/* -*- 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_par(EnvI& env, Ctx ctx, Expression* e, VarDecl* r, VarDecl* b) {
  EE ret;
  if (e->type().cv()) {
    KeepAlive ka = flat_cv_exp(env, ctx, e);
    ret.r = bind(env, ctx, r, ka());
    ret.b = bind(env, Ctx(), b, constants().lit_true);
    return ret;
  }
  if (e->type().dim() > 0) {
    EnvI::CSEMap::iterator it;
    Id* id = e->dyn_cast<Id>();
    if (id && (id->decl()->flat() == NULL || id->decl()->toplevel())) {
      VarDecl* vd = id->decl()->flat();
      if (vd == NULL) {
        vd = flat_exp(env, Ctx(), id->decl(), NULL, constants().var_true).r()->cast<Id>()->decl();
        id->decl()->flat(vd);
        ArrayLit* al = follow_id(vd->id())->cast<ArrayLit>();
        if (al->size() == 0) {
          if (r == NULL)
            ret.r = al;
          else
            ret.r = bind(env, ctx, r, al);
          ret.b = bind(env, Ctx(), b, constants().lit_true);
          return ret;
        }
      }
      ret.r = bind(env, ctx, r, e->cast<Id>()->decl()->flat()->id());
      ret.b = bind(env, Ctx(), b, constants().lit_true);
      return ret;
    } else if ((it = env.cse_map_find(e)) != env.cse_map_end()) {
      ret.r = bind(env, ctx, r, it->second.r()->cast<VarDecl>()->id());
      ret.b = bind(env, Ctx(), b, constants().lit_true);
      return ret;
    } else {
      GCLock lock;
      ArrayLit* al = follow_id(eval_par(env, e))->cast<ArrayLit>();
      if (al->size() == 0 || (r && r->e() == NULL)) {
        if (r == NULL)
          ret.r = al;
        else
          ret.r = bind(env, ctx, r, al);
        ret.b = bind(env, Ctx(), b, constants().lit_true);
        return ret;
      }
      if ((it = env.cse_map_find(al)) != env.cse_map_end()) {
        ret.r = bind(env, ctx, r, it->second.r()->cast<VarDecl>()->id());
        ret.b = bind(env, Ctx(), b, constants().lit_true);
        return ret;
      }
      std::vector<TypeInst*> ranges(al->dims());
      for (unsigned int i = 0; i < ranges.size(); i++) {
        ranges[i] =
            new TypeInst(e->loc(), Type(),
                         new SetLit(Location().introduce(), IntSetVal::a(al->min(i), al->max(i))));
      }
      ASTExprVec<TypeInst> ranges_v(ranges);
      assert(!al->type().isbot());
      TypeInst* ti = new TypeInst(e->loc(), al->type(), ranges_v, NULL);
      VarDecl* vd = newVarDecl(env, ctx, ti, NULL, NULL, al);
      EE ee(vd, NULL);
      env.cse_map_insert(al, ee);
      env.cse_map_insert(vd->e(), ee);

      ret.r = bind(env, ctx, r, vd->id());
      ret.b = bind(env, Ctx(), b, constants().lit_true);
      return ret;
    }
  }
  GCLock lock;
  try {
    ret.r = bind(env, ctx, r, eval_par(env, e));
    ret.b = bind(env, Ctx(), b, constants().lit_true);
  } catch (ResultUndefinedError&) {
    ret.r = createDummyValue(env, e->type());
    ret.b = bind(env, Ctx(), b, constants().lit_false);
  }
  return ret;
}

}  // namespace MiniZinc