{ config, lib, pkgs, inputs, ... }:

{
  # configure z-shell to use omz with some plugins
  programs.zsh = {
    enable = true;
    autosuggestion.enable = true;
    syntaxHighlighting.enable = true;
    oh-my-zsh = {
      enable = true;
      # add git and agents as plugins
      plugins = [ "git" "ssh-agent" "gpg-agent" ];
      # everything here lands before `source $ZSH/oh-my-zsh.sh`
      extraConfig = ''
        # make omz faster on large repositories
        DISABLE_UNTRACKED_FILES_DIRTY=true

        # only display a fancy theme when glyphs are rendered
        if [[ "$TERM" == "linux" || "$TERM" == "screen" ]]; then
          ZSH_THEME="gentoo"
        else
          ZSH_THEME="agnoster"
        fi
      '';
    };

    # Unlike oh-my-zsh.extraConfig above, this lands *after*
    # `source $ZSH/oh-my-zsh.sh`, which is where the theme's prompt functions
    # come into existence.
    initContent = lib.mkAfter ''
      # Keep the prompt on one line in deeply nested trees.
      #
      # Both themes render the working directory as `%~`, the full path with
      # $HOME collapsed to `~`. Somewhere like
      # ~/git/bfh/cas-pml-sem/documents/bericht that is 39 columns on its own,
      # and together with user@host and a long branch name the line wraps.
      #
      # `%(4~|…/%2~|%~)` is a prompt ternary: at four or more components show
      # an ellipsis and the last two, otherwise show the path whole. Short
      # paths like ~/git/nixconfig are left alone.
      if [[ "$ZSH_THEME" == "agnoster" ]]; then
        # agnoster calls prompt_dir on every render, so redefining it is
        # enough. AGNOSTER_DIR_* keep the segment's own colours.
        prompt_dir() {
          prompt_segment "$AGNOSTER_DIR_BG" "$AGNOSTER_DIR_FG" '%(4~|…/%2~|%~)'
        }
      else
        # gentoo builds PROMPT once at load time, so patch the string. Its
        # `%~` is the non-root branch of `%(!.%1~.%~)`, and it is the first
        # literal `%~` in there, so the root branch is untouched. ASCII `...`
        # because this branch is the Linux console, whose font may lack U+2026.
        PROMPT="''${PROMPT/\%~/%(4~|.../%2~|%~)}"
      fi
    '';
  };

  # set important env vars
  home.sessionVariables = {
    EDITOR = "vim";
    NH_FLAKE = "/home/aaron/git/nixconfig";
  };
}