extends Control
class_name DiscoveryUI

const WorldBriefingModal = preload("res://scripts/world_briefing_modal.gd")

## Discovery & Home Screen for browsing, searching, and entering experiences.
##
## docs/planning/discovery.md (task b77bddf31ba5).

signal back_requested
signal world_selected(world_id: int)
signal worlds_loaded(count: int)

@onready var back_button: Button = $VBox/Header/BackButton
@onready var refresh_button: Button = $VBox/Header/RefreshButton
@onready var world_list_button: Button = $VBox/Header.get_node_or_null("WorldListButton")
@onready var status_label: Label = $VBox/StatusLabel

# Filter Controls
@onready var search_edit: LineEdit = $VBox/Filters/SearchEdit
@onready var category_option: OptionButton = $VBox/Filters/CategoryOption
@onready var sort_option: OptionButton = $VBox/Filters/SortOption
@onready var filter_button: Button = $VBox/Filters/FilterButton

# Content
@onready var loading_label: Label = $VBox/Content/LoadingLabel
@onready var error_label: Label = $VBox/Content/ErrorLabel
@onready var empty_label: Label = $VBox/Content/EmptyLabel
@onready var worlds_container: VBoxContainer = $VBox/Content/Scroll/WorldsVBox

# Pagination
@onready var prev_button: Button = $VBox/Pagination/PrevButton
@onready var next_button: Button = $VBox/Pagination/NextButton
@onready var page_label: Label = $VBox/Pagination/PageLabel

var _api_client: Node = null
var _current_page: int = 0
var _page_size: int = 10
var _total_count: int = 0
var _loaded_worlds: Array[DiscoveryApiClient.WorldSummary] = []


func _ready() -> void:
	_api_client = _get_api()
	_wire_signals()
	_setup_sort_options()
	_setup_initial_ui_state()

	# Populate categories then load initial worlds feed
	await load_categories()
	await load_worlds(0)


func _get_api() -> Node:
	if has_node("/root/ApiClient"):
		return get_node("/root/ApiClient")
	var api_script = load("res://scripts/api_client.gd")
	if api_script:
		var api = api_script.new()
		add_child(api)
		return api
	return null


func _setup_initial_ui_state() -> void:
	if loading_label: loading_label.visible = false
	if error_label: error_label.visible = false
	if empty_label: empty_label.visible = false
	if prev_button: prev_button.disabled = true
	if next_button: next_button.disabled = true
	if page_label: page_label.text = "Page 1"


func _setup_sort_options() -> void:
	if not sort_option:
		return
	sort_option.clear()
	sort_option.add_item("Newest", 0)
	sort_option.add_item("Most Played", 1)
	sort_option.add_item("Trending", 2)
	sort_option.selected = 0


func _wire_signals() -> void:
	if back_button and not back_button.pressed.is_connected(_on_back_pressed):
		back_button.pressed.connect(_on_back_pressed)
	if refresh_button and not refresh_button.pressed.is_connected(_on_refresh_pressed):
		refresh_button.pressed.connect(_on_refresh_pressed)
	if filter_button and not filter_button.pressed.is_connected(_on_filter_pressed):
		filter_button.pressed.connect(_on_filter_pressed)
	if search_edit and not search_edit.text_submitted.is_connected(_on_search_submitted):
		search_edit.text_submitted.connect(_on_search_submitted)
	if category_option and not category_option.item_selected.is_connected(_on_category_selected):
		category_option.item_selected.connect(_on_category_selected)
	if sort_option and not sort_option.item_selected.is_connected(_on_sort_selected):
		sort_option.item_selected.connect(_on_sort_selected)
	if prev_button and not prev_button.pressed.is_connected(_on_prev_page_pressed):
		prev_button.pressed.connect(_on_prev_page_pressed)
	if next_button and not next_button.pressed.is_connected(_on_next_page_pressed):
		next_button.pressed.connect(_on_next_page_pressed)
	if world_list_button and not world_list_button.pressed.is_connected(_on_world_list_pressed):
		world_list_button.pressed.connect(_on_world_list_pressed)


func load_categories() -> void:
	if not category_option:
		return
	category_option.clear()
	category_option.add_item("All Categories", 0)

	if _api_client == null:
		return

	var res: Dictionary = await DiscoveryApiClient.get_categories(_api_client)
	if res.ok and res.data is Array:
		var idx := 1
		for cat in res.data:
			var cat_str := str(cat).strip_edges()
			if cat_str != "":
				category_option.add_item(cat_str, idx)
				idx += 1


func load_worlds(page: int = 0) -> void:
	_current_page = page
	if loading_label: loading_label.visible = true
	if error_label: error_label.visible = false
	if empty_label: empty_label.visible = false

	var q := search_edit.text.strip_edges() if search_edit else ""
	var category := ""
	if category_option and category_option.selected > 0:
		category = category_option.get_item_text(category_option.selected)

	var sort := "newest"
	if sort_option:
		match sort_option.selected:
			0: sort = "newest"
			1: sort = "most_played"
			2: sort = "trending"

	var skip := _current_page * _page_size
	var res: Dictionary = await DiscoveryApiClient.get_worlds(
		_api_client,
		q,
		[],
		category,
		sort,
		skip,
		_page_size
	)

	if loading_label: loading_label.visible = false

	if not res.ok:
		if error_label:
			error_label.text = "Error: %s" % res.detail
			error_label.visible = true
		_clear_container()
		return

	var parsed: DiscoveryApiClient.DiscoveryResult = res.get("parsed")
	if parsed == null and res.data is Dictionary:
		parsed = DiscoveryApiClient.DiscoveryResult.from_dict(res.data)

	if parsed == null:
		if error_label:
			error_label.text = "Invalid discovery response"
			error_label.visible = true
		_clear_container()
		return

	_total_count = parsed.total
	_loaded_worlds = parsed.items

	_render_worlds(_loaded_worlds)
	_update_pagination()
	worlds_loaded.emit(_loaded_worlds.size())


func _clear_container() -> void:
	if not worlds_container:
		return
	for c in worlds_container.get_children():
		worlds_container.remove_child(c)
		c.queue_free()


func _render_worlds(worlds: Array[DiscoveryApiClient.WorldSummary]) -> void:
	_clear_container()

	if worlds.is_empty():
		if empty_label:
			empty_label.text = "No experiences found matching your criteria."
			empty_label.visible = true
		return

	if empty_label: empty_label.visible = false

	for world in worlds:
		var card := _create_world_card(world)
		worlds_container.add_child(card)


func _create_world_card(world: DiscoveryApiClient.WorldSummary) -> Control:
	var panel := PanelContainer.new()
	panel.size_flags_horizontal = Control.SIZE_EXPAND_FILL
	panel.custom_minimum_size = Vector2(0, 90)

	var style := StyleBoxFlat.new()
	style.bg_color = Color(0.14, 0.16, 0.20, 1.0)
	style.corner_radius_top_left = 6
	style.corner_radius_top_right = 6
	style.corner_radius_bottom_left = 6
	style.corner_radius_bottom_right = 6
	style.content_margin_left = 16
	style.content_margin_right = 16
	style.content_margin_top = 10
	style.content_margin_bottom = 10
	panel.add_theme_stylebox_override("panel", style)

	var vbox := VBoxContainer.new()
	vbox.size_flags_horizontal = Control.SIZE_EXPAND_FILL
	vbox.add_theme_constant_override("separation", 4)
	panel.add_child(vbox)

	# Title & Category Row
	var title_row := HBoxContainer.new()
	var name_label := Label.new()
	name_label.text = world.name
	name_label.add_theme_font_size_override("font_size", 18)
	name_label.add_theme_color_override("font_color", Color(1.0, 1.0, 1.0, 1.0))
	title_row.add_child(name_label)

	if world.category != "":
		var cat_label := Label.new()
		cat_label.text = "  [%s]" % world.category
		cat_label.add_theme_font_size_override("font_size", 14)
		cat_label.add_theme_color_override("font_color", Color(0.4, 0.7, 1.0, 1.0))
		title_row.add_child(cat_label)

	var spacer := Control.new()
	spacer.size_flags_horizontal = Control.SIZE_EXPAND_FILL
	title_row.add_child(spacer)

	# Enter World Button
	var enter_button := Button.new()
	enter_button.text = "Enter World"
	enter_button.custom_minimum_size = Vector2(110, 30)
	enter_button.pressed.connect(_show_world_briefing.bind(world, enter_button))
	title_row.add_child(enter_button)
	vbox.add_child(title_row)

	# Description
	var desc_label := Label.new()
	desc_label.text = world.description if world.description != "" else "No description provided."
	desc_label.autowrap_mode = TextServer.AUTOWRAP_WORD
	desc_label.add_theme_font_size_override("font_size", 13)
	desc_label.add_theme_color_override("font_color", Color(0.75, 0.75, 0.75, 1.0))
	vbox.add_child(desc_label)

	# Metadata Row: Tags, Plays, Owner
	var meta_row := HBoxContainer.new()
	meta_row.add_theme_constant_override("separation", 16)

	var play_label := Label.new()
	play_label.text = "%d plays" % world.play_count
	play_label.add_theme_font_size_override("font_size", 12)
	play_label.add_theme_color_override("font_color", Color(0.6, 0.9, 0.6, 1.0))
	meta_row.add_child(play_label)

	if world.tags.size() > 0:
		var tags_str: String = ""
		for t in world.tags:
			tags_str += "#" + str(t) + " "
		var tags_label := Label.new()
		tags_label.text = tags_str.strip_edges()
		tags_label.add_theme_font_size_override("font_size", 12)
		tags_label.add_theme_color_override("font_color", Color(0.8, 0.7, 0.4, 1.0))
		meta_row.add_child(tags_label)

	if world.owner_username != "":
		var owner_label := Label.new()
		owner_label.text = "Creator: %s" % world.owner_username
		owner_label.add_theme_font_size_override("font_size", 12)
		owner_label.add_theme_color_override("font_color", Color(0.6, 0.6, 0.6, 1.0))
		meta_row.add_child(owner_label)

	vbox.add_child(meta_row)

	return panel


func _update_pagination() -> void:
	var total_pages := int(ceil(float(_total_count) / float(_page_size)))
	if total_pages <= 0:
		total_pages = 1

	if page_label:
		page_label.text = "Page %d of %d (%d experiences)" % [_current_page + 1, total_pages, _total_count]

	if prev_button:
		prev_button.disabled = (_current_page <= 0)
	if next_button:
		next_button.disabled = ((_current_page + 1) >= total_pages)


func _show_world_briefing(world: DiscoveryApiClient.WorldSummary, button: Button) -> void:
	var modal := WorldBriefingModal.new()
	modal.setup_world_data(
		world.id,
		world.name,
		world.owner_username,
		world.content_guidelines,
		world.tags,
		world.play_count
	)
	modal.entered_confirmed.connect(func(target_wid: int): _on_enter_world_pressed(target_wid, button))
	add_child(modal)


func _on_enter_world_pressed(world_id: int, button: Button) -> void:
	button.disabled = true
	button.text = "Joining…"
	world_selected.emit(world_id)

	# 1. Record visit metric
	if _api_client != null:
		await DiscoveryApiClient.record_visit(_api_client, world_id)

	# 2. Join flow (existing game server orchestration)
	if _api_client != null and _api_client.has_method("join_world"):
		var result: Dictionary = await _api_client.join_world(world_id)
		if result.ok and result.data is Dictionary:
			var d: Dictionary = result.data
			if has_node("/root/Session"):
				get_node("/root/Session").begin(world_id, str(d.get("host", "")), int(d.get("port", 0)))
			get_tree().change_scene_to_file("res://scenes/game.tscn")
			return

		if result.status == 503:
			# Dev fallback: local single-player
			if has_node("/root/Session"):
				get_node("/root/Session").clear()
			get_tree().change_scene_to_file("res://scenes/game.tscn")
			return

		if status_label:
			status_label.text = "Failed to join: " + str(result.detail)
			status_label.visible = true
	else:
		# Fallback if standalone test or not wired
		if has_node("/root/Session"):
			get_node("/root/Session").clear()
		get_tree().change_scene_to_file("res://scenes/game.tscn")
		return

	button.disabled = false
	button.text = "Enter World"


func _on_filter_pressed() -> void:
	load_worlds(0)


func _on_search_submitted(_new_text: String) -> void:
	load_worlds(0)


func _on_category_selected(_index: int) -> void:
	load_worlds(0)


func _on_sort_selected(_index: int) -> void:
	load_worlds(0)


func _on_refresh_pressed() -> void:
	load_worlds(_current_page)


func _on_prev_page_pressed() -> void:
	if _current_page > 0:
		load_worlds(_current_page - 1)


func _on_next_page_pressed() -> void:
	var total_pages := int(ceil(float(_total_count) / float(_page_size)))
	if (_current_page + 1) < total_pages:
		load_worlds(_current_page + 1)


func _on_back_pressed() -> void:
	back_requested.emit()
	if get_tree() and get_tree().current_scene == self:
		get_tree().change_scene_to_file("res://scenes/main_menu.tscn")


func _on_world_list_pressed() -> void:
	if get_tree():
		get_tree().change_scene_to_file("res://scenes/world_list.tscn")


func _unhandled_input(event: InputEvent) -> void:
	if event.is_action_pressed("ui_cancel"):
		for child in get_children():
			if child is WorldBriefingModal:
				child.queue_free()
				get_viewport().set_input_as_handled()
				return
		get_viewport().set_input_as_handled()
		_on_back_pressed()