extends Control

## A draggable modifier piece. Follows the cursor directly — no ghost, no
## Godot drag-and-drop API (which fights with 3D raycasting).
##
## While dragging it asks the DropCatcher which slot is under the cursor, so
## the player can SEE what they're about to hit before committing.

@export var paint_texture: Texture2D:
	set(value):
		paint_texture = value
		queue_redraw()

@export_range(0.0, 1.0) var top_width_ratio := 0.55

# Injected by the tray on spawn.
var drop_catcher: Control
var tray: Node
var modifier: Modifier

var _dragging := false
var _home_position := Vector2.ZERO
var _drag_offset := Vector2.ZERO
var _hovered_slot: StringName = &""


func _ready() -> void:
	mouse_filter = Control.MOUSE_FILTER_STOP
	if custom_minimum_size == Vector2.ZERO:
		custom_minimum_size = Vector2(90, 110)
	size = custom_minimum_size


func _draw() -> void:
	var w := size.x
	var h := size.y
	var inset := w * (1.0 - top_width_ratio) * 0.5

	var points := PackedVector2Array([
		Vector2(inset, 0), Vector2(w - inset, 0),
		Vector2(w, h), Vector2(0, h),
	])

	if paint_texture != null:
		var uvs := PackedVector2Array([
			Vector2(inset / w, 0), Vector2((w - inset) / w, 0),
			Vector2(1, 1), Vector2(0, 1),
		])
		var white := PackedColorArray([Color.WHITE, Color.WHITE, Color.WHITE, Color.WHITE])
		draw_polygon(points, white, uvs, paint_texture)
	else:
		draw_colored_polygon(points, Color(0.8, 0.8, 0.8))

	# Outline turns green when hovering a valid slot — the player's only cue
	# that the drop will land.
	var outline_col := Color(0, 0, 0, 0.6)
	var outline_w := 2.0
	if _dragging and _hovered_slot != &"":
		outline_col = Color(0.3, 1.0, 0.4, 0.9)
		outline_w = 4.0

	var outline := points
	outline.append(points[0])
	draw_polyline(outline, outline_col, outline_w)


func _gui_input(event: InputEvent) -> void:
	if event is InputEventMouseButton and event.button_index == MOUSE_BUTTON_LEFT:
		if event.pressed:
			_start_drag()
		else:
			_end_drag()


func _start_drag() -> void:
	_dragging = true
	_home_position = global_position
	_drag_offset = global_position - get_global_mouse_position()

	# top_level lets us move by global_position without reparenting.
	# Reparenting mid-drag breaks the release event.
	top_level = true
	z_index = 100
	modulate.a = 0.85


func _end_drag() -> void:
	if not _dragging:
		return

	_dragging = false
	_hovered_slot = &""
	modulate.a = 1.0
	z_index = 0

	var applied := false
	if drop_catcher == null:
		push_error("SectorSwatch has no drop_catcher.")
	else:
		applied = drop_catcher.apply_modifier_at_screen_pos(
			get_global_mouse_position(), modifier
		)

	# Always snap home. The tray decides whether to consume the piece.
	top_level = false
	global_position = _home_position
	queue_redraw()

	if applied and tray != null and tray.has_method(&"on_piece_used"):
		tray.on_piece_used(self)


func _process(_delta: float) -> void:
	if not _dragging:
		return

	var mouse := get_global_mouse_position()
	global_position = mouse + _drag_offset

	# Live hover feedback — which slot would this land on right now?
	if drop_catcher != null and drop_catcher.has_method(&"hover"):
		var slot: StringName = drop_catcher.hover(mouse)
		if slot != _hovered_slot:
			_hovered_slot = slot
			queue_redraw()