# shell.nix
/*
# Dev env for elixir


## Environment Variables

- MIX_HOME: Local Mix installation
- HEX_HOME: Local Hex package manager
- PGDIR: PostgreSQL data directory
- PGHOST: Unix domain socket location
- DATABASE_URL: PostgreSQL connection string
*/

let
  # Import nixos-unstable for most packages
  pkgs = import <nixpkgs> {};
  # Import nixpkgs-unstable for outliers
  pkgs-unstable = import <nixpkgs-unstable> {};
  
  extraPackages = [
    pkgs.beam.packages.erlang_27.elixir_1_18
    pkgs.beam.packages.erlang_27.erlang
    pkgs.elixir_ls
    pkgs.inotify-tools
    
    # DB
    pkgs.postgresql
    # JS
    pkgs-unstable.deno
    # PY
    pkgs.python3
    pkgs.python3Packages.laspy
    pkgs.python3Packages.scipy
    pkgs.python3Packages.numpy
    pkgs.python3Packages.pyproj
  ];

  mkShell = pkgs.mkShell;
  PROJECT_ROOT = builtins.toString ./.;

  hooks = ''
    # Set up environment variables

    # PostgreSQL configuration
    export PGDIR=${PROJECT_ROOT}/postgres
    export PGHOST=$PGDIR
    export PGDATA=$PGDIR/data
    export PGLOG=$PGDIR/log
    export DATABASE_URL="postgresql:///postgres?host=$PGDIR"

    # Create PostgreSQL directories if they don't exist
    if test ! -d $PGDIR; then
      mkdir $PGDIR
    fi

    if [ ! -d $PGDATA ]; then
      echo 'Initializing postgresql database...'
      initdb $PGDATA --auth=trust >/dev/null
    fi

    # Print setup instructions
    echo "Elixir development environment ready!"
    echo "To start PostgreSQL, run: postgres -h \'\' -k \'$PGHOST\'"
    echo "To start the project, run : iex -S mix phx.server" 
  '';

in mkShell {
  buildInputs = extraPackages;
  shellHook = hooks;
}