extends Control
class_name GroupsUI
## Groups & Communities UI.
##
## Features:
## - Browse groups with pagination and "My Groups" filter
## - Create new group (creator becomes owner)
## - Detailed group page: description, member count, member list with roles
## - Join and Leave group actions
## - Role management for owner (promote to admin, demote to member, transfer ownership)
## - Delete group (owner only)

signal back_requested

@onready var back_button: Button = $VBoxContainer/HeaderHBox/BackButton
@onready var title_label: Label = $VBoxContainer/HeaderHBox/TitleLabel
@onready var refresh_button: Button = $VBoxContainer/HeaderHBox/RefreshButton
@onready var status_label: Label = $VBoxContainer/StatusMessageLabel

@onready var tab_container: TabContainer = $VBoxContainer/TabContainer

# Browse controls
@onready var my_groups_check: CheckBox = $VBoxContainer/TabContainer/Browse/FilterHBox/MyGroupsCheck
@onready var groups_list_container: VBoxContainer = $VBoxContainer/TabContainer/Browse/Scroll/GroupsList

# Create controls
@onready var new_group_name_edit: LineEdit = $VBoxContainer/TabContainer/Create/FormVBox/NameEdit
@onready var new_group_desc_edit: TextEdit = $VBoxContainer/TabContainer/Create/FormVBox/DescEdit
@onready var create_group_btn: Button = $VBoxContainer/TabContainer/Create/FormVBox/CreateButton

# Group Page controls
@onready var group_page_vbox: VBoxContainer = $VBoxContainer/TabContainer/GroupDetails/Scroll/DetailsVBox
@onready var group_name_label: Label = $VBoxContainer/TabContainer/GroupDetails/Scroll/DetailsVBox/HeaderHBox/GroupNameLabel
@onready var member_count_label: Label = $VBoxContainer/TabContainer/GroupDetails/Scroll/DetailsVBox/HeaderHBox/MemberCountLabel
@onready var group_desc_label: Label = $VBoxContainer/TabContainer/GroupDetails/Scroll/DetailsVBox/GroupDescLabel
@onready var join_btn: Button = $VBoxContainer/TabContainer/GroupDetails/Scroll/DetailsVBox/ActionsHBox/JoinButton
@onready var leave_btn: Button = $VBoxContainer/TabContainer/GroupDetails/Scroll/DetailsVBox/ActionsHBox/LeaveButton
@onready var delete_btn: Button = $VBoxContainer/TabContainer/GroupDetails/Scroll/DetailsVBox/ActionsHBox/DeleteButton
@onready var members_list_container: VBoxContainer = $VBoxContainer/TabContainer/GroupDetails/Scroll/DetailsVBox/MembersVBox/MembersList

var _api_client: Node = null
var _current_user_id: int = 0
var _active_group_id: int = 0
var _active_group_data: Dictionary = {}


func _ready() -> void:
	_api_client = _get_api()
	_wire_signals()
	if _api_client != null and _api_client.has_token():
		_init_user()
		refresh_groups()


func _get_api() -> Node:
	if has_node("/root/ApiClient"):
		return get_node("/root/ApiClient")
	return null


func _init_user() -> void:
	if _api_client == null:
		return
	var me_res: Dictionary = await _api_client.get_me()
	if me_res.ok and me_res.data is Dictionary:
		_current_user_id = int(me_res.data.get("id", 0))


func _wire_signals() -> void:
	if back_button:
		back_button.pressed.connect(_on_back_pressed)
	if refresh_button:
		refresh_button.pressed.connect(refresh_groups)
	if my_groups_check:
		my_groups_check.toggled.connect(func(_t): refresh_groups())
	if create_group_btn:
		create_group_btn.pressed.connect(_on_create_group_pressed)
	if join_btn:
		join_btn.pressed.connect(_on_join_pressed)
	if leave_btn:
		leave_btn.pressed.connect(_on_leave_pressed)
	if delete_btn:
		delete_btn.pressed.connect(_on_delete_pressed)


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


func _unhandled_input(event: InputEvent) -> void:
	if event.is_action_pressed("ui_cancel"):
		get_viewport().set_input_as_handled()
		_on_back_pressed()


func show_message(text: String, is_error: bool = false) -> void:
	if status_label:
		status_label.text = text
		status_label.modulate = Color(1.0, 0.4, 0.4) if is_error else Color(0.4, 1.0, 0.4)


# ── Browse Groups ──

func refresh_groups() -> void:
	if _api_client == null or not _api_client.has_token():
		return
	var mine: bool = my_groups_check.button_pressed if my_groups_check else false
	var res: Dictionary = await _api_client.list_groups(1, 50, mine)
	_clear_children(groups_list_container)

	if not res.ok:
		show_message("Failed to load groups: " + res.detail, true)
		return

	var groups: Array = []
	if res.data is Dictionary and res.data.has("groups"):
		groups = res.data["groups"]
	elif res.data is Array:
		groups = res.data

	if groups.is_empty():
		var empty_lbl := Label.new()
		empty_lbl.text = "No groups found. Create one in the Create Group tab!"
		empty_lbl.modulate = Color(0.6, 0.6, 0.6)
		groups_list_container.add_child(empty_lbl)
		return

	for g in groups:
		var gid: int = int(g.get("id", 0))
		var gname: String = str(g.get("name", "Group"))
		var gdesc: String = str(g.get("description", ""))
		var count: int = int(g.get("member_count", 0))
		_build_group_card(gid, gname, gdesc, count)


func _build_group_card(gid: int, gname: String, gdesc: String, count: int) -> void:
	var panel := PanelContainer.new()
	var margin := MarginContainer.new()
	margin.add_theme_constant_override("margin_left", 12)
	margin.add_theme_constant_override("margin_top", 12)
	margin.add_theme_constant_override("margin_right", 12)
	margin.add_theme_constant_override("margin_bottom", 12)

	var hbox := HBoxContainer.new()
	hbox.add_theme_constant_override("separation", 16)

	var info_vbox := VBoxContainer.new()
	info_vbox.size_flags_horizontal = Control.SIZE_EXPAND_FILL

	var name_lbl := Label.new()
	name_lbl.text = gname
	name_lbl.add_theme_font_size_override("font_size", 18)
	info_vbox.add_child(name_lbl)

	if gdesc != "":
		var desc_lbl := Label.new()
		desc_lbl.text = gdesc.left(100)
		desc_lbl.modulate = Color(0.8, 0.8, 0.8)
		info_vbox.add_child(desc_lbl)

	var count_lbl := Label.new()
	count_lbl.text = "%d member%s" % [count, "" if count == 1 else "s"]
	count_lbl.modulate = Color(0.6, 0.8, 1.0)
	info_vbox.add_child(count_lbl)

	hbox.add_child(info_vbox)

	var view_btn := Button.new()
	view_btn.text = "View Group"
	view_btn.custom_minimum_size = Vector2(110, 36)
	view_btn.size_flags_vertical = Control.SIZE_SHRINK_CENTER
	view_btn.pressed.connect(func(): open_group_page(gid))
	hbox.add_child(view_btn)

	margin.add_child(hbox)
	panel.add_child(margin)
	groups_list_container.add_child(panel)


# ── Create Group ──

func _on_create_group_pressed() -> void:
	if _api_client == null:
		return
	var gname := new_group_name_edit.text.strip_edges()
	var gdesc := new_group_desc_edit.text.strip_edges()
	if gname == "":
		show_message("Group name cannot be empty.", true)
		return

	var res: Dictionary = await _api_client.create_group(gname, gdesc)
	if res.ok and res.data is Dictionary:
		var gid: int = int(res.data.get("id", 0))
		new_group_name_edit.text = ""
		new_group_desc_edit.text = ""
		show_message("Group '%s' created!" % gname)
		await refresh_groups()
		open_group_page(gid)
	else:
		show_message("Failed to create group: " + res.detail, true)


# ── Group Page Details ──

func open_group_page(group_id: int) -> void:
	_active_group_id = group_id
	if tab_container:
		tab_container.current_tab = 2 # Details tab
	await refresh_group_page(group_id)


func refresh_group_page(group_id: int) -> void:
	if _api_client == null or group_id <= 0:
		return
	var res: Dictionary = await _api_client.get_group(group_id)
	if not res.ok:
		show_message("Failed to load group: " + res.detail, true)
		return

	_active_group_data = res.data if res.data is Dictionary else {}
	var gname: String = str(_active_group_data.get("name", "Group"))
	var gdesc: String = str(_active_group_data.get("description", "No description provided."))
	var members: Array = _active_group_data.get("members", [])
	var count: int = int(_active_group_data.get("member_count", members.size()))
	var owner_id: int = int(_active_group_data.get("owner_id", 0))

	if group_name_label:
		group_name_label.text = gname
	if group_desc_label:
		group_desc_label.text = gdesc
	if member_count_label:
		member_count_label.text = "%d Members" % count

	# Check membership of current user
	var is_member := false
	var my_role := ""
	for m in members:
		var uid: int = int(m.get("user_id", 0))
		if uid == _current_user_id:
			is_member = true
			my_role = str(m.get("role", "member"))
			break

	var is_owner := (_current_user_id == owner_id) or my_role == "owner"

	if join_btn:
		join_btn.visible = not is_member
	if leave_btn:
		leave_btn.visible = is_member and not is_owner
	if delete_btn:
		delete_btn.visible = is_owner

	_populate_members_list(members, is_owner)


func _populate_members_list(members: Array, can_manage_roles: bool) -> void:
	_clear_children(members_list_container)

	for m in members:
		var uid: int = int(m.get("user_id", 0))
		var uname: String = "User #%d" % uid
		if m.has("user") and m["user"] is Dictionary:
			uname = str(m["user"].get("username", uname))
		var role: String = str(m.get("role", "member"))

		var hbox := HBoxContainer.new()
		hbox.add_theme_constant_override("separation", 12)

		var name_lbl := Label.new()
		name_lbl.text = "%s (ID: %d)" % [uname, uid]
		name_lbl.size_flags_horizontal = Control.SIZE_EXPAND_FILL
		hbox.add_child(name_lbl)

		var role_badge := Label.new()
		role_badge.text = "[%s]" % role.to_upper()
		if role == "owner":
			role_badge.modulate = Color(1.0, 0.8, 0.2)
		elif role == "admin":
			role_badge.modulate = Color(0.4, 0.8, 1.0)
		else:
			role_badge.modulate = Color(0.7, 0.7, 0.7)
		hbox.add_child(role_badge)

		# Role selector for owner (excluding self/owner)
		if can_manage_roles and role != "owner":
			var opt := OptionButton.new()
			opt.add_item("Member")
			opt.add_item("Admin")
			opt.selected = 1 if role == "admin" else 0
			opt.item_selected.connect(func(idx: int): _on_role_changed(uid, "admin" if idx == 1 else "member"))
			hbox.add_child(opt)

			var xfer_btn := Button.new()
			xfer_btn.text = "Make Owner"
			xfer_btn.pressed.connect(func(): _on_transfer_ownership(uid))
			hbox.add_child(xfer_btn)

		members_list_container.add_child(hbox)


func _on_join_pressed() -> void:
	if _api_client == null or _active_group_id <= 0:
		return
	var res: Dictionary = await _api_client.join_group(_active_group_id)
	if res.ok:
		show_message("Joined group!")
		refresh_group_page(_active_group_id)
	else:
		show_message("Failed to join group: " + res.detail, true)


func _on_leave_pressed() -> void:
	if _api_client == null or _active_group_id <= 0:
		return
	var res: Dictionary = await _api_client.leave_group(_active_group_id)
	if res.ok:
		show_message("Left group.")
		refresh_group_page(_active_group_id)
	else:
		show_message("Failed to leave group: " + res.detail, true)


func _on_delete_pressed() -> void:
	if _api_client == null or _active_group_id <= 0:
		return
	var res: Dictionary = await _api_client.delete_group(_active_group_id)
	if res.ok:
		show_message("Group deleted.")
		tab_container.current_tab = 0
		refresh_groups()
	else:
		show_message("Failed to delete group: " + res.detail, true)


func _on_role_changed(uid: int, new_role: String) -> void:
	if _api_client == null or _active_group_id <= 0:
		return
	var res: Dictionary = await _api_client.set_group_member_role(_active_group_id, uid, new_role)
	if res.ok:
		show_message("Role updated to %s." % new_role)
		refresh_group_page(_active_group_id)
	else:
		show_message("Failed to change role: " + res.detail, true)


func _on_transfer_ownership(new_owner_id: int) -> void:
	if _api_client == null or _active_group_id <= 0:
		return
	var res: Dictionary = await _api_client.transfer_group_ownership(_active_group_id, new_owner_id)
	if res.ok:
		show_message("Ownership transferred to User #%d!" % new_owner_id)
		refresh_group_page(_active_group_id)
	else:
		show_message("Failed to transfer ownership: " + res.detail, true)


func _clear_children(node: Node) -> void:
	if node == null:
		return
	for c in node.get_children():
		c.queue_free()