// Copyright (c) 2018, the R8 project authors. Please see the AUTHORS file
// for details. All rights reserved. Use of this source code is governed by a
// BSD-style license that can be found in the LICENSE file.

package non_null

data class Car(val make: String, val model: String, val year: Int, val plateNumber: String)

fun Collection<Car>.forMakeAndModel(make: String, model: String, sinceYear: Int?) =
  this.asSequence()
    .filter { it.make == make }
    .filter { it.model == model }
    .filter { sinceYear != null && it.year >= sinceYear }
    .groupBy { it.year }
    .toSortedMap()

fun main(args: Array<String>) {
  val leaf = Car("Nissan", "Leaf", 2015, "  LEAF  ")
  val ms1 = Car("Tesla", "Model S", 2015, "  LGTM1 ")
  val ms2 = Car("Tesla", "Model S", 2017, "  LGTM2 ")
  val m3 = Car("Tesla", "Model 3", 2018, "  LGTM3 ")
  val cars: List<Car> = mutableListOf(leaf, ms1, ms2, m3)
  println(cars.forMakeAndModel("Tesla", "Model S", null))
}