#include <libcbd.h>

#include <cbdutil.h>

struct zone_metadata
{
    u8*         pbat;
    u8*         lbat;
};

static void
pblk_read(int fd, u64 pblk, u32 count, u8* data)
{
    off_t pos;
    size_t remain;
    ssize_t ret;

    pos = lseek(fd, pblk * PBLK_SIZE, SEEK_SET);
    if (pos == (off_t)-1) {
        error("Failed to seek\n");
    }

    remain = count * PBLK_SIZE;
    while (remain) {
        ret = read(fd, data, remain);
        if (ret <= 0) {
            error("Failed to read\n");
        }
        remain -= ret;
        data += ret;
    }
}

static void
check_header(const struct cbd_header* header)
{
    if (memcmp(header->magic, CBD_MAGIC, sizeof(header->magic))) {
        error("Bad magic\n");
    }
    if (header->version_major != CBD_VERSION_MAJOR) {
        error("Bad major version\n");
    }
    if (header->version_minor != CBD_VERSION_MINOR) {
        error("Bad major version\n");
    }
    if (header->params.algorithm == CBD_ALG_NONE ||
            header->params.algorithm >= CBD_ALG_MAX) {
        error("Bad algorithm\n");
    }
    if (header->params.compression > 9) {
        error("Bad compression\n");
    }
    if (header->params.lblk_shift < LBLK_SHIFT_MIN ||
            header->params.lblk_shift >= LBLK_SHIFT_MAX) {
        error("Bad logical block shift\n");
    }
}

static void
check_one_lblk(const struct cbd_params* params,
               u32 zone,
               u32 lblk,
               const struct zone_metadata* zm,
               u8** pblk_used)
{
    struct lba* lba;
    u8* lba_buf;
    u32 n_alloc;
    u32 n;
    u64 pblk;

    lba = calloc(1, offsetof(struct lba, pblk[lblk_per_pblk(params)]));
    lba_buf = zm->lbat + lblk * lba_len(params);
    lba_get(params, lba_buf, lba);
    if (lba->len) {
        if (lba->len == CBD_UNCOMPRESSED) {
            printf("  lblk[%u]: UNCOMPRESSED\n", lblk);
        }
        else {
            printf("  lblk[%u]: len=%u\n", lblk, lba->len);
        }
    }
    else {
        printf("  lblk[%u]: EMPTY\n", lblk);
    }
    if (lba->len > PBLK_SIZE * lblk_per_pblk(params)) {
        printf("    :E: Length out of bounds\n");
        return;
    }
    n_alloc = (lba->len == CBD_UNCOMPRESSED) ?
                  lblk_per_pblk(params) :
                  DIV_ROUND_UP(lba->len, PBLK_SIZE);
    for (n = 0; n < n_alloc; ++n) {
        u32 pblk_zone;
        u32 rel_pblk;
        pblk = lba->pblk[n];
        if (pblk < CBD_HEADER_BLOCKS) {
            printf("    [%u] :E: Alloc in header: %lu\n", n, pblk);
            continue;
        }
        pblk_zone = (pblk - CBD_HEADER_BLOCKS) / zone_len(params);
        if (pblk_zone >= params->nr_zones) {
            printf("    [%u] :E: Alloc beyond end: %lu\n", n, pblk);
            continue;
        }
        if (pblk < zone_data_off(params, pblk_zone)) {
            printf("    [%u] :E: Alloc in metadata: %lu\n", n, pblk);
            continue;
        }
        rel_pblk = pblk - zone_data_off(params, pblk_zone);
        /* XXX: Cannot happen? */
        if (rel_pblk >= pbat_len(params) * PBLK_SIZE_BITS) {
            printf("    [%u] :E: Alloc out of zone: %lu\n", n, pblk);
            continue;
        }
        printf("    [%u] pblk=%lu pblk_zone=%u rel_pblk=%u\n", n,
                (unsigned long)pblk, pblk_zone, rel_pblk);
        if (pblk_used[pblk_zone][rel_pblk/8] & (1 << (rel_pblk % 8))) {
            printf("    [%u] :E: Duplicate allocation for zone %u block %u\n",
                    n, pblk_zone, rel_pblk);
            continue;
        }
        pblk_used[pblk_zone][rel_pblk/8] |= (1 << (rel_pblk % 8));
    }

    free(lba);
}

static void
check_one_zone(const struct cbd_params* params,
               u32 zone,
               const struct zone_metadata* zm,
               u8** pblk_used)
{
    u32 lblk_alloc_len;
    u32 n;
    bool zone_empty;
    u32 lblk;

    printf("Zone %u: lbat=[%lu..%lu] alloc=[%lu .. %lu]\n",
            (unsigned int)zone,
            (unsigned long)zone_off(params, zone),
            (unsigned long)(zone_data_off(params, zone) - 1),
            (unsigned long)zone_data_off(params, zone),
            (unsigned long)zone_off(params, zone + 1));
    zone_empty = true;
    lblk_alloc_len = params->lblk_per_zone * lba_len(params);
    for (n = 0; n < lblk_alloc_len; ++n) {
        if (zm->lbat[n]) {
            zone_empty = false;
            break;
        }
    }
    if (zone_empty) {
        printf("  [empty]\n");
        return;
    }
    for (lblk = 0; lblk < params->lblk_per_zone; ++lblk) {
        check_one_lblk(params, zone, lblk,  zm, pblk_used);
    }
}

static void
check_zone_metadata(const struct cbd_params* params,
                    const struct zone_metadata* zmvec)
{
    u8** pblk_used;
    u32 zone;

    pblk_used = calloc(params->nr_zones, sizeof(void*));
    for (zone = 0; zone < params->nr_zones; ++zone) {
        pblk_used[zone] = calloc(pbat_len(params), PBLK_SIZE);
    }

    for (zone = 0; zone < params->nr_zones; ++zone) {
        check_one_zone(params, zone, &zmvec[zone], pblk_used);
    }

    for (zone = 0; zone < params->nr_zones; ++zone) {
        free(pblk_used[zone]);
    }
    free(pblk_used);
}

int
cbd_check(const char* dev,
          tristate_t auto_response)
{
    int devfd;
    struct cbd_header header;
    uint8_t pblkbuf[PBLK_SIZE];
    struct zone_metadata* zmvec;
    u32 zone;

    devfd = open(dev, O_RDONLY);
    if (devfd < 0) {
        error("Cannot open device\n");
    }

    pblk_read(devfd, 0, 1, pblkbuf);
    cbd_header_get(pblkbuf, &header);
    check_header(&header);

    zmvec = calloc(header.params.nr_zones, sizeof(struct zone_metadata));
    for (zone = 0; zone < header.params.nr_zones; ++zone) {
        zmvec[zone].pbat = calloc(pbat_len(&header.params), PBLK_SIZE);
        pblk_read(devfd,
                  pbat_off(&header.params, zone),
                  pbat_len(&header.params),
                  zmvec[zone].pbat);
        zmvec[zone].lbat = calloc(lbat_len(&header.params), PBLK_SIZE);
        pblk_read(devfd,
                  lbat_off(&header.params, zone),
                  lbat_len(&header.params),
                  zmvec[zone].lbat);
    }

    check_zone_metadata(&header.params, zmvec);

    for (zone = 0; zone < header.params.nr_zones; ++zone) {
        free(zmvec[zone].lbat);
        free(zmvec[zone].pbat);
    }
    free(zmvec);

    return 0;
}