install-comments-hook

prepare() {
    PKGS_LOGPATH="/var/log/"
    PKGS_LOGFILE="/var/log/pacman-pkg-comments.log"
    [[ ! -d "$PKGS_LOGPATH" ]] && mkdir -p $PKGS_LOGPATH
    touch "$PKGS_LOGFILE"
    return 0
}

diff_packages() {
    while IFS= read -r PKG; do
        if [[ "$PKG" == \+* ]]; then
            PKGS_ADD+=(${PKG:1})
        else
            PKGS_DEL+=(${PKG:1})
        fi
    done < <(diff -U0 <(cut -d' ' -f1 "$PKGS_LOGFILE" | sort) \
                      <(pacman -Qeq | sort) | tail -n +3 | grep ^[^@])
    return 0
}

update_package_list() {
    # Append newly installed packages
    if [[ ${#PKGS_ADD[@]} -ne 0 ]]; then
        printf '%s\n' "${PKGS_ADD[@]}" >> "$PKGS_LOGFILE"
    fi
    # Remove entries of uninstalled packages
    for PKG_DEL in "${PKGS_DEL[@]}"
    do
        sed -i "/^${PKG_DEL}\(\s\+\|$\)/d" "$PKGS_LOGFILE"
    done
    sort "$PKGS_LOGFILE" -o "$PKGS_LOGFILE"
    return 0
}

add_comments() {
    if [[ ${#PKGS_ADD[@]} -eq 0 ]]; then
        return 0
    fi
    # Is nvim/vim/vi available?
    VEDITOR=$(command -v nvim || command -v vim || command -v vi)
    if [[ -f "$VEDITOR" ]]; then
        SEPARATOR="\|"
        PATTERN="$(printf "${SEPARATOR}^%s\(\s\+\|$\)" "${PKGS_ADD[@]}")"
        # Trim the separator at the beginning of the string
        PATTERN="${PATTERN:${#SEPARATOR}}"
        EXCMD="set expandtab softtabstop=4 tabstop=4 shiftwidth=4"
        # Let vi search for the newly installed packages, redirect I/O to terminal
        $VEDITOR -c "$EXCMD" +/"$PATTERN" "$PKGS_LOGFILE" < /dev/tty > /dev/tty
    else
        echo -e "\033[1;33mwarning:\033[0m vi not available -- add comments to ${PKGS_LOGFILE} manually"
    fi
    return 0
}

prepare
diff_packages
update_package_list
add_comments

# vim: set et ft=sh sts=4 ts=4 sw=4 :