#!/usr/bin/python3

"""

Copy files from a source to the tree

Copies files obtained via a `source` to the tree. Multiple files or

directories can be copied by specifying multiple entries in `paths`.

If no paths are specified the whole contents of `source` is copied.

The source and the target path for each individual path entry might

optionally be specified via `from` and `to`, respectively; if no

path is given for any of the two, the root `/` is assumed.

Supported sources are currently:

 o `archive`: Fetch an archive via the org.osbuild.files source and

   extract it to a temporary directory. Currently only tar archives

   are supported.

"""

import json

import os

import sys

import subprocess

import tempfile

import osbuild.sources

SCHEMA = """

"additionalProperties": false,

"definitions": {

  "source-archive": {

    "description": "Fetch an via org.osbuild.files and extract it",

    "type": "object",

    "required": ["type", "checksum"],

    "additionalProperties": false,

    "properties": {

      "type": {

        "type": "string",

         "description": "The type of the source, here 'archive'",

         "enum": ["archive"]

      },

      "checksum": {

        "type": "string",

        "description": "The checksum of the archive to fetch"

      },

      "strip-components": {

        "type": "number",

        "description": "Strip 'N' leading components from file names on extraction",

        "default": 1

      }

    }

  }

},

"properties": {

  "source": {

    "oneOf": [{ "$ref": "#/definitions/source-archive" }]

  },

  "paths": {

    "description": "Array of items to copy",

    "type": "array",

    "items": {

      "type": "object",

      "additionalProperties": false,

      "properties": {

        "from": {

          "type": "string",

          "description": "The source path",

          "default": "/"

        },

        "to": {

          "type": "string",

          "description": "The destination path",

          "default": "/"

        }

      }

    }

  }

}

"""

def get_archive(options, srcdir, workdir):

    checksum = options["checksum"]

    strip = options.get("strip-components", 1)

    source_path = os.path.join(srcdir, "org.osbuild.files")

    target = os.path.join(workdir, checksum)

    os.makedirs(target)

    # actually fetch the archive

    res = osbuild.sources.get("org.osbuild.files", [checksum])

    tar = [

        "tar",

        "--strip-components=" + str(strip),

        "-x",

        "-C", target,

        "-f", os.path.join(source_path, checksum)

    ]

    subprocess.run(tar, check=True)

    return target, res

def main(tree, srcdir, options, workdir):

    source_options = options["source"]

    source_type = source_options["type"]

    paths = options.get("paths", [{}])

    if source_type == "archive":

        source = get_archive

    else:

        raise ValueError(f"Unsupported source: {source_type}")

    # Fetch the requested data via the selected source

    source_path, _ = source(source_options, srcdir, workdir)

    for path in paths:

        src = path.get("from", "/")

        dst = path.get("to", "/")

        subprocess.run(["cp", "--reflink=auto", "-a",

                        f"{source_path}{src}",

                        f"{tree}{dst}"],

                       check=True)

if __name__ == '__main__':

    stage_args = json.load(sys.stdin)

    with tempfile.TemporaryDirectory(dir="/var/tmp") as _workdir:

        r = main(stage_args["tree"],

                 stage_args["sources"],

                 stage_args["options"],

                 _workdir)

        sys.exit(r)