# Podman needs to be installed and configured on the system for all this to work:
# https://nixos.wiki/wiki/Podman
{
  description = "The Nix-flake for Redox development on NixOS";

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

    rust-overlay = {
      url = "github:oxalica/rust-overlay";
      inputs = {
        nixpkgs.follows = "nixpkgs";
      };
    };
  };

  outputs = {
    self,
    nixpkgs,
    ...
  } @ inputs: let
    supportedSystems = [
      "i686-linux"
      "x86_64-linux"
      "aarch64-linux"
      "x86_64-darwin"
      "aarch64-darwin"
    ];
    forAllSystems = f: nixpkgs.lib.genAttrs supportedSystems (system: (forSystem system f));
    forSystem = system: f:
      f rec {
        inherit system;
        pkgs = import nixpkgs {
          inherit system;
          overlays = [(import inputs.rust-overlay)];
        };
        lib = pkgs.lib;
        rust-bin = pkgs.rust-bin.nightly."2025-01-12".default.override {
          extensions = [
            "rust-analyzer"
            "rust-src"
          ];
          targets = ["x86_64-unknown-redox"];
        };
      };
  in {
    formatter = forAllSystems ({pkgs, ...}: pkgs.nixfmt-rfc-style);
    devShells = forAllSystems (
      {
        system,
        pkgs,
        rust-bin,
        ...
      }: let
        rustPlatform = pkgs.makeRustPlatform {
          cargo = rust-bin;
          rustc = rust-bin;
        };

        cargo-config = rustPlatform.buildRustPackage {
          pname = "cargo-config";
          version = "0.1.1";
          src = pkgs.fetchFromGitHub {
            owner = "wesleywiser";
            repo = "cargo-config";
            rev = "cf576faf65913615ed424914daa960800ed3ebc4";
            sha256 = "sha256-HrITNTfjBppOH1MhfZHfzHc6N8ymcm7vaiBI94ctUOA=";
            fetchSubmodules = true;
          };
          # useFetchCargoVendor = true; # this is recommended, but fails in some python code?
          cargoHash = "sha256-yQpIKclZ8KLE5JGkB/tjKZA8ezaD9SbUthDsuBXYZjQ=";
        };

        # Podman config taken from https://nixos.wiki/wiki/Podman and https://gist.github.com/adisbladis/187204cb772800489ee3dac4acdd9947
        # Provides a script that copies required files to ~/
        podmanSetupScript = let
          registriesConf = pkgs.writeText "registries.conf" ''
            [registries.search]
            registries = ['docker.io']
            [registries.block]
            registries = []
          '';
        in
          pkgs.writeScript "podman-setup" ''
            #!${pkgs.runtimeShell}
            # Dont overwrite customised configuration
            if ! test -f ~/.config/containers/policy.json; then
              install -Dm555 ${pkgs.skopeo.src}/default-policy.json ~/.config/containers/policy.json
            fi
            if ! test -f ~/.config/containers/registries.conf; then
              install -Dm555 ${registriesConf} ~/.config/containers/registries.conf
            fi
            systemctl --user start podman.socket || true
            export PODMAN_SYSTEMD_UNIT=podman.socket
          '';
        # Provides a fake "docker" binary mapping to podman
        dockerCompat = pkgs.runCommandNoCC "docker-podman-compat" {} ''
          mkdir -p $out/bin
          ln -s ${pkgs.podman}/bin/podman $out/bin/docker
        '';

        buildInputs = with pkgs; [
          # Compilation
          rust-bin

          # Utils
          cowsay
          lolcat

          # Cargo utilities
          cargo-config

          # Podman
          dockerCompat
          podman # Docker compat
          runc # Container runtime
          conmon # Container runtime monitor
          skopeo # Interact with container registry
          slirp4netns # User-mode networking for unprivileged namespaces
          fuse-overlayfs # CoW for images, much faster than default vfs

          # Build Redox
          ant
          autoconf
          automake
          bison
          cmake
          curl
          doxygen
          expat
          expect
          file
          flex
          fuse
          gmp
          gnumake
          gnupatch
          gperf
          just
          libjpeg
          libpng
          libtool
          llvmPackages.clang
          llvmPackages.llvm
          lua
          m4
          meson
          nasm
          perl
          perl540Packages.HTMLParser
          perl540Packages.Po4a
          pkgconf
          podman
          protobuf
          (python3.withPackages (ps: with ps; [mako]))
          qemu_kvm
          rust-cbindgen
          scons
          SDL
          syslinux
          texinfo
          unzip
          waf
          wget
          xdg-utils
          zip
        ];
      in {
        default = pkgs.mkShell {
          inherit buildInputs;

          LD_LIBRARY_PATH = pkgs.lib.makeLibraryPath buildInputs;
          NIX_SHELL_BUILD = "1";
          shellHook = ''
            # Install required configuration
            ${podmanSetupScript}
            echo "Redox environment loaded" | cowsay | lolcat
          '';
        };
      }
    );
  };
}