#!/opt/lnxall_app/bin/lua

-- Created by hongbe.he@lnxall.com
-- Software Hotplug Detector
-- 2025/10/21

local posix = require "posix"
local socket = require "posix.sys.socket"
local bit32 = require "bit32"
local invoker = require "invoker"
local hal = require "lnxhal"

local hwt_table = {
	[hal.HWTYPE_RK3568] = true,
	[hal.HWTYPE_RK3588] = true,
}
local G_HANDLERS = {}

local function is_target_board()
	return hwt_table[hal.hw_gettype()] == true
end

-- sync with another services and apps
--
local function display_mode_sync(mode)
	local fp = io.open('/tmp/.screen_mode', 'wb')
	if fp then
		fp:write(mode)
		fp:close()
		return true
	end
	return false
end

local function call_display_detector()
	local status = invoker.readfile('/sys/class/drm/card0-HDMI-A-1/status')
	if type(status) ~= 'string' then return false end
	local hdmi_plugged = string.find(status, 'connected', 1, true) and not string.find(status, 'disconnected', 1, true)

	local rval, xr_out = invoker.invoke(invoker.OUTPUT, 'xrandr')
	if rval ~= 0 or type(xr_out) ~= 'string' then return false end

	local dsi_is_on = string.find(xr_out, 'DSI%-1 connected%s+%d+x%d+')

	-- hdmi plugged & dsi on => shut the dsi fuck up
	if hdmi_plugged then
		if dsi_is_on then
			invoker.msleep(500)
			local mode = string.match(xr_out, 'HDMI%-1 connected[%s%w]-(%d+x%d+)%+%d+%+%d+') or '1920x1080'
			display_mode_sync(mode)
			invoker.invoke(0, 'xrandr', '--output', 'DSI-1', '--off')
			io.stdout:write('INFO: HDMI Active, Force DSI OFF\n')
			io.stdout:flush()
		end
	else
	-- hdmi disconn & dsi off => open dsi
		if not dsi_is_on then
			invoker.msleep(500)
			display_mode_sync('1024x600')
			invoker.invoke(0, 'xrandr', '--output', 'DSI-1', '--auto')

			-- touch remap
			local _, xinput_out = invoker.invoke(invoker.OUTPUT, 'xinput')
			local gid = string.match(xinput_out, 'goodix%-ts%s+id=(%d+)')
			if gid then invoker.invoke(0, 'xinput', 'map-to-output', gid, 'DSI-1') end

			io.stdout:write('INFO: HDMI Disconnected, DSI ON\n')
			io.stdout:flush()
		end
	end
	return true
end

local function wait_for_x_server(timeout)
	local start = invoker.uptime()

	while (invoker.uptime() - start) < timeout do
		local rval = invoker.invoke(invoker.NOSTDIO, 'xrandr', '--query')
		if rval == 0 then
			return true
		end
		invoker.msleep(500)
	end
	return false
end

local function netlink_fds_create()
	local fd = socket.socket(socket.AF_NETLINK, socket.SOCK_RAW, 15)
	if not fd then return -1 end

	if not socket.bind(fd, {
		family = socket.AF_NETLINK,
		pid = 0,
		groups = 1
	}) then return -2 end

	return fd
end

local function dbus_fds_create()
	local rval = invoker.invoke(invoker.NOSTDIO, "which", "gdbus")
	if rval > 0 then
		io.stderr:write("Error, 'gdbus' not found.\n")
		io.stderr:flush()
		return -1, -1
	end

	local iflags = bit32.bor(invoker.NOWAIT, invoker.OUTPUT)
	local command = 'exec stdbuf -oL gdbus monitor --system --dest org.freedesktop.login1 --object-path /org/freedesktop/login1/seat/seat0'
	local pid, fd = invoker.invoke(iflags, 'bash', '-c', command)
	if type(pid) ~= 'number' or pid <= 0 then
		return -1, -1
	end

	invoker.nonblock(fd, true)
	return fd, pid
end

G_HANDLERS.on_netlink_event = function(fd, subscribers)
	local evdata = socket.recv(fd, 4096)
	if type(evdata) == 'string' and string.find(evdata, 'drm') then
		io.stdout:write('Netlink Event Triggered\n')
		io.stdout:flush()
		call_display_detector()
	end
end

G_HANDLERS.on_dbus_event = function(fd, subscribers)
	local act = subscribers[fd]
	if act.revents.HUP or act.revents.ERR then
		io.stderr:write('DBUS loss connection, try reconnectin ...\n')
		io.stderr:flush()
		invoker.kill(act.pid, posix.SIGKILL)
		invoker.waitpid(act.pid, false)

		subscribers[fd] = nil
		invoker.closefd(fd)

		local fd, pid = dbus_fds_create()
		if fd > 0 then
			subscribers[fd] = { events = { IN = true, HUP = true, ERR = true }, callback = G_HANDLERS.on_dbus_event, pid = pid }
			io.stdout:write('DBUS reconnected\n')
			io.stdout:flush()
		else
			invoker.msleep(1000)
		end
		return
	end

	local evdata = invoker.readfd(fd, 4096)
	if type(evdata) == 'string' and string.find(evdata, 'PropertiesChanged') then
		if wait_for_x_server(10000) then
			io.stdout:write('DBUS Event Triggered\n')
			io.stdout:flush()
			call_display_detector()
		else
			io.stderr:write('Error, X server not ready after 10s\n')
			io.stderr:flush()
		end
	end
end

local function main_func()
	invoker.setenv('LANG', 'C')
	invoker.setname('SOFTHPD')
	invoker.setenv('DISPLAY', ":0", true)

	if not is_target_board() then
		io.stderr:write('Unsupported hardware, softhpd sleeping ...\n')
		io.stderr:flush()
		-- service will be restart after 1 days
		invoker.invoke(invoker.NOFORK, 'sleep', '86400')
		return false
	end

	if wait_for_x_server(15000) then
		io.stdout:write('X Server is ready, performing initial check.\n')
	else
		io.stdout:write('Warning: X Server not ready after 15s, initial check skipped.\n')
	end
	io.stdout:flush()
	call_display_detector()

	local nlfd = netlink_fds_create()
	local gdfd, gd_pid = dbus_fds_create()
	if nlfd < 0 or gdfd < 0 then
		io.stderr:write(string.format('Error, failed to create NETLINK(%d) / DBUS-PIPE(%d)\n', nlfd, gdfd))
		io.stderr:flush()
		invoker.invoke(invoker.NOFORK, 'sleep', '86400')
		return false
	end

	local subscribers = {
		[nlfd] = { events = { IN = true }, callback = G_HANDLERS.on_netlink_event },
		[gdfd] = { events = { IN = true, HUP = true, ERR = true }, callback = G_HANDLERS.on_dbus_event, pid = gd_pid }
	}

	while true do
		posix.poll(subscribers, -1)

		for fd, act in pairs(subscribers) do
			if act.revents.IN or act.revents.HUP or act.revents.ERR then
				act.callback(fd, subscribers)
			end
		end
	end
end

main_func(arg[1])
os.exit(1)