/******************************************************************************************[Main.C]
MiniSat -- Copyright (c) 2003-2006, Niklas Een, Niklas Sorensson

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 <ctime>
#include <cstring>
#include <stdint.h>
#include <errno.h>

#include <stdio.h>

#include "Solver.h"

/*************************************************************************************/
#if defined(_MSC_VER) || defined(__XS1B__)
#include <ctime>

static inline double cpuTime(void) {
    return (double)clock() / CLOCKS_PER_SEC; }
#else

#include <sys/time.h>
#include <sys/resource.h>
#include <unistd.h>

static inline double cpuTime(void) {
    struct rusage ru;
    getrusage(RUSAGE_SELF, &ru);
    return (double)ru.ru_utime.tv_sec + (double)ru.ru_utime.tv_usec / 1000000; }
#endif

#if defined(__XS1B__)
#include <unistd.h>
#endif

#if defined(__linux__)
static inline int memReadStat(int field)
{
    char    name[256];
    pid_t pid = getpid();
    sprintf(name, "/proc/%d/statm", pid);
    FILE*   in = fopen(name, "rb");
    if (in == NULL) return 0;
    int     value;
    for (; field >= 0; field--)
        fscanf(in, "%d", &value);
    fclose(in);
    return value;
}
static inline uint64_t memUsed() { return (uint64_t)memReadStat(0) * (uint64_t)getpagesize(); }


#elif defined(__FreeBSD__) || defined(__NetBSD__)
static inline uint64_t memUsed(void) {
    struct rusage ru;
    getrusage(RUSAGE_SELF, &ru);
    return ru.ru_maxrss*1024; }


#else
static inline uint64_t memUsed() { return 0; }
#endif

#if defined(__GLIBC__) && defined(__linux__)
#include <fpu_control.h>
#endif

//=================================================================================================
// DIMACS Parser:

#define CHUNK_LIMIT 1048576

class StreamBuffer {
    FILE   *in;
    char    buf[CHUNK_LIMIT];
    int     pos;
    int     size;

    void assureLookahead() {
        if (pos >= size) {
            pos  = 0;
            size = read(fileno(in), buf, sizeof(buf)); } }

public:
    StreamBuffer(FILE *i) : in(i), pos(0), size(0) {
        assureLookahead(); }

    int  operator *  () { return (pos >= size) ? EOF : buf[pos]; }
    void operator ++ () { pos++; assureLookahead(); }
};

//- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -

template<class B>
static void skipWhitespace(B& in) {
    while ((*in >= 9 && *in <= 13) || *in == 32)
        ++in; }

template<class B>
static void skipLine(B& in) {
    for (;;){
        if (*in == EOF || *in == '\0') return;
        if (*in == '\n') { ++in; return; }
        ++in; } }

template<class B>
static int parseInt(B& in) {
    int     val = 0;
    bool    neg = false;
    skipWhitespace(in);
    if      (*in == '-') neg = true, ++in;
    else if (*in == '+') ++in;
    if (*in < '0' || *in > '9') reportf("PARSE ERROR! Unexpected char: %c\n", *in), exit(3);
    while (*in >= '0' && *in <= '9')
        val = val*10 + (*in - '0'),
        ++in;
    return neg ? -val : val; }

template<class B>
static void readClause(B& in, Solver& S, vec<Lit>& lits) {
    int     parsed_lit, var;
    lits.clear();
    for (;;){
        parsed_lit = parseInt(in);
        if (parsed_lit == 0) break;
        var = abs(parsed_lit)-1;
        while (var >= S.nVars()) S.newVar();
        lits.push( (parsed_lit > 0) ? Lit(var) : ~Lit(var) );
    }
}

template<class B>
static bool match(B& in, char* str) {
    for (; *str != 0; ++str, ++in)
        if (*str != *in)
            return false;
    return true;
}


template<class B>
static void parse_DIMACS_main(B& in, Solver& S) {
    vec<Lit> lits;
    for (;;){
        skipWhitespace(in);
        if (*in == EOF)
            break;
        else if (*in == 'p'){
            if (match(in, "p cnf")){
                int vars    = parseInt(in);
                int clauses = parseInt(in);
                reportf("|  Number of variables:  %-12d                                         |\n", vars);
                reportf("|  Number of clauses:    %-12d                                         |\n", clauses);
            }else{
                reportf("PARSE ERROR! Unexpected char: %c\n", *in), exit(3);
            }
        } else if (*in == 'c' || *in == 'p')
            skipLine(in);
        else
            readClause(in, S, lits),
            S.addClause(lits);
    }
}

// Inserts problem into solver.
//
static void parse_DIMACS(FILE *input_stream, Solver& S) {
    // LLVM: Allocate StreamBuffer on the heap instead of the stack so that
    // this test can run on systems with limited stack size.
    StreamBuffer *in = new StreamBuffer(input_stream);
    parse_DIMACS_main(*in, S);
    delete in;
}


//=================================================================================================


void printStats(Solver& solver)
{
    double   cpu_time = cpuTime();
    uint64_t mem_used = memUsed();
    reportf("restarts              : %lld\n", solver.starts);
    reportf("conflicts             : %-12lld\n", solver.conflicts);
    reportf("decisions             : %-12lld   (%4.2f %% random)\n", solver.decisions, (float)solver.rnd_decisions*100 / (float)solver.decisions);
    reportf("propagations          : %-12lld\n", solver.propagations);
    reportf("conflict literals     : %-12lld   (%4.2f %% deleted)\n", solver.tot_literals, (solver.max_literals - solver.tot_literals)*100 / (double)solver.max_literals);
}

Solver* solver;

//=================================================================================================
// Main:

void printUsage(char** argv)
{
    reportf("USAGE: %s [options] <input-file> <result-output-file>\n\n  where input may be either in plain or gzipped DIMACS.\n\n", argv[0]);
    reportf("OPTIONS:\n\n");
    reportf("  -polarity-mode = {true,false,rnd}\n");
    reportf("  -decay         = <num> [ 0 - 1 ]\n");
    reportf("  -rnd-freq      = <num> [ 0 - 1 ]\n");
    reportf("  -verbosity     = {0,1,2}\n");
    reportf("\n");
}


const char* hasPrefix(const char* str, const char* prefix)
{
    int len = strlen(prefix);
    if (strncmp(str, prefix, len) == 0)
        return strdup(str + len);
    else
        return NULL;
}


int main(int argc, char** argv)
{
    Solver      S;
    S.verbosity = 1;


    int         i, j;
    const char* value;
    for (i = j = 0; i < argc; i++){
        if ((value = hasPrefix(argv[i], "-polarity-mode="))){
            if (strcmp(value, "true") == 0)
                S.polarity_mode = Solver::polarity_true;
            else if (strcmp(value, "false") == 0)
                S.polarity_mode = Solver::polarity_false;
            else if (strcmp(value, "rnd") == 0)
                S.polarity_mode = Solver::polarity_rnd;
            else{
                reportf("ERROR! unknown polarity-mode %s\n", value);
                exit(0); }

        }else if ((value = hasPrefix(argv[i], "-rnd-freq="))){
            double rnd;
            if (sscanf(value, "%lf", &rnd) <= 0 || rnd < 0 || rnd > 1){
                reportf("ERROR! illegal rnd-freq constant %s\n", value);
                exit(0); }
            S.random_var_freq = rnd;

        }else if ((value = hasPrefix(argv[i], "-decay="))){
            double decay;
            if (sscanf(value, "%lf", &decay) <= 0 || decay <= 0 || decay > 1){
                reportf("ERROR! illegal decay constant %s\n", value);
                exit(0); }
            S.var_decay = 1 / decay;

        }else if ((value = hasPrefix(argv[i], "-verbosity="))){
            char *end;
            int verbosity = (int)strtol(value, &end, 10);
            if (end == value || *end != 0){
                reportf("ERROR! illegal verbosity level %s\n", value);
                exit(0); }
            S.verbosity = verbosity;

        }else if (strcmp(argv[i], "-h") == 0 || strcmp(argv[i], "-help") == 0 || strcmp(argv[i], "--help") == 0){
            printUsage(argv);
            exit(0);

        }else if (strncmp(argv[i], "-", 1) == 0){
            reportf("ERROR! unknown flag %s\n", argv[i]);
            exit(0);

        }else
            argv[j++] = argv[i];
    }
    argc = j;


    reportf("This is MiniSat 2.0 beta\n");
#if defined(__linux__) && defined(_FPU_EXTENDED) && defined(_FPU_DOUBLE)
    fpu_control_t oldcw, newcw;
    _FPU_GETCW(oldcw); newcw = (oldcw & ~_FPU_EXTENDED) | _FPU_DOUBLE; _FPU_SETCW(newcw);
#endif
    double cpu_time = cpuTime();

    solver = &S;

    if (argc == 1)
        reportf("Reading from standard input... Use '-h' or '--help' for help.\n");

    FILE *in = (argc == 1) ? stdin : fopen(argv[1], "rb");
    if (in == NULL)
        reportf("ERROR! Could not open file: %s\n", argc == 1 ? "<stdin>" : argv[1]), exit(1);

    reportf("============================[ Problem Statistics ]=============================\n");
    reportf("|                                                                             |\n");

    parse_DIMACS(in, S);
    fclose(in);
    FILE* res = (argc >= 3) ? fopen(argv[2], "wb") : NULL;

    if (!S.simplify()){
        reportf("Solved by unit propagation\n");
        if (res != NULL) fprintf(res, "UNSAT\n"), fclose(res);
        printf("UNSATISFIABLE\n");
        exit(20);
    }

    bool ret = S.solve();
    printStats(S);
    reportf("\n");
    printf(ret ? "SATISFIABLE\n" : "UNSATISFIABLE\n");
    if (res != NULL){
        if (ret){
            fprintf(res, "SAT\n");
            for (int i = 0; i < S.nVars(); i++)
                if (S.model[i] != l_Undef)
                    fprintf(res, "%s%s%d", (i==0)?"":" ", (S.model[i]==l_True)?"":"-", i+1);
            fprintf(res, " 0\n");
        }else
            fprintf(res, "UNSAT\n");
        fclose(res);
    }

#ifdef NDEBUG
    exit(ret ? 10 : 20);     // (faster than "return", which will invoke the destructor for 'Solver')
#endif
}