{ pkgs, sane-lib, ... }:

let
  # powerlevel10k prompt config
  # p10k.zsh is the auto-generated config, and i overwrite those defaults here, below.
  p10k-overrides = ''
    # powerlevel10k launches a gitstatusd daemon to accelerate git prompt queries.
    # this keeps open file handles for any git repo i touch for 60 minutes (by default).
    # that prevents unmounting whatever device the git repo is on -- particularly problematic for ~/private.
    # i can disable gitstatusd and get slower fallback git queries:
    # - either universally
    # - or selectively by path
    # see: <https://github.com/romkatv/powerlevel10k/issues/246>
    typeset -g POWERLEVEL9K_VCS_DISABLED_DIR_PATTERN='(/home/colin/private/*|/home/colin/knowledge/*)'
    # typeset -g POWERLEVEL9K_DISABLE_GITSTATUS=true

    # show user@host also when logged into the current machine.
    # default behavior is to show it only over ssh.
    typeset -g POWERLEVEL9K_CONTEXT_{DEFAULT,SUDO}_CONTENT_EXPANSION='$P9K_CONTENT'
  '';

  prezto-init = ''
    source ${pkgs.zsh-autosuggestions}/share/zsh-autosuggestions/zsh-autosuggestions.zsh
    source ${pkgs.zsh-syntax-highlighting}/share/zsh-syntax-highlighting/zsh-syntax-highlighting.zsh
    source ${pkgs.zsh-prezto}/share/zsh-prezto/init.zsh
  '';
in
{
  sane.user.persist.plaintext = [
    # we don't need to full zsh dir -- just the history file --
    # but zsh will sometimes backup the history file and we get fewer errors if we do proper mounts instead of symlinks.
    # TODO: should be private?
    ".local/share/zsh"
    # cache gitstatus otherwise p10k fetched it from the net EVERY BOOT
    ".cache/gitstatus"
  ];

  # zsh/prezto complains if zshrc doesn't exist; but it does allow an "empty" file.
  sane.user.fs.".config/zsh/.zshrc" = sane-lib.fs.wantedText "# ";

  # enable zsh completions
  environment.pathsToLink = [ "/share/zsh" ];

  programs.zsh = {
    enable = true;
    histFile = "$HOME/.local/share/zsh/history";
    shellAliases = {
      ":q" = "exit";
      # common typos
      "cd.." = "cd ..";
      "cd../" = "cd ../";
    };
    setOptions = [
      # defaults:
      "HIST_IGNORE_DUPS"
      "SHARE_HISTORY"
      "HIST_FCNTL_LOCK"
      # disable `rm *` confirmations
      "rmstarsilent"
    ];

    # .zshenv config:
    shellInit = ''
      ZDOTDIR=$HOME/.config/zsh
    '';

    # .zshrc config:
    interactiveShellInit =
      (builtins.readFile ./p10k.zsh)
    + p10k-overrides
    + prezto-init
    + ''
      # zmv is a way to do rich moves/renames, with pattern matching/substitution.
      # see for an example: <https://filipe.kiss.ink/zmv-zsh-rename/>
      autoload -Uz zmv

      HISTORY_IGNORE='(sane-shutdown *|sane-reboot *|rm *)'

      # extra aliases
      # TODO: move to `shellAliases` config?
      function nd() {
        mkdir -p "$1";
        pushd "$1";
      }

      # auto-cd into any of these dirs by typing them and pressing 'enter':
      hash -d 3rd="/home/colin/dev/3rd"
      hash -d dev="/home/colin/dev"
      hash -d knowledge="/home/colin/knowledge"
      hash -d nixos="/home/colin/nixos"
      hash -d nixpkgs="/home/colin/dev/3rd/nixpkgs"
      hash -d ref="/home/colin/ref"
      hash -d secrets="/home/colin/knowledge/secrets"
      hash -d tmp="/home/colin/tmp"
      hash -d uninsane="/home/colin/dev/uninsane"
      hash -d Videos="/home/colin/Videos"
    '';

    syntaxHighlighting.enable = true;
    vteIntegration = true;
  };

  # enable a command-not-found hook to show nix packages that might provide the binary typed.
  programs.nix-index.enable = true;
  programs.command-not-found.enable = false;  #< mutually exclusive with nix-index

  # prezto = oh-my-zsh fork; controls prompt, auto-completion, etc.
  # see: https://github.com/sorin-ionescu/prezto
  # i believe this file is auto-sourced by the prezto init.zsh script.
  sane.user.fs.".config/zsh/.zpreztorc" = sane-lib.fs.wantedText ''
    zstyle ':prezto:*:*' color 'yes'

    # modules (they ship with prezto):
    # ENVIRONMENT: configures jobs to persist after shell exit; other basic niceties
    # TERMINAL: auto-titles terminal (e.g. based on cwd)
    # EDITOR: configures shortcuts like Ctrl+U=undo, Ctrl+L=clear
    # HISTORY: `history-stat` alias, setopts for good history defaults
    # DIRECTORY: sets AUTO_CD, adds `d` alias to list directory stack, and `1`-`9` to cd that far back the stack
    # SPECTRUM: helpers for term colors and styling. used by prompts? might be unnecessary
    # UTILITY: configures aliases like `ll`, `la`, disables globbing for things like rsync
    #   adds aliases like `get` to fetch a file. also adds `http-serve` alias??
    # COMPLETION: tab completion. requires `utility` module prior to loading
    # TODO: enable AUTO_PARAM_SLASH
    zstyle ':prezto:load' pmodule \
      'environment' \
      'terminal' \
      'editor' \
      'history' \
      'directory' \
      'spectrum' \
      'utility' \
      'completion' \
      'prompt'

    # default keymap. try also `vicmd` (vim normal mode, AKA "cmd mode") or `vi`.
    zstyle ':prezto:module:editor' key-bindings 'emacs'

    zstyle ':prezto:module:prompt' theme 'powerlevel10k'

    # disable `mv` confirmation (and `rm`, too, unfortunately)
    zstyle ':prezto:module:utility' safe-ops 'no'
  '';
}