package snake

import java.nio.file.{Files, Paths}

/** Loads shared fixtures from ../fixtures/<name>.json.
  * Typed decoders (point, direction, status, action, state, opt) arrive with the model (Task 11). */
object Fixtures:
  private val dir = Paths.get(sys.props.getOrElse("user.dir", ".")).resolve("..").resolve("fixtures").normalize

  def load(name: String): ujson.Value =
    ujson.read(Files.readString(dir.resolve(s"$name.json")))

  /** The cases array of a fixture. */
  def cases(name: String): Seq[ujson.Value] = load(name)("cases").arr.toSeq

  /** Decode a nullable JSON value into an Option. */
  def opt[A](v: ujson.Value)(f: ujson.Value => A): Option[A] =
    if v.isNull then None else Some(f(v))