git submodule add -b release-v6.8.1 https://github.com/csprance/gecs.git addons/gecs

# All component properties need a default value or Godot will error on export

# Pattern 1: @export var with default (no constructor needed)
class_name C_Health extends Component
@export var max_health: int = 100
@export var current_health: int = 100

# Pattern 2: _init() with parameter AND a default on the property
class_name C_Velocity extends Component
@export var direction: Vector3 = Vector3.ZERO
func _init(v: Vector3 = Vector3.ZERO) -> void:
    direction = v

# Create entities and add components
var player = Entity.new()
player.add_component(C_Health.new())
player.add_component(C_Velocity.new(Vector3(5, 0, 0)))

var target = Entity.new()
target.add_component(C_Health.new())
target.add_component(C_Velocity.new(Vector3(-5, 0, 0)))

# Add entities to the world
ECS.world.add_entity(player)
ECS.world.add_entity(target)

# Add relationships between entities
player.add_relationship(Relationship.new(C_AllyTo.new(), target))

# Systems define which entities to process
class_name VelocitySystem extends System

func query() -> QueryBuilder:
    return q.with_all([C_Velocity])

func process(entities: Array[Entity], components: Array, delta: float) -> void:
    for entity in entities:
        var vel := entity.get_component(C_Velocity) as C_Velocity
        entity.position += vel.direction * delta

# Register the system and start processing
ECS.world.add_system(VelocitySystem.new())

func _process(delta: float) -> void:
    ECS.process(delta)