mail: HACK mailcheck update

Update `mail-check` script to notify the user both of newly arrived
mail, and in case he has to enter his password to sync the mail.

HACK the paths and ways of finding out if passwords can be decrypted are
static and only applicable to my set up. This needs to be completely
revised and newly approached.

mail/.local/bin/mail-check

@@ -11,7 +11,11 @@
 # for more advanced, per-account/channel hooks, see
 # https://sourceforge.net/p/isync/feature-requests/8/
 
-MBSYNC_MAX_TRIES=3
+# available env vars:
+# MBSYNC_MAX_TRIES=3
+# MBSYNC_PRE="/bin/usr/cmd-to-run"
+# MBSYNC_POST="/bin/usr/cmd-to-run"
+# MBSYNC_NOTIFY=1
 
 prehook() {
   if [ -n "$MBSYNC_PRE" ]; then
@@ -26,8 +30,17 @@ posthook() {
     eval "$MBSYNC_POST"
     return 0
   fi
-  notmuch new --quiet 2>/dev/null
+
-  afew --tag --new
+  notmuch new 2>/dev/null
+  afew --tag --new -C "${XDG_CONFIG_HOME:-/home/marty/.config}/notmuch/config"
+  countnew
+}
+
+# use notmuch to index incoming mail and set the
+# correct number of mails if new ones arrived for notifications
+countnew() {
+  num=$(notmuch count tag:unread and tag:inbox)
+  HASMAIL="${num:-0}"
 }
 
 # fail the routine and optionally send a message why
@@ -37,7 +50,7 @@ fail() {
 }
 
 checkmail() {
-  mbsync -c "$XDG_CONFIG_HOME/isync/mbsyncrc" -a
+  mbsync -c "${XDG_CONFIG_HOME:-$HOME/.config}/isync/mbsyncrc" -a
 }
 
 checkonline() {
@@ -45,6 +58,30 @@ checkonline() {
   ping -c 1 "1.1.1.1" >/dev/null 2>/dev/null || fail "checkmail can not access the internet."
 }
 
+# warn user that he has to enter his password in a moment
+# to stop catching him offguard or entering something by accident
+checkwarnuser() {
+  agt=$(gpg2 --decrypt --no-tty --quiet --no-verbose --for-your-eyes-only --pinentry-mode cancel ~/.local/share/pass/misc/aerc-gmail-app-password.gpg 2>&1)
+  if echo "$agt" | grep -qE 'No secret key'; then
+    notify "Mail: Password phrase needed!"
+    sleep 2.5
+  fi
+}
+
+# send out a notification on new mail, to libnotify and stdout
+notifymail() {
+  [ "${MBSYNC_NOTIFY:-1}" -eq 0 ] && return
+
+  if [ "${HASMAIL:-0}" -gt 0 ]; then
+    notify "($HASMAIL) new mail"
+  fi
+}
+
+notify() {
+  command -v notify-send >/dev/null && notify-send "$@"
+  echo "$@"
+}
+
 # Routine start
 
 # check
@@ -56,6 +93,8 @@ if [ "$1" = "raw" ]; then
 fi
 
 main() {
+  checkwarnuser
+
   prehook
 
   tries=0
@@ -65,13 +104,15 @@ main() {
     fi
 
     tries=$((tries + 1))
-    if [ $tries -gt $MBSYNC_MAX_TRIES ]; then
+    if [ $tries -gt "${MBSYNC_MAX_TRIES:-3}" ]; then
       fail "maximum retries reached without success."
     fi
   done
   unset tries
 
   posthook
+
+  notifymail
 }
 
 notmuch_foldertags() {
@@ -81,4 +122,3 @@ notmuch_foldertags() {
 }
 
 main
-notmuch_foldertags