class_name PropTrajectory
extends RefCounted
## Shared deterministic ballistic solver for director feedback and playback.

const MIN_FLIGHT_TIME: float = 0.35
const MAX_FLIGHT_TIME: float = 1.5
const MAX_LAUNCH_SPEED: float = 900.0

static func solve_throw_velocity(release_point: Vector2, target_point: Vector2, flight_time: float, gravity_vector: Vector2) -> Dictionary:
	if not release_point.is_finite() or not target_point.is_finite() or not gravity_vector.is_finite():
		return {"ok": false, "reason": "non_finite"}
	if not is_finite(flight_time) or flight_time < MIN_FLIGHT_TIME or flight_time > MAX_FLIGHT_TIME:
		return {"ok": false, "reason": "flight_time"}
	var velocity: Vector2 = (target_point - release_point - gravity_vector * 0.5 * flight_time * flight_time) / flight_time
	if not velocity.is_finite() or velocity.length() > MAX_LAUNCH_SPEED:
		return {"ok": false, "reason": "speed"}
	return {"ok": true, "velocity": velocity, "flight_time": flight_time, "reason": ""}