#!/usr/bin/python3
"""
Transforms the tree to an ostree layout

Uses `rpm-ostree compose` to transform a "normal" file system tree into
an OSTree conforming layout (see [1]). Among other things the main steps
are:
  - moves /etc to /usr/etc
  - move /boot to /usr/lib/ostree-boot
  - potentially moving /var/lib/rpm
  - re-creates the initramfs (via dracut)
  - adds altfiles module to NSS
  - Re-compiles SELinux policy (semodule -nB)
  - Migrates /usr/etc/{passwd, group} to /usr/lib/
  - Postprocess SELinux policy
  - Convert /var to use tmpfiles.d
  - Prepares symlinks
    - /usr/local -> /var/usrlocal
    - /var/lib/alternatives -> /usr/lib/alternatives
    - /var/lib/vagrant -> /usr/lib/vagrant
  - copies the rpmdb

The configuration options, `etc_group_members` corresponds to the
Treefile[2] option of rpm-ostree. In brief: The groups mentioned
in `etc_group_members` will be stored in /etc/groups instead of
/usr/etc/groups (which is read-only). Therefore all groups that
human users need to be part of.

[1] https://ostree.readthedocs.io/en/latest/manual/adapting-existing/
[2] https://rpm-ostree.readthedocs.io/en/latest/manual/treefile/
"""


import os
import subprocess
import sys

import osbuild.api
from osbuild.util import ostree


SCHEMA = """
"additionalProperties": false,
"properties": {
  "etc_group_members": {
    "description": "Array of group names to still keep in /etc/group",
    "type": "array",
    "items": { "type": "string" }
  },
  "initramfs-args": {
    "description": "Array of arguments passed to dracut",
    "type": "array",
    "items": { "type": "string" }
  }
}
"""


def main(tree, options):
    etc_group_members = options.get("etc_group_members", [])
    initramfs = options.get("initramfs-args", [])

    # rpm-ostree will either ensure that machine-id is empty
    # when machineid-compat is 'true' is or will remove it
    # otherwise. Since we have to decide, detect the current
    # state and make rpm-ostree follow suit
    machineid_compat = os.path.exists(f"{tree}/etc/machine-id")
    print(f"ostree: machineid-compat: {machineid_compat}")

    treefile = ostree.Treefile()
    treefile["boot-location"] = "new"
    treefile["machineid-compat"] = machineid_compat
    treefile["etc-group-members"] = etc_group_members
    treefile["initramfs-args"] = initramfs

    with treefile.as_tmp_file() as path:
        subprocess.run(["rpm-ostree", "compose", "postprocess",
                        tree, path],
                       check=True)


if __name__ == '__main__':
    args = osbuild.api.arguments()
    r = main(args["tree"], args["options"])
    sys.exit(r)
