#!/usr/bin/env nix-shell
#!nix-shell -i python3 -p "python3.withPackages (ps: [  ])"

import argparse
import json
import os.path

from dataclasses import dataclass

@dataclass
class Connection:
    comment: str | None
    ssid: str  # also used as "id", more generally
    passphrase: str | None
    # LTE connections:
    uuid: str | None
    gsm_apn: str | None
    gsm_number: str | None

    @property
    def type_(self) -> str:
        if self.gsm_apn is not None or self.gsm_number is not None:
            return "gsm"
        return "wifi"

def parse_manifest(manifest_path: str) -> list[Connection]:
    for entry in json.load(open(manifest_path)):
        comment = entry.get("comment")
        ssid = entry["ssid"]
        passphrase = entry.get("passphrase")
        uuid = entry.get("uuid")
        gsm_apn = entry.get("gsm_apn")
        gsm_number = entry.get("gsm_number")
        if ssid != "<EOF>":
            yield Connection(
                comment=comment,
                ssid=ssid,
                passphrase=passphrase,
                uuid=uuid,
                gsm_apn=gsm_apn,
                gsm_number=gsm_number,
            )

def write_iwd(fh: "file", con: Connection) -> None:
    fh.write("[Security]\n")
    if con.passphrase is not None:
        fh.write(f"Passphrase={con.passphrase}\n")

def write_nm(fh: "file", con: Connection) -> None:
    fh.write("[connection]\n")
    fh.write(f"id={con.ssid}\n")
    if con.uuid is not None:
        fh.write(f"uuid={con.uuid}\n")
    fh.write(f"type={con.type_}\n")

    if con.type_ == "wifi":
        fh.write("\n")
        fh.write("[wifi]\n")
        fh.write("mode=infrastructure\n")
        fh.write(f"ssid={con.ssid}\n")

        fh.write("\n")
        fh.write("[wifi-security]\n")
        fh.write("auth-alg=open\n")
        fh.write("key-mgmt=wpa-psk\n")
        if con.passphrase is not None:
            fh.write(f"psk={con.passphrase}\n")
    elif con.type_ == "gsm":
        fh.write("\n")
        fh.write("[gsm]\n")
        if con.gsm_apn is not None:
            fh.write(f"apn={con.gsm_apn}\n")
        if con.gsm_number is not None:
            fh.write(f"number={con.gsm_number}\n")
        fh.write("\n")
        fh.write("[ppp]\n")

    fh.write("\n")
    fh.write("[ipv4]\n")
    fh.write("method=auto\n")

    fh.write("\n")
    fh.write("[ipv6]\n")
    fh.write("addr-gen-mode=default\n")
    fh.write("method=auto\n")

    # fh.write("\n")
    # fh.write("[proxy]\n")

def install_all(manifest: list[Connection], destination: str, flavor: str) -> None:
    ext, writer = dict(
        iwd=("psk", write_iwd),
        nm=("nmconnection", write_nm),
    )[flavor]
    for con in manifest:
        path = os.path.join(destination, f"{con.ssid}.{ext}")
        with open(path, "w") as fh:
            writer(fh, con)

def stamp(destination: str, stamp: str) -> None:
    if stamp:
        with open(os.path.join(destination, stamp), "w"):
            pass

def main() -> None:
    parser = argparse.ArgumentParser(description="create network connection descriptions from a static manifest")
    parser.add_argument("manifest", help="path to the manifest.json")
    parser.add_argument("destination", help="directory in which to install files")
    parser.add_argument("--flavor", help="'nm' or 'iwd' based on which program will read the results", default="iwd")
    parser.add_argument("--stamp", default=".install-nm.stamp", help="relative path of empty file to touch after completion")

    args = parser.parse_args()
    manifest = parse_manifest(args.manifest)
    install_all(manifest, args.destination, flavor=args.flavor)
    stamp(args.destination, args.stamp)

if __name__ == "__main__":
    main()