extends Plugin

## Adds a "Switch to Steam" button to the power menu on ChimeraOS and SteamOS.
##
## OpenGamepadUI's built-in ChimeraOS platform support adds a "Switch to
## Desktop" button but has no way to return to Steam game mode. This plugin
## adds that missing button so users can round-trip between an exclusive
## OpenGamepadUI session and Steam.

const SESSION_SELECT_PATH := "/usr/lib/os-session-select"
const POWER_MENU_GROUP := "power_menu"
const BUTTON_NAME := "SwitchToSteamButton"
const MAX_ATTEMPTS := 600

# ChimeraOS records the session that was active before OpenGamepadUI took over
# in this file when the OpenGamepadUI session is entered. We return to that
# session instead of hardcoding a name so the autologin config is not mangled.
const RETURN_SESSION_FILE := "/.config/chimeraos-session-return"
const DEFAULT_RETURN_SESSION := "gamescope-session-steam-plus"

# Sessions os-session-select can be told to return to (matching the values it
# writes to the return-session file). Returning to the OpenGamepadUI session is
# deliberately excluded: this plugin only runs inside OpenGamepadUI, so a return
# file pointing at it is a stale self-reference (the last os-session-select run
# recorded whatever session autologin was set to, which is OpenGamepadUI itself
# once an exclusive OGPU session is active) and would just bounce back here.
const RETURN_SESSIONS := [
	"gamescope-session-steam-plus",
	"gamescope-session-steam",
]


func _ready() -> void:
	logger = Log.get_logger("SessionSwitch", Log.LEVEL.INFO)
	if not _has_session_switcher():
		logger.info("No session switcher script detected: " + SESSION_SELECT_PATH)
		return
	_add_button_when_ready()


func _add_button_when_ready() -> void:
	for i in MAX_ATTEMPTS:
		if _try_add_button():
			return
		await get_tree().process_frame
	logger.info("Power menu never became available. Skipping 'Switch to Steam' button.")


func _try_add_button() -> bool:
	var power_menu := get_tree().get_first_node_in_group(POWER_MENU_GROUP)
	if not power_menu:
		return false

	var exit_button = power_menu.get("exit_button")
	if not exit_button:
		return false

	var container = exit_button.get_parent()
	if not container:
		return false
	if container.has_node(BUTTON_NAME):
		return true

	var button_scene := load("res://core/ui/components/card_button.tscn") as PackedScene
	if not button_scene:
		logger.error("Unable to load card_button scene.")
		return true
	var button := button_scene.instantiate()
	button.name = BUTTON_NAME
	button.set("click_focuses", false)
	button.set("text", "Switch to Steam")
	button.pressed.connect(_switch_session)

	container.add_child(button)
	container.move_child(button, exit_button.get_index())

	var focus_group = power_menu.get("focus_group")
	if focus_group and focus_group.has_method("recalculate_focus"):
		focus_group.recalculate_focus()

	logger.info("Added 'Switch to Steam' button to the power menu.")
	return true


## Returns true if the session switcher script is present.
func _has_session_switcher() -> bool:
	return FileAccess.file_exists(SESSION_SELECT_PATH)


## Switches back to the session that was active before OpenGamepadUI took
## over, using the OS session switcher.
func _switch_session() -> void:
	_restart_inputplumber()
	var target := _get_return_session()
	var out: Array = []
	var code := OS.execute(SESSION_SELECT_PATH, [target], out)
	if code != OK:
		logger.error("Unable to switch sessions: " + _result_text(out))


## Restarts InputPlumber before switching back so the exclusive OpenGamepadUI
## session does not leave the gamepad intercepted (blocked) for Steam.
## ChimeraOS ships passwordless sudo for exactly this command in its default
## sudoers, so the switch itself remains non-interactive.
func _restart_inputplumber() -> void:
	var out: Array = []
	var code := OS.execute("sudo", ["-n", "systemctl", "restart", "inputplumber"], out)
	if code != OK:
		logger.warning("Unable to restart InputPlumber: " + _result_text(out))


## Returns the session recorded by os-session-select before OpenGamepadUI was
## entered, falling back to the ChimeraOS default Steam session.
func _get_return_session() -> String:
	var home := OS.get_environment("HOME")
	if home.is_empty():
		return DEFAULT_RETURN_SESSION
	var file := FileAccess.open(home + RETURN_SESSION_FILE, FileAccess.READ)
	if file:
		var session := file.get_as_text().strip_edges()
		if session in RETURN_SESSIONS:
			return session
	return DEFAULT_RETURN_SESSION


func _result_text(out: Array) -> String:
	return out[0] if not out.is_empty() else ""