/******************************************************************************

 * Top contributors (to current version):

 *   Haniel Barbosa

 *

 * This file is part of the cvc5 project.

 *

 * Copyright (c) 2009-2021 by the authors listed in the file AUTHORS

 * in the top-level source directory and their institutional affiliations.

 * All rights reserved.  See the file COPYING in the top-level source

 * directory for licensing information.

 * ****************************************************************************

 *

 * The module for processing proof nodes in the prop engine.

 */

#include "cvc5_private.h"

#ifndef CVC5__PROP__PROOF_POST_PROCESSOR_H

#define CVC5__PROP__PROOF_POST_PROCESSOR_H

#include <map>

#include <unordered_set>

#include "expr/proof_node_updater.h"

#include "prop/proof_cnf_stream.h"

namespace cvc5 {

namespace prop {

/**

 * A callback class used by PropEngine for post-processing proof nodes by

 * connecting proofs of resolution, whose leaves are clausified preprocessed

 * assertions and lemmas, with the CNF transformation of these formulas, while

 * expanding the generators of lemmas.

 */

class ProofPostprocessCallback : public ProofNodeUpdaterCallback

{

 public:

  ProofPostprocessCallback(ProofNodeManager* pnm,

                           ProofCnfStream* proofCnfStream);

  /**

   * Initialize, called once for each new ProofNode to process. This initializes

   * static information to be used by successive calls to update. For this

   * callback it resets d_assumpToProof.

   */

  void initializeUpdate();

  /** Should proof pn be updated?

   *

   * For this callback a proof node is updatable if it's an assumption for which

   * the proof cnf straem has a proof. However if the proof node is blocked

   * (which is the case for proof nodes introduced into the proof cnf stream's

   * proof via expansion of its generators) then traversal is the proof node is

   * cancelled, i.e., continueUpdate is set to false.

   */

  bool shouldUpdate(std::shared_ptr<ProofNode> pn,

                    const std::vector<Node>& fa,

                    bool& continueUpdate) override;

  /** Update the proof rule application.

   *

   * Replaces assumptions by their proof in proof cnf stream. Note that in doing

   * this the proof node is blocked, so that future post-processing does not

   * traverse it.

   *

   * This method uses the cache in d_assumpToProof to avoid recomputing proofs

   * for the same assumption (in the same scope).

   */

  bool update(Node res,

              PfRule id,

              const std::vector<Node>& children,

              const std::vector<Node>& args,

              CDProof* cdp,

              bool& continueUpdate) override;

 private:

  /** The proof node manager */

  ProofNodeManager* d_pnm;

  /** The cnf stream proof generator */

  ProofCnfStream* d_proofCnfStream;

  //---------------------------------reset at the begining of each update

  /** Mapping assumptions to their proof from cnf transformation */

  std::map<Node, std::shared_ptr<ProofNode> > d_assumpToProof;

  //---------------------------------end reset at the begining of each update

};

/**

 * The proof postprocessor module. This postprocesses the refutation proof

 * produced by the SAT solver. Its main task is to connect the refutation's

 * assumptions to the CNF transformation proof in ProofCnfStream.

 */

class ProofPostproccess

{

 public:

  ProofPostproccess(ProofNodeManager* pnm, ProofCnfStream* proofCnfStream);

  ~ProofPostproccess();

  /** post-process

   *

   * The post-processing is done via a proof node updater run on pf with this

   * class's callback d_cb.

   */

  void process(std::shared_ptr<ProofNode> pf);

 private:

  /** The post process callback */

  ProofPostprocessCallback d_cb;

  /** The proof node manager */

  ProofNodeManager* d_pnm;

};

}  // namespace prop

}  // namespace cvc5

#endif