/*++
Copyright (c) 2011 Microsoft Corporation

Module Name:

    seq_axioms.h

Abstract:

    Axiomatize string operations that can be reduced to 
    more basic operations.

Author:

    Nikolaj Bjorner (nbjorner) 2020-4-16

Revision History:

--*/
#pragma once

#include "ast/seq_decl_plugin.h"
#include "ast/arith_decl_plugin.h"
#include "ast/rewriter/th_rewriter.h"
#include "ast/rewriter/seq_skolem.h"

namespace seq {

    class axioms {
        ast_manager&    m;
        th_rewriter&    m_rewrite;
        arith_util      a;
        seq_util        seq;
        skolem          m_sk;
        expr_ref_vector m_clause;
        std::function<void(expr_ref_vector const&)> m_add_clause;

        expr_ref mk_len(expr* s);
        expr_ref mk_sub(expr* x, expr* y);
        expr_ref mk_concat(expr* e1, expr* e2, expr* e3) { return expr_ref(seq.str.mk_concat(e1, e2, e3), m); }
        expr_ref mk_concat(expr* e1, expr* e2) { return expr_ref(seq.str.mk_concat(e1, e2), m); }
        expr_ref mk_nth(expr* e, unsigned i) { return expr_ref(seq.str.mk_nth_i(e, a.mk_int(i)), m); }
        expr_ref mk_eq(expr* a, expr* b) { return expr_ref(m.mk_eq(a, b), m); }
        expr_ref mk_seq_eq(expr* a, expr* b) { SASSERT(seq.is_seq(a) && seq.is_seq(b)); return expr_ref(m_sk.mk_eq(a, b), m); }
        expr_ref mk_eq_empty(expr* e) { return expr_ref(m.mk_eq(seq.str.mk_empty(e->get_sort()), e), m); }

        expr_ref mk_ge(expr* x, unsigned n) { return expr_ref(a.mk_ge(x, a.mk_int(n)), m); }
        expr_ref mk_le(expr* x, unsigned n) { return expr_ref(a.mk_le(x, a.mk_int(n)), m); }
        expr_ref mk_ge(expr* x, rational const& n) { return expr_ref(a.mk_ge(x, a.mk_int(n)), m); }
        expr_ref mk_le(expr* x, rational const& n) { return expr_ref(a.mk_le(x, a.mk_int(n)), m); }

        expr_ref is_digit(expr* ch);
        expr_ref purify(expr* e);
        expr_ref mk_digit2int(expr* ch);

        void add_clause(expr_ref const& a);
        void add_clause(expr_ref const& a, expr_ref const& b);
        void add_clause(expr_ref const& a, expr_ref const& b, expr_ref const& c);
        void add_clause(expr_ref const& a, expr_ref const& b, expr_ref const& c, expr_ref const & d);
        void add_clause(expr_ref const& a, expr_ref const& b, expr_ref const& c, expr_ref const & d, expr_ref const& e);

        bool is_drop_last(expr* s, expr* i, expr* l);
        bool is_tail(expr* s, expr* i, expr* l);
        bool is_extract_prefix0(expr* s, expr* i, expr* l);
        bool is_extract_suffix(expr* s, expr* i, expr* l);

        void tail_axiom(expr* e, expr* s);
        void drop_last_axiom(expr* e, expr* s);
        void extract_prefix_axiom(expr* e, expr* s, expr* l);
        void extract_suffix_axiom(expr* e, expr* s, expr* l);
        void tightest_prefix(expr* s, expr* x);

    public:

        axioms(th_rewriter& rw);

        void set_add_clause(std::function<void(expr_ref_vector const&)>& ac) { m_add_clause = ac; }

        void suffix_axiom(expr* n);
        void prefix_axiom(expr* n);
        void extract_axiom(expr* n);
        void indexof_axiom(expr* n);
        void last_indexof_axiom(expr* n);
        void replace_axiom(expr* n);
        void at_axiom(expr* n);
        void nth_axiom(expr* n);
        void itos_axiom(expr* n);
        void stoi_axiom(expr* n);
        void stoi_axiom(expr* e, unsigned k);
        void itos_axiom(expr* s, unsigned k);
        void lt_axiom(expr* n);
        void le_axiom(expr* n);
        void is_digit_axiom(expr* n);
        void str_to_code_axiom(expr* n);
        void str_from_code_axiom(expr* n);
        void unit_axiom(expr* n);
        void length_axiom(expr* n);
        void unroll_not_contains(expr* e);

        expr_ref length_limit(expr* s, unsigned k);
    };

};