#!/usr/bin/python3

"""

Create /etc/fstab entries for filesystems

Create /etc/fstab entries for the given `filesystems`.

Each filesystem item must have at least `uuid` or `label` and

a `path` (mount point).

This stage replaces /etc/fstab, removing any existing entries.

"""

import json

import sys

SCHEMA = """

"additionalProperties": false,

"required": ["filesystems"],

"properties": {

  "filesystems": {

    "type": "array",

    "description": "array of filesystem objects",

    "items": {

      "type": "object",

      "oneOf": [{

        "required": ["uuid", "path"]

      }, {

        "required": ["label", "path"]

      }],

      "properties": {

        "uuid": {

          "description": "Filesystem UUID",

          "type": "string"

        },

        "label": {

          "description": "Filesystem label",

          "type": "string"

        },

        "path": {

          "description": "Filesystem mountpoint",

          "type": "string"

        },

        "vfs_type": {

          "description": "Filesystem type",

          "type": "string",

          "default": "none"

        },

        "options": {

          "description": "Filesystem options (comma-separated)",

          "type": "string",

          "default": "defaults"

        },

        "freq": {

          "description": "dump(8) period in days",

          "type": "number",

          "default": 0

        },

        "passno": {

          "description": "pass number on parallel fsck(8)",

          "type": "number",

          "default": 0

        }

      }

    }

  }

}

"""

def main(tree, options):

    filesystems = options["filesystems"]

    with open(f"{tree}/etc/fstab", "w") as f:

        for filesystem in filesystems:

            uuid = filesystem.get("uuid")

            path = filesystem["path"]

            label = filesystem.get("label")

            vfs_type = filesystem.get("vfs_type", "none")

            options = filesystem.get("options", "defaults")

            freq = filesystem.get("freq", 0)

            passno = filesystem.get("passno", 0)

            if uuid:

                fs_spec = f"UUID={uuid}"

            elif label:

                fs_spec = f"LABEL={label}"

            else:

                raise ValueError("Need 'uuid' or 'label'")

            f.write(f"{fs_spec}\t{path}\t{vfs_type}\t{options}\t{freq}\t{passno}\n")

if __name__ == '__main__':

    args = json.load(sys.stdin)

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

    sys.exit(r)