/*
 * IceWM
 *
 * Copyright (C) 1998-2002 Marko Macek
 */
#include "config.h"
#include "yapp.h"

#include "ypoll.h"
#include "ytimer.h"
#include "yprefs.h"

#include "sysdep.h"
#include "sys/resource.h"

#include "intl.h"

//#define USE_SIGNALFD

#ifdef USE_SIGNALFD
#include <sys/signalfd.h>
#endif

// FIXME: get rid of this global
extern char const *ApplicationName;
char const *&YApplication::Name = ApplicationName;

YApplication *app = 0;
IMainLoop *mainLoop = 0;
static int signalPipe[2] = { 0, 0 };
static sigset_t oldSignalMask;
static sigset_t signalMask;
static int measure_latency = 0;

static const char * libDir = LIBDIR;
static const char * configDir = CFGDIR;

void YApplication::initSignals() {
    sigemptyset(&signalMask);
    sigaddset(&signalMask, SIGHUP);
    sigprocmask(SIG_BLOCK, &signalMask, &oldSignalMask);

#ifdef USE_SIGNALFD
    signalPipe[0] = signalfd(-1, &signalMask, 0);
    if(signalPipe[0]<0)
    	perror("signalfd");
    // XXX: with kernel 2.6.27 the flags above should become effective
    // but let's not require that yet
    fcntl(signalPipe[0], F_SETFL, O_NONBLOCK);
    fcntl(signalPipe[0], F_SETFD, FD_CLOEXEC);
#else
    sigemptyset(&signalMask);
    sigprocmask(SIG_BLOCK, &signalMask, &oldSignalMask);

    if (pipe(signalPipe) != 0)
        die(2, "Failed to create anonymous pipe (errno=%d).", errno);
    fcntl(signalPipe[1], F_SETFL, O_NONBLOCK);
    fcntl(signalPipe[0], F_SETFD, FD_CLOEXEC);
    fcntl(signalPipe[1], F_SETFD, FD_CLOEXEC);
#endif
    sfd.registerPoll(this, signalPipe[0]);
}

#ifdef linux
void alrm_handler(int /*sig*/) {
    show_backtrace();
}
#endif

YApplication::YApplication(int * /*argc*/, char ***/*argv*/) {
    app = this;
    ::mainLoop = this;
    
    fLoopLevel = 0;
    fExitApp = 0;
    fFirstTimer = fLastTimer = 0;
    fFirstPoll = fLastPoll = 0;

#if 0
    {
        char const * cmd(**argv);
        char cwd[PATH_MAX + 1];

        if ('/' == *cmd)
            fExecutable = newstr(cmd);
        else if (strchr (cmd, '/'))
            fExecutable = cstrJoin(getcwd(cwd, sizeof(cwd)), "/", cmd, NULL);
        else
            fExecutable = findPath(ustring(getenv("PATH")), X_OK, upath(cmd));
    }
#endif

    initSignals();
#if 0
    struct sigaction sig;
    sig.sa_handler = SIG_IGN;
    sigemptyset(&sig.sa_mask);
    sig.sa_flags = 0;
    sigaction(SIGCHLD, &sig, &oldSignalCHLD);
#endif

#ifdef linux
    if (measure_latency) {
        struct sigaction sa;
        sa.sa_handler = alrm_handler;
        sigemptyset(&sa.sa_mask);
        sa.sa_flags = 0;
        sigaction(SIGALRM, &sa, NULL);
    }
#endif
}

YApplication::~YApplication() {
    sfd.unregisterPoll();
    app = 0;
    ::mainLoop = 0;
}

void YApplication::registerTimer(YTimer *t) {
    t->fPrev = 0;
    t->fNext = fFirstTimer;
    if (fFirstTimer)
        fFirstTimer->fPrev = t;
    else
        fLastTimer = t;
    fFirstTimer = t;
}

void YApplication::unregisterTimer(YTimer *t) {
    if (t->fPrev)
        t->fPrev->fNext = t->fNext;
    else
        fFirstTimer = t->fNext;
    if (t->fNext)
        t->fNext->fPrev = t->fPrev;
    else
        fLastTimer = t->fPrev;
    t->fPrev = t->fNext = 0;
}

void YApplication::nextTimeout(struct timeval *timeout) {
    bool fFirst = true;
    const YTimer *t;

    t = fFirstTimer;

    while (t) {
        if (t->isRunning() && (fFirst || timercmp(timeout, &t->timeout, >))) {
            *timeout = t->timeout;
            fFirst = false;
        }
        t = t->fNext;
    }
}

void YApplication::nextTimeoutWithFuzziness(struct timeval *timeout) {
    const YTimer *t;
    struct timeval timeout_min, timeout_fuzzy, timeout_fixed, timeout_max;
    bool fFixedExists = false, fFuzzyExists = false; // are there any timers with strict/fuzzy timeout?

    timeout_min = timeout_fuzzy = timeout_fixed = timeout_max = *timeout;

    t = fFirstTimer;

    while (t) {
        if (t->isRunning()) {
	    if (!t->isFixed()) {
	        if (fFuzzyExists) {
		    if (timercmp(&t->timeout, &timeout_fuzzy, <)) {
			// this fuzzy timer is earlier than previous one, update
			if (timercmp(&t->timeout, &timeout_min, <))
			    timeout_min = t->timeout; // don't use new min value, to avoid moving out of area of later timers and thus not catching them with the calculated result timeout
			timeout_fuzzy = t->timeout; // update desired timeout spot
			if (timercmp(&t->timeout_max, &timeout_max, <))
			    timeout_max = t->timeout_max;
		    }
		} else {
		    // encountered first fuzzy timer, register everything
		    timeout_min = t->timeout_min;
		    timeout_fuzzy = t->timeout;
		    timeout_max = t->timeout_max;
		    fFuzzyExists = true;
		}
	    } else {
		// update if no fixed timer yet or current is earlier than previously registered one
		if ((!fFixedExists) || timercmp(&t->timeout, &timeout_fixed, <)) {
		    timeout_fixed = t->timeout;
		    fFixedExists = true;
		}
	    }
        }
        t = t->fNext;
    }
    // ok, now that we walked over all timers and calculated border values,
    // let's figure out which timeout actually to choose
    if (fFixedExists) {
        *timeout = timeout_fixed;
	if (fFuzzyExists) {
	    if (timercmp(&timeout_max, &timeout_fixed, <))
	        // ok, the maximum timeout of our fuzzy timer(s) is less
		// than the first fixed timer's accurate timeout
		// --> we need to give up the fixed timer in this round
	        *timeout = timeout_max;
	}
    } else {
        // we choose the max timeout to try to catch as many fuzzy timers as possible
        *timeout = timeout_max;
    }
}

void YApplication::getTimeout(struct timeval *timeout) {
    struct timeval curtime;

    if (fFirstTimer == 0)
        return;

    gettimeofday(&curtime, 0);
    timeout->tv_sec += curtime.tv_sec;
    timeout->tv_usec += curtime.tv_usec;
    while (timeout->tv_usec >= 1000000) {
        timeout->tv_usec -= 1000000;
        timeout->tv_sec++;
    }

    if (DelayFuzziness > 0)
        nextTimeoutWithFuzziness(timeout);
    else
        nextTimeout(timeout);

    if ((curtime.tv_sec == timeout->tv_sec &&
         curtime.tv_usec == timeout->tv_usec)
        || timercmp(&curtime, timeout, >))
    {
        timeout->tv_sec = 0;
        timeout->tv_usec = 1;
    } else {
        timeout->tv_sec -= curtime.tv_sec;
        timeout->tv_usec -= curtime.tv_usec;
        while (timeout->tv_usec < 0) {
            timeout->tv_usec += 1000000;
            timeout->tv_sec--;
        }
    }
    PRECONDITION(timeout->tv_sec >= 0);
    PRECONDITION(timeout->tv_usec >= 0);
}

void YApplication::handleTimeouts() {
    YTimer *t, *n;
    struct timeval curtime;
    gettimeofday(&curtime, 0);

    t = fFirstTimer;
    while (t) {
        n = t->fNext;
        if (t->isRunning() && timercmp(&curtime, &t->timeout_min, >)) {
            YTimerListener *l = t->getTimerListener();
            t->stopTimer();
            if (l && l->handleTimer(t))
                t->startTimer();
        }
        t = n;
    }
}

void YApplication::decreaseTimeouts(struct timeval difftime) {
    YTimer *t = fFirstTimer;

    while (t) {
        t->timeout.tv_sec += difftime.tv_sec;
        t->timeout.tv_usec += difftime.tv_usec;
        if (t->timeout.tv_usec < 0) {
            t->timeout.tv_sec--;
            t->timeout.tv_usec += difftime.tv_usec;
        }
        t = t->fNext;
    }
}

void YApplication::registerPoll(YPollBase *t) {
    PRECONDITION(t->fFd != -1);
    t->fPrev = 0;
    t->fNext = fFirstPoll;
    if (fFirstPoll)
        fFirstPoll->fPrev = t;
    else
        fLastPoll = t;
    fFirstPoll = t;
}

void YApplication::unregisterPoll(YPollBase *t) {
    if (t->fPrev)
        t->fPrev->fNext = t->fNext;
    else
        fFirstPoll = t->fNext;
    if (t->fNext)
        t->fNext->fPrev = t->fPrev;
    else
        fLastPoll = t->fPrev;
    t->fPrev = t->fNext = 0;
}

YPollBase::~YPollBase() {
    unregisterPoll();
}

void YPollBase::unregisterPoll() {
    if (fFd != -1) {
        app->unregisterPoll(this);
        fFd = -1;
    }
}


void YPollBase::registerPoll(int fd) {
    unregisterPoll();
    fFd = fd;
    if (fFd != -1)
        app->registerPoll(this);
}

int YApplication::mainLoop() {
    fLoopLevel++;
    if (!fExitApp)
        fExitLoop = 0;

    struct timeval timeout, *tp;
    struct timeval prevtime;
    struct timeval idletime;

    gettimeofday(&idletime, 0);
    gettimeofday(&prevtime, 0);
    while (!fExitApp && !fExitLoop) {
        int rc;
        fd_set read_fds;
        fd_set write_fds;

        bool didIdle = handleIdle();
#if 0
        gettimeofday(&idletime, 0);
        {
            struct timeval difftime;
            struct timeval curtime;
            gettimeofday(&curtime, 0);
            difftime.tv_sec = curtime.tv_sec - idletime.tv_sec;
            difftime.tv_usec = curtime.tv_usec - idletime.tv_usec;
            if (difftime.tv_usec < 0) {
                difftime.tv_sec--;
                difftime.tv_usec += 1000000;
            }
            if (difftime.tv_sec != 0 || difftime.tv_usec > 50 * 1000) {
                didIdle = handleIdle();
                gettimeofday(&idletime, 0);
            }
        }
#endif

        if (measure_latency) {
            struct timeval difftime;
            struct timeval curtime;
            gettimeofday(&curtime, 0);
            difftime.tv_sec = curtime.tv_sec - prevtime.tv_sec;
            difftime.tv_usec = curtime.tv_usec - prevtime.tv_usec;
            if (difftime.tv_usec < 0) {
                difftime.tv_sec--;
                difftime.tv_usec += 1000000;
            }
            if (difftime.tv_sec > 0 || difftime.tv_usec >= 50 * 1000) {
                DBG warn("latency: %d.%06d",
                     difftime.tv_sec, difftime.tv_usec);
            }
        }

        FD_ZERO(&read_fds);
        FD_ZERO(&write_fds);
        {
            for (YPollBase *s = fFirstPoll; s; s = s->fNext) {
                PRECONDITION(s->fFd != -1);
                if (s->forRead()) {
                    FD_SET(s->fd(), &read_fds);
                    //MSG(("wait read"));
                }
                if (s->forWrite()) {
                    FD_SET(s->fd(), &write_fds);
                    //MSG(("wait connect"));
                }
            }
        }

        gettimeofday(&prevtime, 0);

        tp = &timeout;
        if (didIdle) {
            timeout.tv_sec = 0;
            timeout.tv_usec = 0;
        } else {
            timeout.tv_sec = 0;
            timeout.tv_usec = 0;
            getTimeout(&timeout);
            if (timeout.tv_sec == 0 && timeout.tv_usec == 0)
                tp = 0;
        }

#if 0
        if (tp == NULL) {
            msg("sleeping");
        } else {
            msg("waiting: %d.%06d",
                 tp->tv_sec, tp->tv_usec);
        }
#endif

#ifndef USE_SIGNALFD
        sigprocmask(SIG_UNBLOCK, &signalMask, NULL);
#endif

        if (measure_latency) {
            itimerval it;
            it.it_interval.tv_sec = 0;
            it.it_interval.tv_usec = 0;
            it.it_value.tv_sec = 0;
            it.it_value.tv_usec = 0;
            setitimer(ITIMER_REAL, &it, 0);
        }

        rc = select(sizeof(fd_set) * 8,
                    SELECT_TYPE_ARG234 &read_fds,
                    SELECT_TYPE_ARG234 &write_fds,
                    0,
                    tp);

        if (measure_latency) {
            itimerval it;
            it.it_interval.tv_sec = 0;
            it.it_interval.tv_usec = 10000;
            it.it_value.tv_sec = 0;
            it.it_value.tv_usec = 10000;
            setitimer(ITIMER_REAL, &it, 0);
        }
#ifndef USE_SIGNALFD
        sigprocmask(SIG_BLOCK, &signalMask, NULL);
#endif

#if 0
        sigset_t mask;
        sigpending(&mask);
        if (sigismember(&mask, SIGINT))
            handleSignal(SIGINT);
        if (sigismember(&mask, SIGTERM))
            handleSignal(SIGTERM);
        if (sigismember(&mask, SIGHUP))
            handleSignal(SIGHUP);
#endif

        {
            struct timeval difftime;
            struct timeval curtime;

            gettimeofday(&curtime, 0);
            difftime.tv_sec = curtime.tv_sec - prevtime.tv_sec;
            difftime.tv_usec = curtime.tv_usec - prevtime.tv_usec;
            if (difftime.tv_usec < 0) {
                difftime.tv_sec--;
                difftime.tv_usec += 1000000;
            }
            // if time travel to past, decrease the timeouts
            if (difftime.tv_sec < 0 ||
                (difftime.tv_sec == 0 && difftime.tv_usec < 0))
            {
                warn("time warp of %d.%06d",
                     difftime.tv_sec, difftime.tv_usec);
                decreaseTimeouts(difftime);
            } else {
                // no detection for time travel to the future
            }
        }
        gettimeofday(&prevtime, 0);

        if (rc == 0) {
            handleTimeouts();
        } else if (rc == -1) {
            if (errno != EINTR)
                warn(_("Message Loop: select failed (errno=%d)"), errno);
        } else {
            for (YPollBase *s = fFirstPoll; s; s = s->fNext) {
                PRECONDITION(s->fFd != -1);
                int fd = s->fd();
                if (FD_ISSET(fd, &read_fds)) {
                    //MSG(("got read"));
                    s->notifyRead();
                }
                if (FD_ISSET(fd, &write_fds)) {
                    MSG(("got connect"));
                    s->notifyWrite();
                }
            }
        }
    }
    fLoopLevel--;
    return fExitCode;
}

void YApplication::exitLoop(int exitCode) {
    fExitLoop = 1;
    fExitCode = exitCode;
}

void YApplication::exit(int exitCode) {
    fExitApp = 1;
    exitLoop(exitCode);
}

void YApplication::handleSignal(int sig) {
    if (sig == SIGCHLD) {
        int s, rc;
        do {
            rc = waitpid(-1, &s, WNOHANG);
        } while (rc > 0);
    }
}

bool YApplication::handleIdle() {
    return false;
}

#ifndef USE_SIGNALFD
void sig_handler(int sig) {
    unsigned char uc = (unsigned char)sig;
    if (write(signalPipe[1], &uc, 1) != 1)
	fprintf(stderr, "icewm: signal error\n");
}
#endif

void YApplication::catchSignal(int sig) {
    sigaddset(&signalMask, sig);
    sigprocmask(SIG_BLOCK, &signalMask, NULL);

#ifdef USE_SIGNALFD
    signalPipe[0]=signalfd(signalPipe[0], &signalMask, 0);
#else
    struct sigaction sa;
    sa.sa_handler = sig_handler;
    sigemptyset(&sa.sa_mask);
    sa.sa_flags = 0;
    sigaction(sig, &sa, NULL);
#endif
}

void YApplication::resetSignals() {
    sigset_t mask;
    //struct sigaction old_sig;

    //sigaction(SIGCHLD, &oldSignalCHLD, &old_sig);
    sigprocmask(SIG_SETMASK, &oldSignalMask, &mask);
}

void YApplication::closeFiles() {
#ifdef linux   /* for now, some debugging code */
    int             i, max = 1024;
    struct rlimit   lim;

    if (getrlimit(RLIMIT_NOFILE, &lim) == 0)
        max = lim.rlim_max;

    for (i = 3; i < max; i++) {
        int fl = 0;
        if (fcntl(i, F_GETFD, &fl) == 0) {
            if (!(fl & FD_CLOEXEC)) {
                char path[64];
                char buf[1024];

                memset(buf, 0, sizeof(buf));
                sprintf(path, "/proc/%d/fd/%d", getpid(), i);
                if (readlink(path, buf, sizeof(buf) - 1) == -1)
		    buf[0] = '\0';

                warn("File still open: fd=%d, target='%s' (missing FD_CLOEXEC?)", i, buf);
                warn("Closing file descriptor: %d", i);
                close (i);
            }
        }
    }
#endif
}

int YApplication::runProgram(const char *path, const char *const *args) {
    flushXEvents();

    int cpid = -1;
    if (path && (cpid = fork()) == 0) {
        app->resetSignals();
        sigemptyset(&signalMask);
        sigaddset(&signalMask, SIGHUP);
        sigprocmask(SIG_UNBLOCK, &signalMask, NULL);

        /* perhaps the right thing to to:
         create ptys .. and show console window when an application
         attempts to use it (how do we detect input with no output?) */
        setsid();
#if 0
        close(0);
        if (open("/dev/null", O_RDONLY) != 0)
            _exit(1);
#endif
        closeFiles();

        if (args)
            execvp(path, (char **)args);
        else
            execlp(path, path, (void *)NULL);

        _exit(99);
    }
    return cpid;
}

#if for_old_worker_code_see_attic
int YApplication::startWorker(int socket, const char *path, const char *const *args) {
    flushXEvents();

    int cpid = -1;
    if (path && (cpid = fork()) == 0) {
        app->resetSignals();
        sigemptyset(&signalMask);
        sigaddset(&signalMask, SIGHUP);
        sigprocmask(SIG_UNBLOCK, &signalMask, NULL);

        close(0);
        if (dup2(socket, 0) != 0)
            _exit(1);
        close(1);
        if (dup2(socket, 1) != 1)
            _exit(1);
        close(socket);

        closeFiles();

        if (args)
            execvp(path, (char **)args);
        else
            execlp(path, path, (void *)NULL);

        _exit(99);
    }
    return cpid;
}
#endif

int YApplication::waitProgram(int p) {
    int status;

    if (p == -1)
        return -1;

    if (waitpid(p, &status, 0) != p)
        return -1;
    return status;
}

void YApplication::runCommand(const char *cmdline) {
/// TODO #warning calling /bin/sh is considered to be bloat
    char const * argv[] = { "/bin/sh", "-c", cmdline, NULL };
    runProgram(argv[0], argv);
}

#ifndef USE_SIGNALFD
void YApplication::handleSignalPipe() {
    unsigned char sig;
    if (read(signalPipe[0], &sig, 1) == 1) {
        handleSignal(sig);
    }
}


void YSignalPoll::notifyRead() {
    owner()->handleSignalPipe();
}
#else
void YSignalPoll::notifyRead()
{
	struct signalfd_siginfo fdsi;
	int s = read(signalPipe[0], &fdsi, sizeof(struct signalfd_siginfo));
	if (s == sizeof(struct signalfd_siginfo))
		owner()->handleSignal(fdsi.ssi_signo);
}
#endif

void YSignalPoll::notifyWrite() {
}

bool YSignalPoll::forRead() {
    return true;
}

bool YSignalPoll::forWrite() {
    return false;
}

const char *YApplication::getLibDir() {
    return libDir;
}

const char *YApplication::getConfigDir() {
    return configDir;
}

const char *YApplication::getPrivConfDir() {
    static char cfgdir[PATH_MAX] = "";

    if (*cfgdir == '\0') {
        const char *env = getenv("ICEWM_PRIVCFG");

        if (NULL == env) {
            env = getenv("HOME");
            strcpy(cfgdir, env ? env : "");
            strcat(cfgdir, "/.icewm");
        } else {
            strcpy(cfgdir, env);
        }

        msg("using %s for private configuration files", cfgdir);
    }

    return cfgdir;
}

upath YApplication::findConfigFile(upath name) {
    upath p;

    if (name.isAbsolute())
        return name;

    p = upath(getPrivConfDir()).relative(name);
    if (p.fileExists())
        return p;

    p = upath(configDir).relative(name);
    if (p.fileExists())
        return p;

    p = upath(REDIR_ROOT(libDir)).relative(name);
    if (p.fileExists())
        return p;

    return null;
}
