From 8c5c61656fdd7c00c695dc883dd6f5c74dd1f20a Mon Sep 17 00:00:00 2001
From: attila <attila@haqistan.net>
Date: Thu, 23 Sep 2021 11:16:23 -0500
Subject: [PATCH] Greatly improve UX when the list does not fit in the tmux
 pane (which is almost always).  We scroll the list of folders with new mail
 slowly up and down once before pausing, and we pause for much less time if we
 have done that (because it takes a while).

The pauses are all hard-coded as are the tput sequences... but then
nobody but me even knows this exists, so meh.
---
 foldercheck | 173 ++++++++++++++++++++++++++++++++++++++++++++++------
 1 file changed, 156 insertions(+), 17 deletions(-)

diff --git a/foldercheck b/foldercheck
index 717155e..119a600 100755
--- a/foldercheck
+++ b/foldercheck
@@ -4,12 +4,46 @@
 # sometimes so it must conform itself to its current size to look
 # respectable.
 
-alias my=typeset
-# pirate version:
-# alias me=typeset
+ORIG_CMD="$0 $*"
 
-sleep=$1
+MBLAZE=${MBLAZE-$HOME/.mblaze}
+profile="$MBLAZE/profile"
+
+date_fmt=$(mhdr -h FolderCheckDateFmt $profile)
+[ -z "$date_fmt" ] && date_fmt="%Y-%m-%d %H:%M"
+sleep=$(mhdr -h FolderCheckSleep $profile)
 [ -z "$sleep" ] && sleep=30
+default_sleep=$sleep
+
+TEMPFILES=""
+
+if [ $# -gt 0 ]; then
+	sleep=$1
+	shift
+fi
+
+################################################
+
+remember_tempfile () {
+	local fn=$1
+	case $TEMPFILES in
+		*${fn}*) ;;
+		*) TEMPFILES="${TEMPFILES} $fn" ;;
+	esac
+}
+
+forget_tempfile () {
+	local fn=$1
+	TEMPFILES=$(echo $TEMPFILES | perl -lpe "s,${fn},,gs; s,^\s+,,; s,\s+\$,,;")
+}
+
+ts () {
+	date +"$date_fmt"
+}
+
+debug () {
+	echo "$(ts) DEBUG: $*" 1>&2
+}
 
 stty_size_field () {
 	stty -a | perl -lne '/(\d+)\s+'$1'/ && print qq|$1\n|'
@@ -24,7 +58,7 @@ tty_cols () {
 }
 
 center_msg () {
-	my x y str mid_len
+	local x y str mid_len
 	str="$*"
 	mid_len=${#str}
 	mid_len=$(expr $mid_len / 2)
@@ -40,47 +74,152 @@ center_msg () {
 	tput sgr0 civis
 }
 
+count_file_lines () {
+	wc -l $1 | awk '{print $1}'
+}
+
+# ticker-tape-style file display in a potentially small window
+# if the output of rs doesn't fit nicely in the window, we
+# scroll it slowly down and then back up.
+# note: all this tput'ery works in a small tmux pane on OpenBSD, which
+# is where I run this... YMMV
+
+had=0
+display_file () {
+	local fn=$1 cols=$(tty_cols) rows=$(tty_rows) n=0 rs nlines thee_sleep=$sleep
+	[ -z "$cols" ] && cols=$COLUMNS
+	[ -z "$rows" ] && rows=$ROWS
+	tput clear
+	nlines=$(count_file_lines $fn)
+	if [ $nlines -eq 0 ]; then
+		center_msg '~no mail~'
+		had=0
+		return 0
+	fi
+	had=1
+	rs=${fn}.rs.txt
+	rs -e -w$cols <$fn >$rs
+	remember_tempfile $rs
+	n=$(count_file_lines $rs)
+	# suss out title
+	local title="~ $nlines w/new mail ~" mid_len x
+	mid_len=${#title}
+	mid_len=$(expr $mid_len / 2)
+	x=$(expr $cols / 2)
+	x=$(expr $x - $mid_len)
+	if [ $x -gt 0 ]; then
+		x=$(expr $x - 1)
+		title=$(printf %${x}s%s " " "$title")
+	fi
+	# looks purty
+	tput bold
+	echo "$title"
+	# sgr0=cancel effects(bold), sc=save position
+	tput sgr0 sc
+	if [ $n -lt $(expr $rows - 1) ]; then
+		cat $rs
+	else
+		local rm1=$(expr $rows - 2) r=0
+		local last=$(expr $n - $rm1)
+		# scroll the list forward slowly
+		while [ $r -le $last ]; do
+			# rc=return to saved position
+			# ed=clear to end of screen
+			tput rc ed
+			if [ $r -eq 0 ]; then
+				head -$rm1 $rs
+			else
+				sed -e "1,${r}d" <$rs | head -$rm1
+			fi
+			sleep 2
+			thee_sleep=$(expr $thee_sleep - 2)
+			r=$(expr $r + 1)
+		done
+		sleep 1 # pause between
+		thee_sleep=$(expr $thee_sleep - 1)
+		r=$(expr $r - 1)
+		while [ $r -ge 0 ]; do
+			tput rc ed
+			if [ $r -eq 0 ]; then
+				head -$rm1 $rs
+			else
+				sed -e "1,${r}d" <$rs | head -$rm1
+			fi
+			sleep 2
+			thee_sleep=$(expr $thee_sleep - 2)
+			r=$(expr $r - 1)
+		done
+		case $thee_sleep in
+			-*) thee_sleep="" ;;
+			*)
+				if [ $thee_sleep -gt 5 ]; then
+					thee_sleep=2
+				fi
+				;;
+		esac
+	fi
+	forget_tempfile $rs
+	rm -f $rs
+	sleep=$thee_sleep
+}
+
 check () {
-	my cols had=0 tmpf=$1
+	local cols tmpf=$1
 	cols=$(tty_cols)
 	[ -z "$cols" ] && cols=$COLUMNS
 	[ $had -eq 0 ] && center_msg '~looking...~'
 	mnewdirs > ${tmpf}
 	if [ ! -s "$tmpf" ]; then
+		tput clear
 		center_msg '~no unread mail~'
 		had=0
+		sleep=$default_sleep
 	else
-		[ $had -eq 0 ] && tput clear
-		cat ${tmpf} | rs -e -w$cols
-		had=1
+		display_file $tmpf
 	fi
 }
 
 sleeper_pid=0
 
 shleep () {
-	sleep $1 & sleeper_pid=$!
+	local secs=$1
+	sleep $secs & sleeper_pid=$!
 	wait $sleeper_pid 2>/dev/null
 	sleeper_pid=0
 }
 
 wakeup () {
-	[ $sleeper_pid -ne 0 ] && kill $sleeper_pid && wait $sleeper_pid
+	[ $sleeper_pid -ne 0 ] && \
+		kill $sleeper_pid >/dev/null 2>&1 && \
+		wait $sleeper_pid
+	sleep=0
 }
 
-tmpf=${TMPDIR-/tmp}/foldercheck.$$
+restart () {
+	tput clear sgr0 cvvis
+	exec $ORIG_CMD
+}
 
 interrupted () {
 	wakeup
+	if [ -n "$TEMPFILES" ]; then
+		echo "$(ts) cleaning up tempfiles: $TEMPFILES"
+		rm -rf $TEMPFILES
+	fi
 	rm -f ${tmpf}
-	reset
+	tput sgr0 cvvis
+	echo ''
+	echo "$(ts) exiting ..."
 	exit 1
 }
 
-trap 'interrupted' INT TERM QUIT
-trap 'wakeup' INFO WINCH
+trap 'interrupted' INT TERM
+trap 'wakeup; restart' INFO WINCH QUIT
+
+tmpf=${TMPDIR-/tmp}/foldercheck.$$
 
 while true; do
-	check ${tmpf}
-	shleep ${sleep}
+	check $tmpf
+	[[ -n "$sleep" ]] && shleep $sleep
+	sleep=$default_sleep
 done