#!/usr/bin/env python3

import os
import sys
import tempfile

from posix_parity import cleanup_paths
from posix_parity import compare_calls
from posix_parity import fail
from posix_parity import join
from posix_parity import touch


def main():
    if len(sys.argv) != 2:
        print("usage: TEST_posix_open_read_write <mountpoint>", file=sys.stderr)
        return 1

    mount = sys.argv[1]

    with tempfile.TemporaryDirectory() as native:
        merge_file = join(mount, "posix-rw/file")
        native_file = join(native, "posix-rw/file")
        merge_missing = join(mount, "posix-rw/missing")
        native_missing = join(native, "posix-rw/missing")
        merge_dir = join(mount, "posix-rw/dir")
        native_dir = join(native, "posix-rw/dir")
        merge_notdir = join(mount, "posix-rw/notdir")
        native_notdir = join(native, "posix-rw/notdir")

        cleanup_paths([merge_file, merge_notdir])
        touch(merge_file, b"123456", 0o644)
        touch(native_file, b"123456", 0o644)
        os.makedirs(merge_dir, exist_ok=True)
        os.makedirs(native_dir, exist_ok=True)
        touch(merge_notdir, b"x", 0o644)
        touch(native_notdir, b"x", 0o644)

        err = compare_calls("open ENOENT", lambda: os.open(merge_missing, os.O_RDONLY), lambda: os.open(native_missing, os.O_RDONLY))
        if err:
            return fail(err)

        err = compare_calls("open EISDIR", lambda: os.open(merge_dir, os.O_WRONLY), lambda: os.open(native_dir, os.O_WRONLY))
        if err:
            return fail(err)

        err = compare_calls(
            "open ENOTDIR",
            lambda: os.open(join(merge_notdir, "child"), os.O_RDONLY),
            lambda: os.open(join(native_notdir, "child"), os.O_RDONLY),
        )
        if err:
            return fail(err)

        mfd = os.open(merge_file, os.O_RDWR)
        nfd = os.open(native_file, os.O_RDWR)
        try:
            os.lseek(mfd, 0, os.SEEK_SET)
            os.lseek(nfd, 0, os.SEEK_SET)
            m_data = os.read(mfd, 6)
            n_data = os.read(nfd, 6)
            if m_data != n_data:
                return fail(f"read parity mismatch mergerfs={m_data!r} native={n_data!r}")

            os.lseek(mfd, 0, os.SEEK_SET)
            os.lseek(nfd, 0, os.SEEK_SET)
            mw = os.write(mfd, b"abc")
            nw = os.write(nfd, b"abc")
            if mw != nw:
                return fail(f"write count mismatch mergerfs={mw} native={nw}")
        finally:
            os.close(mfd)
            os.close(nfd)

        return 0


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