infra/nix/default.nix

{ versionsPath }:

{
  channelSources =
    let
      channelVersions = (import versionsPath);
      mkChannelSource = channel:
        let
          channelVersion = builtins.getAttr channel channelVersions;
        in builtins.fetchGit {
          # Descriptive name to make the store path easier to identify
          name = "nixpkgs-channels-${channel}";
          url = if builtins.hasAttr "url" channelVersion
            then channelVersion."url"
            else "https://github.com/NixOS/nixpkgs-channels/"
          ;
          ref = (builtins.getAttr channel channelVersions)."ref";
          rev = (builtins.getAttr channel channelVersions)."rev";
      };
      nix_path = builtins.foldl' (sum: elem: sum +":" + builtins.concatStringsSep "=" elem) "" [
        [ "nixpkgs" (mkChannelSource "channelsNixosStable") ]
        [ "nixos" (mkChannelSource "channelsNixosStable" + "/nixos") ]
        [ "channels-nixos-stable" (mkChannelSource "channelsNixosStable") ]
        [ "channels-nixos-unstable" (mkChannelSource "channelsNixosUnstable") ]
        [ "nixpkgs-master" (mkChannelSource "nixpkgsMaster") ]
        [ "home-manager-module" (mkChannelSource "homeManagerModule") ]
      ];
    in (import (mkChannelSource "channelsNixosStable") {}).writeText "channels.rc" ''
      export NIX_PATH=${nix_path}
    '';
  }