{ config, lib, pkgs, unstable-pkgs, mypkgs, ... }:

with lib;
let xsession-enable = config.my.xsession.enable;
    optional-dependencies = config.my.emacs.optional-dependencies;
    unstable-epkgs = unstable-pkgs.emacsPackagesNg;
    # Optional config (draws too much dependencies on some platforms)
    optional-configs = if optional-dependencies
      then [
        {
            file = ./haskell-pack/haskell-pack.el;
            pkgs = epkgs: with epkgs; [
              haskell-mode ghci-completion
            ];
        }
      ]
      else [ ];
    configs = [
      {
        file = ./init.el;
        pkgs = epkgs: with epkgs; [
          use-package
        ];
      }
      {
        file = ./theme-pack/theme-pack.el;
        pkgs = epkgs: with epkgs; [
          s deferred dash smart-mode-line spacemacs-theme
          mypkgs.emacs-powerline
        ];
      }
      {
        file = ./prelude-pack/prelude-pack.el;
        pkgs = epkgs: with epkgs; [
          crux projectile helm
        ];
      }
      {
        file = ./mail-pack/mail-pack.el;
        pkgs = epkgs: with epkgs; [
          creds dash s offlineimap async google-contacts notmuch
        ];
      }
      {
        file = ./weechat-pack/weechat-pack.el;
        pkgs = epkgs: with epkgs; [ weechat ];
      }
      {
        file = ./buffer-pack/buffer-pack.el;
        pkgs = epkgs: with epkgs; [
          move-text dockerfile-mode projectile
          dash markdown-mode iedit markdown-toc yaml-mode
			    multiple-cursors git-gutter buffer-move company
			    ace-window iy-go-to-char s git-gutter popwin ht
        ];
      }
      {
        file = ./git-pack/git-pack.el;
        pkgs = epkgs: with epkgs; [
          fullframe magit magit-popup git-gutter
          magithub
        ];
      }
      {
        file = ./prog-mode-pack/prog-mode-pack.el;
        pkgs = epkgs: with epkgs; [
          crux smartscan
        ];
      }
      {
        file = ./helm-pack/helm-pack.el;
        pkgs = epkgs: [ epkgs.helm ];
      }
      {
        file = ./help-pack/help-pack.el;
        pkgs = epkgs: with epkgs; [ which-key helpful ];
      }
      {
        file = ./popup-pack/popup-pack.el;
        pkgs = epkgs: [];
      }
      {
        file = ./modeline-pack/modeline-pack.el;
        pkgs = epkgs: with epkgs; [ dash s diminish ];
      }
      {
        file = ./shell-pack/shell-pack.el;
        pkgs = epkgs: [ epkgs.popwin ];
      }
      {
        file = ./orgmode-pack/orgmode-pack.el;
        pkgs = epkgs: with epkgs; [
          org ac-math smartscan dash auto-complete
        ];
      }
      {
        file = ./python-pack/python-pack.el;
        pkgs = epkgs: [ unstable-epkgs.elpy epkgs.smartparens ];
      }
      {
        file = ./twitter-pack/twitter-pack.el;
        pkgs = epkgs: with epkgs; [ twittering-mode ];
      }
      {
        file = ./lisp-pack/lisp-pack.el;
        pkgs = epkgs: with epkgs; [ eval-sexp-fu paredit fold-dwim cider ];
      }
      {
        file = ./elisp-pack/elisp-pack.el;
        pkgs = epkgs: with epkgs; [
          bug-hunter el-mock goto-last-change dash aggressive-indent
			    overseer
          page-break-lines
          request-deferred
          # emr
        ];
      }
      {
        file = ./puppet-pack/puppet-pack.el;
        pkgs = epkgs: with epkgs; [ puppet-mode ];
      }
      {
        file = ./blog-pack/blog-pack.el;
        pkgs = epkgs: with epkgs; [ org2jekyll kv ];
      }
      {
        file = ./wiki-pack/wiki-pack.el;
        pkgs = epkgs: with epkgs; [ mediawiki ox-mediawiki ];
      }
      {
        file = ./irc-pack/irc-pack.el;
        pkgs = epkgs: with epkgs; [ dash creds ];
      }
      {
        file = ./mercurial-pack/mercurial-pack.el;
        pkgs = epkgs: with epkgs; [ monky ];
      }
      {
        file = ./conkeror-pack/conkeror-pack.el;
        pkgs = epkgs: with epkgs; [ conkeror-minor-mode ];
      }
      {
        file = ./pres-pack/pres-pack.el;
        pkgs = epkgs: with epkgs; [ ox-reveal ];
      }
      {
        file = ./browser-pack/browser-pack.el;
        pkgs = epkgs: with epkgs; [ restclient ];
      }
      {
        file = ./scratch-pack/scratch-pack.el;
        pkgs = epkgs: with epkgs; [ htmlize google-this hydra ];
      }
      {
        file = ./viewer-pack/viewer-pack.el;
        pkgs = epkgs: [ ];
      }
      {
        file = ./marmalade-pack/marmalade-pack.el;
        pkgs = epkgs: with epkgs; [
          marmalade-client
        ];
      }
      {
        file = ./nix-pack/nix-pack.el;
        pkgs = epkgs: with epkgs; [ nix-mode smartscan ];
      }
      {
        file = ./macro-pack/macro-pack.el;
        pkgs = epkgs: [ ];
      }
      {
        file = ./devops-pack/devops-pack.el;
        pkgs = epkgs: with epkgs; [ terraform-mode ];
      }
      {
        file = ./nounou/employeur.el;
        pkgs = epkgs: [ ];
      }
    ] ++
    optional-configs;

    # raw file content
    raw_configs = [
      {
        pkgs = epkgs: with epkgs; [ rust-mode ];
        raw = with pkgs; ''
(require 'rust-mode)

(add-hook 'rust-mode-hook
          (lambda () (setq indent-tabs-mode nil)))

(define-key rust-mode-map (kbd "C-c C-c") 'rust-run)

(custom-set-variables
 '(rust-rustfmt-bin "${rustfmt}/bin/rustfmt")
 '(rust-cargo-bin "${cargo}/bin/cargo")
 '(rust-format-on-save t))

(provide 'rust-pack)

'';
      }
    ];

    # system packages emacs' config depends upon
    # On some platform, compiling those are too heavy
    optional-runtime-dependencies =
      if optional-dependencies then [ pkgs.shellcheck ] else [ ];
    extra-runtime-packages = with pkgs; [
      ag aspell notmuch cask git
      arcanist python3Packages.tox
    ] ++ optional-runtime-dependencies;
    cfg = config.my.emacs;
in {
  options.my.emacs = {
    optional-dependencies = mkEnableOption "Install emacs with optional dependencies";
  };

  config = {
    programs.emacs = with pkgs; {
      enable = true;
      # emacs no x if no x session
      package = if xsession-enable then emacs26 else emacs26-nox;
      # nevertheless, install the deps
      extraPackages =
        epkgs: concatMap (config: config.pkgs epkgs) configs ++
               concatMap (config: config.pkgs epkgs) raw_configs ++
               extra-runtime-packages;
    };

    services.emacs.enable = true;

    # Inline the packs into the init.el
    home.file.".emacs.d/init.el" = {
      text = ( foldl ( soFar: config: soFar + readFile config.file + "\n" ) "" configs ) +
             ( foldl ( soFar: config: soFar + config.raw + "\n" ) "" raw_configs ) +
             ( readFile ./end.el );
    };
  };

}