# Tests where the block device returns invalid values

try:
    import vfs

    vfs.VfsFat
    vfs.VfsLfs2
except (ImportError, AttributeError):
    print("SKIP")
    raise SystemExit


class RAMBlockDevice:
    ERASE_BLOCK_SIZE = 512

    def __init__(self, blocks):
        self.data = bytearray(blocks * self.ERASE_BLOCK_SIZE)
        self.read_res = 0
        self.write_res = 0

    def readblocks(self, block, buf, off=0):
        # print("readblocks", block, len(buf), off)
        addr = block * self.ERASE_BLOCK_SIZE + off
        for i in range(len(buf)):
            buf[i] = self.data[addr + i]
        return self.read_res

    def writeblocks(self, block, buf, off=None):
        if off is None:
            # erase, then write
            off = 0
        addr = block * self.ERASE_BLOCK_SIZE + off
        for i in range(len(buf)):
            self.data[addr + i] = buf[i]
        return self.write_res

    def ioctl(self, op, arg):
        if op == 4:  # block count
            return len(self.data) // self.ERASE_BLOCK_SIZE
        if op == 5:  # block size
            return self.ERASE_BLOCK_SIZE
        if op == 6:  # erase block
            return 0


try:
    bdev = RAMBlockDevice(50)
except MemoryError:
    print("SKIP-TOO-LARGE")
    raise SystemExit


ERROR_EIO = (OSError, "[Errno 5] EIO")
ERROR_EINVAL = (OSError, "[Errno 22] EINVAL")
ERROR_TYPE = (TypeError, "can't convert str to int")


def test(vfs_class, test_data):
    bdev.read_res = 0  # reset function results
    bdev.write_res = 0

    vfs_class.mkfs(bdev)
    fs = vfs_class(bdev)

    with fs.open("test", "w") as f:
        f.write("a" * 64)

    for res, error_open, error_read in test_data:
        # This variant will fail on open
        bdev.read_res = res
        try:
            with fs.open("test", "r") as f:
                assert error_open is None
        except Exception as e:
            assert error_open is not None
            assert (type(e), str(e)) == error_open

        # This variant should succeed on open, may fail on read
        # unless the filesystem cached the contents already
        bdev.read_res = 0
        try:
            with fs.open("test", "r") as f:
                bdev.read_res = res
                assert f.read(1) == "a"
                assert f.read() == "a" * 63
                assert error_read is None
        except Exception as e:
            assert error_read is not None
            assert (type(e), str(e)) == error_read


try:
    test(
        vfs.VfsLfs2,
        (
            (0, None, None),
            (-5, ERROR_EIO, None),
            (5, ERROR_EINVAL, None),
            (33, ERROR_EINVAL, None),
            ("invalid", ERROR_TYPE, None),
        ),
    )
    test(
        vfs.VfsFat,
        (
            (0, None, None),
            (-5, ERROR_EIO, ERROR_EIO),
            (5, ERROR_EIO, ERROR_EIO),
            (33, ERROR_EIO, ERROR_EIO),
            ("invalid", ERROR_TYPE, ERROR_TYPE),
        ),
    )
    print("OK")
except MemoryError:
    print("SKIP-TOO-LARGE")