gma.lua

local OUTPUT_FILE = assert(arg[1], "Missing argument #1 (output file)")
local ADDON_JSON = assert(arg[2], "Missing argument #2 (path to addon.json)")
local PATH_SEP = package.config:sub(1,1)

local function read(path --[[@param path string]]) ---@return string
	local handle = assert(io.open(path, "rb"))
	local content = handle:read("*a")
	handle:close()
	return content
end

---@generic T, V
---@param t T[]
---@param f fun(v: T, k: integer): V
---@return V[]
local function map(t, f)
	local out = {}
	for k, v in ipairs(t) do out[k] = f(v, k) end
	return out
end

---@param name string
---@param desc string
---@param author string
---@param files { path: string, content: string }[] # List of 'files'
---@param steamid integer? # SteamID64 of person who packed the addon. Defaults 0
---@param timestamp integer? # Timestamp of when addon was packed. Defaults to os.time()
---@return string gma # Packed gma file contents
local function pack(name, desc, author, files, steamid, timestamp)
	return "GMAD"
		.. ("< I1 I8 I8 x z z z I4"):pack(3 --[[version]], steamid or 0, timestamp or os.time(), name, desc, author, 1)
		.. table.concat(map(files, function(v, k)
			return ("< I4 z I8 I4"):pack(k, v.path, #v.content, 0 --[[crc]])
		end))
		.. "\0\0\0\0"
		.. table.concat(map(files, function(v)
			return v.content
		end))
		.. "\0\0\0\0"
end

-- JSON parser originally from qjson.lua
local function decode(json --[[@param json string]]) ---@return table
	local ptr = 0
	local function consume(pattern --[[@param pattern string]]) ---@return string?
		ptr = json:find("%S", ptr) or ptr

		local start, finish, match = json:find(pattern, ptr)
		if start then
			ptr = finish + 1
			return match or true
		end
	end

	local object, array
	local function number() return tonumber(consume("^(%-?%d+%.%d+)") or consume("^(%-?%d+)")) end
	local function bool() return consume("^(true)") or consume("^(false)") end
	local function string() return consume("^\"([^\"]*)\"") end
	local function value() return object() or string() or number() or bool() or array() end

	function object()
		if consume("^{") then
			local fields = {}
			while true do
				if consume("^}") then return fields end
				local key = assert(string(), "Expected field for table")
				assert(consume("^:"))
				fields[key] = assert(value(), "Expected value for field " .. key)
				consume("^,")
			end
		end
	end

	function array()
		if consume("^%[") then
			local values = {}
			while true do
				if consume("^%]") then return values end
				values[#values + 1] = assert(value(), "Expected value for field #" .. #values + 1)
				consume("^,")
			end
		end
	end

	return object() or array()
end

local function wildcard2pattern(s --[[@param s string]])
	return "^%./" .. s:gsub("%.", "%%."):gsub("%*", ".*") .. "$"
end

do
	---@type { title: string?, description: string?, author: string?, ignore: string[]?, authors: string[]? }
	local addon = assert( decode( read(ADDON_JSON) ), "Failed to parse addon.json file" )

	---@type { path: string, content: string }[]
	local files = {}

	---@type string[]
	local blocklist = {}

	-- Retrieved from https://github.com/Facepunch/gmad/blob/master/include/AddonWhiteList.h
	local allowlist = map({
		"lua/*.lua",
		"scenes/*.vcd",
		"particles/*.pcf",
		"resource/fonts/*.ttf",
		"scripts/vehicles/*.txt",
		"resource/localization/*/*.properties",
		"maps/*.bsp",
		"maps/*.lmp",
		"maps/*.nav",
		"maps/*.ain",
		"maps/thumb/*.png",
		"sound/*.wav",
		"sound/*.mp3",
		"sound/*.ogg",
		"materials/*.vmt",
		"materials/*.vtf",
		"materials/*.png",
		"materials/*.jpg",
		"materials/*.jpeg",
		"materials/colorcorrection/*.raw",
		"models/*.mdl",
		"models/*.vtx",
		"models/*.phy",
		"models/*.ani",
		"models/*.vvd",
		"gamemodes/*/*.txt",
		"gamemodes/*/*.fgd",
		"gamemodes/*/logo.png",
		"gamemodes/*/icon24.png",
		"gamemodes/*/gamemode/*.lua",
		"gamemodes/*/entities/effects/*.lua",
		"gamemodes/*/entities/weapons/*.lua",
		"gamemodes/*/entities/entities/*.lua",
		"gamemodes/*/backgrounds/*.png",
		"gamemodes/*/backgrounds/*.jpg",
		"gamemodes/*/backgrounds/*.jpeg",
		"gamemodes/*/content/models/*.mdl",
		"gamemodes/*/content/models/*.vtx",
		"gamemodes/*/content/models/*.phy",
		"gamemodes/*/content/models/*.ani",
		"gamemodes/*/content/models/*.vvd",
		"gamemodes/*/content/materials/*.vmt",
		"gamemodes/*/content/materials/*.vtf",
		"gamemodes/*/content/materials/*.png",
		"gamemodes/*/content/materials/*.jpg",
		"gamemodes/*/content/materials/*.jpeg",
		"gamemodes/*/content/materials/colorcorrection/*.raw",
		"gamemodes/*/content/scenes/*.vcd",
		"gamemodes/*/content/particles/*.pcf",
		"gamemodes/*/content/resource/fonts/*.ttf",
		"gamemodes/*/content/scripts/vehicles/*.txt",
		"gamemodes/*/content/resource/localization/*/*.properties",
		"gamemodes/*/content/maps/*.bsp",
		"gamemodes/*/content/maps/*.nav",
		"gamemodes/*/content/maps/*.ain",
		"gamemodes/*/content/maps/thumb/*.png",
		"gamemodes/*/content/sound/*.wav",
		"gamemodes/*/content/sound/*.mp3",
		"gamemodes/*/content/sound/*.ogg",

		-- Immutable version of `data` folder: https://github.com/Facepunch/gmad/commit/d55a4438a5bc0d2f25c02bda1e73e8034fdf736b
		"data_static/*.txt",
		"data_static/*.dat",
		"data_static/*.json",
		"data_static/*.xml",
		"data_static/*.csv",
		"data_static/*.dem",
		"data_static/*.vcd",

		"data_static/*.vtf",
		"data_static/*.vmt",
		"data_static/*.png",
		"data_static/*.jpg",
		"data_static/*.jpeg",

		"data_static/*.mp3",
		"data_static/*.wav",
		"data_static/*.ogg",
	}, wildcard2pattern)

	if addon.ignore then -- if specified list of files to ignore.
		blocklist = map(addon.ignore, wildcard2pattern)
	end

	do
		local dir = assert(io.popen(PATH_SEP == "\\" and "dir /s /b ." or "find . -type f"))

		for path in dir:lines() do
			local normalized = path:gsub(PATH_SEP, "/") -- normalize

			for _, allow_pattern in ipairs(allowlist) do
				if normalized:match(allow_pattern) then
					for _, block_pattern in ipairs(blocklist) do
						if normalized:match(block_pattern) then
							print("Blocked ", normalized)
							goto cont
						end
					end

					files[#files + 1] = {
						path = normalized:sub(3), -- strip initial ./ part
						content = read(path)
					}

					goto cont
				end
			end

			print("Warning: File " .. normalized .. " not whitelisted. Skipping..")
			::cont::
		end

		dir:close()
	end

	local handle = assert(io.open(OUTPUT_FILE, "wb"), "Failed to create/overwrite output file")
	handle:write(
		pack(
			addon.title or "No title provided",
			addon.description or "No description provided",
			addon.author or (addon.authors and table.concat(addon.authors, ", ")) or "No author provided",
			files
		)
	)
	handle:close()
end