From ffb28bb11a6bd6d6a5addeb2a3732d535b71b18a Mon Sep 17 00:00:00 2001
From: Daniel Langbein <daniel@systemli.org>
Date: Wed, 4 Sep 2024 22:12:26 +0200
Subject: [PATCH] print info during boot

---
 modules/base.nix                |   2 +
 modules/initrd-contact-info.nix | 119 ++++++++++++++++++++++++++++++++
 2 files changed, 121 insertions(+)
 create mode 100644 modules/initrd-contact-info.nix

diff --git a/modules/base.nix b/modules/base.nix
index 7983838..8633ca9 100644
--- a/modules/base.nix
+++ b/modules/base.nix
@@ -5,6 +5,8 @@
     ./dns.nix
     # Nix garbage collection.
     ./nix-gc.nix
+    # Display contact information during boot.
+    ./initrd-contact-info.nix
   ];
 
   # Firmware.
diff --git a/modules/initrd-contact-info.nix b/modules/initrd-contact-info.nix
new file mode 100644
index 0000000..60d15c8
--- /dev/null
+++ b/modules/initrd-contact-info.nix
@@ -0,0 +1,119 @@
+# Display contact information during boot. https://discourse.nixos.org/t/display-contact-info-in-nixos-boot-stage-1/38118/4
+
+{ config, pkgs, lib, ... }:
+let
+  contact_name = "Daniel Langbein";
+  # TODO: move phone number to secret file
+  contact_phone = "+49 xxx yyy";
+  contact_mail = "daniel@systemli.org";
+
+  # https://wiki.nixos.org/wiki/Shell_Scripts
+  contact-info-str = pkgs.stdenv.mkDerivation rec {
+    name = "Contact information string";
+    # disable unpackPhase etc
+    phases = "buildPhase";
+    builder = pkgs.writeShellScript "builder.sh" ''
+      set -eu -o pipefail
+      echo -e "If found, please contact:\n${contact_name}\n${contact_phone}\n${contact_mail}" \
+      | cowsay --bold --aurora -f dragon > $out
+    '';
+    nativeBuildInputs = with pkgs; [ coreutils neo-cowsay ];
+    PATH = lib.makeBinPath nativeBuildInputs;
+  };
+
+  contact-info-img = pkgs.stdenv.mkDerivation rec{
+    name = "Contact information image";
+    nativeBuildInputs = with pkgs; [ imagemagick liberation_ttf ];
+    phases = "installPhase";
+    # magick add label: https://imagemagick.org/Usage/text/#label
+    # magick font list: magick -list font | grep Font
+    installPhase = ''
+      set -eu -o pipefail
+      mkdir -p $out
+      #export XDG_CACHE_HOME="$out/.cache"
+      magick -background black -fill 'hsb(120, 255,   63.75)' -font ${pkgs.liberation_ttf}/share/fonts/truetype/LiberationSans-Regular.ttf -pointsize 92 'label:If found, please contact:\n${contact_name}\n${contact_phone}\n${contact_mail}' $out/img.png
+    '';
+  };
+in
+{
+  # Plymouth boot splash screen.
+  # TODO: Only on graphical installations!
+  #
+  # To see the splash screen. https://wiki.archlinux.org/title/Plymouth#Installation
+  #boot.kernelParams = [ "splash" ];
+  #
+  boot.plymouth = lib.mkIf (config.boot.initrd.systemd.enable) {
+    enable = true;
+    #theme = "breeze";
+    logo = "${contact-info-img}/img.png";
+  };
+
+  # Print contact info as text during boot.
+  boot.initrd.preDeviceCommands = lib.mkIf (! config.boot.initrd.systemd.enable) ''
+    cat <<'EOF'
+    ${builtins.readFile contact-info-str}
+    EOF
+  '';
+
+# TODO: cleanup
+
+#
+# TODO: systemd service output is not displayed during boot. onyl [info] service xxx started
+#
+
+#  # https://github.com/oxalica/nixpkgs/blob/3562c1d5c6ff868924fe95ba7b51344f3c141311/nixos/modules/config/console.nix#L158
+#  boot.initrd.systemd.storePaths = [
+#    "${config.boot.initrd.systemd.package.kbd}/bin/some-foo-package"
+#  ];
+#
+#  boot.initrd.systemd.services."If-found-please-send-email-to___${mail}___" = lib.mkIf (config.boot.initrd.systemd.enable) {
+#    description = "Display part of the contact information inside service name";
+#    wantedBy = [ "initrd.target" ];
+#    after = [ "systemd-vconsole-setup.service" ];
+#    before = [ "cryptsetup-pre.target" "local-fs-pre.target" ];
+#    unitConfig.DefaultDependencies = "no";
+#    serviceConfig.Type = "oneshot";
+#    script = ''
+#      wall TESTING-SOMETHING-OUT
+#    '';
+#  };
+#
+#  # Soruces:
+#  # - https://discourse.nixos.org/t/zfs-rollback-not-working-using-boot-initrd-systemd/37195/3
+#  # - https://github.com/cole-h/nixos-config/blob/26f77d5d24e5859a1bb690cff63371d1ebf7d707/hosts/nixos/scadrial/modules/boot/remote-unlock.nix#L57-L69
+#  boot.initrd.systemd.services."contact-info" = lib.mkIf (config.boot.initrd.systemd.enable) {
+#    description = "Display contact information";
+#    wantedBy = [
+#      "initrd.target"
+#    ];
+#    after = [
+#      "systemd-vconsole-setup.service"
+#    ];
+#    before = [
+#      # Flowchart displaying the ordering of targets: https://www.freedesktop.org/software/systemd/man/latest/bootup.html
+#      #   cryptsetup-pre.target and local-fs-pre.target don't depend on each other but are instead orthogonal
+#
+#      # This passive target unit may be pulled in by services that want to run before any encrypted block device is set up.
+#      # https://www.freedesktop.org/software/systemd/man/systemd.special#cryptsetup-pre.target
+#      "cryptsetup-pre.target"
+#
+#      # This target unit is automatically ordered before all local mount points marked with auto.
+#      # https://www.freedesktop.org/software/systemd/man/systemd.special#local-fs-pre.target
+#      "local-fs-pre.target"
+#
+#      # If the root device can be mounted at /sysroot, the sysroot.mount unit becomes active and initrd-root-fs.target is reached.
+#      # https://man7.org/linux/man-pages/man7/bootup.7.html
+#      #"sysroot.mount"
+#    ];
+##    path = with pkgs; [
+##      neo-cowsay
+##    ];
+#    unitConfig.DefaultDependencies = "no";
+#    serviceConfig.Type = "oneshot";
+#    script = ''
+#      cat <<'EOF'
+#      ${builtins.readFile contact-info-str}
+#      EOF
+#    '';
+#  };
+}