flake.nix

{
  description = "This is a nix with flakes package";

  inputs = {
    nixpkgs.url = "github:nixos/nixpkgs";

    flake-utils.url = "github:numtide/flake-utils";
    podman-rootless.url = "github:ES-Nix/podman-rootless/from-nixpkgs";

    podman-rootless.inputs.nixpkgs.follows = "nixpkgs";
  };

  outputs = attrs@{
    self,
    nixpkgs,
    flake-utils,
    podman-rootless
  }:
    flake-utils.lib.eachDefaultSystem (system:
      let

        pkgsAllowUnfree = import nixpkgs {
          inherit system;
          config = { allowUnfree = true; };
        };

        # https://gist.github.com/tpwrules/34db43e0e2e9d0b72d30534ad2cda66d#file-flake-nix-L28
        pleaseKeepMyInputs = pkgsAllowUnfree.writeTextDir "bin/.please-keep-my-inputs"
          (builtins.concatStringsSep " " (builtins.attrValues attrs));
      in
      {

        # nix fmt
        formatter = pkgsAllowUnfree.nixpkgs-fmt;

        devShells.default = pkgsAllowUnfree.mkShell {
          buildInputs = with pkgsAllowUnfree; [
            bashInteractive
            coreutils
            gnumake
            podman-rootless.packages.${system}.podman
            pleaseKeepMyInputs
          ];

          shellHook = ''
            export TMPDIR=/tmp

            test -d .profiles || mkdir -v .profiles

            test -L .profiles/dev \
            || nix develop .# --profile .profiles/dev --command echo

            test -L .profiles/dev-shell-default \
            || nix build $(nix eval --impure --raw .#devShells."$system".default.drvPath) --out-link .profiles/dev-shell-"$system"-default

            echo "Entering the nix devShell"
          '';
        };
      });
}