class_name StageGizmos
extends Node2D
## StageGizmos - Hover highlight, selection outlines and a rotate ring for the
## Sandbox Stage Builder (Phase 2).
##
## Translation is done by dragging an object directly (no move handle); a drag
## moves the whole multi-selection. The rotate ring only appears when exactly one
## object is selected (rotating a multi-selection isn't useful). Pure drawing +
## distance-based hit-testing (no Area2D). Dragging drives global_position /
## global_rotation so it works for any Node2D. Hidden and disabled in PLAY mode.

const STAGE_SELECTION := preload("res://scripts/stage_selection.gd")

# ---------------------------------------------------------------------------
# Enums
# ---------------------------------------------------------------------------

enum Handle { NONE, TRANSLATE, ROTATE }

# ---------------------------------------------------------------------------
# Signals
# ---------------------------------------------------------------------------

signal transform_committed(nodes: Array[Node2D])

# ---------------------------------------------------------------------------
# Style constants (screen-space px; divided by zoom for world-space drawing)
# ---------------------------------------------------------------------------

const SELECTION_COLOR := Color(1.0, 1.0, 1.0, 0.9)
const HOVER_COLOR := Color(1.0, 0.9, 0.2, 0.5)
const ROTATE_COLOR := Color(0.3, 0.6, 1.0, 0.9)

const SELECTION_WIDTH := 2.0
const HOVER_WIDTH := 1.5
const ROTATE_WIDTH := 2.0

const ROTATE_HANDLE_MARGIN_PX := 48.0
const ROTATE_RING_TOLERANCE_PX := 12.0

# ---------------------------------------------------------------------------
# State
# ---------------------------------------------------------------------------

var camera: Camera2D = null

## When > 0, translation drags snap to this grid size (0 = off).
var snap_size: float = 0.0

var _enabled: bool = true
var _targets: Array[Node2D] = []
var _hovered: Node2D = null
var _dragging: Handle = Handle.NONE
var _drag_last: Vector2 = Vector2.ZERO
var _drag_anchor: Node2D = null
var _rotate_start_rotation: float = 0.0
var _rotate_start_angle: float = 0.0
var _rotate_center: Vector2 = Vector2.ZERO
var _box_rect: Rect2 = Rect2()

# ---------------------------------------------------------------------------
# Public API
# ---------------------------------------------------------------------------

func set_targets(nodes: Array[Node2D]) -> void:
	_targets = nodes.duplicate()
	queue_redraw()


func set_hover(node: Node2D) -> void:
	_hovered = node
	queue_redraw()


func set_enabled(enabled: bool) -> void:
	_enabled = enabled
	visible = enabled
	queue_redraw()


func set_box_rect(rect: Rect2) -> void:
	_box_rect = rect
	queue_redraw()


## Returns ROTATE if the cursor is on the rotate ring (single selection only).
func hit_test(world_pos: Vector2) -> Handle:
	if not _enabled or _targets.size() != 1:
		return Handle.NONE
	var target := _targets[0]
	if target == null or not is_instance_valid(target):
		return Handle.NONE
	var rect := STAGE_SELECTION.get_world_aabb(target)
	var ring := _rotate_ring_radius(rect)
	if absf(world_pos.distance_to(rect.get_center()) - ring) <= ROTATE_RING_TOLERANCE_PX / _zoom():
		return Handle.ROTATE
	return Handle.NONE


## Begins a rotate drag (used when the ring is clicked).
func begin_drag(world_pos: Vector2) -> void:
	_dragging = hit_test(world_pos)
	_drag_last = world_pos
	if _dragging == Handle.ROTATE and _targets.size() == 1 and is_instance_valid(_targets[0]):
		_rotate_center = STAGE_SELECTION.get_world_aabb(_targets[0]).get_center()
		_rotate_start_rotation = _targets[0].global_rotation
		_rotate_start_angle = (world_pos - _rotate_center).angle()


## Begins a translate drag anchored on `node` (used when an object body is
## clicked). The drag moves the whole current selection (`_targets`); if `node`
## is not currently selected, the drag targets just `node`.
func begin_translate_drag(node: Node2D, world_pos: Vector2) -> void:
	_drag_anchor = node
	if not _targets.has(node):
		_targets = [node]
	_dragging = Handle.TRANSLATE
	_drag_last = world_pos


func drag_to(world_pos: Vector2) -> void:
	if _dragging == Handle.NONE or _targets.is_empty():
		return
	var delta := world_pos - _drag_last
	if _dragging == Handle.TRANSLATE:
		var actual := delta
		if snap_size > 0.0 and _drag_anchor != null and is_instance_valid(_drag_anchor):
			var old := _drag_anchor.global_position
			actual = _snap(old + delta) - old
		for node: Node2D in _targets:
			if is_instance_valid(node):
				node.global_position += actual
	elif _dragging == Handle.ROTATE:
		if _targets.size() == 1 and is_instance_valid(_targets[0]):
			var target := _targets[0]
			var current_angle := (world_pos - _rotate_center).angle()
			var angle_delta := current_angle - _rotate_start_angle
			var new_rotation := _rotate_start_rotation + angle_delta
			if Input.is_key_pressed(KEY_CTRL):
				new_rotation = snappedf(new_rotation, deg_to_rad(15.0))
			target.global_rotation = new_rotation
	_drag_last = world_pos
	queue_redraw()


func end_drag() -> void:
	if _dragging != Handle.NONE and not _targets.is_empty():
		transform_committed.emit(_targets.duplicate())
	_dragging = Handle.NONE
	_drag_anchor = null


func is_dragging() -> bool:
	return _dragging != Handle.NONE

# ---------------------------------------------------------------------------
# Frame / drawing
# ---------------------------------------------------------------------------

func _process(_delta: float) -> void:
	if _enabled and (_targets.size() > 0 or _hovered != null or _box_rect.size != Vector2.ZERO):
		queue_redraw()


func _draw() -> void:
	if not _enabled:
		return
	var zoom := _zoom()
	if _hovered != null and is_instance_valid(_hovered) and not _targets.has(_hovered):
		draw_rect(STAGE_SELECTION.get_world_aabb(_hovered), HOVER_COLOR, false, HOVER_WIDTH / zoom)
	# A selection outline for every selected object.
	for node: Node2D in _targets:
		if node != null and is_instance_valid(node):
			draw_rect(STAGE_SELECTION.get_world_aabb(node), SELECTION_COLOR, false, SELECTION_WIDTH / zoom)
	# Rotate ring only for a single selection.
	if _targets.size() == 1 and is_instance_valid(_targets[0]):
		var rect := STAGE_SELECTION.get_world_aabb(_targets[0])
		draw_arc(rect.get_center(), _rotate_ring_radius(rect), 0.0, TAU, 64, ROTATE_COLOR, ROTATE_WIDTH / zoom, true)
	if _box_rect.size != Vector2.ZERO:
		draw_rect(_box_rect.abs(), HOVER_COLOR, false, HOVER_WIDTH / zoom)

# ---------------------------------------------------------------------------
# Internal helpers
# ---------------------------------------------------------------------------

func _zoom() -> float:
	if camera != null and is_instance_valid(camera):
		return maxf(camera.zoom.x, 0.0001)
	return 1.0


func _rotate_ring_radius(rect: Rect2) -> float:
	return rect.size.length() * 0.5 + ROTATE_HANDLE_MARGIN_PX / _zoom()


func _snap(v: Vector2) -> Vector2:
	return Vector2(roundf(v.x / snap_size) * snap_size, roundf(v.y / snap_size) * snap_size)