# Fg42 - Emacs Editor for advance users
#
# Copyright (c) 2010-2024 Sameer Rahmani <lxsameer@gnu.org>
#
# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation, version 2.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program.  If not, see <http://www.gnu.org/licenses/>.
{ lib
, config
, stdenv
, git
, texinfo
, gcc
, bash
, utils
, emacsPackagesFor
, makeFontsConf
, xorg
, maintainers
, writeTextFile
, writeShellApplication
, ...
}:

with builtins;
let
  cfg = config.fg42;
  emacs = cfg.emacs;
  version = cfg.version;

  emacsBundle = (emacsPackagesFor emacs).withPackages (_: cfg.elispPackages);

  paths = map (x: "${x}/bin/") cfg.paths;
  pathsStr = lib.strings.concatStrings (lib.strings.intersperse ":" paths);

  mimeTypes = builtins.concatStringsSep ";" cfg.mimeTypes;

  fontsConf = makeFontsConf { fontDirectories = cfg.fonts; };

  # Whatever that needs to be in the PATH is considered a runtime
  # dependency.
  # Fonts are obviously runtime dependency as well
  runtimeDependencies = cfg.paths ++ cfg.fonts ++ cfg.elispPackages;

  configFile = writeTextFile {
    name = "config.json";
    text = (toJSON {
      fg42 = {
        inherit (cfg) vars consts requires;
      };
    });
    executable = false;
  };

in
stdenv.mkDerivation rec {
  inherit version;
  pname = builtins.trace ">>> ${configFile}" "FG42";

  src = ../../.;

  buildPhase = ''
    runHook preBuild

    LISPDIR=$out/share/fg42/
    STARTUP_FILE=$LISPDIR/lisp/fg42_init.el

    mkdir -p $out/bin
    mkdir -p $out/share/applications/

    install -d $LISPDIR

    mkdir -p $LISPDIR/lisp
    cp -rv ${src}/lisp/build.el $LISPDIR/lisp

    cp -rv ${src}/share $out/
    cp -rv ${src}/snippets $LISPDIR/snippets
    cp "${fontsConf}" $LISPDIR/fonts.conf
    cp "${configFile}" $LISPDIR/config.json

    export FONTCONFIG_FILE="$LISPDIR/fonts.conf"
    chmod 755 $LISPDIR -R

    emacs --batch -l $LISPDIR/lisp/build.el $LISPDIR/config.json $STARTUP_FILE
    #emacs -Q --batch -l package --eval "(package-generate-autoloads \"fg42_init" \"$LISPDIR\")"
    emacs --batch -l loaddefs-gen -f loaddefs-generate-batch $LISPDIR/lisp/ $LISPDIR/lisp/ ${emacsBundle}

    cat >> $out/share/applications/FG42.desktop << EOF
    [Desktop Entry]
    Encoding=UTF-8
    Name=FG42
    GenericName=FG42
    Comment=The nix base Emacs bundle for advance users
    MimeType=${mimeTypes}
    Type=Application
    Terminal=false
    Categories=Development;TextEditor;
    StartupWMClass=FG42
    Exec=${placeholder "out"}/bin/fg42
    Icon=fg42
    Version=${version}
    EOF

    cat >> $out/share/runtime_deps << EOF
    ${lib.strings.concatLines runtimeDependencies}
    ${emacsBundle}
    EOF

    cd $LISPDIR
    #compile stuff
    cd -

    cat >> $out/bin/fg42 << EOF
    #!${stdenv.shell}

    export PATH=${pathsStr}:$PATH
    export FONTCONFIG_FILE="$LISPDIR/fonts.conf"
    export STARTUP_FILE=$LISPDIR/lisp/fg42_init.el

    LIBRARY_PATH="\$(${stdenv.cc}/bin/cc -print-file-name=libgccjit.so):\$LIBRARY_PATH" \
      FG42_WM=fales ${emacsBundle}/bin/emacs \
      --name FG42 \
      -q --no-splash --title FG42 \
      -l "$STARTUP_FILE" "\$@"
    EOF
    chmod +x $out/bin/fg42


    LISPDIR=$out/share/fg42/lisp/
    mkdir -p $LISPDIR
    #emacs --batch -l package --eval "(package-generate-autoloads \"${pname}\" \"$LISPDIR\")"

    runHook postBuild

    cat >> $out/bin/fg42-wm << EOF
    #!${stdenv.shell}

    export PATH=${pathsStr}:\$PATH
    export FONTCONFIG_FILE="$LISPDIR/fonts.conf"
    export STARTUP_FILE=$LISPDIR/lisp/fg42_init.el

    # Disable access control for the current user.
    ${xorg.xhost}/bin/xhost +SI:localuser:\$USER

    # Make Java applications aware this is a non-reparenting window manager.
    export _JAVA_AWT_WM_NONREPARENTING=1

    # Set default cursor.
    xsetroot -cursor_name left_ptr

    # Set keyboard repeat rate.
    xset r rate 400 30

    # Uncomment the following block to use the exwm-xim module.
    # export XMODIFIERS=@im=exwm-xim
    # export GTK_IM_MODULE=xim
    # export QT_IM_MODULE=xim
    # export CLUTTER_IM_MODULE=xim

    LIBRARY_PATH="\$(${stdenv.cc}/bin/cc -print-file-name=libgccjit.so):\$LIBRARY_PATH" \
      FG42_WM=true ${emacsBundle}/bin/emacs \
      --name FG42 \
     -q --no-splash --title FG42 \
      -l $STARTUP_FILE "\$@"
    EOF
    chmod +x $out/bin/fg42-wm


    runHook postBuild
  '';

  buildInputs = [ emacs emacsBundle git texinfo gcc bash ];

  addEmacsNativeLoadPath = true;

  meta = {
    broken = false;
    platforms = emacs.meta.platforms;
    homepage = "https://fg42.org/";
    maintainers = [ maintainers.lxsameer ];
    description = "The mighty editor for the Emacsians";
    longDescription = ''
      FG42 is a framework to create and editor and window manager based on GNU/Emacs.
      It has a pre-defined setup as well which can be installed out of the box. But the
      goal of this project is to provide the API necessary to create an integrated editor.

      So you need to know about Emacs in advance.
    '';
    license = lib.licenses.gpl3Plus;
  };
}