## Represents a single 3D grid cell on the game board.
##
## It's a data structure for occupancy state, owner tetromino, bounds, and 
## visual feedback.
class_name GridCell
extends Object

# Properties
var position: Vector3i  # Grid coordinates
var owner: Tetromino = null  # Tetromino occupying this cell
var bounds: AABB = AABB()  # 3D axis-aligned bounding box

# Visual state
var is_highlighted: bool = false
var is_valid_placement: bool = true


## Checks if the cell is currently empty.
func is_empty() -> bool:
	return owner == null


## Marks the cell as occupied by a tetromino.
func occupy(tetromino: Tetromino) -> void:
	owner = tetromino


## Marks the cell as empty.
func clear() -> void:
	owner = null


## Returns a string representation of the cell state.
func _to_string() -> String:
	return "GridCell3D[pos=%v, occupied=%s, valid=%s]" % [
		position,
		"yes" if owner else "no",
		"yes" if is_valid_placement else "no"
	]