package snake

import Fixtures.*

class M02ModelSuite extends munit.FunSuite:
  cases("m02-delta").foreach { c =>
    test(s"delta: ${c("name").str}") {
      assertEquals(Model.delta(direction(c("args")(0))), point(c("expected")))
    }
  }

  cases("m02-opposite").foreach { c =>
    test(s"opposite: ${c("name").str}") {
      assertEquals(Model.opposite(direction(c("args")(0))), direction(c("expected")))
    }
  }

  // pointEquals has no Scala function: case classes already compare structurally with `==`.
  // The shared fixture is kept so every track checks the same four situations.
  cases("m02-point-equals").foreach { c =>
    test(s"pointEquals (case-class ==): ${c("name").str}") {
      val a = point(c("args")(0))
      val b = point(c("args")(1))
      assertEquals(a == b, c("expected").bool)
    }
  }

  cases("m02-initial-state").foreach { c =>
    test(s"initialState: ${c("name").str}") {
      assertEquals(Model.initialState(c("args")(0).num.toLong), gameState(c("expected")))
    }
  }

  test("Point holds its coordinates") {
    val p = Point(3, 4)
    assertEquals((p.x, p.y), (3, 4))
  }

  test("opposite is its own inverse") {
    Direction.values.foreach(d => assertEquals(Model.opposite(Model.opposite(d)), d))
  }

  test("Action.Turn carries the direction") {
    assertEquals(Action.Turn(Direction.Left), Action.Turn(Direction.Left))
    assertNotEquals(Action.Turn(Direction.Left), Action.Turn(Direction.Right))
    Action.Turn(Direction.Left) match
      case Action.Turn(d) => assertEquals(d, Direction.Left)
      case other          => fail(s"expected Turn, got $other")
  }

  test("the other Actions are distinct constants") {
    val all = List(Action.Tick, Action.TogglePause, Action.Restart, Action.Frame)
    assertEquals(all.distinct.length, 4)
  }