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/** \file
 * \brief NFA acceleration analysis code.
 */

#ifndef NG_LIMEX_ACCEL_H
#define NG_LIMEX_ACCEL_H

#include "ng_holder.h"
#include "ng_misc_opt.h"
#include "ue2common.h"
#include "nfa/accelcompile.h"
#include "util/charreach.h"
#include "util/order_check.h"
#include "util/ue2_containers.h"

#include <map>
#include <vector>

namespace ue2 {

/* compile time accel defs */
#define MAX_ACCEL_DEPTH 4
#define MAX_MERGED_ACCEL_STOPS 200
#define ACCEL_MAX_STOP_CHAR 24
#define ACCEL_MAX_FLOATING_STOP_CHAR 192 /* accelerating sds is important */
#define MULTIACCEL_MIN_LEN 3
#define MULTIACCEL_MAX_LEN_SSE 15
#define MULTIACCEL_MAX_LEN_AVX2 31

// forward-declaration of CompileContext
struct CompileContext;

void findAccelFriends(const NGHolder &g, NFAVertex v,
                  const std::map<NFAVertex, BoundedRepeatSummary> &br_cyclic,
                      u32 offset,
                      ue2::flat_set<NFAVertex> *friends);

struct DoubleAccelInfo {
    DoubleAccelInfo() : offset(0) {}
    u32 offset;                         //!< offset correction to apply
    CharReach stop1;                    //!< single-byte accel stop literals
    flat_set<std::pair<u8, u8>> stop2;  //!< double-byte accel stop literals
};

DoubleAccelInfo findBestDoubleAccelInfo(const NGHolder &g, NFAVertex v);

struct AccelScheme {
    AccelScheme(const CharReach &cr_in, u32 offset_in)
        : cr(cr_in), offset(offset_in) {
        assert(offset <= MAX_ACCEL_DEPTH);
    }
    AccelScheme() : cr(CharReach::dot()), offset(MAX_ACCEL_DEPTH + 1) {}

    bool operator<(const AccelScheme &b) const {
        const AccelScheme &a = *this;

        // Don't use ORDER_CHECK as it will (stupidly) eval count() too many
        // times.
        const size_t a_count = cr.count(), b_count = b.cr.count();
        if (a_count != b_count) {
            return a_count < b_count;
        }

        /* TODO: give bonus if one is a 'caseless' character */
        ORDER_CHECK(offset);
        ORDER_CHECK(cr);
        return false;
    }

    bool operator>(const AccelScheme &b) const {
        return b < *this;
    }

    CharReach cr;
    u32 offset;
};

NFAVertex get_sds_or_proxy(const NGHolder &g);

AccelScheme nfaFindAccel(const NGHolder &g, const std::vector<NFAVertex> &verts,
                    const std::vector<CharReach> &refined_cr,
                    const std::map<NFAVertex, BoundedRepeatSummary> &br_cyclic,
                    bool allow_wide);

AccelScheme findBestAccelScheme(std::vector<std::vector<CharReach> > paths,
                                const CharReach &terminating);

/** \brief Check if vertex \a v is an accelerable state (for a limex NFA). */
bool nfaCheckAccel(const NGHolder &g, NFAVertex v,
                   const std::vector<CharReach> &refined_cr,
                   const std::map<NFAVertex, BoundedRepeatSummary> &br_cyclic,
                   AccelScheme *as, bool allow_wide);

/** \brief Check if vertex \a v is a multi accelerable state (for a limex NFA). */
MultibyteAccelInfo nfaCheckMultiAccel(const NGHolder &g,
                                      const std::vector<NFAVertex> &verts,
                                      const CompileContext &cc);

} // namespace ue2

#endif