{ config, lib, pkgs, nix-matlab, ... }: let
  # The matlab installation is held in the MATLAB_INSTALL_DIR MATLAB
  # updates and toolboxes can primarily be handled with the matlab_mpm
  # tool defined below. This file, alongside the matlab_install.txt
  # describe the current version of MATLAB available on the
  # system. Nix *can* fetch MATLAB and all its toolboxes, however not
  # all MATLAB toolboxes can be installed via commands, some *must* be
  # installed graphically, and otherwise are unsupported. So, for now,
  # we try to make installation as documented and reproducible as
  # possible.

  MATLAB_INSTALL_DIR = "/opt/MATLAB";

  # MATLAB Package Manager: MPM
  #
  # This tool is used to guarantee (nearly)
  # reproducible installations of MATLAB, and to easily allow for
  # controlling what version of MATLAB is currently installed
  
  matlab-mpm = pkgs.stdenv.mkDerivation rec {
    pname = "matlab-package-manager";
    version = "2023.12.1";

    src = pkgs.fetchurl {
      url = "https://ssd.mathworks.com/supportfiles/downloads/mpm/${version}/glnxa64/mpm";
      hash = "sha256-NlfPLDnpRIaKLLuIZAudnFHBKL04gzmypzp98QOa6+g=";
    };

    nativeBuildInputs = with pkgs; [
      autoPatchelfHook
    ];

    buildInputs = with pkgs; [
      gawk
      gnugrep
      unzip

      linux-pam
      libz
    ];

    unpackPhase = "cp $src ./mpm";

    buildPhase = ''
      tail -n +$(head -n20 ./mpm | grep "tail -n" | awk '{print $3}' | grep -o -E "[0-9]+") ./mpm > ./mpm.zip
    '';
    
    installPhase = ''
      unzip -d $out ./mpm.zip
    '';

    passthru = {
      executable = "bin/glnxa64/mpm";
    };
  };


  # Environment with the dependencies needed to run matlab (and
  # matlab's installers)
  matlab-env = pkgs.buildFHSUserEnv {
    name = "matlab-env";
    targetPkgs = (ps: nix-matlab.targetPkgs ps);
  };

  # Script used to get the most up to date version of the desired MATLAB
  matlab-update-script = pkgs.writeScriptBin "matlab_update_installation.sh" ''
    #!${pkgs.bash}/bin/bash

    if [ "''${EUID:-$(id -u)}" -ne 0 ]; then
      echo "Please make sure to run this script as root"
      exit -1
    fi

    if [ ! -d "${MATLAB_INSTALL_DIR}" ]; then
      echo "Make sure that '${MATLAB_INSTALL_DIR}' exists"
      exit -1
    fi

    cd ${MATLAB_INSTALL_DIR}
    cp ${./matlab/install_file.txt} ./install_file.txt
    sed -e "s#@MATLAB_INSTALL_DIR@#${MATLAB_INSTALL_DIR}#" -i ./install_file.txt

    ${matlab-env}/bin/${matlab-env.name} -c '${matlab-mpm}/${matlab-mpm.executable} install --inputfile ./install_file.txt'
  '';
  
  desktopItem = pkgs.makeDesktopItem {
    desktopName = "Matlab";
    name = "matlab";
    # We use substituteInPlace after we run `install`
    # -desktop is needed, see:
    # https://www.mathworks.com/matlabcentral/answers/20-how-do-i-make-a-desktop-launcher-for-matlab-in-linux#answer_25
    exec = "@out@/bin/matlab -desktop %F";
    icon = "matlab";
    # Most of the following are copied from octave's desktop launcher
    categories = [
      "Utility"
      "TextEditor"
      "Development"
      "IDE"
    ];
    mimeTypes = [
      "text/x-octave"
      "text/x-matlab"
    ];
    keywords = [
      "science"
      "math"
      "matrix"
      "numerical computation"
      "plotting"
    ];
  };

  # Produce acessible executables to "f", e.g. "matlab" or "mex"
  matlab-run = f: pkgs.buildFHSUserEnv {
    name = f;
    targetPkgs = nix-matlab.targetPkgs;
    # If making MATLAB available, create Application Icon etc.
    extraInstallCommands = pkgs.lib.strings.optionalString (f == "matlab") ''
      install -Dm644 ${desktopItem}/share/applications/matlab.desktop $out/share/applications/matlab.desktop
      substituteInPlace $out/share/applications/matlab.desktop \
        --replace "@out@" ${placeholder "out"}
      install -Dm644 ${nix-matlab}/icons/hicolor/256x256/matlab.png $out/share/icons/hicolor/256x256/matlab.png
      install -Dm644 ${nix-matlab}/icons/hicolor/512x512/matlab.png $out/share/icons/hicolor/512x512/matlab.png
      install -Dm644 ${nix-matlab}/icons/hicolor/64x64/matlab.png $out/share/icons/hicolor/64x64/matlab.png
    '';
    runScript = pkgs.writeScript "matlab-run-${f}-script" ''
      export QT_QPA_PLATFORM=xcb
      ${MATLAB_INSTALL_DIR}/bin/${f} "$@"
    '';
  };

in {
  environment.sessionVariables = {
    inherit MATLAB_INSTALL_DIR;
  };
  environment.systemPackages = (with nix-matlab.packages.x86_64-linux; [
    matlab-update-script
    (matlab-run "matlab")
    (matlab-run "mex")
  ]) ++ (with pkgs; [
    octaveFull
  ]);
}