repo-clone/service.nix

{ config, service, pkgs }:

let
  inherit (pkgs)
    writeShellScriptBin;
in
{
  Unit = {
    Description = "${service} service";
    X-Restart-Triggers = [ "${config.repo-clone.pkg}" ];
  };
  Service = {
    Type = "exec";
    ExecStart =
      let
        execName = service;
        script = writeShellScriptBin execName ''
          clone_repo() {
            git clone "$1" "$2"
          }

          while IFS="" read -r p || [ -n "$p" ]
          do
            args=($p) # [0]: repo-url [1]: target-path
            repo=''${args[0]}
            target=''${args[1]}

            if [ -d "$target" ]; then
              if ${pkgs.findutils}/bin/find "$target" -maxdepth 0 -empty | read v; then
                clone_repo "$repo" "$target"
              else
                echo "Files already found: $target"
              fi
            else
              clone_repo "$repo" "$target"
            fi
          done < "${config.repo-clone.pkg}"
        '';
      in
      "${script}/bin/${execName}";
    RemainAfterExit = "yes";
  };
  Install.WantedBy = [ "multi-user.target" ];
}