{ lib, stdenv, fetchgit, elixir, erlang, rebar3, git }:

stdenv.mkDerivation rec {
  pname = "systant";
  version = "0.1.0";

  src = fetchgit {
    url = "https://git.ryanpandya.com/ryan/systant.git";
    rev = "f8173a1afb03623039ff504c587d7322a9876f3d";
    sha256 = "sha256-1cRfSoH+JdO4a7q4hRZSkoDMk2wMCYRIyCIN56FSUgg=";
  };

  nativeBuildInputs = [ elixir erlang rebar3 git ];

  # Disable network access - we'll handle deps manually
  MIX_ENV = "prod";
  
  configurePhase = ''
    export MIX_HOME=$TMPDIR/mix
    export HEX_HOME=$TMPDIR/hex
    export REBAR_CACHE_DIR=$TMPDIR/rebar3
    
    # Install hex and rebar locally
    mix local.hex --force
    mix local.rebar --force
  '';

  buildPhase = ''
    # This will fail but that's OK - we're using it to get deps info
    mix deps.get || true
    
    # Manual dependency installation (you'd need to add each dep here)
    # For now, let's try without deps to see if it builds
    mix deps.compile --skip-deps || true
    mix compile
    mix release
    
    echo "=== Build phase debug ==="
    find _build/prod/rel/ -name "*COOKIE*" || echo "No COOKIE in build"
  '';

  installPhase = ''
    mkdir -p $out
    cp -r _build/prod/rel/systant/* $out/
    
    # Force create COOKIE file
    mkdir -p $out/releases
    echo "systant-cookie-change-in-production" > $out/releases/COOKIE
    
    echo "=== Install phase debug ==="
    echo "COOKIE created manually in installPhase" > /tmp/manual-nix-debug
    ls -la $out/releases/
    cat $out/releases/COOKIE
  '';

  meta = with lib; {
    description = "Systant - System stats MQTT daemon";
    homepage = "https://git.ryanpandya.com/ryan/systant";
    license = licenses.mit;
    platforms = platforms.linux;
  };
}