try:
    import errno
    import os
except ImportError:
    print("SKIP")
    raise SystemExit

try:
    os.VfsFat
except AttributeError:
    print("SKIP")
    raise SystemExit


class RAMFS:
    SEC_SIZE = 512

    def __init__(self, blocks):
        self.data = bytearray(blocks * self.SEC_SIZE)

    def readblocks(self, n, buf):
        # print("readblocks(%s, %x(%d))" % (n, id(buf), len(buf)))
        for i in range(len(buf)):
            buf[i] = self.data[n * self.SEC_SIZE + i]

    def writeblocks(self, n, buf):
        # print("writeblocks(%s, %x)" % (n, id(buf)))
        for i in range(len(buf)):
            self.data[n * self.SEC_SIZE + i] = buf[i]

    def ioctl(self, op, arg):
        # print("ioctl(%d, %r)" % (op, arg))
        if op == 4:  # MP_BLOCKDEV_IOCTL_BLOCK_COUNT
            return len(self.data) // self.SEC_SIZE
        if op == 5:  # MP_BLOCKDEV_IOCTL_BLOCK_SIZE
            return self.SEC_SIZE


try:
    bdev = RAMFS(50)
    os.VfsFat.mkfs(bdev)
except MemoryError:
    print("SKIP")
    raise SystemExit

vfs = os.VfsFat(bdev)
os.mount(vfs, "/ramdisk")
os.chdir("/ramdisk")

try:
    vfs.mkdir("foo_dir")
except OSError as e:
    print(e.errno == errno.EEXIST)

try:
    vfs.remove("foo_dir")
except OSError as e:
    print(e.errno == errno.EISDIR)

try:
    vfs.remove("no_file.txt")
except OSError as e:
    print(e.errno == errno.ENOENT)

try:
    vfs.rename("foo_dir", "/null/file")
except OSError as e:
    print(e.errno == errno.ENOENT)

# file in dir
with open("foo_dir/file-in-dir.txt", "w+t") as f:
    f.write("data in file")

with open("foo_dir/file-in-dir.txt", "r+b") as f:
    print(f.read())

with open("foo_dir/sub_file.txt", "w") as f:
    f.write("subdir file")

# directory not empty
try:
    vfs.rmdir("foo_dir")
except OSError as e:
    print(e.errno == errno.EACCES)

# trim full path
vfs.rename("foo_dir/file-in-dir.txt", "foo_dir/file.txt")
print(list(vfs.ilistdir("foo_dir")))

vfs.rename("foo_dir/file.txt", "moved-to-root.txt")
print(list(vfs.ilistdir()))

# check that renaming to existing file will overwrite it
with open("temp", "w") as f:
    f.write("new text")
vfs.rename("temp", "moved-to-root.txt")
print(list(vfs.ilistdir()))
with open("moved-to-root.txt") as f:
    print(f.read())

# valid removes
vfs.remove("foo_dir/sub_file.txt")
vfs.rmdir("foo_dir")
print(list(vfs.ilistdir()))

# disk full
try:
    bsize = vfs.statvfs("/ramdisk")[0]
    free = vfs.statvfs("/ramdisk")[2] + 1
    f = open("large_file.txt", "wb")
    f.write(bytearray(bsize * free))
except OSError as e:
    print("ENOSPC:", e.errno == 28)  # errno.ENOSPC
f.close()