rimlike/scenes/world/designation.gd

extends Node
class_name Designation
## Phase 5 — Designation paint mode.
##
## Captures mouse input to drag-paint ghost tiles on Layer 3 (designation_layer)
## of the world TileMap.  Each new cell painted emits EventBus.designation_added;
## removing a ghost emits EventBus.designation_cleared.
##
## Integrates with Selection: raises Selection.designation_active while a non-none
## tool is active so Selection does not also process those clicks.
##
## Opus wires the node into world.tscn and calls bind() + set_active_tool() from
## the build-drawer UI.

# ── tool constants ───────────────────────────────────────────────────────────
const TOOL_NONE:        StringName = &"none"
const TOOL_BUILD_WALL:  StringName = &"build_wall"
const TOOL_BUILD_FLOOR: StringName = &"build_floor"
const TOOL_BUILD_DOOR:  StringName = &"build_door"

# Atlas coords on the shared placeholder tileset (source 0).
# build_wall → stone-grey (2, 0); build_floor → dirt-brown (1, 0).
# build_door → dark stone (3, 0) so the ghost reads visually distinct from walls.
const _ATLAS_BY_TOOL: Dictionary = {
	&"build_wall":  Vector2i(2, 0),
	&"build_floor": Vector2i(1, 0),
	&"build_door":  Vector2i(3, 0),
}

# Placeholder source ID — mirrors World.PLACEHOLDER_SOURCE_ID.
const _SOURCE_ID: int = 0

# Tile-size in pixels — mirrors World.TILE_SIZE_PX.
const _TILE_SIZE_PX: float = 16.0

# ── signals ──────────────────────────────────────────────────────────────────
signal designation_added(cell: Vector2i, tool: StringName)
signal designation_cleared(cell: Vector2i)

# ── state ────────────────────────────────────────────────────────────────────
var _tool:       StringName  = TOOL_NONE
var _paint_layer: TileMapLayer = null
var _selection: Selection    = null   # optional; raised/lowered for input hand-off

# cell → tool that placed the ghost.
var _painted: Dictionary = {}  # Dictionary[Vector2i, StringName]

# Stroke deduplication — cells touched in the current mouse-down session.
var _stroke_cells: Dictionary = {}  # Dictionary[Vector2i, bool]
var _stroke_active: bool = false


# ── public API ───────────────────────────────────────────────────────────────

## Call once from World._ready() with the TileMapLayer at index 3 (Designation)
## and the sibling Selection node.
func bind(paint_layer: TileMapLayer, selection: Selection = null) -> void:
	assert(paint_layer != null, "Designation.bind: paint_layer is null")
	_paint_layer = paint_layer
	_selection   = selection


## Activate a paint tool.  Pass TOOL_NONE to deactivate.
func set_active_tool(tool: StringName) -> void:
	assert(
		tool in [TOOL_NONE, TOOL_BUILD_WALL, TOOL_BUILD_FLOOR, TOOL_BUILD_DOOR],
		"Designation.set_active_tool: unknown tool '%s'" % tool
	)
	_tool = tool
	_stroke_active = false
	_stroke_cells.clear()
	_sync_selection_flag()
	if tool == TOOL_NONE:
		Audit.log("designation", "tool deactivated")
	else:
		Audit.log("designation", "tool set to '%s'" % tool)


func active_tool() -> StringName:
	return _tool


## Remove the ghost for a single cell and emit designation_cleared.
func clear_cell(cell: Vector2i) -> void:
	if not _painted.has(cell):
		return
	_painted.erase(cell)
	if _paint_layer != null:
		_paint_layer.erase_cell(cell)
	designation_cleared.emit(cell)
	EventBus.designation_cleared.emit(cell)
	Audit.log("designation", "cleared cell %s" % cell)


## Returns all cells that currently have an active ghost.
func cells() -> Array[Vector2i]:
	var result: Array[Vector2i] = []
	for c: Vector2i in _painted.keys():
		result.append(c)
	return result


# ── input ────────────────────────────────────────────────────────────────────

func _unhandled_input(event: InputEvent) -> void:
	if _tool == TOOL_NONE or _paint_layer == null:
		return

	if event is InputEventMouseButton and event.button_index == MOUSE_BUTTON_LEFT:
		if event.pressed:
			_stroke_active = true
			_stroke_cells.clear()
			_paint_at_screen(event.position)
		else:
			_stroke_active = false
			_stroke_cells.clear()
		get_viewport().set_input_as_handled()
		return

	if event is InputEventMouseMotion and _stroke_active:
		_paint_at_screen(event.position)
		get_viewport().set_input_as_handled()


# ── helpers ──────────────────────────────────────────────────────────────────

func _paint_at_screen(screen_pos: Vector2) -> void:
	var world_pos: Vector2 = get_viewport().get_canvas_transform().affine_inverse() * screen_pos
	var cell := Vector2i(
		floori(world_pos.x / _TILE_SIZE_PX),
		floori(world_pos.y / _TILE_SIZE_PX),
	)

	# Deduplication within the current stroke.
	if _stroke_cells.has(cell):
		return
	_stroke_cells[cell] = true

	# Don't re-paint the same tool over itself.
	if _painted.get(cell) == _tool:
		return

	_apply_ghost(cell)


func _apply_ghost(cell: Vector2i) -> void:
	var atlas_coord: Vector2i = _ATLAS_BY_TOOL.get(_tool, Vector2i(2, 0))
	_paint_layer.set_cell(cell, _SOURCE_ID, atlas_coord)
	_painted[cell] = _tool

	# Modulate the whole paint layer based on whether this cell is placeable.
	# Phase 5 simplification: validity applies globally to the layer.
	var ok: bool = _cell_is_placeable(cell)
	_paint_layer.modulate = Color(0.4, 1.0, 0.4, 0.7) if ok else Color(1.0, 0.4, 0.4, 0.7)

	designation_added.emit(cell, _tool)
	EventBus.designation_added.emit(cell, _tool)
	Audit.log("designation", "painted %s at %s (placeable=%s)" % [_tool, cell, ok])


func _cell_is_placeable(cell: Vector2i) -> bool:
	# For Phase 5: a cell is placeable for build_wall if it is currently walkable
	# (no wall present), and for build_floor if it is walkable.  Items-on-tile
	# check is deferred to Phase 5 BuildJob validation; we only gate on geometry here.
	if World.pathfinder == null:
		return true
	return World.pathfinder.is_walkable(cell)


func _sync_selection_flag() -> void:
	if _selection == null:
		return
	_selection.designation_active = (_tool != TOOL_NONE)