/******************************************
Copyright (c) 2016, Mate Soos

Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in
all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
THE SOFTWARE.
***********************************************/

#include "distillerallwithall.h"
#include "clausecleaner.h"
#include "time_mem.h"
#include "solver.h"
#include "watchalgos.h"
#include "clauseallocator.h"
#include "sqlstats.h"

#include <iomanip>
using namespace CMSat;
using std::cout;
using std::endl;

//#define DEBUG_STAMPING

#ifdef VERBOSE_DEBUG
#define VERBOSE_SUBSUME_NONEXIST
#endif

//#define VERBOSE_SUBSUME_NONEXIST

DistillerAllWithAll::DistillerAllWithAll(Solver* _solver) :
    solver(_solver)
{}

bool DistillerAllWithAll::distill(uint32_t queueByBy)
{
    assert(solver->ok);
    numCalls++;

    solver->clauseCleaner->clean_clauses(solver->longIrredCls);

    if (!distill_long_irred_cls(queueByBy)) {
        goto end;
    }

end:
    globalStats += runStats;
    if (solver->conf.verbosity) {
        if (solver->conf.verbosity >= 3)
            runStats.print(solver->nVars());
        else
            runStats.print_short(solver);
    }
    runStats.clear();

    return solver->ok;
}

struct ClauseSizeSorter
{
    ClauseSizeSorter(const ClauseAllocator& _cl_alloc, const bool _invert = false) :
        cl_alloc(_cl_alloc)
        , invert(_invert)
    {}

    const ClauseAllocator& cl_alloc;
    const bool invert;

    bool operator()(const ClOffset off1, const ClOffset off2) const
    {
        const Clause* cl1 = cl_alloc.ptr(off1);
        const Clause* cl2 = cl_alloc.ptr(off2);

        if (!invert)
            return cl1->size() > cl2->size();
        else
            return cl1->size() < cl2->size();
    }
};

bool DistillerAllWithAll::distill_long_irred_cls(uint32_t queueByBy)
{
    assert(solver->ok);
    if (solver->conf.verbosity >= 6) {
        cout
        << "c Doing distillation branch for long irred clauses"
        << endl;
    }

    double myTime = cpuTime();
    const size_t origTrailSize = solver->trail_size();

    //Time-limiting
    uint64_t maxNumProps =
        solver->conf.distill_long_irred_cls_time_limitM*1000LL*1000ULL
        *solver->conf.global_timeout_multiplier;
    if (solver->litStats.irredLits + solver->litStats.redLits < 500000)
        maxNumProps *=2;

    extraTime = 0;
    uint64_t oldBogoProps = solver->propStats.bogoProps;
    bool time_out = false;
    runStats.potentialClauses = solver->longIrredCls.size();
    runStats.numCalled = 1;

    std::sort(solver->longIrredCls.begin()
        , solver->longIrredCls.end()
        , ClauseSizeSorter(solver->cl_alloc)
    );
    uint64_t origLitRem = runStats.numLitsRem;
    uint64_t origClShorten = runStats.numClShorten;

    //Make queueByBy = 1 in case we are late in the search
    if (numCalls > 8
        && (solver->litStats.irredLits + solver->litStats.redLits < 4000000)
        && (solver->longIrredCls.size() < 50000)
    ) {
        queueByBy = 1;
    }

    vector<ClOffset>::iterator i, j;
    i = j = solver->longIrredCls.begin();
    for (vector<ClOffset>::iterator end = solver->longIrredCls.end()
        ; i != end
        ; i++
    ) {
        //Check if we are in state where we only copy offsets around
        if (time_out || !solver->ok) {
            *j++ = *i;
            continue;
        }

        //if done enough, stop doing it
        if (solver->propStats.bogoProps-oldBogoProps + extraTime >= maxNumProps
            || solver->must_interrupt_asap()
        ) {
            if (solver->conf.verbosity >= 3) {
                cout
                << "c Need to finish distillation -- ran out of prop (=allocated time)"
                << endl;
            }
            runStats.timeOut++;
            time_out = true;
        }

        //Get pointer
        ClOffset offset = *i;
        Clause& cl = *solver->cl_alloc.ptr(offset);
        //Time to dereference
        extraTime += 5;

        //If we already tried this clause, then move to next
        if (cl.getdistilled()) {
            *j++ = *i;
            continue;
        } else {
            //Otherwise, this clause has been tried for sure
            cl.set_distilled(true);
        }

        extraTime += cl.size();
        runStats.checkedClauses++;

        //Sanity check
        assert(cl.size() > 2);
        assert(!cl.red());

        //Copy literals
        uselessLits.clear();
        lits.resize(cl.size());
        std::copy(cl.begin(), cl.end(), lits.begin());

        //Try to distill clause
        ClOffset offset2 = try_distill_clause_and_return_new(
            offset
            , cl.red()
            , &cl.stats
            , queueByBy
        );

        if (offset2 != CL_OFFSET_MAX) {
            *j++ = offset2;
        }
    }
    solver->longIrredCls.resize(solver->longIrredCls.size()- (i-j));

    //Didn't time out, so it went through the whole list. Reset distill for all.
    if (!time_out) {
        for (vector<ClOffset>::const_iterator
            it = solver->longIrredCls.begin(), end = solver->longIrredCls.end()
            ; it != end
            ; ++it
        ) {
            Clause* cl = solver->cl_alloc.ptr(*it);
            cl->set_distilled(false);
        }
    }

    const double time_used = cpuTime() - myTime;
    const double time_remain = float_div(solver->propStats.bogoProps-oldBogoProps + extraTime, maxNumProps);
    if (solver->conf.verbosity) {
        cout << "c [distill] longirred"
        << " tried: " << runStats.checkedClauses << "/" << solver->longIrredCls.size()
        << " cl-r:" << runStats.numClShorten- origClShorten
        << " lit-r:" << runStats.numLitsRem - origLitRem
        << solver->conf.print_times(time_used, time_out, time_remain)
        << endl;
    }
    if (solver->sqlStats) {
        solver->sqlStats->time_passed(
            solver
            , "distill long irred"
            , time_used
            , time_out
            , time_remain
        );
    }

    //Update stats
    runStats.time_used = cpuTime() - myTime;
    runStats.zeroDepthAssigns = solver->trail_size() - origTrailSize;

    return solver->ok;
}

ClOffset DistillerAllWithAll::try_distill_clause_and_return_new(
    ClOffset offset
    , const bool red
    , const ClauseStats* stats
    , const uint32_t queueByBy
) {
    #ifdef DRAT_DEBUG
    if (solver->conf.verbosity >= 6) {
        cout << "Trying to distill clause:" << lits << endl;
    }
    #endif

    //Try to enqueue the literals in 'queueByBy' amounts and see if we fail
    bool failed = false;
    uint32_t done = 0;
    solver->new_decision_level();
    for (; done < lits.size();) {
        uint32_t i2 = 0;
        for (; (i2 < queueByBy) && ((done+i2) < lits.size()); i2++) {
            lbool val = solver->value(lits[done+i2]);
            if (val == l_Undef) {
                solver->enqueue(~lits[done+i2]);
            } else if (val == l_False) {
                //Record that there is no use for this literal
                uselessLits.push_back(lits[done+i2]);
            }
        }
        done += i2;
        extraTime += 5;
        failed = (!solver->propagate<true>().isNULL());
        if (failed) {
            break;
        }
    }
    solver->cancelUntil<false>(0);
    assert(solver->ok);

    if (uselessLits.size() > 0 || (failed && done < lits.size())) {
        //Stats
        runStats.numClShorten++;
        extraTime += 20;
        const uint32_t origSize = lits.size();

        //Remove useless literals from 'lits'
        lits.resize(done);
        for (uint32_t i2 = 0; i2 < uselessLits.size(); i2++) {
            remove(lits, uselessLits[i2]);
        }

        //Make new clause
        Clause *cl2;
        if (stats) {
            cl2 = solver->add_clause_int(lits, red, *stats);
        } else {
            cl2 = solver->add_clause_int(lits, red);
        }

        //Print results
        if (solver->conf.verbosity >= 5) {
            cout
            << "c Distillation branch effective." << endl;
            if (offset != CL_OFFSET_MAX) {
                cout
                << "c --> orig clause:" <<
                 *solver->cl_alloc.ptr(offset)
                 << endl;
            } else {
                cout
                << "c --> orig clause: TRI/BIN" << endl;
            }
            cout
            << "c --> orig size:" << origSize << endl
            << "c --> new size:" << (cl2 == NULL ? 0 : cl2->size()) << endl
            << "c --> removing lits from end:" << origSize - done << endl
            << "c --> useless lits in middle:" << uselessLits.size()
            << endl;
        }

        //Detach and free old clause
        if (offset != CL_OFFSET_MAX) {
            solver->detachClause(offset);
            solver->cl_alloc.clauseFree(offset);
        }

        runStats.numLitsRem += origSize - lits.size();

        if (cl2 != NULL) {
            cl2->set_distilled(true);

            return solver->cl_alloc.get_offset(cl2);
        } else {
            return CL_OFFSET_MAX;
        }
    } else {
        return offset;
    }
}

DistillerAllWithAll::Stats& DistillerAllWithAll::Stats::operator+=(const Stats& other)
{
    time_used += other.time_used;
    timeOut += other.timeOut;
    zeroDepthAssigns += other.zeroDepthAssigns;
    numClShorten += other.numClShorten;
    numLitsRem += other.numLitsRem;
    checkedClauses += other.checkedClauses;
    potentialClauses += other.potentialClauses;
    numCalled += other.numCalled;

    return *this;
}

void DistillerAllWithAll::Stats::print_short(const Solver* _solver) const
{
    cout
    << "c [distill] tri+long"
    << " useful: "<< numClShorten
    << "/" << checkedClauses << "/" << potentialClauses
    << " lits-rem: " << numLitsRem
    << " 0-depth-assigns: " << zeroDepthAssigns
    << _solver->conf.print_times(time_used, timeOut)
    << endl;
}

void DistillerAllWithAll::Stats::print(const size_t nVars) const
{
    cout << "c -------- DISTILL STATS --------" << endl;
    print_stats_line("c time"
        , time_used
        , ratio_for_stat(time_used, numCalled)
        , "per call"
    );

    print_stats_line("c timed out"
        , timeOut
        , stats_line_percent(timeOut, numCalled)
        , "% of calls"
    );

    print_stats_line("c distill/checked/potential"
        , numClShorten
        , checkedClauses
        , potentialClauses
    );

    print_stats_line("c lits-rem",
        numLitsRem
    );
    print_stats_line("c 0-depth-assigns",
        zeroDepthAssigns
        , stats_line_percent(zeroDepthAssigns, nVars)
        , "% of vars"
    );
    cout << "c -------- DISTILL STATS END --------" << endl;
}

double DistillerAllWithAll::mem_used() const
{
    double mem_used = sizeof(DistillerAllWithAll);
    mem_used += lits.size()*sizeof(Lit);
    mem_used += uselessLits.size()*sizeof(Lit);
    return mem_used;
}