{
  description = "Zig Host + Zig Xtensa (ESP32) Environment";

  inputs = {
    nixpkgs.url = "github:NixOS/nixpkgs/nixos-unstable";
    zig-overlay.url = "github:mitchellh/zig-overlay";
    zls-overlay.url = "github:zigtools/zls";
  };

  outputs = { self, nixpkgs, zig-overlay, zls-overlay, ... }:
    let
      system = "x86_64-linux";
      pkgs = nixpkgs.legacyPackages.${system};
      zig_host = zig-overlay.packages.${system}.master;
      zls = zls-overlay.packages.${system}.zls;

      zig_xtensa = pkgs.stdenvNoCC.mkDerivation {
        pname = "zig-xtensa";
        version = "0.15.2";
        src = pkgs.fetchzip {
          url = "https://github.com/haivivi/embed-zig/releases/download/espressif-0.15.2/zig-x86_64-linux-gnu-baseline.tar.xz";
          # Opraveny hash podla hlásenia Nixu
          hash = "sha256-Wyc36nKM2PqljI4W8LsnEcVtrmchwQDoaUHAYOI0g1I=";
          stripRoot = false;
        };
        dontBuild = true;
        installPhase = ''
          mkdir -p $out/bin
          cp -r . $out/
          # Symlink na binárku vo vnútri vnoreného adresára
          ln -s $out/zig-x86_64-linux-gnu-baseline/zig $out/bin/zig-xtensa
        '';
      };
    in {
      devShells.${system}.default = pkgs.mkShell {
        packages = [
          zig_host
          zls
          zig_xtensa
          pkgs.esptool
          pkgs.espflash
        ];
        shellHook = ''
          echo ">>> Zig Master (host): $(zig version)"
          echo ">>> Zig Xtensa (esp32): $(zig-xtensa version 2>/dev/null || echo 'Executable ready')"
          
          export PATH=$HOME/.rustup/toolchains/esp/xtensa-esp-elf/esp-14.2.0_20240906/xtensa-esp-elf/bin:$PATH
          
          if command -v xtensa-esp32-elf-gcc >/dev/null; then
            echo ">>> Xtensa GCC: $(xtensa-esp32-elf-gcc --version | head -n 1)"
          fi
        '';
      };
    };
}