dot-tangle

#!/bin/env bash
# Following script installs and tangles literate dotfiles written in Org mode.


# Directory which contains dotfiles (same even with =sudo=):
if [ -v SUDO_USER ]; then
    HOME=$(eval echo "~$SUDO_USER")
fi

DOTFILES_HOME=$HOME/.dotfiles


# Following function Exports Org file to another Org file.
# Exporting is needed because =#+INCLUDE= isn't executed during tangling.
emacs_export_to_org() {
    emacs -Q --batch --eval "
        (progn
          (setq make-backup-files nil)
          (dolist (file command-line-args-left)
            (with-current-buffer
              (find-file-noselect file)
              (org-org-export-to-org)
            )
          )
        )" "$1"
}

# Following function decrypts entries encrypted by =org-crypt=.
# It is required to set =<<crypt_key>>= in file secrets.org;
# same key must be used for encryption of Org entries.
emacs_decrypt_entries() {
    emacs -Q --batch --eval "
        (progn
          (require 'org-crypt)
          (require 'epa-file)
          (epa-file-enable)
          (setq org-crypt-key \"9C4E20813A852D1F\")
          (setf epa-pinentry-mode 'ask)
          (setq make-backup-files nil)
          (dolist (file command-line-args-left)
            (with-current-buffer
              (find-file-noselect file)
              (org-decrypt-entries)
              (save-buffer)
            )
          )
        )" "$1"
}

# Following function tangles all specified Org files.
emacs_tangle() {
    emacs -Q --batch --eval "
        (progn
          (setq make-backup-files nil)
          (dolist (file command-line-args-left)
            (with-current-buffer
              (find-file-noselect file)
              (org-babel-tangle)
            )
          )
        )" "$1"
}


# Export all Org files matching passed arguments except the files in the root directory:
FILES=$(find "$DOTFILES_HOME/$*" -path "$DOTFILES_HOME/[!.]*/*.org")
emacs_export_to_org "$FILES"

# Decrypt exported files.
# It is required to drop =sudo= privileges; otherwise files are not decrypted correctly.
EXPORTED_FILES=${FILES//'.org'/.org.org}
if [ -v SUDO_USER ]; then
    chown "$SUDO_USER" "$EXPORTED_FILES"
    sudo -u "$SUDO_USER" bash -c "$(declare -f emacs_decrypt_entries); emacs_decrypt_entries $EXPORTED_FILES"
else
    emacs_decrypt_entries "$EXPORTED_FILES"
fi

# Tangle exported files.
emacs_tangle "$EXPORTED_FILES"

# Delete exported files.
rm "$EXPORTED_FILES"

exit 0