/*++
Copyright (c) 2011 Microsoft Corporation

Module Name:

    expr2polynomial.h

Abstract:

    Translator from Z3 expressions into multivariate polynomials (and back).
    
    
Author:

    Leonardo (leonardo) 2011-12-23

Notes:

--*/
#ifndef _EXPR2POLYNOMIAL_H_
#define _EXPR2POLYNOMIAL_H_

#include"ast.h"
#include"polynomial.h"

class expr2var;

class expr2polynomial {
    struct imp;
    imp * m_imp;
public:
    expr2polynomial(ast_manager & am, polynomial::manager & pm, expr2var * e2v);
    virtual ~expr2polynomial();

    ast_manager & m() const;
    polynomial::manager & pm() const;
    
    /**
       \brief Convert a Z3 expression into a polynomial in Z[x0, ..., x_n].
       Since Z3 expressions may be representing polynomials in Q[x0, ..., x_n],
       the method also returns a "denominator" d. 
       Thus, we have that n is equal to p/d

       \remark Return false if t is not an integer or real expression.
       
       \pre The only supported operators are MUL, ADD, SUB, UMINUS, TO_REAL, TO_INT, POWER (with constants) 
    */
    bool to_polynomial(expr * t, polynomial::polynomial_ref & p, polynomial::scoped_numeral & d);
    
    /**
       \brief Convert a polynomial into a Z3 expression.
       
       \remark If the polynomial has one real variable, then the resultant 
       expression is an real expression. Otherwise, it is an integer
    */
    void to_expr(polynomial::polynomial_ref const & p, bool use_power, expr_ref & r);

    /**
       \brief Return true if t was encoded as a variable by the translator.
    */
    bool is_var(expr * t) const;
    
    
    /**
       \brief Return the mapping from expressions to variables
    */
    expr2var const & get_mapping() const;

    /**
       \brief Cancel/Interrupt execution.
    */
    void set_cancel(bool f);

    /**
       \brief Return true if the variable is associated with an expression of integer sort.
    */
    virtual bool is_int(polynomial::var x) const = 0;

protected:
    virtual polynomial::var mk_var(bool is_int) = 0;
};

class default_expr2polynomial : public expr2polynomial {
    svector<bool> m_is_int;
public:
    default_expr2polynomial(ast_manager & am, polynomial::manager & pm);
    virtual ~default_expr2polynomial();
    virtual bool is_int(polynomial::var x) const;
protected:
    virtual polynomial::var mk_var(bool is_int); 
};

#endif