/*
*   An abstracted interface to the Multi-Pattern Matching routines,
*   thats why we're passing 'void *' objects around.
*
*/

#include "log/messages.h"
#include "framework/mpse.h"

#include <vector>
#include <string>

using namespace snort;

//-------------------------------------------------------------------------
// "bruteforce"
//-------------------------------------------------------------------------

class BruteforceMpse : public Mpse
{
private:
    std::vector<std::string> patterns;

public:
    BruteforceMpse(const MpseAgent* agent) : Mpse("bruteforce") {

    }

    ~BruteforceMpse() override {

    }

    /**
     *
     * @param P the new pattern.
     * @param m length of the pattern.
     * @param desc found in mpse.h. info about no_case, negated, literal, multi_match, flags.
     * @param user ???
     * @return 0 for succes.
     */
    int add_pattern(const uint8_t* P, unsigned m, const PatternDescriptor& desc, void* user) override {
        patterns.push_back(std::string());
        patterns.back().reserve(m);

        std::copy(P, P+m, patterns.back().begin());

        return 0;
    }

    /**
     * probably called after all add_pattern().
     * @param sc found in ??? (snort::SnortConfig). Doesn't seem modified anywhere by lowmem.
     * @return 0 for succes.
     */
    int prep_patterns(SnortConfig* sc) override {
        return 0;
    }

    /**
     *
     * @param T text in which we have to search all patterns.
     * @param n length of T.
     * @param match
     * @param context
     * @param current_state
     * @return count of found patterns. (?) if the first pattern was found 2x, and the second one 1x, return 3.
     */
    int _search(const uint8_t* T, int n, MpseMatch match, void* context, int* current_state) override {
        int matches = 0;
        for (std::string &pat: patterns) {
            for (int i = 0; i + pat.size() - 1 < n; i++) {
                int j = 0;
                while (j < (int)pat.size() && T[i + j] == pat[j]) j++;
                if (j >= (int)pat.size()) matches++;
            }
        }

        return matches;
    }

    /**
     * how many times was add_pattern called?
     * @return how many patterns do I have.
     */
    int get_pattern_count() const override {
        return (int)patterns.size();
    }
};

//-------------------------------------------------------------------------
// api
//-------------------------------------------------------------------------

static Mpse* bf_ctor(const SnortConfig*, class Module*, const MpseAgent* agent)
{
    return new BruteforceMpse(agent);
}

static void bf_dtor(Mpse* p)
{
    delete p;
}

static void bf_init()
{

}

static void bf_print()
{
    LogMessage("bruteforce idk.");
}

static const MpseApi bf_api =
{
    {
        PT_SEARCH_ENGINE,
        sizeof(MpseApi),
        SEAPI_VERSION,
        0,
        API_RESERVED,
        API_OPTIONS,
        "bruteforce",
        "Bruteforce MPSE",
        nullptr,
        nullptr
    },
    MPSE_BASE,
    nullptr,
    nullptr,
    nullptr,
    nullptr,
    bf_ctor,
    bf_dtor,
    bf_init,
    bf_print,
    nullptr
};

const BaseApi* se_bruteforce = &bf_api.base;