/******************************************
Copyright (C) 2009-2020 Authors of CryptoMiniSat, see AUTHORS file

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 <set>
#include <map>
#include <iomanip>
#include <iostream>
#include "compfinder.h"
#include "time_mem.h"
#include "cloffset.h"
#include "solver.h"
#include "varreplacer.h"
#include "clausecleaner.h"
#include "clauseallocator.h"
#include "sqlstats.h"

using namespace CMSat;

using std::set;
using std::map;
using std::cout;
using std::endl;

//#define VERBOSE_DEBUG



//#define PART_FINDING

CompFinder::CompFinder(Solver* _solver) :
    timedout(false)
    , seen(_solver->seen)
    , solver(_solver)
{
}

void CompFinder::print_found_components() const
{
    size_t notPrinted = 0;
    size_t totalSmallSize = 0;
    size_t i = 0;
    size_t print_limit = 300;
    for(map<uint32_t, vector<uint32_t> >::const_iterator
        it = reverseTable.begin(), end = reverseTable.end()
        ; it != end
        ; ++it, i++
    ) {
        if (it->second.size() < print_limit || solver->conf.verbosity >= 3) {
            totalSmallSize += it->second.size();
            notPrinted++;
        } else {
            cout
            << "c [comp] large component " << std::setw(5) << i
            << " size: " << std::setw(10) << it->second.size()
            << endl;
        }
    }

    if (solver->conf.verbosity < 3 && notPrinted > 0) {
        cout
        << "c [comp] Unprinted small (<" << print_limit << " var) components:" << notPrinted
        << " vars: " << totalSmallSize
        << endl;
    }
}

bool CompFinder::reverse_table_is_correct() const
{
    for (map<uint32_t, vector<uint32_t> >::const_iterator
        it = reverseTable.begin()
        ; it != reverseTable.end()
        ; ++it
    ) {
        for (size_t i2 = 0; i2 < it->second.size(); i2++) {
            assert(table[(it->second)[i2]] == it->first);
        }
    }

    return true;
}

void CompFinder::find_components()
{
    assert(solver->okay());
    const double myTime = cpuTime();

    table.clear();
    table.resize(solver->nVars(), std::numeric_limits<uint32_t>::max());
    reverseTable.clear();
    comp_no = 0;
    used_comp_no = 0;

    solver->clauseCleaner->remove_and_clean_all();

    //Add the clauses to the sets
    bogoprops_remain =
        solver->conf.comp_find_time_limitM*1000ULL*1000ULL
        *solver->conf.global_timeout_multiplier;
    orig_bogoprops = bogoprops_remain;
    timedout = false;
    add_clauses_to_component(solver->longIrredCls);
    addToCompImplicits();
    if (timedout) {
        reverseTable.clear();
    }
    print_and_add_to_sql_result(myTime);

    assert(solver->okay());
}

void CompFinder::print_and_add_to_sql_result(const double myTime) const
{
    const double time_used = cpuTime() - myTime;
    const double time_remain = float_div(bogoprops_remain, orig_bogoprops);

    assert(reverse_table_is_correct());

    if (solver->conf.verbosity) {
        cout
        << "c [comp] Found component(s): " <<  reverseTable.size()
        << " BP: "
        << std::setprecision(2) << std::fixed
        << (double)(orig_bogoprops-bogoprops_remain)/(1000.0*1000.0)<< "M"
        << solver->conf.print_times(time_used, timedout, time_remain)
        << endl;

        if (reverseTable.size() > 1) {
            print_found_components();
        }
    }

    if (solver->sqlStats) {
        solver->sqlStats->time_passed(
            solver
            , "compfinder"
            , time_used
            , timedout
            , time_remain
        );
     }
}

void CompFinder::add_clauses_to_component(const vector<ClOffset>& cs)
{
    for (ClOffset offset: cs) {
        if (bogoprops_remain <= 0) {
            timedout = true;
            break;
        }
        bogoprops_remain -= 10;
        Clause* cl = solver->cl_alloc.ptr(offset);
        add_clause_to_component(*cl);
    }
}

void CompFinder::addToCompImplicits()
{
    vector<Lit> lits;

    for (size_t var = 0; var < solver->nVars(); var++) {
        if (bogoprops_remain <= 0) {
            timedout = true;
            break;
        }

        bogoprops_remain -= 2;
        Lit lit(var, false);
        lits.clear();
        lits.push_back(lit);
        for(int sign = 0; sign < 2; sign++) {
            lit = Lit(var, sign);
            watch_subarray ws = solver->watches[lit];

            //If empty, skip
            if (ws.empty())
                continue;

            bogoprops_remain -= (int64_t)ws.size() + 10;
            for(const Watched *it2 = ws.begin(), *end2 = ws.end()
                ; it2 != end2
                ; it2++
            ) {
                if (it2->isBin()
                    //Only irred
                    && !it2->red()
                    //Only do each binary once
                    && lit < it2->lit2()
                ) {
                    if (!seen[it2->lit2().var()]) {
                        lits.push_back(it2->lit2());
                        seen[it2->lit2().var()] = 1;
                    }
                }
            }
        }

        if (lits.size() > 1) {
            //Clear seen
            for(vector<Lit>::const_iterator
                it = lits.begin(), end = lits.end()
                ; it != end
                ; ++it
            ) {
                seen[it->var()] = 0;
            }

            add_clause_to_component(lits);
        }

    }
}

template<class T>
bool CompFinder::belong_to_same_component(const T& cl)
{
    if (table[cl[0].var()] != std::numeric_limits<uint32_t>::max()) {
        bogoprops_remain -= (int64_t)cl.size()/2 + 1;
        const uint32_t comp = table[cl[0].var()];

        for (const Lit l: cl) {
            if (table[l.var()] != comp) {
                return false;
            }
        }

        return true;
    }

    return false;
}

template<class T>
void CompFinder::fill_newset_and_tomerge(const T& cl)
{
    bogoprops_remain -= (int64_t)cl.size()*2;

    for (const Lit lit: cl) {
        if (table[lit.var()] != std::numeric_limits<uint32_t>::max()
        ) {
            if (!seen[table[lit.var()]]) {
                tomerge.push_back(table[lit.var()]);
                seen[table[lit.var()]] = 1;
            }
        } else {
            newSet.push_back(lit.var());
        }
    }
}

void CompFinder::merge_newset_into_single_component()
{
    const uint32_t into = tomerge[0];
    seen[into] = 0;
    map<uint32_t, vector<uint32_t> >::iterator intoReverse
        = reverseTable.find(into);

    //Put the new lits into this set
    for (const uint32_t v: newSet) {
        intoReverse->second.push_back(v);
        table[v] = into;
    }
}

template<class T>
void CompFinder::add_clause_to_component(const T& cl)
{
    assert(cl.size() > 1);
    tomerge.clear();
    newSet.clear();

    if (belong_to_same_component(cl)) {
        return;
    }

    fill_newset_and_tomerge(cl);

    //no sets to merge, only merge the clause into one tree
    if (tomerge.size() == 1) {
        merge_newset_into_single_component();
        return;
    }

    //Expensive merging coming up
    bogoprops_remain -= 20;

    //Delete tables to merge and put their elements into newSet
    for (const uint32_t merge: tomerge) {
        //Clear seen
        seen[merge] = 0;

        //Find in reverseTable
        bogoprops_remain -= (int64_t)reverseTable.size()*2;
        map<uint32_t, vector<uint32_t> >::iterator it2 = reverseTable.find(merge);
        assert(it2 != reverseTable.end());

        //Add them all
        bogoprops_remain -= (int64_t)it2->second.size();
        newSet.insert(
            newSet.end()
            , it2->second.begin()
            , it2->second.end()
        );

        //Delete this comp
        bogoprops_remain -= (int64_t)reverseTable.size();
        reverseTable.erase(it2);
        used_comp_no--;
    }

    //No literals lie outside of already seen components
    if (newSet.empty())
        return;

    //Mark all lits not belonging to seen components as belonging to comp_no
    bogoprops_remain -= (int64_t)newSet.size();
    for (const uint32_t v: newSet) {
        table[v] = comp_no;
    }

    reverseTable[comp_no] = newSet;
    comp_no++;
    used_comp_no++;
}
