#mine + 1] = { name = NEW, state = f.new } end
		for _, o in ipairs(f.olds) do mine[#mine + 1] = o end
		for _, c in ipairs(mine) do
			if not healthy then
				kept[#kept + 1] = nm .. ": " .. c.name .. " (needed for a repair)"
			elseif c.state == "original" and s == "speed" then
				backups[#backups + 1] = { inst = inst, name = c.name }   -- the original next to a speed build: asked
			else
				drop(dir .. "\\" .. c.name, false, nm .. ": " .. c.name)
			end
		end
	end
	gone[#gone + 1] = "this kit's temporary files"
	local body = "The kit will remove:\n" .. table.concat(gone, "\n")
	if #kept > 0 then body = body .. "\n\nIt keeps:\n" .. table.concat(kept, "\n") end
	if #backups > 0 then body = body .. "\n\nCopies of the original next to a speed build: you are asked next." end
	if not confirm("Remove kit files", "", body, "Aurora.xex, .bad files and your own Aurora.xex.* copies are never deleted. Continue?", "Remove", "Cancel") then return end
	if #backups > 0 then
		local names = {}
		for _, b in ipairs(backups) do names[#names + 1] = name(b.inst) .. ": " .. b.name end
		-- Lab fix F6: the focused first button must be the safe answer. In the lab "Delete them" was focused, so one
		-- quick A press deleted every backup (and B did not close the box). Now only an explicit "Delete them" deletes.
		if choose("Remove backups too?", "These are copies of the original next to a speed build:\n" .. table.concat(names, "\n")
			.. "\n\nDelete them too? Without them, Undo needs another original copy on the console, or the patch (download or USB).", "Keep them", "Delete them") == 2 then
			for _, b in ipairs(backups) do jobs[#jobs + 1] = { path = b.inst.op .. "\\" .. b.name, isDir = false } end
		end
	end
	local count, failed = 0, {}
	for i, j in ipairs(jobs) do
		status("Removing kit files...", i - 1, #jobs)
		local ok = (j.isDir and removeKitDir(j.path)) or (not j.isDir and remove(j.path))
		log("remove " .. j.path .. ": " .. (ok and "ok" or "failed"))
		if ok then count = count + 1 else failed[#failed + 1] = j.path end
	end
	removeDir(K.base .. TMP)
	status("Finished", 1, 1)
	local msg = "Removed " .. count .. " item(s)."
	if #failed > 0 then msg = msg .. "\nNot removed (other files inside, or in use):\n" .. table.concat(failed, "\n") end
	msg = msg .. "\n\nThe kit itself is still in this instance:\n" .. K.base .. "\nTo remove it too, delete that folder with Aurora's File Manager."
	local url = baseUrl()
	local host = url and string.match(url, "^https?://([^/:]+)")
	if host then msg = msg .. "\nIf you added TheVault to Homebrew Store, also delete Game:\\User\\Scripts\\Utility\\HomebrewStore\\Repos\\" .. host .. ".ini" end
	say("Remove kit files", msg)
end

-- ----- Entry point ------------------------------------------------------------------------------------------
function main()
	local okb, b = pcall(Script.GetBasePath)
	if not okb or type(b) ~= "string" or b == "" then
		return say(KIT_TITLE, "The kit could not find its own folder, so it stopped. Nothing was changed.")
	end
	if string.sub(b, -1) ~= "\\" then b = b .. "\\" end
	K.base = b
	if fileSize(b .. LOG_FILE) > 262144 then remove(b .. LOG_FILE) end
	log("start: kit v" .. KIT_VERSION .. " in " .. b)

	local okv, v = pcall(Aurora.GetDashVersion)
	if not okv or type(v) ~= "table" or v.Major ~= 0 or v.Minor ~= 7 or v.Type ~= 2 or v.Revision ~= 1655 then
		local got = "unknown"
		if okv and type(v) == "table" then
			got = tostring(v.Major) .. "." .. tostring(v.Minor) .. " type " .. tostring(v.Type) .. " revision " .. tostring(v.Revision)
		end
		log("wrong Aurora version: " .. got)
		return say(KIT_TITLE, "This kit only works with Aurora 0.7b.2 (revision 1655).\nThis Aurora reports version " .. got .. ".\n\nNothing was changed.")
	end

	K.mainSha = fileSha1(b .. MAIN_FILE)
	K.mainId = kitId(b .. MAIN_FILE)
	removeDir(b .. TMP)   -- leftovers of an interrupted run
	local menu = { "Check status", "Install speed fix", "Undo (restore original Aurora)", "Remove kit files", "Exit" }
	local actions = { doCheck, function() return doChange(true) end, function() return doChange(false) end, doRemove }
	while true do
		local k = pick(KIT_TITLE .. " v" .. KIT_VERSION, menu)
		if not k or not actions[k] then break end
		local ok, res = pcall(actions[k])
		removeDir(b .. TMP)
		if not ok then
			log("ERROR: " .. tostring(res))
			say(KIT_TITLE, "Something unexpected went wrong, so the kit stopped:\n" .. tostring(res) .. "\n\nRun Check status to see where things are.")
		elseif res == "restart" then
			log("restarting Aurora")
			status("Restarting Aurora...", 1, 1)
			pcall(Aurora.Restart)   -- after the running instance's file was switched: restart without asking (m13)
			return
		end
	end
	log("end")
end