#!/opt/lnxall_app/bin/lua

-- Created by hongbo.he@lnxall.com
-- 2025/11/24

local invoker = require "invoker"

local g_config_file = '/etc/frpc.toml'
local g_oldconfig_file = '/etc/frpc.ini'
local g_maxretries = 5

local function get_random_string(length)
	math.randomseed(os.time())
	local chars = "abcdefghijklmnopqrstuvwxyz0123456789"
	local rstr = ''

	for i = 1, length do
		local rand = math.random(1, #chars)
		rstr = rstr .. string.sub(chars, rand, rand)
	end
	return rstr
end

local function get_gateway_sn()
    local gwsn = nil
    local eval, output = invoker.invoke(invoker.NOSTDIO + invoker.OUTPUT, "factory", "get")
    if eval == 0 and type(output) == "string" then gwsn = string.match(output, "SN=(%x+)") end
    if not gwsn then
        output = invoker.readfile("/app/config/fac.ini")
        if type(output) == "string" then gwsn = string.match(output, "sn%s*=%s*(%x+)") end
    end
    if not gwsn then
        io.stderr:write("Error, failed to determine gateway SN!\n")
        io.stderr:flush()
        return nil
    end
    io.stdout:write(string.format("Gateway SN: %s\n", gwsn))
    io.stdout:flush()
	return gwsn
end

local function set_config_subdomain(rstr)
	if not rstr then return false end

	local content = invoker.readfile(g_config_file)
	if content then
		local domain = string.match(content, 'subdomain%s*=%s*"([^\n"]*)"')
		if domain then
			if domain == '' or #domain ~= 10 then
				content = string.gsub(content, 'subdomain%s*=%s*"[^\n"]*"', 'subdomain = "' .. rstr .. '"')

				local fp = io.open(g_config_file, 'wb');
				if fp then
					fp:write(content)
					fp:close()
					io.stdout:write(string.format("set 'subdomain': %s => %s\n", domain, rstr))
					io.stdout:flush()
					return true
				end
			end
		else
			io.stderr:write(string.format("Error, no 'subdomain' word, please check: %s\n", g_config_file))
			io.stderr:flush()
		end
	end
	return false
end

local function set_config_user(gwsn)
	if not gwsn then return false end

	local content = invoker.readfile(g_config_file)
	if content then
		local _, user = string.match(content, '([^%.]user)%s*=%s*"([^\n"]*)"')
		print(user)
		if user then
			if user == '' or user ~= gwsn then
				content = string.gsub(content, '([^%.]user)%s*=%s*"[^\n"]*"', '%1 = "' .. gwsn .. '"')

				local fp = io.open(g_config_file, 'wb')
				if fp then
					fp:write(content)
					fp:close()
					io.stdout:write(string.format("set 'user': %s\n", gwsn))
					io.stdout:flush()
					return true
				end
				return false
			end
		else
			io.stderr:write(string.format("Error, no 'user' word, please check: %s\n", g_config_file))
			io.stderr:flush()
		end
	end
	return true
end

local function set_config()
	local link = invoker.readlink(g_config_file)
	if type(link) ~= 'string' or #link == 0 or not string.find(link, g_config_file) then
		io.stderr:write(string.format("Error, %s is not a real frpc.toml\n", g_config_file))
		io.stderr:flush()
		return false
	end

	local gwsn = get_gateway_sn()
	if gwsn then
		set_config_user(gwsn)
	end

	local output = invoker.readfile(g_config_file)
    if not output or output == "" then
        io.stderr:write(string.format("Error, read config: %s\n", g_config_file))
        io.stderr:flush()
        return false
	end

	local rstr = get_random_string(10)
	if rstr then
		set_config_subdomain(rstr)
	end
	return true
end

local function start_frpc()
	local _, output = invoker.invoke(invoker.OUTPUT, '/usr/bin/frpc', '-v')
	if type(output) ~= 'string' or #output == 0 then
		io.stderr:write("Error, 'frpc' execute failed\n")
		io.stderr:flush()
		return false
	end

	-- if old frpc version
	if string.find(output, '0.25.3') then
		io.stdout:write(string.format("Warn, 'frpc' version: %s\n", output))
		io.stdout:flush()
		invoker.invoke(invoker.NOFORK, 'frpc', '-c', g_oldconfig_file)
		return false
	end

	local retries = 0
	while retries < g_maxretries do
		if set_config() then
			invoker.invoke(invoker.NOFORK, 'frpc', '-c', g_config_file)
		end

		retries = retries + 1
		invoker.msleep(2000)
	end

	io.stderr:write(string.format("Error, reach to max retries: %d\n", g_maxretries))
	io.stderr:flush()
	return false
end

start_frpc()
os.exit(1)