class_name SoundtrackCard
extends PanelContainer
## One soundtrack in the statistics view: its name, how often and when it was last
## played, and its most and least played songs. Songs never played are not listed, and
## the least played are only shown when there are enough played songs to not repeat
## any. Clicking it asks for all its songs.
##
## Its cover shows on the left once [method load_cover] has fetched it; until then, and
## when the soundtrack has no cover, the soundtrack's initials stand in for it.

## Emitted when the card is clicked.
signal pressed(soundtrack: SoundtrackWithSongs)

## How many of the most and least played songs the card lists. With fewer than twice
## as many played songs, all of them are listed as most played.
const SONGS_SHOWN: int = 3

## The soundtrack the card shows.
var soundtrack: SoundtrackWithSongs

# The cover time asked for, so a cover is only asked for again when it changed
var _cover_asked: int = 0

@onready var cover_picture: TextureRect = %CoverPicture
@onready var cover_placeholder: Label = %CoverPlaceholder
@onready var name_label: Label = %NameLabel
@onready var played_label: Label = %PlayedLabel
@onready var last_played_label: Label = %LastPlayedLabel
@onready var most_played_header: Label = %MostPlayedHeader
@onready var most_played_list: VBoxContainer = %MostPlayedList
@onready var least_played_header: Label = %LeastPlayedHeader
@onready var least_played_list: VBoxContainer = %LeastPlayedList


func _ready() -> void:
	mouse_entered.connect(_set_hovered.bind(true))
	mouse_exited.connect(_set_hovered.bind(false))
	gui_input.connect(_on_gui_input)


## Shows [param data] on the card.
func show_soundtrack(data: SoundtrackWithSongs) -> void:
	var cover_changed: bool = soundtrack == null \
			|| soundtrack.soundtrack_uuid != data.soundtrack_uuid \
			|| soundtrack.cover_modified != data.cover_modified
	soundtrack = data
	if cover_changed:
		show_cover(null)
		_cover_asked = 0
	cover_placeholder.text = initials(data.soundtrack_name)
	name_label.text = data.soundtrack_name
	tooltip_text = data.soundtrack_name
	played_label.text = played_text(data.soundtrack_played)
	last_played_label.text = last_played_text(data.soundtrack_last_played)
	last_played_label.visible = !data.soundtrack_last_played.is_empty()

	var most_played: Array[SongInfoForStats] = []
	var least_played: Array[SongInfoForStats] = []
	var played: Array[SongInfoForStats] = played_songs(data.songs)
	if played.size() >= SONGS_SHOWN * 2:
		most_played = played.slice(0, SONGS_SHOWN)
		least_played = songs_by_plays(played, true).slice(0, SONGS_SHOWN)
	else:
		# Too few to split without listing a song twice, so all of them are most played
		most_played = played

	most_played_header.text = song_list_header(data.songs.size(), played.size())
	_fill_song_list(most_played_list, most_played)
	least_played_header.visible = !least_played.is_empty()
	_fill_song_list(least_played_list, least_played)


## Asks [param covers] for the soundtrack's cover, unless it already has, and shows it
## when it comes. Soundtracks without a cover keep their initials.
func load_cover(covers: CoverCache) -> void:
	if soundtrack == null || soundtrack.cover_modified <= 0 \
			|| _cover_asked == soundtrack.cover_modified:
		return
	_cover_asked = soundtrack.cover_modified
	covers.fetch_cover(soundtrack.soundtrack_uuid, soundtrack.cover_modified, show_cover)


## Takes the soundtrack's new cover time [param modified], 0 when its cover was removed,
## and shows the initials until [method load_cover] fetches the new cover.
func set_cover_time(modified: int) -> void:
	soundtrack.cover_modified = modified
	show_cover(null)
	_cover_asked = 0


## Shows [param cover], or the initials when it is null.
func show_cover(cover: Image) -> void:
	cover_picture.texture = ImageTexture.create_from_image(cover) if cover != null else null
	cover_placeholder.visible = cover == null


## Up to two initials of [param soundtrack_name], e.g. "FF" for "Final Fantasy VI".
static func initials(soundtrack_name: String) -> String:
	var letters: String = ""
	for word: String in soundtrack_name.split(" ", false):
		var first: String = word.left(1)
		if first.to_upper() != first.to_lower():
			letters += first.to_upper()
		if letters.length() == 2:
			break
	return letters if !letters.is_empty() else soundtrack_name.left(1)


## "Played 3 times", or "Never played" for [code]0[/code].
static func played_text(times_played: int) -> String:
	if times_played == 0:
		return "Never played"
	return "Played %d %s" % [times_played, "time" if times_played == 1 else "times"]


## "Last played 2026-10-01" from the server's date and time, or an empty String when
## there is none.
static func last_played_text(last_played: String) -> String:
	if last_played.is_empty():
		return ""
	return "Last played " + last_played.substr(0, 10)


## The songs of [param songs] that have been played, most played first. Songs never
## played are left out: the card only lists them in the popup with every song.
static func played_songs(songs: Array[SongInfoForStats]) -> Array[SongInfoForStats]:
	var played: Array[SongInfoForStats] = []
	played.assign(songs_by_plays(songs).filter(
			func(song: SongInfoForStats) -> bool: return song.times_played > 0))
	return played


## The header above the most played songs, for a soundtrack with [param song_count]
## songs of which [param played_count] have been played.
static func song_list_header(song_count: int, played_count: int) -> String:
	if song_count == 0:
		return "No songs"
	if played_count == 0:
		return "No songs played yet"
	return "Most played"


## One line of a song list: how often the song was played, then its name.
static func song_text(song: SongInfoForStats) -> String:
	return "%d × %s" % [song.times_played, song.song_name]


## [param songs] sorted with the most played first, or the least played first with
## [param least_first], and by name when played as often.
static func songs_by_plays(
		songs: Array[SongInfoForStats], least_first: bool = false) -> Array[SongInfoForStats]:
	var sorted: Array[SongInfoForStats] = songs.duplicate()
	sorted.sort_custom(func(a: SongInfoForStats, b: SongInfoForStats) -> bool:
		if a.times_played != b.times_played:
			return (a.times_played < b.times_played) == least_first
		return a.song_name.naturalnocasecmp_to(b.song_name) < 0
	)
	return sorted


func _fill_song_list(list: VBoxContainer, songs: Array[SongInfoForStats]) -> void:
	while list.get_child_count() < songs.size():
		var label: Label = Label.new()
		label.text_overrun_behavior = TextServer.OVERRUN_TRIM_ELLIPSIS
		list.add_child(label)
	for i: int in list.get_child_count():
		var label: Label = list.get_child(i)
		label.visible = i < songs.size()
		if label.visible:
			label.text = song_text(songs[i])


func _set_hovered(hovered: bool) -> void:
	theme_type_variation = &"StatisticsCardHover" if hovered else &"StatisticsCard"


func _on_gui_input(event: InputEvent) -> void:
	if event is InputEventMouseButton && event.pressed \
			&& event.button_index == MOUSE_BUTTON_LEFT:
		accept_event()
		pressed.emit(soundtrack)