// The OS/K Team licenses this file to you under the MIT license.
// See the LICENSE file in the project root for more information.

#include <pc/device.h>
#include <sys/stat.h>
#include <dirent.h>
#include <unistd.h>
#include <fcntl.h>

#define MAXOPEN 4096
#define MAXRW 0x800000      // 8MB

typedef struct disk_t       disk_t;
typedef struct dirent       dirent_t;

struct disk_t
{
    // disk directory
    DIR        *dir;

    // opened files
    int         table[MAXOPEN];
    uint        opened;
};

#define GETDISK() \
    disk_t *disk = (disk_t *)dev->data

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

long diskdev_findnext(ctx_t *ctx, dev_t *dev)
{
    struct stat st;
    char name[NAME_MAX+4];
    dirent_t *ent;
    GETDISK();

    for (;;)
    {
        ent = readdir(disk->dir);

        if (ent == NULL)
        {
            R(RAX) = 0;
            return 0;
        }

        if (!strcmp(ent->d_name, ".") || !strcmp(ent->d_name, ".."))
            continue;

        break;
    }

    R(RAX) = writestr(ctx, R(AX0), R(AX1), ent->d_name);

    snprintf(name, NAME_MAX+4, "fs/%s", ent->d_name);

    if (stat(name, &st) < 0)
    {
        perror("diskdev: couldn't stat file in directory: ");
        R(RDX) = -1;
    }

    else
        R(RDX) = st.st_size;

    return 0;
}

long diskdev_findfirst(ctx_t *ctx, dev_t *dev)
{
    GETDISK();

    rewinddir(disk->dir);

    return diskdev_findnext(ctx, dev);
}

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

long diskdev_open(ctx_t *ctx, dev_t *dev)
{
    GETDISK();

    int fd, tmp;
    char buf[NAME_MAX+4] = { 'f', 's', '/', 0 };

    readstr(ctx, R(AX0), NAME_MAX, buf+3);

    for (fd = 0; fd < MAXOPEN; fd++)
        if (disk->table[fd] == 0)
            break;

    if (fd == MAXOPEN)
        return -1;

    tmp = open(buf, O_RDWR);

    if (tmp < 0)
    {
        perror("diskdev: open");
        return -1;
    }

    disk->table[fd] = tmp;
    R(RAX) = fd;

    return 0;
}

long diskdev_close(ctx_t *ctx, dev_t *dev)
{
    GETDISK();

    if (R(AX0) >= MAXOPEN)
        return -1;

    if (disk->table[R(AX0)] <= 0)
        return -1;

    close(disk->table[R(AX0)]);

    return 0;
}

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

long diskdev_read(ctx_t *ctx, dev_t *dev)
{
    GETDISK();

    if (R(AX0) >= MAXOPEN || disk->table[R(AX0)] <= 0 || R(AX2) >= MAXRW)
        return -1;

    int ret;
    char *buf = malloc(MAXRW);

    if (buf == NULL)
        return -1;

    ret = read(disk->table[R(AX0)], buf, R(AX2));

    if (ret < 0)
    {
        free(buf);
        return -1;
    }

    R(RAX) = ret;

    // Xxx dedicated function & faster copy
    for (; ret; ret--, R(AX1)++, buf++)
        writemem(ctx, *buf, R(AX1), 1);
    return 0;
}

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

long diskdev_poweron(ctx_t *ctx, dev_t *dev)
{
    disk_t *disk = calloc(1, sizeof(disk_t));

    disk->dir = opendir("fs");

    if (disk->dir == NULL)
    {
        logerr("diskdev: couldn't open fs directory\n");
        return -1;
    }

    dev->data = (void *)disk;

    dev->fslots[16] = diskdev_findfirst;
    dev->fslots[17] = diskdev_findnext;

    dev->fslots[25] = diskdev_open;
    dev->fslots[26] = diskdev_close;

    dev->fslots[32] = diskdev_read;

    dev->state = DEVGOOD;

    return 0;
}

long diskdev_poweroff(ctx_t *ctx, dev_t *dev)
{
    GETDISK();
    int fd;

    if (disk)
    {
        if (disk->dir)
            closedir(disk->dir);

        for (fd = 0; fd < MAXOPEN; fd++)
            if (disk->table[fd] > 0)
                close(disk->table[fd]);

        free(disk);
    }

    dev->data = NULL;
    dev->state = DEVPWOF;

    return 0;
}

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

dev_t diskdev =
{
    .type = "disk",
    .name = "disk",
    .modl = "",
    .vend = "The OS/K Team",

    .major = KARCH_MAJOR,
    .minor = KARCH_MINOR,
    .revis = KARCH_REVIS,

    .fpwon = diskdev_poweron,
    .fpwoff = diskdev_poweroff,
};