## MapWorkshop — In-game Workshop-style Map Browser
##
## Full-screen UI for browsing, downloading, and managing community maps.
## Two tabs: "Installed" (local cache) and "Online" (registry server).
## Follows the visual style of the existing ServerBrowserUI.
##
## Signals:
##   map_selected(map_name: String)  — Player clicked "Play" on a map
##
## Usage:
##   var workshop = preload("res://client/scripts/map_workshop.gd").new()
##   add_child(workshop)
##   workshop.show_tab("online")  # or "installed"

extends Control

signal map_selected(map_name: String)

# ---------------------------------------------------------------------------
# Constants
# ---------------------------------------------------------------------------

const COL_WIDTHS := {
	"name": 0.32,
	"version": 0.08,
	"size": 0.10,
	"status": 0.20,
	"action": 0.30,
}

const SIZE_SUFFIXES := ["B", "KB", "MB", "GB"]

# ---------------------------------------------------------------------------
# State
# ---------------------------------------------------------------------------

var _current_tab: String = "installed"  # "installed" or "online"
var _registry_maps: Array[Dictionary] = []
var _cached_maps: Array[String] = []
var _downloading: Dictionary = {}       # map_name → float (progress 0.0-1.0)

# UI nodes
var _panel: Panel
var _title_label: Label
var _tab_installed: Button
var _tab_online: Button
var _filter_edit: LineEdit
var _map_list: ItemList
var _status_label: Label
var _action_button: Button
var _close_button: Button
var _refresh_button: Button

# ---------------------------------------------------------------------------
# Lifecycle
# ---------------------------------------------------------------------------

func _ready() -> void:
	_build_ui()

	# Hook into MapDownloader signals
	if Engine.has_singleton("MapDownloader"):
		var md = Engine.get_singleton("MapDownloader")
		md.map_list_loaded.connect(_on_map_list_loaded)
		md.map_download_complete.connect(_on_download_complete)
		md.map_loaded.connect(_on_map_loaded)

	# Load initial data
	_refresh_installed()
	_refresh_online()

func _build_ui() -> void:
	# Main panel
	_panel = Panel.new()
	_panel.name = "WorkshopPanel"
	_panel.anchor_right = 1.0
	_panel.anchor_bottom = 1.0
	add_child(_panel)

	var margin := 8
	var style = StyleBoxFlat.new()
	style.bg_color = Color(0.12, 0.12, 0.14, 0.95)
	style.corner_radius_top_left = 4
	style.corner_radius_top_right = 4
	style.corner_radius_bottom_left = 4
	style.corner_radius_bottom_right = 4
	style.content_margin_left = margin
	style.content_margin_top = margin
	style.content_margin_right = margin
	style.content_margin_bottom = margin
	_panel.add_theme_stylebox_override("panel", style)

	# Title
	_title_label = Label.new()
	_title_label.name = "TitleLabel"
	_title_label.text = "MAP WORKSHOP"
	_title_label.horizontal_alignment = HORIZONTAL_ALIGNMENT_CENTER
	_title_label.add_theme_font_size_override("font_size", 18)
	_title_label.add_theme_color_override("font_color", Color(1.0, 0.84, 0.0))  # gold
	_title_label.position = Vector2(margin, margin)
	_panel.add_child(_title_label)

	# Tab buttons
	_tab_installed = Button.new()
	_tab_installed.name = "TabInstalled"
	_tab_installed.text = "Installed"
	_tab_installed.toggle_mode = true
	_tab_installed.button_pressed = true
	_tab_installed.pressed.connect(_on_tab_changed.bind("installed"))
	_panel.add_child(_tab_installed)

	_tab_online = Button.new()
	_tab_online.name = "TabOnline"
	_tab_online.text = "Online"
	_tab_online.toggle_mode = true
	_tab_online.pressed.connect(_on_tab_changed.bind("online"))
	_panel.add_child(_tab_online)

	# Filter
	_filter_edit = LineEdit.new()
	_filter_edit.name = "FilterEdit"
	_filter_edit.placeholder_text = "Filter maps by name..."
	_filter_edit.text_changed.connect(_on_filter_changed)
	_panel.add_child(_filter_edit)

	# Map list
	_map_list = ItemList.new()
	_map_list.name = "MapList"
	_map_list.allow_reselect = false
	_map_list.select_mode = ItemList.SELECT_SINGLE
	_map_list.item_selected.connect(_on_map_selected)
	_map_list.nothing_selected.connect(_clear_selection)
	_panel.add_child(_map_list)

	# Action button (changes context: "Play" / "Download" / "Remove")
	_action_button = Button.new()
	_action_button.name = "ActionButton"
	_action_button.text = "—"
	_action_button.disabled = true
	_action_button.pressed.connect(_on_action_pressed)
	_panel.add_child(_action_button)

	# Refresh button
	_refresh_button = Button.new()
	_refresh_button.name = "RefreshButton"
	_refresh_button.text = "↻ Refresh"
	_refresh_button.pressed.connect(_on_refresh_pressed)
	_panel.add_child(_refresh_button)

	# Status bar
	_status_label = Label.new()
	_status_label.name = "StatusLabel"
	_status_label.text = "Ready"
	_status_label.horizontal_alignment = HORIZONTAL_ALIGNMENT_CENTER
	_status_label.add_theme_color_override("font_color", Color(0.6, 0.6, 0.6))
	_panel.add_child(_status_label)

	# Close button
	_close_button = Button.new()
	_close_button.name = "CloseButton"
	_close_button.text = "✕"
	_close_button.pressed.connect(_on_close_pressed)
	_panel.add_child(_close_button)

func _notification(what: int) -> void:
	if what == NOTIFICATION_RESIZED or what == NOTIFICATION_SORT_CHILDREN:
		_resize_ui()

func _resize_ui() -> void:
	var w = _panel.size.x
	var h = _panel.size.y
	var m := 8
	var y := m

	# Title
	_title_label.position = Vector2(m, y)
	_title_label.size = Vector2(w - m * 2, 24)
	y += 30

	# Tabs row
	var tab_w = (w - m * 3) / 2
	_tab_installed.position = Vector2(m, y)
	_tab_installed.size = Vector2(tab_w, 26)
	_tab_online.position = Vector2(m + tab_w + m, y)
	_tab_online.size = Vector2(tab_w, 26)
	y += 34

	# Filter
	_filter_edit.position = Vector2(m, y)
	_filter_edit.size = Vector2(w - m * 2, 24)
	y += 32

	# Map list
	var list_height = h - y - 80
	_map_list.position = Vector2(m, y)
	_map_list.size = Vector2(w - m * 2, max(list_height, 60))
	y += _map_list.size.y + 8

	# Buttons row
	var btn_w = (w - m * 3) / 3
	_action_button.position = Vector2(m, y)
	_action_button.size = Vector2(btn_w, 28)

	_refresh_button.position = Vector2(m + btn_w + m / 2, y)
	_refresh_button.size = Vector2(btn_w, 28)

	y += 36

	# Status
	_status_label.position = Vector2(m, y)
	_status_label.size = Vector2(w - m * 2, 20)

	# Close button (top-right corner)
	_close_button.position = Vector2(w - 28, 4)
	_close_button.size = Vector2(24, 24)

# ---------------------------------------------------------------------------
# Public API
# ---------------------------------------------------------------------------

## Open to a specific tab.
func show_tab(tab: String) -> void:
	match tab:
		"installed":
			_tab_installed.button_pressed = true
			_tab_online.button_pressed = false
			_current_tab = "installed"
			_populate_list()
		"online":
			_tab_installed.button_pressed = false
			_tab_online.button_pressed = true
			_current_tab = "online"
			_refresh_online()
			_populate_list()

# ---------------------------------------------------------------------------
# Data
# ---------------------------------------------------------------------------

func _refresh_installed() -> void:
	if Engine.has_singleton("MapDownloader"):
		var md = Engine.get_singleton("MapDownloader")
		_cached_maps = md.get_cached_maps()
	else:
		_cached_maps = []

func _refresh_online() -> void:
	if Engine.has_singleton("MapDownloader"):
		var md = Engine.get_singleton("MapDownloader")
		md.fetch_map_list()
		_status_label.text = "Fetching map list..."
	else:
		_status_label.text = "MapDownloader not available"

# ---------------------------------------------------------------------------
# List population
# ---------------------------------------------------------------------------

func _populate_list() -> void:
	_map_list.clear()
	_action_button.disabled = true
	_action_button.text = "—"

	var filter_text = _filter_edit.text.strip_edges().to_lower()

	match _current_tab:
		"installed":
			_populate_installed(filter_text)
		"online":
			_populate_online(filter_text)

func _populate_installed(filter_text: String) -> void:
	if _cached_maps.is_empty():
		_map_list.add_item("  No maps installed")
		_status_label.text = "No maps cached. Switch to Online tab to download maps."
		return

	if Engine.has_singleton("MapDownloader"):
		var md = Engine.get_singleton("MapDownloader")
		var count := 0

		for name in _cached_maps:
			if not filter_text.is_empty() and not name.to_lower().contains(filter_text):
				continue

			var info = md.get_cached_map_info(name)
			var size_bytes = info.get("size", 0)
			var version = info.get("version", 1)

			var size_str = _format_size(size_bytes)
			var status = "Ready"
			var icon = "✓"

			var label = "%s %s  v%d  %s  %s" % [icon, name, version, size_str, status]
			_map_list.add_item(label)
			count += 1

		_status_label.text = "%d installed map(s)" % count
	else:
		_map_list.add_item("  MapDownloader not loaded")
		_status_label.text = "MapDownloader singleton not found"

func _populate_online(filter_text: String) -> void:
	if _registry_maps.is_empty():
		_map_list.add_item("  Fetching map list... (press Refresh)")
		_status_label.text = "No maps from registry yet"
		return

	if Engine.has_singleton("MapDownloader"):
		var md = Engine.get_singleton("MapDownloader")
		var count := 0

		for m in _registry_maps:
			if not (m is Dictionary):
				continue

			var name: String = m.get("name", "")
			if name.is_empty():
				continue

			if not filter_text.is_empty() and not name.to_lower().contains(filter_text):
				continue

			var size_bytes = m.get("size", 0)
			var description = m.get("description", "")
			var reg_version = m.get("version", 1)

			var is_cached = md.is_map_cached(name)
			var cached_version = md.get_cached_version(name) if is_cached else 0
			var needs_update = is_cached and reg_version > cached_version

			var status: String
			var icon: String
			if _downloading.has(name):
				status = "Downloading..."
				icon = "⏳"
			elif needs_update:
				status = "Update available"
				icon = "↑"
			elif is_cached:
				status = "Installed"
				icon = "✓"
			else:
				status = description if not description.is_empty() else "Not installed"
				icon = "+"

			var size_str = _format_size(size_bytes)
			var label = "%s %s  v%d  %s  %s" % [icon, name, reg_version, size_str, status]
			_map_list.add_item(label)
			count += 1

		_status_label.text = "%d map(s) on registry" % count
	else:
		_status_label.text = "MapDownloader not available"

# ---------------------------------------------------------------------------
# UI callbacks
# ---------------------------------------------------------------------------

func _on_tab_changed(tab: String) -> void:
	_current_tab = tab

	# Update toggle states
	_tab_installed.button_pressed = (tab == "installed")
	_tab_online.button_pressed = (tab == "online")

	if tab == "installed":
		_refresh_installed()
	elif tab == "online":
		_refresh_online()

	_populate_list()

func _on_filter_changed(_new_text: String) -> void:
	_populate_list()

func _on_map_selected(index: int) -> void:
	if index < 0:
		_clear_selection()
		return

	var label: String = _map_list.get_item_text(index)
	if label.begins_with("  "):
		_clear_selection()
		return

	# Parse the map name from the label (skipping icon prefix)
	var map_name = _extract_map_name(label)
	if map_name.is_empty():
		_clear_selection()
		return

	match _current_tab:
		"installed":
			_action_button.disabled = false
			_action_button.text = "► Play"
		"online":
			if Engine.has_singleton("MapDownloader"):
				var md = Engine.get_singleton("MapDownloader")
				if md.is_map_cached(map_name):
					_action_button.disabled = false
					_action_button.text = "► Play"
				else:
					_action_button.disabled = false
					_action_button.text = "↓ Download"
			else:
				_action_button.disabled = true
				_action_button.text = "—"

func _clear_selection() -> void:
	_action_button.disabled = true
	_action_button.text = "—"

func _on_action_pressed() -> void:
	var selected = _map_list.get_selected_items()
	if selected.is_empty():
		return

	var index = selected[0]
	var label = _map_list.get_item_text(index)
	var map_name = _extract_map_name(label)
	if map_name.is_empty():
		return

	var action = _action_button.text

	if action.contains("Play"):
		map_selected.emit(map_name)
	elif action.contains("Download"):
		_start_download(map_name)

func _on_refresh_pressed() -> void:
	match _current_tab:
		"installed":
			_refresh_installed()
		"online":
			_refresh_online()
	_populate_list()
	_status_label.text = "Refreshed"

func _on_close_pressed() -> void:
	queue_free()

# ---------------------------------------------------------------------------
# Download handling
# ---------------------------------------------------------------------------

func _start_download(map_name: String) -> void:
	_downloading[map_name] = 0.0

	if Engine.has_singleton("MapDownloader"):
		var md = Engine.get_singleton("MapDownloader")
		md.download_map(map_name)

	_status_label.text = "Downloading %s..." % map_name
	_populate_list()

func _on_map_list_loaded(maps: Array) -> void:
	_registry_maps = maps
	if _current_tab == "online":
		_populate_list()

func _on_download_complete(map_name: String, success: bool) -> void:
	_downloading.erase(map_name)

	if success:
		_status_label.text = "%s downloaded and loaded" % map_name
		_refresh_installed()
	else:
		_status_label.text = "Download failed: %s" % map_name

	if _current_tab == "online":
		_populate_list()

func _on_map_loaded(map_name: String) -> void:
	print("[MapWorkshop] Map loaded: %s" % map_name)
	# The caller can now load res://scenes/maps/<name>.tscn

# ---------------------------------------------------------------------------
# Helpers
# ---------------------------------------------------------------------------

## Extract the map name from a formatted list item label.
## Labels are formatted: "✓ map_name  v1  12.3 MB  Ready"
func _extract_map_name(label: String) -> String:
	# Skip the first character (icon) and space
	if label.length() < 3:
		return ""
	var rest = label.substr(2).strip_edges()
	# The map name runs until we hit two consecutive spaces or " v"
	var v_idx = rest.find("  v")
	if v_idx < 0:
		v_idx = rest.find("  v")
		if v_idx < 0:
			v_idx = rest.find(" v")
	if v_idx > 0:
		return rest.substr(0, v_idx).strip_edges()
	return rest.strip_edges()

## Format bytes to human-readable size.
static func _format_size(bytes: int) -> String:
	if bytes <= 0:
		return "0 B"

	var unit_idx := 0
	var size := float(bytes)
	while size >= 1024.0 and unit_idx < SIZE_SUFFIXES.size() - 1:
		size /= 1024.0
		unit_idx += 1

	if unit_idx == 0:
		return "%d %s" % [bytes, SIZE_SUFFIXES[unit_idx]]
	return "%.1f %s" % [size, SIZE_SUFFIXES[unit_idx]]