{ pkgs, ... }:
{
  programs = {
    zoxide = {
      enable = true;
      enableZshIntegration = true;
      options = [
        "--cmd cd"
      ];
    };

    zsh = {
      enable = true;
      package = pkgs.zsh;
      dotDir = ".config/zsh";

      defaultKeymap = "viins";
      enableCompletion = true;
      autosuggestion.enable = false;

      syntaxHighlighting = {
        enable = true;
        package = pkgs.zsh-syntax-highlighting;
      };

      history = {
        save = 10000;
        size = 10000;
        ignoreDups = true;
      };

      historySubstringSearch = {
        enable = true;
        searchUpKey = "^P";
        searchDownKey = "^N";
      };

      envExtra = ''
        export EDITOR=nvim || export EDITOR=vim
        export BROWSER=firefox

        # Clean up the home folder.
        export GCC_COLORS="error=01;31:warning=01;35:note=01;36:caret=01;32:locus=01:quote=01"
        export GNUPGHOME="$XDG_DATA_HOME/gnupg"
        export _JAVA_OPTIONS=-Djava.util.prefs.userRoot="$XDG_CONFIG_HOME/java"
        export LC_ALL=en_US.UTF-8
        export LESSHISTFILE="-"
        export MANPAGER="nvim +Man!"
        export PARALLEL_HOME="$XDG_CONFIG_HOME/parallel"
        export SQLITE_HISTORY="$XDG_DATA_HOME/sqlite_history"

        # Add these directories to PATH on shell startup.
        PATH=$PATH:$HOME/scripts
        PATH=$PATH:$HOME/.local/bin
      '';

      initExtra = ''
        autoload -U colors && colors
        # Manually set the prompt.
        PS1="
        %{$fg[blue]%}%n %{$fg[yellow]%}at %{$fg[blue]%}%m %{$fg[yellow]%}in %{$fg[blue]%}%~
        %{$fg[yellow]%}λ%{$reset_color%} "

        set -o noclobber
        setopt interactive_comments

        export KEYTIMEOUT=1

        # Use 'k' and 'j' for substring searching when in cmd mode.
        bindkey -M vicmd 'k' history-substring-search-up
        bindkey -M vicmd 'j' history-substring-search-down

        # Use <C-y> for autosuggestions, similar to nvim.
        bindkey '^Y' autosuggest-accept

        # Cycle back through previous suggestions with <S-Tab>.
        bindkey '^[[Z' reverse-menu-complete
      '';

      shellAliases = {
        cp = "cp -i";
        mv = "mv -i";
        rm = "rm -I";
        ls = "ls --color=auto";
        cat = "bat -pp";
        grep = "grep --color=auto";
        diff = "diff --color=auto";
        mutt = "neomutt";
        song = "yt-dlp --continue --no-check-certificate --format=bestaudio -x --add-metadata --audio-format=flac";
        mkdir = "mkdir -p";
      };
    };
  };
}