dotfiles.nix/home/fish.nix

{ pkgs, lib, ... }:
let
  nixConfigDirectory = "~/dotfiles.nix";
in
{
  programs.fish = {
    enable = true;

    # see flake.nix and pkgs/default.nix
    plugins = pkgs.fishPlugins.flakePlugins;

    functions =
      {
        # user functions
        mkdcd = {
          argumentNames = [ "target" ];
          body = ''
            if test -z "$target"
              echo "mkdcd requires an argument" 1>&2
              return 1
            end
            mkdir -p $target
            cd $target
          '';
        };

        from-dir = {
          argumentNames = [ "dir" ];
          body = ''
            pushd $dir
            set -e argv[1]
            $argv
            popd
          '';
        };

        darwin-rebuild-edit-with = {
          argumentNames = [
            "editor"
            "file"
          ];
          body = ''
            if test -z "$file"
              set file flake.nix
            end
            from-nix $editor $file
          '';
        };

        # TODO: use these to implement !! and .. abbreviations
        # blocked on additional support for abbr in home-manager
        # https://github.com/nix-community/home-manager/issues/3706
        #
        # taken from
        # https://fishshell.com/docs/current/relnotes.html#fish-3-6-0-released-january-7-2023
        # last-history-item.body = ''
        #   echo $history[1]
        # '';
        # multi-cd.body = ''
        #   echo cd (string repeat -n (math (string length -- $argv[1]) - 1) ../)
        # '';
      }
      // lib.optionalAttrs pkgs.stdenv.isDarwin {
        # light/dark mode helpers
        # determine if dark mode is active
        is-dark-mode.body = ''
          defaults read -g AppleInterfaceStyle &>/dev/null
        '';

        # toggles `$term_background` between "light" and "dark". other Fish functions trigger when this
        # variable changes. we use a universal variable so that all instances of Fish have the same
        # value for the variable.
        toggle-background.body = ''
          if test "$term_background" = light
            set -U term_background dark
          else
            set -U term_background light
          end
        '';

        # set `$term_background` based on whether macOS is light or dark mode
        set-background-to-macOS.body = ''
          if is-dark-mode
            set -U term_background dark
          else
            set -U term_background light
          end
        '';

        # set `$term_background` based on an env var
        set-background-to-env = {
          argumentNames = [ "env_var" ];
          body = ''
            switch $$env_var
            case 1
              echo "Setting dark mode"
              set -U term_background dark
            case 0
              echo "Setting light mode"
              set -U term_background light
            end
          '';
        };

        # sets shell utilities to light or dark colorscheme based on `$term_background`.
        set-shell-colors = {
          body = ''
            # Use correct theme for `btm` and `bat`
            if test "$term_background" = light
              alias btm "btm --color nord-light"
              set -xg BAT_THEME OneHalfLight
            else
              alias btm "btm --color nord"
              set -xg BAT_THEME OneHalfDark
            end
            # Set LS_COLORS
            set -xg LS_COLORS (${pkgs.vivid}/bin/vivid generate one-$term_background)
          '';
          onVariable = "term_background";
        };
      };

    shellAbbrs =
      {
        ".." = "cd ..";

        # darwin-rebuild build
        drb = "from-nix darwin-rebuild build --flake .";
        # darwin-rebuild switch full
        drsf = "from-nix darwin-rebuild switch --flake .";
        # darwin-rebuild switch (no homebrew)
        drs = "from-nix darwin-rebuild switch --flake . --override-input homebrew-enabled github:boolean-option/false";
        # edit darwin-rebuild config in helix
        drh = "darwin-rebuild-edit-with hx";
        # edit darwin-rebuild config in zed
        drz = "zed ${nixConfigDirectory}";

        nb = "nix build";
        nd = "nix develop";
        nf = "nix flake";
        nfc = "nix flake check";
        nfi = "nix flake init";
        nfs = "nix flake show";
        nfu = "nix flake update";
        nr = "nix run";
        ns = "nix search nixpkgs";
        nsh = "nix shell";
        nrp = "nix repl --expr '{ pkgs = (import <nixpkgs> { }); }'";
        g = "git";
        ga = "git add";
        gc = "git commit";
        gd = "git diff";
        gl = "git log";
        gp = "git push";
        stage = "git add .";
        commit = "git commit";
        push = "git push";
        pull = "git pull";
      }
      // lib.optionalAttrs pkgs.stdenv.isDarwin {
        tb = "toggle-background";
        sb = "set-background-to-macOS";
      };

    shellAliases = {
      # nix related
      from-nix = "from-dir ${nixConfigDirectory}";

      # other
      ":q" = "exit";
      cat = "bat --style=plain --paging=never";
      du = "dust";
      http = "xh";
      https = "xhs";
      top = "btm";
      htop = "btm --basic";
      colortest = "terminal-colors -o";
    };

    # configuration that should be above `loginShellInit` and `interactiveShellInit`.
    shellInit = ''
      set -U fish_term24bit 1
      ${lib.optionalString pkgs.stdenv.isDarwin "set-background-to-macOS"}
    '';

    interactiveShellInit = ''
      set -g fish_greeting (set_color red)"(づ￣ ³￣)づ"(set_color yellow)" hello "(set_color blue)"(づ￣ ³￣)づ"(set_color normal)
      fish_vi_key_bindings
      ${lib.optionalString pkgs.stdenv.isDarwin "set-shell-colors"}
    '';
  };
  home.sessionVariables.VIRTUAL_ENV_DISABLE_PROMPT = "true";
}