/* -*- mode: C++; c-basic-offset: 2; indent-tabs-mode: nil -*- */

/*
 *  Main authors:
 *     Guido Tack <guido.tack@monash.edu>
 */

/* This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */

#include <minizinc/flat_exp.hh>

namespace MiniZinc {

EE flatten_unop(EnvI& env, Ctx ctx, Expression* e, VarDecl* r, VarDecl* b) {
  CallStackItem _csi(env, e);
  EE ret;
  UnOp* uo = e->cast<UnOp>();
  switch (uo->op()) {
    case UOT_NOT: {
      Ctx nctx = ctx;
      nctx.b = -nctx.b;
      nctx.neg = !nctx.neg;
      ret = flat_exp(env, nctx, uo->e(), r, b);
    } break;
    case UOT_PLUS:
      ret = flat_exp(env, ctx, uo->e(), r, b);
      break;
    case UOT_MINUS: {
      GC::lock();
      if (UnOp* uo_inner = uo->e()->dyn_cast<UnOp>()) {
        if (uo_inner->op() == UOT_MINUS) {
          ret = flat_exp(env, ctx, uo_inner->e(), r, b);
          break;
        }
      }
      Expression* zero;
      if (uo->e()->type().bt() == Type::BT_INT)
        zero = IntLit::a(0);
      else
        zero = FloatLit::a(0.0);
      BinOp* bo = new BinOp(Location().introduce(), zero, BOT_MINUS, uo->e());
      bo->type(uo->type());
      KeepAlive ka(bo);
      GC::unlock();
      ret = flat_exp(env, ctx, ka(), r, b);
    } break;
    default:
      break;
  }
  return ret;
}
}  // namespace MiniZinc