extends Node2D

const BUILDING_DEFINITIONS = preload("res://buildings/BuildingDefinitions.gd")

@export var definition_id: String = "mothership"
@export var building_id: int = 0
@export var interact_radius: float = 150.0

var definition: Resource
var visual: Node2D

var building_type: String:
	get: return definition_id
	set(value): definition_id = value


# #99: drawn only once the structure has actually been hit. A full bar over
# every building would be permanent clutter saying nothing, and the fleet
# would be flying over a field of meters in peacetime.
# #215 made it bigger and brighter. It stays a DAMAGE-ONLY bar: the reason
# above still holds, and a field of full meters in peacetime is clutter, not
# visibility. What was actually hard to see was the bar when it was there -
# 74x7 of muted colour against a lit structure, at the zoom the game is
# usually played at.
const HEALTH_BAR_WIDTH: float = 104.0
const HEALTH_BAR_HEIGHT: float = 14.0
const HEALTH_BAR_OFFSET: float = -88.0
# The dark plate the bar sits on, drawn past its edges so the meter reads
# against the structure's own glow instead of competing with it.
const HEALTH_BAR_PAD: float = 3.0
const HEALTH_FULL_COLOR: Color = Color(0.5, 1.0, 0.55)
const HEALTH_HURT_COLOR: Color = Color(1.0, 0.28, 0.2)
const HEALTH_PLATE_COLOR: Color = Color(0.02, 0.02, 0.06, 0.92)
const HEALTH_FRAME_COLOR: Color = Color(0.85, 0.96, 1.0, 0.95)
const HEALTH_FRAME_WIDTH: float = 2.0

var _drawn_health: float = 1.0


func _ready() -> void:
	add_to_group("buildings")
	z_index = -1
	definition = BUILDING_DEFINITIONS.get_definition(definition_id)
	if definition == null or definition.visual_scene == null:
		return
	visual = definition.visual_scene.instantiate()
	get_node("VisualHost").add_child(visual)


func health_fraction() -> float:
	return GameState.building_health_fraction(building_id) if building_id != 0 else 1.0


func is_damaged() -> bool:
	return health_fraction() < 0.999


func _process(_delta: float) -> void:
	# Redraw only when the number moves. A building that is not being shot at
	# costs nothing, which is the same bargain Ship.gd's constant glow makes.
	var health: float = health_fraction()
	if is_equal_approx(health, _drawn_health):
		return
	_drawn_health = health
	queue_redraw()


func _draw() -> void:
	if not is_damaged():
		return
	# Above the structure rather than across it: the visual scenes all draw
	# around their own origin, and a bar laid over one would be read as part
	# of the building.
	var health: float = health_fraction()
	var left: float = -HEALTH_BAR_WIDTH * 0.5
	var top: float = HEALTH_BAR_OFFSET
	var fill_color: Color = HEALTH_HURT_COLOR.lerp(HEALTH_FULL_COLOR, health)
	draw_rect(Rect2(left - HEALTH_BAR_PAD, top - HEALTH_BAR_PAD,
		HEALTH_BAR_WIDTH + HEALTH_BAR_PAD * 2.0,
		HEALTH_BAR_HEIGHT + HEALTH_BAR_PAD * 2.0), HEALTH_PLATE_COLOR)
	# The empty part is not left blank: a dim wash of the fill colour shows
	# how much has GONE, which is the thing being reported.
	draw_rect(Rect2(left, top, HEALTH_BAR_WIDTH, HEALTH_BAR_HEIGHT),
		Color(fill_color.r, fill_color.g, fill_color.b, 0.16))
	draw_rect(Rect2(left, top, HEALTH_BAR_WIDTH * health, HEALTH_BAR_HEIGHT),
		fill_color)
	# A bright square cap on the fill's leading edge, so the level itself has
	# an edge to catch rather than only the colour changing.
	if health > 0.001:
		draw_rect(Rect2(left + HEALTH_BAR_WIDTH * health - HEALTH_FRAME_WIDTH,
			top, HEALTH_FRAME_WIDTH, HEALTH_BAR_HEIGHT), HEALTH_FRAME_COLOR)
	draw_rect(Rect2(left, top, HEALTH_BAR_WIDTH, HEALTH_BAR_HEIGHT),
		HEALTH_FRAME_COLOR, false, HEALTH_FRAME_WIDTH)


func available_actions() -> PackedStringArray:
	if visual == null:
		return PackedStringArray()
	var provider: Node = visual.get_node_or_null("ActionProvider")
	return provider.actions if provider != null else PackedStringArray()


func primary_action() -> String:
	for action in available_actions():
		if action != "transfer" and action != "hangar":
			return action
	return ""


func get_display_name() -> String:
	return String(definition.display_name) if definition != null else definition_id.capitalize()