extends GdUnitTestSuite
## Checks that every node of the main window is where it was when the baseline was taken.
##
## [code]tests/data/layout_baseline.json[/code] is written by
## [code]tools/take_screenshots.gd[/code] (run it with --headless and copy its layout.json).
## It holds the position, size and visibility of every node in each UiTour state, keyed
## by the node's path from the main window. Take a new baseline when the layout is
## meant to change, e.g. after moving a button.

const BASELINE_PATH: String = "res://tests/data/layout_baseline.json"

## Nodes whose height follows text that changes between versions, such as the changelog.
## Their position and width are still checked.
const HEIGHT_FOLLOWS_TEXT: Array[String] = [
	"AboutPopup/AboutPanel/ScrollContainer/ContentVBox",
]

## How far a node may be from its old place, in pixels.
const TOLERANCE: float = 0.5

var _snapshot: AutoloadSnapshot
var _server: FakeHttpTransport
var _main: Control
var _layout: Dictionary = {}


func before() -> void:
	_snapshot = AutoloadSnapshot.take([Settings, Playlist])
	UiTour.prepare_autoloads()
	_server = UiTour.make_server().install()
	# Laid out at the size the baseline was taken at, like the screenshots
	var viewport: SubViewport = auto_free(SubViewport.new())
	viewport.size = Vector2i(1920, 1080)
	viewport.gui_embed_subwindows = true
	Engine.get_main_loop().root.add_child(viewport)
	_main = load("res://main/MainWindow.tscn").instantiate()
	viewport.add_child(_main)
	await UiTour.new(_main).run(func(state: String, popup: Node) -> void:
		_layout[state] = UiTour.dump_layout(_main, _main if popup == null else popup))


func after() -> void:
	_main.free()
	await Engine.get_main_loop().process_frame
	_server.uninstall()
	_snapshot.restore()


func _baseline() -> Dictionary:
	return JSON.parse_string(FileAccess.get_file_as_string(BASELINE_PATH))


func test_tour_has_the_same_states_as_the_baseline() -> void:
	assert_array(_layout.keys()).contains_exactly_in_any_order(_baseline().keys())


func test_every_node_is_where_it_was() -> void:
	var problems: Array[String] = []
	var baseline: Dictionary = _baseline()
	for state: String in baseline:
		var actual: Dictionary = _layout.get(state, {})
		for path: String in baseline[state]:
			var expected: Dictionary = baseline[state][path]
			if !actual.has(path):
				problems.append("%s: %s is missing" % [state, path])
				continue
			var rect: Array = actual[path].rect
			var sides: int = 3 if _height_follows_text(path) else 4
			for i: int in sides:
				if absf(rect[i] - expected.rect[i]) > TOLERANCE:
					problems.append("%s: %s is at %s, was %s"
							% [state, path, rect, expected.rect])
					break
			if actual[path].visible != expected.visible:
				problems.append("%s: %s visible is %s, was %s"
						% [state, path, actual[path].visible, expected.visible])
	assert_array(problems).override_failure_message(
			"%d nodes moved:\n%s" % [problems.size(), "\n".join(problems.slice(0, 30))]) \
			.is_empty()


static func _height_follows_text(path: String) -> bool:
	return HEIGHT_FOLLOWS_TEXT.any(func(node_path: String) -> bool:
		return path == node_path || path.begins_with(node_path + "/"))