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

 * Top contributors (to current version):

 *   Andrew Reynolds, Andres Noetzli, Mathias Preiner

 *

 * 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.

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

 *

 * Term database sygus class.

 */

#include "cvc5_private.h"

#ifndef CVC5__THEORY__QUANTIFIERS__TERM_DATABASE_SYGUS_H

#define CVC5__THEORY__QUANTIFIERS__TERM_DATABASE_SYGUS_H

#include <unordered_set>

#include "expr/dtype.h"

#include "smt/env_obj.h"

#include "theory/evaluator.h"

#include "theory/quantifiers/extended_rewrite.h"

#include "theory/quantifiers/fun_def_evaluator.h"

#include "theory/quantifiers/sygus/sygus_eval_unfold.h"

#include "theory/quantifiers/sygus/sygus_explain.h"

#include "theory/quantifiers/sygus/type_info.h"

#include "theory/quantifiers/term_database.h"

namespace cvc5 {

namespace theory {

namespace quantifiers {

class SynthConjecture;

/** role for registering an enumerator */

enum EnumeratorRole

{

  /** The enumerator populates a pool of terms (e.g. for PBE). */

  ROLE_ENUM_POOL,

  /** The enumerator is the single solution of the problem. */

  ROLE_ENUM_SINGLE_SOLUTION,

  /**

   * The enumerator is part of the solution of the problem (e.g. multiple

   * functions to synthesize).

   */

  ROLE_ENUM_MULTI_SOLUTION,

  /** The enumerator must satisfy some set of constraints */

  ROLE_ENUM_CONSTRAINED,

};

std::ostream& operator<<(std::ostream& os, EnumeratorRole r);

// TODO :issue #1235 split and document this class

class TermDbSygus : protected EnvObj

{

 public:

  TermDbSygus(Env& env, QuantifiersState& qs);

  /** Finish init, which sets the inference manager */

  void finishInit(QuantifiersInferenceManager* qim);

  /** Reset this utility */

  bool reset(Theory::Effort e);

  /** Identify this utility */

  std::string identify() const { return "TermDbSygus"; }

  /** register the sygus type

   *

   * This initializes this database for sygus datatype type tn. This may

   * throw an assertion failure if the sygus grammar has type errors. Otherwise,

   * after registering a sygus type, the query function getTypeInfo can be

   * called for tn.

   *

   * This method returns true if tn is a sygus datatype type and false

   * otherwise.

   */

  bool registerSygusType(TypeNode tn);

  //------------------------------utilities

  /** get the explanation utility */

  /** get the evaluator */

  /** (recursive) function evaluator utility */

  /** evaluation unfolding utility */

  //------------------------------end utilities

  //------------------------------enumerators

  /**

   * Register a variable e that we will do enumerative search on.

   *

   * conj : the conjecture that the enumeration of e is for.

   *

   * f : the synth-fun that the enumeration of e is for.Notice that enumerator

   * e may not be one-to-one with f in synthesis-through-unification approaches

   * (e.g. decision tree construction for PBE synthesis).

   *

   * erole : the role of this enumerator (see definition of EnumeratorRole).

   * Depending on this and the policy for actively-generated enumerators

   * (--sygus-active-gen), the enumerator may be "actively-generated".

   * For example, if --sygus-active-gen=var-agnostic, then the enumerator will

   * only generate values whose variables are in canonical order (only x1-x2

   * and not x2-x1 will be generated, assuming x1 and x2 are in the same

   * "subclass", see getSubclassForVar).

   *

   * An "active guard" may be allocated by this method for e based on erole

   * and the policies for active generation.

   */

  void registerEnumerator(Node e,

                          Node f,

                          SynthConjecture* conj,

                          EnumeratorRole erole);

  /** is e an enumerator registered with this class? */

  bool isEnumerator(Node e) const;

  /** return the conjecture e is associated with */

  SynthConjecture* getConjectureForEnumerator(Node e) const;

  /** return the function-to-synthesize e is associated with */

  Node getSynthFunForEnumerator(Node e) const;

  /** get active guard for e */

  Node getActiveGuardForEnumerator(Node e) const;

  /** are we using symbolic constructors for enumerator e? */

  bool usingSymbolicConsForEnumerator(Node e) const;

  /** is this enumerator agnostic to variables? */

  bool isVariableAgnosticEnumerator(Node e) const;

  /** is this enumerator a "basic" enumerator.

   *

   * A basic enumerator is one that does not rely on the sygus extension of the

   * datatypes solver. Basic enumerators enumerate all concrete terms for their

   * type for a single abstract value.

   */

  bool isBasicEnumerator(Node e) const;

  /** is this a "passively-generated" enumerator?

   *

   * A "passively-generated" enumerator is one for which the terms it enumerates

   * are obtained by looking at its model value only. For passively-generated

   * enumerators, it is the responsibility of the user of that enumerator (say

   * a SygusModule) to block the current model value of it before asking for

   * another value. By default, the Cegis module uses passively-generated

   * enumerators and "conjecture-specific refinement" to rule out models

   * for passively-generated enumerators.

   *

   * On the other hand, an "actively-generated" enumerator is one for which the

   * terms it enumerates are not necessarily a subset of the model values the

   * enumerator takes. Actively-generated enumerators are centrally managed by

   * SynthConjecture. The user of actively-generated enumerators are prohibited

   * from influencing its model value. For example, conjecture-specific

   * refinement in Cegis is not applied to actively-generated enumerators.

   */

  bool isPassiveEnumerator(Node e) const;

  /** get all registered enumerators */

  void getEnumerators(std::vector<Node>& mts);

  /** Register symmetry breaking lemma

   *

   * This function registers lem as a symmetry breaking lemma template for

   * subterms of enumerator e. For more information on symmetry breaking

   * lemma templates, see datatypes/datatypes_sygus.h.

   *

   * tn : the (sygus datatype) type that lem applies to, i.e. the

   * type of terms that lem blocks models for,

   * sz : the minimum size of terms that the lem blocks,

   * isTempl : if this flag is false, then lem is a (concrete) lemma.

   * If this flag is true, then lem is a symmetry breaking lemma template

   * over x, where x is returned by the call to getFreeVar( tn, 0 ).

   */

  void registerSymBreakLemma(

      Node e, Node lem, TypeNode tn, unsigned sz, bool isTempl = true);

  /** Has symmetry breaking lemmas been added for any enumerator? */

  bool hasSymBreakLemmas(std::vector<Node>& enums) const;

  /** Get symmetry breaking lemmas

   *

   * Returns the set of symmetry breaking lemmas that have been registered

   * for enumerator e. It adds these to lemmas.

   */

  void getSymBreakLemmas(Node e, std::vector<Node>& lemmas) const;

  /** Get the type of term symmetry breaking lemma lem applies to */

  TypeNode getTypeForSymBreakLemma(Node lem) const;

  /** Get the minimum size of terms symmetry breaking lemma lem applies to */

  unsigned getSizeForSymBreakLemma(Node lem) const;

  /** Returns true if lem is a lemma template, false if lem is a lemma */

  bool isSymBreakLemmaTemplate(Node lem) const;

  /** Clear information about symmetry breaking lemmas for enumerator e */

  void clearSymBreakLemmas(Node e);

  //------------------------------end enumerators

  //-----------------------------conversion from sygus to builtin

  /** get free variable

   *

   * This class caches a list of free variables for each type, which are

   * used, for instance, for constructing canonical forms of terms with free

   * variables. This function returns the i^th free variable for type tn.

   * If useSygusType is true, then this function returns a variable of the

   * analog type for sygus type tn (see d_fv for details).

   */

  TNode getFreeVar(TypeNode tn, int i, bool useSygusType = false);

  /** get free variable and increment

   *

   * This function returns the next free variable for type tn, and increments

   * the counter in var_count for that type.

   */

  TNode getFreeVarInc(TypeNode tn,

                      std::map<TypeNode, int>& var_count,

                      bool useSygusType = false);

  /** returns true if n is a cached free variable (in d_fv). */

  bool isFreeVar(Node n) const;

  /** returns the identifier for a cached free variable. */

  size_t getFreeVarId(Node n) const;

  /** returns true if n has a cached free variable (in d_fv). */

  bool hasFreeVar(Node n);

  /** get sygus proxy variable

   *

   * Returns a fresh variable of type tn with the SygusPrintProxyAttribute set

   * to constant c. The type tn should be a sygus datatype type, and the type of

   * c should be the analog type of tn. The semantics of the returned node

   * is "the variable of sygus datatype tn that encodes constant c".

   */

  Node getProxyVariable(TypeNode tn, Node c);

  /** make generic

   *

   * This function returns a builtin term f( t1, ..., tn ) where f is the

   * builtin op of the sygus datatype constructor specified by arguments

   * dt and c. The mapping pre maps child indices to the term for that index

   * in the term we are constructing. That is, for each i = 1,...,n:

   *   If i is in the domain of pre, then ti = pre[i].

   *   If i is not in the domain of pre, then ti = d_fv[1][ var_count[Ti ] ],

   *     and var_count[Ti] is incremented.

   * If doBetaRed is true, then lambda operators are eagerly eliminated via

   * beta reduction.

   */

  Node mkGeneric(const DType& dt,

                 unsigned c,

                 std::map<TypeNode, int>& var_count,

                 std::map<int, Node>& pre,

                 bool doBetaRed = true);

  /** same as above, but with empty var_count */

  Node mkGeneric(const DType& dt,

                 int c,

                 std::map<int, Node>& pre,

                 bool doBetaRed = true);

  /** same as above, but with empty pre */

  Node mkGeneric(const DType& dt, int c, bool doBetaRed = true);

  /** makes a symbolic term concrete

   *

   * Given a sygus datatype term n of type tn with holes (symbolic constructor

   * applications), this function returns a term in which holes are replaced by

   * unique variables. To track counters for introducing unique variables, we

   * use the var_count map.

   */

  Node canonizeBuiltin(Node n);

  Node canonizeBuiltin(Node n, std::map<TypeNode, int>& var_count);

  /** sygus to builtin

   *

   * Given a sygus datatype term n of type tn, this function returns its analog,

   * that is, the term that n encodes.

   */

  Node sygusToBuiltin(Node n, TypeNode tn);

  /** same as above, but without tn */

  /** evaluate builtin

   *

   * bn is a term of some sygus datatype tn. This function returns the rewritten

   * form of bn [ args / vars(tn) ], where vars(tn) is the sygus variable

   * list for type tn (see Datatype::getSygusVarList).

   *

   * If the argument tryEval is true, we consult the evaluator before the

   * rewriter, for performance reasons.

   */

  Node evaluateBuiltin(TypeNode tn,

                       Node bn,

                       const std::vector<Node>& args,

                       bool tryEval = true);

  /** is evaluation point?

   *

   * Returns true if n is of the form eval( x, c1...cn ) for some variable x

   * and constants c1...cn.

   */

  bool isEvaluationPoint(Node n) const;

  /** return the builtin type of tn

   *

   * The type tn should be a sygus datatype type that has been registered to

   * this database.

   */

  TypeNode sygusToBuiltinType(TypeNode tn);

  //-----------------------------end conversion from sygus to builtin

  /**

   * Get type information about sygus datatype type tn. The type tn should be

   * (a subfield type of) a type that has been registered to this class.

   */

  SygusTypeInfo& getTypeInfo(TypeNode tn);

  /**

   * Rewrite the given node using the utilities in this class. This may

   * involve (recursive function) evaluation.

   */

  Node rewriteNode(Node n) const;

  /** print to sygus stream n on trace c */

  static void toStreamSygus(const char* c, Node n);

  /** print to sygus stream n on output out */

  static void toStreamSygus(std::ostream& out, Node n);

 private:

  /** Reference to the quantifiers state */

  QuantifiersState& d_qstate;

  /** Pointer to the quantifiers inference manager */

  QuantifiersInferenceManager* d_qim;

  //------------------------------utilities

  /** sygus explanation */

  std::unique_ptr<SygusExplain> d_syexp;

  /** evaluator */

  std::unique_ptr<Evaluator> d_eval;

  /** (recursive) function evaluator utility */

  std::unique_ptr<FunDefEvaluator> d_funDefEval;

  /** evaluation function unfolding utility */

  std::unique_ptr<SygusEvalUnfold> d_eval_unfold;

  //------------------------------end utilities

  //------------------------------enumerators

  /** mapping from enumerator terms to the conjecture they are associated with

   */

  std::map<Node, SynthConjecture*> d_enum_to_conjecture;

  /** mapping from enumerator terms to the function-to-synthesize they are

   * associated with

   */

  std::map<Node, Node> d_enum_to_synth_fun;

  /** mapping from enumerator terms to the guard they are associated with

   * The guard G for an enumerator e has the semantics

   *   if G is true, then there are more values of e to enumerate".

   */

  std::map<Node, Node> d_enum_to_active_guard;

  /**

   * Mapping from enumerators to whether we allow symbolic constructors to

   * appear as subterms of them.

   */

  std::map<Node, bool> d_enum_to_using_sym_cons;

  /** mapping from enumerators to symmetry breaking clauses for them */

  std::map<Node, std::vector<Node> > d_enum_to_sb_lemmas;

  /** mapping from symmetry breaking lemmas to type */

  std::map<Node, TypeNode> d_sb_lemma_to_type;

  /** mapping from symmetry breaking lemmas to size */

  std::map<Node, unsigned> d_sb_lemma_to_size;

  /** mapping from symmetry breaking lemmas to whether they are templates */

  std::map<Node, bool> d_sb_lemma_to_isTempl;

  /** enumerators to whether they are actively-generated */

  std::map<Node, bool> d_enum_active_gen;

  /** enumerators to whether they are variable agnostic */

  std::map<Node, bool> d_enum_var_agnostic;

  /** enumerators to whether they are basic */

  std::map<Node, bool> d_enum_basic;

  //------------------------------end enumerators

  //-----------------------------conversion from sygus to builtin

  /** a cache of fresh variables for each type

   *

   * We store two versions of this list:

   *   index 0: mapping from builtin types to fresh variables of that type,

   *   index 1: mapping from sygus types to fresh varaibles of the type they

   *            encode.

   */

  std::map<TypeNode, std::vector<Node> > d_fv[2];

  /** Maps free variables to the domain type they are associated with in d_fv */

  std::map<Node, TypeNode> d_fv_stype;

  /** Id count for free variables terms */

  std::map<TypeNode, size_t> d_fvTypeIdCounter;

  /**

   * Maps free variables to a unique identifier for their builtin type. Notice

   * that, e.g. free variables of type Int and those that are of a sygus

   * datatype type that encodes Int must have unique identifiers. This is

   * to ensure that sygusToBuiltin for non-ground terms maps variables to

   * unique variabales.

   */

  std::map<Node, size_t> d_fvId;

  /** recursive helper for hasFreeVar, visited stores nodes we have visited. */

  bool hasFreeVar(Node n, std::map<Node, bool>& visited);

  /** cache of getProxyVariable */

  std::map<TypeNode, std::map<Node, Node> > d_proxy_vars;

  //-----------------------------end conversion from sygus to builtin

  // TODO :issue #1235 : below here needs refactor

 public:

  Node d_true;

  Node d_false;

 private:

  /** computes the map d_min_type_depth */

  void computeMinTypeDepthInternal( TypeNode root_tn, TypeNode tn, unsigned type_depth );

  bool involvesDivByZero( Node n, std::map< Node, bool >& visited );

 private:

  /**

   * Maps types that we have called registerSygusType to a flag indicating

   * whether that type is a sygus datatype type. Sygus datatype types that

   * are in this map have initialized type information stored in the map below.

   */

  std::map<TypeNode, bool> d_registerStatus;

  /**

   * The type information for each sygus datatype type that has been registered

   * to this class.

   */

  std::map<TypeNode, SygusTypeInfo> d_tinfo;

  /** a cache for getSelectorWeight */

  std::map<TypeNode, std::map<Node, unsigned> > d_sel_weight;

 public:  // general sygus utilities

  bool isRegistered(TypeNode tn) const;

  /** get the weight of the selector, where tn is the domain of sel */

  unsigned getSelectorWeight(TypeNode tn, Node sel);

  /** get arg type */

  TypeNode getArgType(const DTypeConstructor& c, unsigned i) const;

  /** Do constructors c1 and c2 have the same type? */

  bool isTypeMatch(const DTypeConstructor& c1, const DTypeConstructor& c2);

  /** return whether n is an application of a symbolic constructor */

  bool isSymbolicConsApp(Node n) const;

  /** can construct kind

   *

   * Given a sygus datatype type tn, if this method returns true, then there

   * exists values of tn whose builtin analog is equivalent to

   * <k>( t1, ..., tn ). The sygus types of t1...tn are added to arg_types.

   *

   * For example, if:

   *   A -> A+A | ite( B, A, A ) | x | 1 | 0

   *   B -> and( B, B ) | not( B ) | or( B, B ) | A = A

   * - canConstructKind( A, +, ... ) returns true and adds {A,A} to arg_types,

   * - canConstructKind( B, not, ... ) returns true and adds { B } to arg types.

   *

   * We also may infer that operator is constructable. For example,

   * - canConstructKind( B, ite, ... ) may return true, adding { B, B, B } to

   * arg_types, noting that the term

   *   (and (or (not b1) b2) (or b1 b3)) is equivalent to (ite b1 b2 b3)

   * The argument aggr is whether we use aggressive techniques like the one

   * above to infer a kind is constructable. If this flag is false, we only

   * check if the kind is literally a constructor of the grammar.

   */

  bool canConstructKind(TypeNode tn,

                        Kind k,

                        std::vector<TypeNode>& argts,

                        bool aggr = false);

  Node getSygusNormalized( Node n, std::map< TypeNode, int >& var_count, std::map< Node, Node >& subs );

  Node getNormalized(TypeNode t, Node prog);

  /** involves div-by-zero */

  bool involvesDivByZero( Node n );

  /** get anchor */

  static Node getAnchor( Node n );

  static unsigned getAnchorDepth( Node n );

};

}  // namespace quantifiers

}  // namespace theory

}  // namespace cvc5

#endif /* CVC5__THEORY__QUANTIFIERS__TERM_DATABASE_H */