{ ... }:
{
  perSystem = { system, pkgs, ... }: let
    zshrc = ''
      autoload -U compinit && compinit

      # Setup custom interactive shell init stuff.
      # Bind gpg-agent to this TTY if gpg commands are used.
      export GPG_TTY=$(tty)


      unsetopt nomatch # no matches found urls
      setopt autocd extendedglob
      bindkey -e

      #C-x C-e open line in editor
      autoload -z edit-command-line
      zle -N edit-command-line
      bindkey "^X^E" edit-command-line

      #fzf inclusion
      source ${pkgs.fzf}/share/fzf/completion.zsh
      source ${pkgs.fzf}/share/fzf/key-bindings.zsh

      # atuin distributed shell history
      export ATUIN_CONFIG_DIR=${pkgs.writeTextDir "/config.toml" ''
        auto_sync = true
        update_check = false
        sync_address = "http://green.r:8888"
        sync_frequency = 0
        style = "compact"
      ''};
      export ATUIN_NOBIND="true" # disable all keybdinings of atuin
      eval "$(atuin init zsh)"
      bindkey '^r' _atuin_search_widget # bind ctrl+r to atuin
      # use zsh only session history
      fc -p

      #completion magic
      autoload -Uz compinit
      compinit
      zstyle ':completion:*' menu select

      #enable automatic rehashing of $PATH
      zstyle ':completion:*' rehash true

      # fancy mv which interactively gets the second argument if not given
      function mv() {
        if [[ "$#" -ne 1 ]] || [[ ! -e "$1" ]]; then
          command mv -v "$@"
          return
        fi

        newfilename="$1"
        vared newfilename
        command mv -v -- "$1" "$newfilename"
      }

      #emacs bindings
      bindkey "[7~" beginning-of-line
      bindkey "[8~" end-of-line
      bindkey "Oc" emacs-forward-word
      bindkey "Od" emacs-backward-word

      # direnv integration
      eval "$(${pkgs.direnv}/bin/direnv hook zsh)"

      # This function is called whenever a command is not found.
      command_not_found_handler() {
        local p='${pkgs.nix-index}/etc/profile.d/command-not-found.sh'
        if [ -x "$p" ] && [ -f '/nix/var/nix/profiles/per-user/root/channels/nixos/programs.sqlite' ]; then
          # Run the helper program.
          "$p" "$@"

          # Retry the command if we just installed it.
          if [ $? = 126 ]; then
            "$@"
          else
            return 127
          fi
        else
          # Indicate than there was an error so ZSH falls back to its default handler
          echo "$1: command not found" >&2
          return 127
        fi
      }


      # Setup aliases.
      alias -- grep='grep --color=auto'
      alias -- ip='ip -color=auto'
      alias -- l='ls -alh'
      alias -- la='ls -la'
      alias -- ll='ls -l'
      alias -- ls='ls --color'
      alias -- ns='nix-shell --command zsh'

      # Setup prompt.
      autoload -U promptinit
      promptinit

      p_error='%(?..%F{red}%?%f )'
      t_error='%(?..%? )'

      case $UID in
        0)
          p_username='%F{red}root%f'
          t_username='root'
          ;;
        1337)
          p_username=""
          t_username=""
          ;;
        *)
          p_username='%F{blue}%n%f'
          t_username='%n'
          ;;
      esac

      if test -n "$SSH_CLIENT"; then
        p_hostname='@%F{magenta}%M%f '
        t_hostname='@%M '
      else
        p_hostname=""
        t_hostname=""
      fi

      #check if in nix shell
      if test -n "$IN_NIX_SHELL"; then
        p_nixshell='%F{green}[s]%f '
        t_nixshell='[s] '
      else
        p_nixshell=""
        t_nixshell=""
      fi

      PROMPT="$p_error$p_username$p_hostname$p_nixshell%~ "
      TITLE="$t_error$t_username$t_hostname$t_nixshell%~"
      case $TERM in
        (*xterm* | *rxvt*)
          function precmd {
            PROMPT_EVALED=$(print -P "$TITLE")
            echo -ne "\033]0;$$ $PROMPT_EVALED\007"
          }
          # This seems broken for some reason
          # # This is seen while the shell waits for a command to complete.
          # function preexec {
          #   PROMPT_EVALED=$(print -P "$TITLE")
          #   echo -ne "\033]0;$$ $PROMPT_EVALED $1\007"
          # }
        ;;
      esac


      # Disable some features to support TRAMP.
      if [ "$TERM" = dumb ]; then
          unsetopt zle prompt_cr prompt_subst
          unset RPS1 RPROMPT
          PS1='$ '
          PROMPT='$ '
      fi
    '';
  in {
    packages.sh = pkgs.writeScriptBin "sh" ''
      zdotdir=$(mktemp -d)
      export ZDOTDIR=${pkgs.writeTextDir "/.zshrc" zshrc}
      exec ${pkgs.zsh}/bin/zsh "$@"
    '';
  };
}