class_name NowPlaying
extends HBoxContainer
## The soundtrack and song that are playing, in large text at the top of the quiz. They
## fade in when they change. Once the answer is shown, the soundtrack's cover shows on
## their left, when it has one, and the cover and titles are centered together. Both are
## centered up and down too, so the titles only move sideways when a cover comes. Each
## title has at most two lines.

## The covers on disk. No cover is shown without it.
var covers: CoverCache:
	set(value):
		covers = value
		if covers != null:
			covers.cover_times_changed.connect(_load_cover)
			_load_cover()

# The soundtrack whose cover is shown or on its way, and the cover time asked for
var _cover_uuid: String = ""
var _cover_time: int = 0

@onready var soundtrack_label: Label = %SoundtrackLabel
@onready var song_label: Label = %SongLabel
@onready var cover_frame: Panel = %CoverFrame
@onready var cover_picture: TextureRect = %CoverPicture
@onready var titles: VBoxContainer = %Titles


func _ready() -> void:
	resized.connect(_fit_titles)
	_fit_titles()


## Shows [param soundtrack_title] and [param song_title]. The playlist hides them as
## question marks until the answer is shown, and only then gives the
## [param soundtrack_uuid] whose cover is shown.
func show_song(soundtrack_title: String, song_title: String,
		soundtrack_uuid: String = "") -> void:
	var changed: bool = soundtrack_label.text != soundtrack_title \
			|| song_label.text != song_title
	soundtrack_label.text = soundtrack_title
	song_label.text = song_title
	_fit_titles()
	if soundtrack_uuid != _cover_uuid:
		_cover_uuid = soundtrack_uuid
		_cover_time = 0
		_show_cover(null)
		_load_cover()
	# A new song, or the answer being shown, fades in
	if changed:
		Anim.fade_in(self, Anim.SLOW)


## Whether a cover is shown.
func has_cover() -> bool:
	return cover_frame.visible


# Asks for the cover, again when its time changed, e.g. once the soundtrack list loaded
func _load_cover() -> void:
	if covers == null || _cover_uuid.is_empty() || !is_node_ready():
		return
	var time: int = covers.cover_time(_cover_uuid)
	if time == _cover_time:
		return
	_cover_time = time
	if time <= 0:
		_show_cover(null)
		return
	covers.fetch_cover(_cover_uuid, time, _show_cover_of.bind(_cover_uuid, time))


# Covers arrive later; one for a song no longer shown is left out
func _show_cover_of(cover: Image, uuid: String, time: int) -> void:
	if uuid == _cover_uuid && time == _cover_time:
		_show_cover(cover)


func _show_cover(cover: Image) -> void:
	var was_shown: bool = cover_frame.visible
	cover_picture.texture = ImageTexture.create_from_image(cover) if cover != null else null
	cover_frame.visible = cover != null
	_fit_titles()
	if cover_frame.visible && !was_shown:
		Anim.fade_in(cover_frame, Anim.SLOW)


# The titles take the width of the longer one, so they stay next to the cover, but no
# more than there is room for; longer titles wrap. Beside a cover they line up with it
# on the left.
func _fit_titles() -> void:
	var room: float = size.x
	if cover_frame.visible:
		room -= cover_frame.custom_minimum_size.x + get_theme_constant(&"separation")
	var widest: float = maxf(_text_width(soundtrack_label), _text_width(song_label))
	titles.custom_minimum_size.x = clampf(ceilf(widest), 1.0, maxf(room, 1.0))
	var alignment: HorizontalAlignment = HORIZONTAL_ALIGNMENT_LEFT if cover_frame.visible \
			else HORIZONTAL_ALIGNMENT_CENTER
	soundtrack_label.horizontal_alignment = alignment
	song_label.horizontal_alignment = alignment


static func _text_width(label: Label) -> float:
	var font: Font = label.get_theme_font(&"font")
	return font.get_string_size(label.text, HORIZONTAL_ALIGNMENT_LEFT, -1,
			label.get_theme_font_size(&"font_size")).x