extends Control

# Main menu: one handler per game mode. Match's opponent is a curated
# Easy/Medium/Hard difficulty picker (DIFFICULTIES) rather than a raw
# checkpoint list — see TRAINING.md for promoting new tiers into
# res://bots/promoted/. Raw-checkpoint testing and Spectate (bot vs bot) are
# dev-only tools, grouped under DevSection and hidden outside debug builds so
# they disappear automatically from release exports. Selections are pushed
# into the GameSettings autoload for the target mode to read, and restored
# when returning to the menu within a session.

const BOTS_DIR := "res://bots"

# Every tier runs its promoted checkpoint at full trained capability —
# difficulty is a genuinely different policy, never the same policy
# handicapped with reaction delay or action noise. Easy and Medium are now
# distinct models (medium.json beats easy.json 65-22-13 head-to-head); Hard
# still points at medium.json, the strongest promoted policy, and stays a
# label-only duplicate until a stronger one earns hard.json. Keep the tiers
# monotonic: never leave a lower tier pointing at a stronger model than the
# one above it.
const DIFFICULTIES := [
	{"name": "Easy", "model": "res://bots/promoted/easy.json", "reaction_ticks": 8, "action_noise": 0.0},
	{"name": "Medium", "model": "res://bots/promoted/medium.json", "reaction_ticks": 8, "action_noise": 0.0},
	{"name": "Hard", "model": "res://bots/promoted/medium.json", "reaction_ticks": 8, "action_noise": 0.0},
]

@onready var difficulty_dropdown: OptionButton = %DifficultyDropdown
@onready var arena_dropdown: OptionButton = %ArenaDropdown
@onready var dev_section: Control = %DevSection
@onready var dev_bot_dropdown: OptionButton = %DevBotDropdown
@onready var bot_a_dropdown: OptionButton = %BotADropdown
@onready var bot_b_dropdown: OptionButton = %BotBDropdown


func _ready() -> void:
	_populate_difficulty_dropdown()
	_populate_arena_dropdown()
	dev_section.visible = OS.is_debug_build()
	if dev_section.visible:
		var bots := _list_bots()
		_populate_dropdown(dev_bot_dropdown, bots, GameSettings.dev_bot_override_path, true)
		_populate_dropdown(bot_a_dropdown, bots, GameSettings.spectate_bot_a_path)
		_populate_dropdown(bot_b_dropdown, bots, GameSettings.spectate_bot_b_path)
	$CenterContainer/VBoxContainer/FreePlayButton.grab_focus()


func _populate_difficulty_dropdown() -> void:
	difficulty_dropdown.clear()
	for tier in DIFFICULTIES:
		difficulty_dropdown.add_item(tier["name"])
	var selected := 0
	for i in DIFFICULTIES.size():
		if DIFFICULTIES[i]["name"] == GameSettings.selected_difficulty_name:
			selected = i
			break
	difficulty_dropdown.select(selected)


# Free Play only — Match/Spectate pick a random arena in code instead.
func _populate_arena_dropdown() -> void:
	arena_dropdown.clear()
	for tier in ArenaRegistry.ARENAS:
		arena_dropdown.add_item(tier["name"])
	var selected := 0
	for i in ArenaRegistry.ARENAS.size():
		if ArenaRegistry.ARENAS[i]["path"] == GameSettings.selected_arena_path:
			selected = i
			break
	arena_dropdown.select(selected)


# Lists bot checkpoints as paths relative to BOTS_DIR, including the
# top-level curriculum checkpoints and anything under promoted/.
func _list_bots() -> Array[String]:
	var files: Array[String] = []
	var dir := DirAccess.open(BOTS_DIR)
	if dir:
		for f in dir.get_files():
			if f.get_extension() == "json":
				files.append(f)
	var promoted_dir := DirAccess.open(BOTS_DIR + "/promoted")
	if promoted_dir:
		for f in promoted_dir.get_files():
			if f.get_extension() == "json":
				files.append("promoted/" + f)
	files.sort()
	return files


# Fills a dropdown with bot names (metadata = full model path). When
# include_none is true, prepends a "(Use difficulty)" sentinel (metadata "")
# and defaults selection to it. Reselects `preferred_path` if it's still on
# disk, else the newest (last) bot.
func _populate_dropdown(dropdown: OptionButton, bots: Array[String], preferred_path: String, include_none: bool = false) -> void:
	dropdown.clear()
	if include_none:
		dropdown.add_item("(Use difficulty)")
		dropdown.set_item_metadata(0, "")
	for f in bots:
		dropdown.add_item(f.get_basename())
		dropdown.set_item_metadata(dropdown.item_count - 1, BOTS_DIR + "/" + f)
	if dropdown.item_count == 0:
		return
	dropdown.select(0 if include_none else dropdown.item_count - 1)
	for i in dropdown.item_count:
		if dropdown.get_item_metadata(i) == preferred_path:
			dropdown.select(i)
			break


func _selected_path(dropdown: OptionButton) -> String:
	if dropdown.item_count > 0 and dropdown.selected >= 0:
		return dropdown.get_item_metadata(dropdown.selected)
	return ""


func _on_free_play_pressed() -> void:
	var chosen: Dictionary = ArenaRegistry.ARENAS[0] if arena_dropdown.selected < 0 else ArenaRegistry.ARENAS[arena_dropdown.selected]
	GameSettings.selected_arena_path = chosen["path"]
	get_tree().change_scene_to_file("res://scenes/free_play.tscn")


func _on_match_pressed() -> void:
	var tier: Dictionary = DIFFICULTIES[difficulty_dropdown.selected] if difficulty_dropdown.selected >= 0 else DIFFICULTIES[0]
	var override_path := _selected_path(dev_bot_dropdown) if dev_section.visible else ""
	GameSettings.dev_bot_override_path = override_path
	GameSettings.selected_difficulty_name = tier["name"]
	if override_path.is_empty():
		GameSettings.selected_bot_path = tier["model"]
		GameSettings.selected_bot_reaction_ticks = tier["reaction_ticks"]
		GameSettings.selected_bot_action_noise = tier["action_noise"]
	else:
		GameSettings.selected_bot_path = override_path
		GameSettings.selected_bot_reaction_ticks = -1
		GameSettings.selected_bot_action_noise = -1.0
	get_tree().change_scene_to_file("res://scenes/match.tscn")


func _on_settings_pressed() -> void:
	get_tree().change_scene_to_file("res://scenes/settings.tscn")


func _on_spectate_pressed() -> void:
	GameSettings.spectate_bot_a_path = _selected_path(bot_a_dropdown)
	GameSettings.spectate_bot_b_path = _selected_path(bot_b_dropdown)
	get_tree().change_scene_to_file("res://scenes/spectate.tscn")