class_name SearchPopup
extends PopupWindow

@onready
var search_list: VBoxContainer = $ScrollContainer/VBoxContainer

@onready
var search_panel: Panel = %SearchPanel

@onready
var clear_button: Button = $ClearButton

@onready
var search_bar: TextEdit = $Searchbar

var soundtracks: Array = []

# Precomputed soundtrack data: array of dicts with original, lowercase, and cleaned fields
var precomputed_soundtracks: Array = []

# Regex cache: maps cleaned search terms to compiled RegEx objects
var regex_cache: Dictionary = {}

var label_pool: Array[Label] = []

# Called when the node enters the scene tree for the first time.
func _ready() -> void:
	clear_button.pressed.connect(clear)
	search_bar.grab_focus()
	search_bar.text_changed.connect(search)
	visibility_changed.connect(focus)

func focus() -> void:
	if self.visible == true:
		search_bar.grab_focus()
		clear()

func close() -> void:
	clear()
	super()

func search() -> void:
	GameLog.debug(search_bar.text)
	var search_text: String = search_bar.text
	
	if search_text == "":
		show_all_soundtracks()
		return
	
	perform_search(search_text)

func show_all_soundtracks() -> void:
	# Hide all visible labels and add to pool
	for child: Label in search_list.get_children():
		if child.visible:
			child.visible = false
			label_pool.append(child)
	
	# Show all soundtracks in order
	for soundtrack: String in soundtracks:
		add_soundtrack_reuse(soundtrack)

func perform_search(search_text: String) -> void:
	# Hide all visible labels and add to pool
	for child: Label in search_list.get_children():
		if child.visible:
			child.visible = false
			label_pool.append(child)

	for soundtrack: String in find_matches(search_text):
		add_soundtrack_reuse(soundtrack)

## Returns the soundtracks matching [param search_text], best matches first: plain
## case-insensitive matches, then matches ignoring spaces and special characters,
## then matches with the letters in order but not next to each other.
func find_matches(search_text: String) -> Array[String]:
	var seen: Dictionary = {}
	var search_text_lower: String = search_text.to_lower()
	var clean_search_text: String = clean_term(search_text)

	var matches: Array[String] = []

	# Pass 1: Exact case-insensitive contains match on lowercase versions
	for i in range(precomputed_soundtracks.size()):
		var st_data = precomputed_soundtracks[i]
		if st_data["lowercase"].contains(search_text_lower):
			if not st_data["original"] in seen:
				seen[st_data["original"]] = true
				matches.append(st_data["original"])

	# Pass 2: Contains match on cleaned terms
	for i in range(precomputed_soundtracks.size()):
		var st_data = precomputed_soundtracks[i]
		if st_data["cleaned"].contains(clean_search_text):
			if not st_data["original"] in seen:
				seen[st_data["original"]] = true
				matches.append(st_data["original"])

	# Pass 3: Regex match on cleaned terms
	var regex = compile_regex_cached(clean_search_text)
	for i in range(precomputed_soundtracks.size()):
		var st_data = precomputed_soundtracks[i]
		if regex.search(st_data["cleaned"]):
			if not st_data["original"] in seen:
				seen[st_data["original"]] = true
				matches.append(st_data["original"])

	return matches

# Cleans a term by removing spaces and replacing special characters.
# Matches MusicServer's clean_term() function.
func clean_term(term: String) -> String:
	return term.replace(" ", "").replace("é", "e").replace("+", "plus").replace("&", "and").replace("'n", "and").to_lower()

# Compiles a regex pattern with caching to avoid recompiling the same pattern multiple times.
func compile_regex_cached(search_term: String) -> RegEx:
	if not search_term in regex_cache:
		var regex = RegEx.new()
		var regText: String = ".*"
		for letter: String in search_term:
			# Escape regex metacharacters so searches like "Q*bert" or "(Remix)" work
			if "\\^$.|?*+()[]{}".contains(letter):
				regText += "\\"
			regText += letter + ".*"
		regex.compile(regText)
		regex_cache[search_term] = regex
	return regex_cache[search_term]

func add_soundtrack(soundtrack: String) -> void:
	# Backward compatibility - delegates to reuse version
	add_soundtrack_reuse(soundtrack)

# Optimized version that reuses label nodes from pool instead of creating new ones
func add_soundtrack_reuse(soundtrack: String) -> void:
	var label: Label
	if label_pool.size() > 0:
		label = label_pool.pop_front()
		label.text = soundtrack
		label.visible = true
		# Move to end to maintain display order
		search_list.move_child(label, search_list.get_child_count() - 1)
	else:
		label = Label.new()
		label.text = soundtrack
		label.autowrap_mode = TextServer.AUTOWRAP_WORD
		search_list.add_child(label)
		label.visible = true

func check_if_soundtrack_exists(soundtrack: String) -> bool:
	var soundtrack_exists: bool = false
	for child: Label in search_list.get_children():
		if child.text == soundtrack and child.visible:
			soundtrack_exists = true
	return soundtrack_exists

func get_list_of_soundtracks() -> void:
	GameLog.debug("get_list_of_soundtracks")
	var handle_soundtracks: Callable = func handle_soundtracks(array) -> void:
		if typeof(array) == TYPE_ARRAY:
			# Reuse existing labels: hide all and add to pool
			for child: Label in search_list.get_children():
				child.visible = false
				label_pool.append(child)
			set_soundtracks(array)
			for soundtrack: String in soundtracks:
				add_soundtrack_reuse(soundtrack)
		else:
			GameLog.warning("Unexpected data")
	MusicServerClient.fetch_all_soundtracks_ordered(handle_soundtracks)

## Replaces the searchable soundtracks and precomputes their search forms.
func set_soundtracks(list: Array) -> void:
	soundtracks = []
	precomputed_soundtracks = []
	soundtracks.append_array(list)
	for soundtrack: String in soundtracks:
		precomputed_soundtracks.append({
			"original": soundtrack,
			"lowercase": soundtrack.to_lower(),
			"cleaned": clean_term(soundtrack)
		})

func clear() -> void:
	search_bar.text = ""
	show_all_soundtracks()
	search_bar.grab_focus()