flake.nix

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

  outputs = { self, nixpkgs, ... }:
    let
      system = "x86_64-linux";

      pkgs = import nixpkgs { inherit system; };
      beamPkgs = with pkgs.beam_minimal; packagesWith interpreters.erlang_27;
      erlang = beamPkgs.erlang;
      elixir = beamPkgs.elixir_1_17;
    in
    {
      devShells."${system}".default = pkgs.mkShell {
        buildInputs = [
          erlang
          elixir

          beamPkgs.hex
          beamPkgs.elixir-ls

          pkgs.inotifyTools
          pkgs.nodejs
        ];

        ERL_INCLUDE_PATH = "${erlang}/lib/erlang/usr/include";
        ERL_AFLAGS = "-kernel shell_history enabled";

        shellHook = ''
          # Allow mix to work on local directory
          mkdir -p .nix-mix
          mkdir -p .nix-hex
          export MIX_HOME=$PWD/.nix-mix
          export HEX_HOME=$PWD/.nix-hex
          export ERL_LIBS=$HEX_HOME/lib/erlang/lib

          # Concat paths
          export PATH=$MIX_HOME/bin:$PATH
          export PATH=$MIX_HOME/escripts:$PATH
          export PATH=$HEX_HOME/bin:$PATH

          # "Run: `mix archive.install hex phx_new` for phoenix."
        '';
      };
    };
}