erlan-ip-parse.nix

{
  lib ? import <nixpkgs/lib>,
}:
rec {
  parse =
    val:
    let
      isIPv4 = (lib.match "^([0-9]+\\.){3}[0-9]+$" val) != null;
      isIpv6Localhost = (lib.match "^::1$" val) != null;
    in
    if isIPv4 then
      "{${lib.concatStringsSep "," (lib.splitString "." val)}}"
    else if isIpv6Localhost then
      "{0,0,0,0,0,0,0,1}"
    else
      let
        inherit (lib.network.ipv6.fromString val) address;
        fin = lib.map (x: if x != "0" then "16#${x}" else x) (lib.splitString ":" address);
      in
      "{${lib.concatStringsSep "," fin}}";

  tests = lib.runTests {
    testIpv4 = {
      expr = parse "127.0.0.1";
      expected = "{127,0,0,1}";
    };

    # {0,0,0,0,0,0,0,1}
    testIpv6LocalHost = {
      expr = parse "::1";
      expected = "{0,0,0,0,0,0,0,1}";
    };

    testIvp6NoZeros = {
      expr = parse "3ffe:b80:1f8d:2:204:acff:fe17:bf38";
      expected = "{16#3ffe,16#b80,16#1f8d,16#2,16#204,16#acff,16#fe17,16#bf38}";
    };

    testIpv6WithZeros = {
      expr = parse "fe80::204:acff:fe17:bf38";
      expected = "{16#fe80,0,0,0,16#204,16#acff,16#fe17,16#bf38}";
    };
  };
}