extends Control
class_name BoltRule

## A lightning bolt struck through a horizontal rule.
##
## The motif the whole UI is built around, in one reusable widget: menus use it
## as a section divider, the HUD uses it to underline a heading. It is drawn
## rather than shipped as an image so it takes the theme's colours and scales to
## any width without a second asset.
##
## The zigzag is deliberately not centred. A bolt centred in its rule reads as an
## ornament; struck a third of the way along, it reads as something that HIT the
## line — which is the difference between decorative and energetic.

@export var line_color: Color = Color(1.0, 0.47, 0.10)
@export var bolt_color: Color = Color(1.0, 0.93, 0.22)
@export var ink: Color = Color(0.045, 0.040, 0.075)
## Where along the rule the bolt strikes, 0..1.
@export var strike_at: float = 0.34
@export var thickness: float = 3.0


func _init() -> void:
	custom_minimum_size = Vector2(0, 22)
	mouse_filter = Control.MOUSE_FILTER_IGNORE


func _draw() -> void:
	var w := size.x
	var h := size.y
	if w <= 1.0:
		return
	var mid := h * 0.5
	var strike := w * clampf(strike_at, 0.05, 0.95)
	var half := h * 0.42

	# The rule, broken where the bolt lands so the bolt reads as passing
	# THROUGH it rather than sitting on top.
	var gap := h * 0.55
	draw_line(Vector2(0, mid), Vector2(maxf(0.0, strike - gap), mid),
		line_color, thickness)
	draw_line(Vector2(minf(w, strike + gap), mid), Vector2(w, mid),
		line_color, thickness)

	# The bolt, as a SIMPLE polygon — six points, no edge crossing another.
	# `draw_colored_polygon` triangulates, and a self-intersecting outline fails
	# triangulation outright and draws nothing but a console full of "Invalid
	# polygon data". The obvious zigzag (down-right, back-left, down-right)
	# crosses itself; this is the same silhouette walked as a closed loop
	# instead: down the left edge, out to the tip, back up the right edge.
	var pts := PackedVector2Array([
		Vector2(strike + half * 0.55, mid - half),          # top, right of centre
		Vector2(strike - half * 0.45, mid + half * 0.05),   # down-left to the notch
		Vector2(strike + half * 0.00, mid + half * 0.05),   # step right
		Vector2(strike - half * 0.35, mid + half),          # down-left to the tip
		Vector2(strike + half * 0.55, mid - half * 0.15),   # back up the right edge
		Vector2(strike + half * 0.10, mid - half * 0.15),   # step left
	])
	draw_colored_polygon(pts, bolt_color)
	# Ink edge ON TOP as a closed polyline, not as a second, larger polygon —
	# growing a concave shape from its centroid can push a point past its
	# neighbour and produce exactly the self-intersection above.
	var loop := pts.duplicate()
	loop.append(pts[0])
	draw_polyline(loop, ink, 2.5)