class_name BrowserIndexScreen
extends Control
## Index screen for one entity kind in the data browser (T-1133, D-254 §4).
## A scrollable ImplantDataRow list (primary + secondary summary column),
## filterable by a live-typed search string. One instance handles all six
## kinds — parameterized by set_kind(), not six near-duplicate screens.
##
## Filtering (D-254 §4: "filterable/searchable by name"): typed characters
## append to the search buffer and re-filter live; Backspace removes the
## last character; the implant has no OS textbox, so this is the same
## "keyboard IS the input surface" convention the Atlas/Economics apps
## already use for navigation.

signal row_selected(entity_id: String)
signal back_requested

const COLOR_BG: Color = Color("#0d1117")
const PANEL_WIDTH: float = 460.0
const PANEL_MARGIN: float = 16.0
const LIST_MAX_HEIGHT: float = 520.0

var _kind: String = ""
var _all_rows: Array = []  # BrowserAdapter row view-models, unfiltered
var _filtered_rows: Array = []
var _selected_idx: int = 0
var _search: String = ""
var _loading: bool = false
var _error: String = ""

var _panel = null  # ImplantPanel
var _scroll: ScrollContainer = null
var _list_box: VBoxContainer = null
var _implant_theme = null  # ImplantTheme
var _row_labels: Array = []  # Array[ImplantDataRow], one per filtered row
var _pending: ImplantPending = null


func _ready() -> void:
	mouse_filter = Control.MOUSE_FILTER_STOP
	set_anchors_and_offsets_preset(Control.PRESET_FULL_RECT)


func _draw() -> void:
	draw_rect(Rect2(Vector2.ZERO, get_rect().size), COLOR_BG)


func setup(implant_theme) -> void:
	_implant_theme = implant_theme
	_build_panel()
	_build_pending(implant_theme)


## Set the entity kind this screen shows and (re)issue the index request.
## filter_system_id is forwarded to SimBridge.request_browse_index — only
## meaningful for kind == BrowserAdapter.KIND_BODY.
func set_kind(kind: String, filter_system_id: String = "") -> void:
	_kind = kind
	_all_rows = []
	_filtered_rows = []
	_selected_idx = 0
	_search = ""
	_error = ""
	_loading = true
	_rebuild_list()
	if _pending:
		_pending.start("QUERYING " + BrowserAdapter.kind_label(kind))
	SimBridge.request_browse_index(kind, filter_system_id)


## Feed a decoded BrowseResponse (SimBridge.browse_response_received handler,
## owned by BrowserApp) into this screen. Ignored if the response's kind
## doesn't match what this screen currently shows (a stale response arriving
## after the player already navigated elsewhere).
func receive_response(response: Dictionary) -> void:
	if response.get("kind", "") != _kind:
		return
	_loading = false
	if _pending:
		_pending.stop()
	var status: String = BrowserAdapter.response_status(response)
	if status == "Error":
		_error = BrowserAdapter.response_error(response)
		_all_rows = []
	else:
		_error = ""
		_all_rows = BrowserAdapter.index_rows(response)
	_apply_filter()


func enter(payload: Dictionary) -> void:
	var kind: String = payload.get("kind", "")
	var filter_system_id: String = payload.get("filter_system_id", "")
	if kind != _kind or _all_rows.is_empty():
		set_kind(kind, filter_system_id)
	else:
		_rebuild_list()


func leave() -> void:
	pass


func current_kind() -> String:
	return _kind


func has_selection() -> bool:
	return not _filtered_rows.is_empty()


func selected_entity_id() -> String:
	if _filtered_rows.is_empty():
		return ""
	_selected_idx = clampi(_selected_idx, 0, _filtered_rows.size() - 1)
	return str(_filtered_rows[_selected_idx].get("id", ""))


func trigger_enter() -> void:
	if has_selection():
		row_selected.emit(selected_entity_id())


func navigate(delta: int) -> void:
	if _filtered_rows.is_empty():
		return
	_selected_idx = wrapi(_selected_idx + delta, 0, _filtered_rows.size())
	_rebuild_list()


## Append a character to the live search filter. Called from BrowserApp's
## key handler for printable keys while this screen is current.
func append_search_char(ch: String) -> void:
	_search += ch
	_apply_filter()


func backspace_search() -> void:
	if _search.is_empty():
		return
	_search = _search.substr(0, _search.length() - 1)
	_apply_filter()


func clear_search() -> void:
	if _search.is_empty():
		return
	_search = ""
	_apply_filter()


func has_search_text() -> bool:
	return not _search.is_empty()


func _apply_filter() -> void:
	_filtered_rows = BrowserAdapter.filter_rows(_all_rows, _search)
	_selected_idx = 0
	_rebuild_list()


# =============================================================================
# Panel / list
# =============================================================================


func _build_panel() -> void:
	_panel = ImplantPanel.new()
	_panel.name = "IndexPanel"
	_panel.theme_resource = _implant_theme
	_panel.custom_minimum_size.x = PANEL_WIDTH
	_panel.mouse_filter = Control.MOUSE_FILTER_IGNORE
	_panel.position = Vector2(PANEL_MARGIN, PANEL_MARGIN)
	add_child(_panel)


func _build_pending(implant_theme) -> void:
	_pending = ImplantPending.new()
	_pending.apply_implant_theme(implant_theme)
	_pending.position = Vector2(PANEL_MARGIN + PANEL_WIDTH + 24.0, PANEL_MARGIN)
	add_child(_pending)


func _rebuild_list() -> void:
	if not _panel:
		return
	_panel.clear()
	_row_labels.clear()

	var subtitle: String = "%d / %d" % [_filtered_rows.size(), _all_rows.size()]
	_panel.add_component(ImplantHeader.new(BrowserAdapter.kind_label(_kind), subtitle))
	_panel.add_component(ImplantSeparator.new())

	var search_line: String = "search  " + (_search if not _search.is_empty() else "—")
	_panel.add_component(ImplantDataRow.new(search_line))
	_panel.add_component(ImplantSeparator.new())

	if _loading:
		_panel.add_component(ImplantTextBlock.new("querying registry…"))
	elif not _error.is_empty():
		_panel.add_component(ImplantTextBlock.new("[ERROR] " + _error))
	elif _filtered_rows.is_empty():
		var msg: String = "no matches" if not _search.is_empty() else "no entries"
		_panel.add_component(ImplantTextBlock.new(msg))
	else:
		_build_scroll_list()

	_panel.add_component(ImplantSeparator.new())
	_panel.add_component(
		ImplantTextBlock.new("↑ ↓  select    enter  open    type  search    esc  back")
	)


func _build_scroll_list() -> void:
	_scroll = ScrollContainer.new()
	_scroll.custom_minimum_size = Vector2(PANEL_WIDTH, minf(LIST_MAX_HEIGHT, _list_natural_height()))
	_scroll.horizontal_scroll_mode = ScrollContainer.SCROLL_MODE_DISABLED
	_panel.add_component(_scroll)

	_list_box = VBoxContainer.new()
	_list_box.add_theme_constant_override("separation", 0)
	_list_box.size_flags_horizontal = Control.SIZE_EXPAND_FILL
	_scroll.add_child(_list_box)

	for i: int in range(_filtered_rows.size()):
		var row: Dictionary = _filtered_rows[i]
		var primary: String = str(row.get("primary", ""))
		var secondary: String = str(row.get("secondary", ""))
		var text: String = primary
		if not secondary.is_empty():
			text += "   ·   " + secondary
		var prefix: String = "▸ " if i == _selected_idx else "  "
		var label := ImplantDataRow.new(prefix + text)
		if _implant_theme:
			label.apply_implant_theme(_implant_theme)
		_list_box.add_child(label)
		_row_labels.append(label)

	_scroll_to_selected()


func _list_natural_height() -> float:
	var line_h: float = float(_implant_theme.line_height) if _implant_theme else 18.0
	return float(_filtered_rows.size()) * line_h


func _scroll_to_selected() -> void:
	if not _scroll or _row_labels.is_empty():
		return
	_selected_idx = clampi(_selected_idx, 0, _row_labels.size() - 1)
	var target: Control = _row_labels[_selected_idx]
	# ensure_control_visible needs one layout pass to have valid rects on a
	# freshly-built list — defer so the ScrollContainer has sized itself.
	_scroll.ensure_control_visible.call_deferred(target)