extends Node2D

var player: CharacterBody2D
var _display_ratio := 1.0
var _display_shield_ratio := 1.0
var _display_hull_ratio := 1.0
var _background: StyleBoxFlat

func _ready() -> void:
	# World rendering interpolates this position together with the ship and camera.
	top_level = true
	process_physics_priority = 1
	global_position = player.global_position
	reset_physics_interpolation()
	z_index = 24
	_display_ratio = _energy_ratio()
	_display_shield_ratio = _shield_ratio()
	_display_hull_ratio = _hull_ratio()
	_background = StyleBoxFlat.new()
	_background.bg_color = Color("101925")
	_background.border_color = Color("456277")
	_background.set_border_width_all(1)
	_background.set_corner_radius_all(4)
	_background.shadow_color = Color(0, 0, 0, 0.5)
	_background.shadow_size = 3

func _physics_process(_delta: float) -> void:
	if is_instance_valid(player):
		var teleported := global_position.distance_to(player.global_position) > 600.0
		global_position = player.global_position
		if teleported:
			reset_physics_interpolation()

func _process(delta: float) -> void:
	if not is_instance_valid(player):
		return
	visible = not bool(player.get("_is_destroyed"))
	var target := _energy_ratio()
	_display_ratio = lerpf(_display_ratio, target, 1.0 - exp(-20.0 * delta))
	if absf(_display_ratio - target) < 0.001:
		_display_ratio = target
	var shield_target := _shield_ratio()
	_display_shield_ratio = lerpf(_display_shield_ratio, shield_target, 1.0 - exp(-20.0 * delta))
	if absf(_display_shield_ratio - shield_target) < 0.001:
		_display_shield_ratio = shield_target
	var hull_target := _hull_ratio()
	_display_hull_ratio = lerpf(_display_hull_ratio, hull_target, 1.0 - exp(-20.0 * delta))
	if absf(_display_hull_ratio - hull_target) < 0.001:
		_display_hull_ratio = hull_target
	queue_redraw()

func _energy_ratio() -> float:
	return clampf(float(player.get("energy")) / maxf(1.0, float(player.get("max_energy"))), 0.0, 1.0)

func _shield_ratio() -> float:
	return clampf(float(player.get("shields")) / maxf(1.0, float(player.get("max_shields"))), 0.0, 1.0)

func _hull_ratio() -> float:
	return clampf(float(player.get("hull")) / maxf(1.0, float(player.get("max_hull"))), 0.0, 1.0)

func _draw() -> void:
	if not is_instance_valid(player):
		return
	_draw_bar(Vector2(-46, 58), _display_ratio, Color("efbd62"), 0)
	_draw_bar(Vector2(-46, 72), _display_shield_ratio, Color("66cfff"), 1)
	_draw_bar(Vector2(-46, 86), _display_hull_ratio, Color("ef6875"), 2)

func _draw_bar(position: Vector2, ratio: float, color: Color, kind: int) -> void:
	draw_style_box(_background, Rect2(position - Vector2(14, 3), Vector2(110, 12)))
	# Ten illuminated cells, with partial cells tracking the exact current value.
	for index in 10:
		var cell := Rect2(position + Vector2(index * 9.2, 0), Vector2(7.6, 6))
		draw_rect(cell, color.darkened(0.8))
		var fraction := clampf(ratio * 10.0 - index, 0.0, 1.0)
		if fraction > 0:
			cell.size.x *= fraction
			draw_rect(cell, color)
			draw_rect(Rect2(cell.position, Vector2(cell.size.x, 2)), color.lightened(0.4))
	var center := position + Vector2(-8, 3)
	match kind:
		0:
			draw_polyline(PackedVector2Array([center + Vector2(1, -4), center + Vector2(-2, 0), center + Vector2(2, 0), center + Vector2(-1, 4)]), color, 1.4, true)
		1:
			draw_polyline(PackedVector2Array([center + Vector2(-3, -3), center + Vector2(3, -3), center + Vector2(2, 2), center + Vector2(0, 4), center + Vector2(-2, 2), center + Vector2(-3, -3)]), color, 1.2, true)
		2:
			draw_polyline(PackedVector2Array([center + Vector2(0, -4), center + Vector2(3, 0), center + Vector2(2, 3), center + Vector2(-2, 3), center + Vector2(-3, 0), center + Vector2(0, -4)]), color, 1.2, true)