extends Control
## Main menu with login/register UI wired to the backend auth API.
##
## The AuthPanel is hidden by default. When the user clicks the LoginButton or
## RegisterButton (AuthButtonsRow, above the panel), the auth panel slides in.
## The Login and Register buttons on the AuthButtonsRow directly set the panel's
## mode, so the user can switch between Login and Register at any time while
## the panel is open.
##
## On successful auth the token is stored via ApiClient, AuthButtonsRow hides,
## the welcome label shows the username, and the Play button becomes enabled.
## The auth form fields are hidden, leaving only the welcome message visible.
##
## When returning from another scene (e.g. world_list), _ready() checks whether
## ApiClient already holds a valid token. If so, it restores the authenticated
## UI state (Play enabled, welcome message visible) instead of forcing the user
## back to the login form.


## Emitted once _ready()'s session check (has_token() + the awaited
## get_me() call) has actually resolved, whichever way -- lets a test (or
## anything else) know the UI state is trustworthy now, rather than
## guessing from a frame count or from UI properties that are ambiguous
## mid-await (e.g. AuthButtonsRow.visible is true both before the check
## resolves AND in a genuine logged-out end state).
signal auth_state_ready

# ─── UI references ────────────────────────────────────────────────────────────

var _auth_buttons_row: HBoxContainer
var _login_button: Button
var _register_button: Button
var _auth_panel: PanelContainer
var _auth_mode_label: Label
var _username_edit: LineEdit
var _password_edit: LineEdit
var _email_edit: LineEdit
var _over_18_check: CheckBox
var _auth_button: Button
var _status_label: Label
var _welcome_label: Label
var _play_button: Button
var _quit_button: Button

var _is_register_mode: bool = false
var _is_authenticating: bool = false


# ─── Lifecycle ────────────────────────────────────────────────────────────────

func _ready() -> void:
	# Cache node references.
	_auth_buttons_row = $CenterContainer/VBoxContainer/AuthButtonsRow
	_login_button = $CenterContainer/VBoxContainer/AuthButtonsRow/LoginButton
	_register_button = $CenterContainer/VBoxContainer/AuthButtonsRow/RegisterButton
	_auth_panel = $CenterContainer/VBoxContainer/AuthPanel
	_auth_mode_label = $CenterContainer/VBoxContainer/AuthPanel/MarginContainer/AuthVBox/AuthModeLabel
	_username_edit = $CenterContainer/VBoxContainer/AuthPanel/MarginContainer/AuthVBox/UsernameEdit
	_password_edit = $CenterContainer/VBoxContainer/AuthPanel/MarginContainer/AuthVBox/PasswordEdit
	_email_edit = $CenterContainer/VBoxContainer/AuthPanel/MarginContainer/AuthVBox/EmailEdit
	_over_18_check = $CenterContainer/VBoxContainer/AuthPanel/MarginContainer/AuthVBox/Over18Check
	_auth_button = $CenterContainer/VBoxContainer/AuthPanel/MarginContainer/AuthVBox/AuthButton
	_status_label = $CenterContainer/VBoxContainer/AuthPanel/MarginContainer/AuthVBox/AuthStatusLabel
	_welcome_label = $CenterContainer/VBoxContainer/AuthPanel/MarginContainer/AuthVBox/WelcomeLabel
	_play_button = $CenterContainer/VBoxContainer/PlayButton
	_quit_button = $CenterContainer/VBoxContainer/QuitButton

	# Default to Play being gated. When a token exists, the async session
	# check below may take several frames (a real get_me() round-trip);
	# keeping the button disabled until validation succeeds prevents a fast
	# click from navigating to world_list with an expired/invalid token.
	_play_button.disabled = true

	# Check whether a valid session already exists (e.g. user logged in,
	# navigated to world_list, then clicked Back). If so, restore the
	# authenticated UI state instead of forcing the login form again.
	if ApiClient.has_token():
		var me_result: Dictionary = await ApiClient.get_me()
		if me_result.ok and me_result.data is Dictionary:
			var username: String = str((me_result.data as Dictionary).get("username", ""))
			if username != "":
				_show_authenticated(username)
				auth_state_ready.emit()
				return

	# Token missing or invalid — fall through to logged-out state.
	_reset_to_logged_out()
	auth_state_ready.emit()


## Restore the UI to the authenticated state (Play enabled, welcome message
## visible, auth buttons hidden). AuthPanel itself stays visible -- the
## welcome label lives inside it, so hiding the panel hides the label too
## even when the label's own `visible` is true (real bug, 2026-08-20: a
## review caught the panel being hidden here while the label claimed to be
## visible, which is a no-op UI-wise since Control.visible doesn't override
## an ancestor's hidden state).
func _show_authenticated(username: String) -> void:
	_auth_panel.visible = true
	_status_label.visible = false
	_welcome_label.text = "Welcome, %s!" % username
	_welcome_label.visible = true
	_email_edit.visible = false
	_over_18_check.visible = false
	_play_button.disabled = false
	_auth_buttons_row.visible = false
	print("Restored authenticated session for: ", username)


## Reset the UI to the logged-out state (Play disabled, auth panel hidden,
## login/register buttons visible).
func _reset_to_logged_out() -> void:
	_auth_panel.visible = false
	_status_label.visible = false
	_welcome_label.visible = false
	_email_edit.visible = false
	_over_18_check.visible = false
	_over_18_check.button_pressed = false
	_play_button.disabled = true  # Gate play behind successful auth.
	_update_auth_mode_ui()


# ─── Play / Quit ──────────────────────────────────────────────────────────────

func _on_play_button_pressed() -> void:
	if _play_button.disabled:
		return
	# Browse worlds is the first real screen past login -- actual gameplay
	# (joining a world) doesn't exist yet, browsing does.
	get_tree().change_scene_to_file("res://scenes/world_list.tscn")


func _on_quit_button_pressed() -> void:
	get_tree().quit()


# ─── Auth panel toggle ────────────────────────────────────────────────────────

func _on_login_button_pressed() -> void:
	"""Show the auth panel in login mode, called from AuthButtonsRow/LoginButton."""
	_auth_panel.visible = true
	_is_register_mode = false
	_update_auth_mode_ui()
	_clear_status()
	_username_edit.grab_focus()


func _on_register_button_pressed() -> void:
	"""Show the auth panel in register mode, called from AuthButtonsRow/RegisterButton."""
	_auth_panel.visible = true
	_is_register_mode = true
	_update_auth_mode_ui()
	_clear_status()
	_username_edit.grab_focus()


func _update_auth_mode_ui() -> void:
	"""Update labels and field visibility based on login vs register mode."""
	if _is_register_mode:
		_auth_mode_label.text = "Register"
		_auth_button.text = "Register"
		_email_edit.visible = true
		_over_18_check.visible = true
	else:
		_auth_mode_label.text = "Login"
		_auth_button.text = "Login"
		_email_edit.visible = false
		_over_18_check.visible = false


# ─── Auth submission ──────────────────────────────────────────────────────────

func _on_auth_button_pressed() -> void:
	"""Handle login or register button press."""
	if _is_authenticating:
		return

	# Validate inputs.
	var username := _username_edit.text.strip_edges()
	var password := _password_edit.text

	if username == "":
		_show_status("Username is required.")
		return
	if password == "":
		_show_status("Password is required.")
		return

	if _is_register_mode:
		var email := _email_edit.text.strip_edges()

		if email == "":
			_show_status("Email is required.")
			return
		if not _over_18_check.button_pressed:
			_show_status("You must confirm you are 18 or older to register.")
			return

		_auth_button.disabled = true
		_auth_button.text = "Registering..."
		_is_authenticating = true
		_clear_status()

		var result := await ApiClient.register(username, email, password, true)
		_on_auth_complete(result)
	else:
		_auth_button.disabled = true
		_auth_button.text = "Logging in..."
		_is_authenticating = true
		_clear_status()

		var result := await ApiClient.login(username, password)
		_on_auth_complete(result)


func _on_auth_complete(result: Dictionary) -> void:
	"""Handle the result of a login or register call."""
	_auth_button.disabled = false
	_auth_button.text = "Register" if _is_register_mode else "Login"
	_is_authenticating = false

	if result.ok:
		# Success — hide the auth form fields, show only the welcome label.
		_username_edit.visible = false
		_password_edit.visible = false
		_email_edit.visible = false
		_over_18_check.visible = false
		_auth_button.visible = false
		_auth_mode_label.visible = false
		_status_label.visible = false
		_welcome_label.text = "Welcome, %s!" % _username_edit.text.strip_edges()
		_welcome_label.visible = true
		_play_button.disabled = false
		_auth_buttons_row.visible = false
		print("Auth successful. Token stored.")
	else:
		# Failure — show backend error detail.
		_show_status(result.detail)


# ─── Status helpers ───────────────────────────────────────────────────────────

func _show_status(message: String) -> void:
	_status_label.text = message
	_status_label.visible = true


func _clear_status() -> void:
	_status_label.text = ""
	_status_label.visible = false