#include <libcbd.h>

#include <libdevmapper.h>

#include <cbdutil.h>

static uint64_t
device_logical_size(const char* dev)
{
    int fd;
    uint8_t pblkbuf[PBLK_SIZE];
    struct cbd_header header;

    fd = open(dev, O_RDONLY);
    if (fd < 0) {
        error("Cannot open device\n");
    }
    if (read(fd, pblkbuf, sizeof(pblkbuf)) != sizeof(pblkbuf)) {
        error("Cannot read device\n");
    }
    cbd_header_get(pblkbuf, &header);
    close(fd);

    return (header.params.lblk_per_zone << header.params.lblk_shift) * header.params.nr_zones;
}

int
cbd_open(const char* dev,
         uint64_t loff, uint64_t lsize,
         const char* name)
{
    int ret;
    struct stat st;
    struct dm_task* dmt;
    uint32_t cookie = 0;

    ret = stat(dev, &st);
    if (ret) {
        error("Failed to stat device\n");
    }
    if (!S_ISBLK(st.st_mode)) {
        error("Not a block device\n");
    }

    if (!lsize) {
        lsize = device_logical_size(dev);
    }

    dmt = dm_task_create(DM_DEVICE_CREATE);
    if (!dmt) {
        error("dm_task_create failed\n");
    }
    ret = dm_task_set_name(dmt, name);
    if (ret == 0) {
        error("dm_task_set_name failed\n");
    }
    printf("%s: start_sector=%lu num_sectors=%lu\n", __func__,
           (unsigned long)(loff * PBLK_PER_SECTOR),
           (unsigned long)(lsize * PBLK_PER_SECTOR));
    ret = dm_task_add_target(dmt,
                             loff * PBLK_PER_SECTOR,
                             lsize * PBLK_PER_SECTOR,
                             "compress",
                             dev);
    if (ret == 0) {
        error("dm_task_add_target failed\n");
    }
    ret = dm_task_set_cookie(dmt, &cookie, 0);
    if (ret == 0) {
        error("dm_task_set_cookie failed\n");
    }

    ret = dm_task_run(dmt);
    if (ret == 0) {
        error("dm_task_run failed\n");
    }
    dm_udev_wait(cookie);

    dm_task_destroy(dmt);

    return 0;
}