#!/usr/bin/python3

import json
import os
import subprocess
import sys
import tempfile

from osbuild.util import ostree


STAGE_DESC = "Assemble a file system tree into a ostree commit"
STAGE_INFO = """
Takes a file system tree that is already conforming to the ostree
system layout[1] and commits it to an archive repository.

The repository is located at the `/repo` directory and additional
metadata is stored in `/commit.id` and `/compose.json` which contain
the commit id and the compose information respectively.


[1] https://ostree.readthedocs.io/en/stable/manual/adapting-existing/
"""
STAGE_OPTS = """
"required": ["ref"],
"properties": {
  "ref": {
    "description": "OStree ref to create for the commit",
    "type": "string",
    "default": ""
  },
  "tmp-is-dir": {
    "description": "Create a regular directory for /tmp",
    "type": "boolean",
    "default": true
  },
  "parent": {
    "description": "commit id of the parent commit",
    "type": "string"
  }
}
"""

TOPLEVEL_DIRS = ["dev", "proc", "run", "sys", "sysroot", "var"]
TOPLEVEL_LINKS = {
    "home": "var/home",
    "media": "run/media",
    "mnt": "var/mnt",
    "opt": "var/opt",
    "ostree": "sysroot/ostree",
    "root": "var/roothome",
    "srv": "var/srv",
}


def copy(name, source, dest):
    subprocess.run(["cp", "--reflink=auto", "-a",
                    os.path.join(source, name),
                    os.path.join(dest, name)],
                   check=True)


def init_rootfs(root, tmp_is_dir):
    """Initialize a pristine root file-system"""

    fd = os.open(root, os.O_DIRECTORY)

    os.fchmod(fd, 0o755)

    for d in TOPLEVEL_DIRS:
        os.mkdir(d, mode=0o755, dir_fd=fd)
        os.chmod(d, mode=0o755, dir_fd=fd)

    for l, t in TOPLEVEL_LINKS.items():
        # <dir_fd>/l -> t
        os.symlink(t, l, dir_fd=fd)

    if tmp_is_dir:
        os.mkdir("tmp", mode=0o1777, dir_fd=fd)
        os.chmod("tmp", mode=0o1777, dir_fd=fd)
    else:
        os.symlink("tmp", "sysroot/tmp", dir_fd=fd)


def main(tree, output_dir, options):
    ref = options["ref"]
    tmp_is_dir = options.get("tmp-is-dir", True)
    parent = options.get("parent", None)

    with tempfile.TemporaryDirectory(dir=output_dir) as root:
        print("Initializing root filesystem", file=sys.stderr)
        init_rootfs(root, tmp_is_dir)

        print("Copying data", file=sys.stderr)
        copy("usr", tree, root)
        copy("boot", tree, root)
        copy("var", tree, root)

        for name in ["bin", "lib", "lib32", "lib64", "sbin"]:
            if os.path.lexists(f"{tree}/{name}"):
                copy(name, tree, root)

        repo = os.path.join(output_dir, "repo")

        subprocess.run(["ostree",
                        "init",
                        "--mode=archive",
                        f"--repo={repo}"],
                       stdout=sys.stderr,
                       check=True)

        treefile = ostree.Treefile()
        treefile["ref"] = ref

        argv = ["rpm-ostree", "compose", "commit"]
        argv += [f"--repo={repo}"]

        if parent:
            argv += [f"--parent={parent}"]

        argv += [f"--write-composejson-to={output_dir}/compose.json"]

        with treefile.as_tmp_file() as path:
            argv += [path, root]

            subprocess.run(argv,
                           stdout=sys.stderr,
                           check=True)


if __name__ == '__main__':
    args = json.load(sys.stdin)
    r = main(args["tree"], args["output_dir"], args["options"])
    sys.exit(r)