keychron_qmk_firmware/shell.nix

{ avr ? true, arm ? true, teensy ? true }:

let
  overlay = self: super:
    let addDarwinSupport = pkg: pkg.overrideAttrs (oldAttrs: {
      meta.platforms = (oldAttrs.meta.platforms or []) ++ self.lib.platforms.darwin;
    });
    in {
      dfu-programmer = addDarwinSupport super.dfu-programmer;
      teensy-loader-cli = addDarwinSupport super.teensy-loader-cli;

      avrgcc = super.avrgcc.overrideAttrs (oldAttrs: rec {
        name = "avr-gcc-8.1.0";
        src = super.fetchurl {
          url = "mirror://gcc/releases/gcc-8.1.0/gcc-8.1.0.tar.xz";
          sha256 = "0lxil8x0jjx7zbf90cy1rli650akaa6hpk8wk8s62vk2jbwnc60x";
        };
      });
    };

  nixpkgs = builtins.fetchTarball {
    url = "https://github.com/NixOS/nixpkgs/archive/0260747427737b980f0.tar.gz";
    sha256 = "1p2yc6b40xvvxvmlqd9wb440pkrimnlc2wsbpa5rddlpx1dn8qmf";
  };

  pkgs = import nixpkgs { overlays = [ overlay ]; };
in

with pkgs;
let avr_incflags = [
    "-isystem ${avrlibc}/avr/include"
    "-B${avrlibc}/avr/lib/avr5"
    "-L${avrlibc}/avr/lib/avr5"
    "-B${avrlibc}/avr/lib/avr35"
    "-L${avrlibc}/avr/lib/avr35"
    "-B${avrlibc}/avr/lib/avr51"
    "-L${avrlibc}/avr/lib/avr51"
  ];
in
stdenv.mkDerivation {
  name = "qmk-firmware";

  buildInputs = [ dfu-programmer dfu-util diffutils git python3 ]
    ++ lib.optional avr [ avrbinutils avrgcc avrlibc avrdude ]
    ++ lib.optional arm [ gcc-arm-embedded ]
    ++ lib.optional teensy [ teensy-loader-cli ];

  AVR_CFLAGS = lib.optional avr avr_incflags;
  AVR_ASFLAGS = lib.optional avr avr_incflags;
}