/*
 * mpl-core.c
 *
 * by Alexander Zhirov (alexander@zhirov.kz)
 * Telegram @alexanderzhirov
 */

#include "mpl-core.h"

#include <sys/stat.h>
#include <sys/file.h>
#include <unistd.h>

#define LOCKFILE "/run/lock/mportlink.lock"
#define DEV_PATH "/dev/"
#define DONGLE_PATH (DEV_PATH "dongle/")

static int mpl_create_dongle_dir()
{
    struct stat st;

    if (stat(DONGLE_PATH, &st) == 0)
    {
        if (!S_ISDIR(st.st_mode))
        {
            MPLOG(LOG_WARNING, "%s exists and is not a directory", DONGLE_PATH);
            return 1;
        }
    }
    else if (mkdir(DONGLE_PATH, S_IRWXU | S_IRGRP | S_IXGRP | S_IROTH | S_IXOTH) == -1)
    {
        MPLOG(LOG_ERR, "unable to create a directory %s", DONGLE_PATH);
        return 1;
    }

    return 0;
}

void static mpl_free(MPL *mpl)
{
    if (mpl)
        free(mpl);
}

MPL *mpl_init(MPL_PARAMETERS *parameters)
{
    MPL *mpl = (MPL *)calloc(1, sizeof(MPL));

    if (!mpl)
    {
        MPLOG(LOG_ERR, "error getting the MPL structure");
        exit(1);
    }

    mpl->parameters.check_device = parameters->check_device;
    mpl->cancellable.signal = 0;
    mpl->cancellable.exit = 0;

    mpl->fd = open(LOCKFILE, O_CREAT | O_RDWR, 0644);
    if (mpl->fd < 0)
    {
        MPLOG(LOG_ERR, "unable to create a lockfile");
        exit(1);
    }

    int rc = flock(mpl->fd, LOCK_EX | LOCK_NB);
    if (rc || errno == EWOULDBLOCK)
    {
        MPLOG(LOG_ERR, "only one instance of %s is allowed", MPL_NAME);
        exit(1);
    }

    if (mpl_create_dongle_dir())
    {
        MPLOG(LOG_ERR, "%s will be stopped", MPL_NAME);
        exit(1);
    }

    if (mpl_udev_init(&mpl->udev))
    {
        MPLOG(LOG_ERR, "%s will be stopped", MPL_NAME);
        mpl_free(mpl);
        exit(1);
    }

    MPLOG(LOG_NOTICE, "starting the %s daemon", MPL_NAME);

    return mpl;
}

void mpl_stop(MPL *mpl)
{
    mpl_udev_free(&mpl->udev);

    flock(mpl->fd, LOCK_UN);

    mpl_free(mpl);

    if (mpl->cancellable.exit)
        MPLOG(LOG_NOTICE, "stopping the %s daemon", MPL_NAME);
    else
        MPLOG(LOG_NOTICE, "successful completion of the process %d", getpid());
    closelog();
}

void mpl_loop(MPL *mpl)
{
    if (mpl->parameters.check_device)
        mpl_udev_check_devices(&mpl->udev);
    
    mpl_udev_loop(&mpl->udev, &mpl->cancellable);
}