(*
 * Copyright (c) 2016 - present Facebook, Inc.
 * All rights reserved.
 *
 * This source code is licensed under the BSD style license found in the
 * LICENSE file in the root directory of this source tree. An additional grant
 * of patent rights can be found in the PATENTS file in the same directory.
 *)

open! IStd

module F = Format



(** mocks for creating CFG's from adjacency lists *)
module MockNode = struct
  type t = int
  type id = int

  let instrs _ = []
  let instr_ids _ = []
  let hash = Hashtbl.hash
  let to_instr_nodes _ = assert false
  let id n = n
  let loc _ = assert false
  let underlying_node _ = assert false
  let kind _ = Procdesc.Node.Stmt_node ""
  let compare_id = Int.compare
  let pp_id fmt i =
    F.fprintf fmt "%i" i
end

module MockProcCfg = struct
  type node = int
  include (MockNode : module type of MockNode with type t := node)
  type t = (node * node list) list

  let equal_id = Int.equal

  let succs t n =
    let node_id = id n in
    List.find
      ~f:(fun (node, _) -> equal_id (id node) node_id)
      t |>
    Option.value_map ~f:snd ~default:[]

  let preds t n =
    try
      let node_id = id n in
      List.filter
        ~f:(fun (_, succs) ->
           List.exists ~f:(fun node -> equal_id (id node) node_id) succs)
        t
      |> IList.map fst
    with Not_found -> []

  let nodes t = IList.map fst t

  let normal_succs = succs
  let normal_preds = preds
  let exceptional_succs _ _ = []
  let exceptional_preds _ _ = []
  let from_adjacency_list t = t
  (* not called by the scheduler *)
  let start_node _ = assert false
  let exit_node _ = assert false
  let proc_desc _ = assert false
  let from_pdesc _ = assert false
  let is_loop_head _ = assert false
end

module S = Scheduler.ReversePostorder (MockProcCfg)

let create_test test_graph expected_result _ =
  (* keep popping and scheduling until the queue is empty, record the results *)
  let rec pop_schedule_record q visited_acc =
    match S.pop q with
    | Some (n, _, q') ->
        pop_schedule_record (S.schedule_succs q' n) (n :: visited_acc)
    | None -> IList.rev visited_acc in
  let pp_diff fmt (exp, actual) =
    let pp_sched fmt l =
      F.pp_print_list ~pp_sep:F.pp_print_space (fun fmt i -> F.fprintf fmt "%d" i) fmt l in
    F.fprintf fmt "Expected schedule %a but got schedule %a" pp_sched exp pp_sched actual in
  let cfg = MockProcCfg.from_adjacency_list test_graph in
  let q = S.schedule_succs (S.empty cfg) 1 in
  let result = pop_schedule_record q [1] in
  OUnit2.assert_equal ~pp_diff result expected_result

let tests =
  let open OUnit2 in
  let test_list = [
    ("straightline",
     [(1, [2]);
      (2, [3]);
      (3, [4])],
     [1; 2; 3; 4]);
    ("if_then_else",
     [(1, [2; 3]);
      (2, [4]);
      (3, [4]);
      (4, [5])],
     [1; 2; 3; 4; 5]);
    ("if_then",
     [(1, [2; 4]);
      (2, [3]);
      (3, [4]);
      (4, [5])],
     [1; 2; 3; 4; 5]);
    ("diamond",
     [(1, [2; 3]);
      (2, [4]);
      (3, [4]);
      (4, [5; 6]);
      (5, [7]);
      (6, [7]);
      (7, [8])],
     [1; 2; 3; 4; 5; 6; 7; 8]);
    ("switch",
     [(1, [2; 3; 4; 5;]);
      (2, [6]);
      (3, [6]);
      (4, [6]);
      (5, [6]);
      (6, [7])],
     [1; 2; 3; 4; 5; 6; 7;]);
    ("nums_order_irrelevant",
     [(11, [10];);
      (1, [7; 2]);
      (2, [3; 11]);
      (7, [11]);
      (3, [7]);],
     [1; 2; 3; 7; 11; 10]);
  ]
    |> IList.map
      (fun (name, test, expected) -> name>::create_test test expected) in
  "scheduler_suite">:::test_list