@tool
class_name NeonPanel
extends Control

# A bounded dialog card drawn in the game's own style: a dark chamfered
# body with a glowing border and bright corner brackets. Chamfered rather
# than square because cut corners read as "console panel" and match the
# hard-edged neon of the buttons and HUD.
#
# Draws itself from its own rect, so it can be sized freely in the scene.
#
# #92: it also SHRINKS itself to whatever window it is in. The card is
# authored at a fixed size around a portrait phone, and on a landscape
# window - where the canvas is far wider than it is tall - a card taller
# than the screen simply ran off the top and the bottom, taking the confirm
# and cancel buttons with it. The buttons are anchored to the panel's own
# bottom edge, so bringing the edge back on screen brings them back too.
#
# Only ever shrinks. Growing the card on a big screen would blow the
# authored proportions up with it, and the layout inside is tuned, not
# fluid.

@export var glow_color: Color = Color(0.25, 0.85, 1.0)
@export var core_color: Color = Color(1.0, 1.0, 1.0)
# Fully opaque: at even 97% the bright neon of whatever sits behind the
# panel ghosts through and makes the text harder to read.
@export var fill_color: Color = Color(0.02, 0.03, 0.07, 1.0)
@export var corner_cut: float = 26.0
@export var bracket_length: float = 46.0
# Breathing room kept between the card and the edge of the screen, so a
# fitted panel reads as a card on a backdrop rather than as a full-bleed
# page that happens to have a border.
@export var screen_margin: float = 24.0

# The size the card was authored at, and the point it is centred on. Read
# once, before any fitting has happened - re-reading them later would
# measure a previous fit and let the card ratchet smaller on every resize.
var design_size: Vector2 = Vector2.ZERO
var design_centre: Vector2 = Vector2.ZERO


func _ready() -> void:
	# _fit_to_screen() below rewrites offset_left/right/top/bottom. Under
	# @tool that runs against the editor viewport, overwriting the authored
	# layout and dirtying the scene, so the card previews at its authored
	# size and is only ever fitted at runtime.
	if Engine.is_editor_hint():
		return
	# Fitting adjusts the four offsets around a fixed centre, which is only
	# meaningful for a card pinned to a point - both anchor pairs collapsed,
	# as a centred dialog's are. A panel stretched between different anchors
	# already follows its parent and is left alone.
	if not (is_equal_approx(anchor_left, anchor_right) \
			and is_equal_approx(anchor_top, anchor_bottom)):
		return
	design_size = Vector2(offset_right - offset_left, offset_bottom - offset_top)
	design_centre = Vector2(offset_left + offset_right, offset_top + offset_bottom) * 0.5
	get_viewport().size_changed.connect(_fit_to_screen)
	_fit_to_screen()


func _fit_to_screen() -> void:
	if design_size == Vector2.ZERO:
		return
	# The viewport rect, not the window: with stretch/mode "canvas_items" the
	# UI is laid out in stretched canvas units, and those are the units these
	# offsets are in.
	var available: Vector2 = get_viewport_rect().size - Vector2(screen_margin, screen_margin) * 2.0
	var fitted: Vector2 = Vector2(
		minf(design_size.x, maxf(available.x, 0.0)),
		minf(design_size.y, maxf(available.y, 0.0)))
	offset_left = design_centre.x - fitted.x * 0.5
	offset_right = design_centre.x + fitted.x * 0.5
	offset_top = design_centre.y - fitted.y * 0.5
	offset_bottom = design_centre.y + fitted.y * 0.5
	queue_redraw()


func _draw() -> void:
	var w: float = size.x
	var h: float = size.y
	var c: float = corner_cut

	var body: PackedVector2Array = PackedVector2Array([
		Vector2(c, 0.0), Vector2(w - c, 0.0),
		Vector2(w, c), Vector2(w, h - c),
		Vector2(w - c, h), Vector2(c, h),
		Vector2(0.0, h - c), Vector2(0.0, c),
	])
	draw_colored_polygon(body, fill_color)
	NeonDraw.draw_glowing_polygon(self, body, glow_color, 1.0, core_color)

	# Corner brackets: short doubled strokes just inside each cut corner,
	# which is what gives it the heads-up-display feel rather than looking
	# like a plain outlined box.
	var b: float = bracket_length
	var inset: float = 10.0
	var corners: Array = [
		[Vector2(inset, c + inset), Vector2(inset, c + inset + b), Vector2(c + inset, inset), Vector2(c + inset + b, inset)],
		[Vector2(w - inset, c + inset), Vector2(w - inset, c + inset + b), Vector2(w - c - inset, inset), Vector2(w - c - inset - b, inset)],
		[Vector2(inset, h - c - inset), Vector2(inset, h - c - inset - b), Vector2(c + inset, h - inset), Vector2(c + inset + b, h - inset)],
		[Vector2(w - inset, h - c - inset), Vector2(w - inset, h - c - inset - b), Vector2(w - c - inset, h - inset), Vector2(w - c - inset - b, h - inset)],
	]
	for corner in corners:
		NeonDraw.draw_glowing_line(self, corner[0], corner[1], glow_color, 0.9, 0.3, core_color)
		NeonDraw.draw_glowing_line(self, corner[2], corner[3], glow_color, 0.9, 0.3, core_color)