#!/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 json

import os

import subprocess

import sys

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 = json.load(sys.stdin)

    r = main(args["tree"], args["options"])

    sys.exit(r)