tool
extends TK_Context
class_name TK_GridContext

## todo: Cell visualization.
## todo: Integration of TileMap.

export var cell_size: Vector2 = Vector2(64, 64) setget _set_cell_size

signal cell_size_changed(p_old_cell_size, p_new_cell_size)

var _colliders: Dictionary # Node to null (set)

func local_position_to_context_position(p_position: Vector2) -> Vector2:
    return p_position / cell_size

func is_path_traversible(p_game_object: Node2D, p_from: Vector2, p_to: Vector2) -> bool:
    for collider in _colliders:
        if not collider.is_path_traversible(p_game_object, p_from, p_to):
            return false
    return true

# todo: Effectful traversal.
func try_moving(p_game_object: Node2D, p_from: Vector2, p_to: Vector2) -> bool:
    if not is_path_traversible(p_game_object, p_from, p_to):
        return false

    p_game_object.position = cell_size * p_to
    return true

func register_collider(p_collider: Node) -> void:
    _colliders[p_collider] = null
    if p_collider.connect("child_exiting_tree", self, "_on_collider_exiting_tree") != OK:
        assert(false)

func _on_collider_exiting_tree(p_collider) -> void:
    if not _colliders.erase(p_collider):
        pass

func _set_cell_size(p_new_cell_size: Vector2) -> void:
    if p_new_cell_size.x == 0 or p_new_cell_size.y == 0:
        push_error("Cell size cannot be zero")
        return

    var cell_size_cache = cell_size
    cell_size = p_new_cell_size
    emit_signal("cell_size_changed", cell_size_cache, p_new_cell_size)