@tool
class_name TerrainBlock
extends StaticBody2D
## TerrainBlock - Reusable StaticBody2D vector-terrain component (Phase 1).
##
## A self-contained terrain block: a StaticBody2D root with three children built
## in code — a Polygon2D (interior fill), a Line2D (crisp vector outline, closed
## by appending the first vertex, rounded joints/caps), and a CollisionPolygon2D
## configured with BUILD_SOLIDS so concave terrain blocks collide correctly.
## Fully @tool: exported properties update the children live in the editor.

# ---------------------------------------------------------------------------
# Child node names
# ---------------------------------------------------------------------------

const POLYGON_NODE_NAME := "Polygon2D"
const OUTLINE_NODE_NAME := "Outline"
const COLLISION_NODE_NAME := "CollisionPolygon2D"

# ---------------------------------------------------------------------------
# Exported properties
# ---------------------------------------------------------------------------

## The terrain polygon's vertices (local space). The unified setter pushes the
## array to the Polygon2D and CollisionPolygon2D, and closes the Line2D loop by
## appending the first vertex to the end.
@export var polygon_points: PackedVector2Array = PackedVector2Array():
	set(value):
		polygon_points = value
		_apply_points()

## Interior fill color (Polygon2D).
@export var fill_color: Color = Color(0.25, 0.55, 0.25, 1.0):
	set(value):
		fill_color = value
		if _polygon != null:
			_polygon.color = value

## Outline color (Line2D).
@export var outline_color: Color = Color(0.05, 0.10, 0.05, 1.0):
	set(value):
		outline_color = value
		if _outline != null:
			_outline.default_color = value

## Outline width in pixels (Line2D).
@export var outline_width: float = 2.0:
	set(value):
		outline_width = value
		if _outline != null:
			_outline.width = value

# ---------------------------------------------------------------------------
# Internal node references (built in _ready, @tool-safe)
# ---------------------------------------------------------------------------

var _polygon: Polygon2D
var _outline: Line2D
var _collision: CollisionPolygon2D

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

func _ready() -> void:
	_ensure_children()
	_apply_points()
	_apply_style()

# ---------------------------------------------------------------------------
# Internal build / apply
# ---------------------------------------------------------------------------

func _ensure_children() -> void:
	_polygon = get_node_or_null(NodePath(POLYGON_NODE_NAME)) as Polygon2D
	if _polygon == null:
		_polygon = Polygon2D.new()
		_polygon.name = POLYGON_NODE_NAME
		add_child(_polygon)

	_outline = get_node_or_null(NodePath(OUTLINE_NODE_NAME)) as Line2D
	if _outline == null:
		_outline = Line2D.new()
		_outline.name = OUTLINE_NODE_NAME
		_outline.joint_mode = Line2D.LINE_JOINT_ROUND
		_outline.begin_cap_mode = Line2D.LINE_CAP_ROUND
		_outline.end_cap_mode = Line2D.LINE_CAP_ROUND
		add_child(_outline)

	_collision = get_node_or_null(NodePath(COLLISION_NODE_NAME)) as CollisionPolygon2D
	if _collision == null:
		_collision = CollisionPolygon2D.new()
		_collision.name = COLLISION_NODE_NAME
		_collision.build_mode = CollisionPolygon2D.BUILD_SOLIDS
		add_child(_collision)


## Pushes the current polygon_points to the Polygon2D and CollisionPolygon2D,
## and appends the first vertex to the Line2D to close the border loop.
func _apply_points() -> void:
	if _polygon != null:
		_polygon.polygon = polygon_points
	if _collision != null:
		_collision.polygon = polygon_points if polygon_points.size() >= 3 else PackedVector2Array()
	if _outline != null:
		var outline_points := polygon_points.duplicate()
		if not outline_points.is_empty():
			outline_points.append(polygon_points[0])
		_outline.points = outline_points


func _apply_style() -> void:
	if _polygon != null:
		_polygon.color = fill_color
	if _outline != null:
		_outline.default_color = outline_color
		_outline.width = outline_width