#!/usr/bin/env python3

import errno
import os
import sys

from posix_parity import cleanup_dir
from posix_parity import fail
from posix_parity import join
from posix_parity import mergerfs_branches
from posix_parity import mergerfs_get_option
from posix_parity import mergerfs_mount
from posix_parity import mergerfs_set_option
from posix_parity import temp_dir
from posix_parity import touch


SKIP = 77


def main():
    try:
        with mergerfs_mount(num_branches=2) as (mount, branches):
            try:
                orig_moveonenospc = mergerfs_get_option(mount, "moveonenospc")
            except (PermissionError, FileNotFoundError):
                print("moveonenospc runtime option unavailable", end="")
                return SKIP
            except OSError as exc:
                if exc.errno == errno.EOPNOTSUPP:
                    print("moveonenospc runtime option unsupported", end="")
                    return SKIP
                raise

            if len(branches) < 2:
                print("moveonenospc test requires at least 2 branches", end="")
                return SKIP

            merge_base = temp_dir(mount)

            try:
                mergerfs_set_option(mount, "moveonenospc", "mfs")
                if mergerfs_get_option(mount, "moveonenospc") != "mfs":
                    return fail("moveonenospc: failed to set documented policy value")

                merge_file = join(merge_base, "enospc_test")
                touch(merge_file, b"test data for enospc")

                if not os.path.exists(merge_file):
                    return fail("moveonenospc: file was not created")

                fullpath = None
                try:
                    fullpath = os.getxattr(merge_file, "user.mergerfs.fullpath").decode()
                except OSError:
                    pass

                if fullpath and not os.path.exists(fullpath):
                    return fail(f"moveonenospc: fullpath does not exist on disk: {fullpath}")

                with open(merge_file, "r") as f:
                    content = f.read()

                if content != "test data for enospc":
                    return fail(f"moveonenospc: file content mismatch: got {content!r}")

                mergerfs_set_option(mount, "moveonenospc", orig_moveonenospc)

                print("moveonenospc ENOSPC path requires a constrained branch", end="")
                return SKIP
            except Exception as exc:
                try:
                    mergerfs_set_option(mount, "moveonenospc", orig_moveonenospc)
                except Exception:
                    pass
                return fail(str(exc))
            finally:
                cleanup_dir(merge_base)
    except RuntimeError as exc:
        print(str(exc), end="")
        return 77


if __name__ == "__main__":
    raise SystemExit(main())