From 6a06b1c14308dee4b44f67b6b88bcd6a43c92a76 Mon Sep 17 00:00:00 2001
From: Florian Schlegel <Florz@florz.net>
Date: Sat, 29 Aug 2020 18:39:01 +0200
Subject: [PATCH] implement basic caching

---
 departure.sh | 36 +++++++++++++++++++++++-------------
 1 file changed, 23 insertions(+), 13 deletions(-)

diff --git a/departure.sh b/departure.sh
index 64d97e9..bbb637b 100755
--- a/departure.sh
+++ b/departure.sh
@@ -148,6 +148,7 @@ get_cvag_station_name()
 	local -n _STATION_ID=$2
 
 	COMPLETE_STATION_LIST="$(curl --connect-timeout 5 -s "http://www.cvag.de/eza/mis/stations?minLat=0&maxLat=100&minLon=0&maxLon=100")"
+	[ -z "$(echo $COMPLETE_STATION_LIST | grep -oe "^{.*}$")" ] && return 1
 	for ((i=0; i<${#_STATION_ID[*]}; i++)); 	do
 		case ${_STATION_ID[$i]} in
 			""|*[!0-9]*)
@@ -161,6 +162,7 @@ get_cvag_station_name()
 	done
 }
 
+STATION_SCHEDULE=()
 get_cvag_station_info()
 {
 	local -n _STATION_STOPS=$2
@@ -170,11 +172,14 @@ get_cvag_station_info()
 	local -n _STATION_ACTUAL_DEPARTURE=$6
 	local -n _REALSTATION_NOW=$7
 	local -n _THISDATE=$8
+	_ERROR=0
 
-	STATION_SCHEDULE="$(curl --connect-timeout 5 -s "http://www.cvag.de/eza/mis/stops/station/CAG-${STATION_ID[$1]}")"
+	THIS_STATION_SCHEDULE="$(curl --connect-timeout 5 -s "http://www.cvag.de/eza/mis/stops/station/CAG-${STATION_ID[$1]}")"
+	[ ! -z "$(echo "$THIS_STATION_SCHEDULE" | grep -oe "^{.*}$")" ] && STATION_SCHEDULE[$1]=$THIS_STATION_SCHEDULE || _ERROR=1	# return data from cache
+	[ -z "$STATION_SCHEDULE[$1]" ] && _ERROR=2											# no data cached yet
 
-	_STATION_STOPS=$(echo "$STATION_SCHEDULE" | jq -r ".stops | .[]")
-	_STATION_NOW=$(echo "$STATION_SCHEDULE" | jq -r ".now")
+	_STATION_STOPS=$(echo "${STATION_SCHEDULE[$1]}" | jq -r ".stops | .[]")
+	_STATION_NOW=$(echo "${STATION_SCHEDULE[$1]}" | jq -r ".now")
 	_STATION_DESTINATIONS=($(echo -n "$_STATION_STOPS" | jq -r ".destination"))
 	_STATION_LINES=($(echo -n "$_STATION_STOPS" | jq -r ".line"))
 	_STATION_ACTUAL_DEPARTURE=($(echo -n "$_STATION_STOPS" | jq -r ".actualDeparture"))
@@ -183,6 +188,8 @@ get_cvag_station_info()
 	[ ${#REALSTATION_NOWMS} -lt 3 ] && REALSTATION_NOWMS="0$REALSTATION_NOWMS"
 	_REALSTATION_NOW=$(( "$_STATION_NOW" / 1000))
 	_THISDATE=$(date --date="@$_REALSTATION_NOW" +"%d.%m.%Y %T")",$REALSTATION_NOWMS"
+
+	return $_ERROR
 }
 
 draw_logo_time()
@@ -200,8 +207,8 @@ draw_logo_time()
 LOGO_LINES_POSITION=0
 STATION_NAME=()
 while true; do
-	[ ${#STATION_NAME[@]} -eq 0 ] && get_cvag_station_name STATION_NAME STATION_ID
-	if [ ${#STATION_NAME[@]} -eq 0 -o  -z "$(curl --connect-timeout 5 -s "http://www.cvag.de/eza/mis/stops/station/CAG-0" | grep -oe "^{.*}$")" ]; then
+	[ ${#STATION_NAME[*]} -eq 0 ] && get_cvag_station_name STATION_NAME STATION_ID
+	if [ ${#STATION_NAME[*]} -eq 0 ]; then
 		clear
 		echo -e "\\n\\n\\n\\tService unavailable!"
 		sleep 10
@@ -212,20 +219,23 @@ while true; do
 		for ((j=0; j<="${#STATION_ID[*]}"; j++)); do
 			if [ ! "$j" -eq "$LOGO_LINES_POSITION" ]; then
 				[ "$j" -gt "$LOGO_LINES_POSITION" ] && THIS_STATION_ID=$(($j-1)) || THIS_STATION_ID=$j
-				get_cvag_station_info $THIS_STATION_ID STATION_STOPS STATION_NOW STATION_DESTINATIONS STATION_LINES STATION_ACTUAL_DEPARTURE REALSTATION_NOW THISDATE
 
-				MYOUTPUT[$j]="${MYOUTPUT[$j]}\n\n\
+				get_cvag_station_info $THIS_STATION_ID STATION_STOPS STATION_NOW STATION_DESTINATIONS STATION_LINES STATION_ACTUAL_DEPARTURE REALSTATION_NOW THISDATE
+				STATION_INFO_ERR=$?
+				if [ ! $STATION_INFO_ERR -eq 2 ]; then		# FIXME: add warning, when STATION_INFO_ERR == 1
+					MYOUTPUT[$j]="${MYOUTPUT[$j]}\n\n\
 \t\t┌────────────────────────────────┬─────────────────────────┐ \n\
 \t\t│ ${STATION_NAME[$THIS_STATION_ID]}$(printf "%-$((31-${#STATION_NAME[$THIS_STATION_ID]}))s" "")│ $THISDATE │\n\
 \t\t├────────────────────┬─────┬─────┴─────────────────────────┤\n"
-				for ((i=0; i<"${#STATION_LINES[*]}"; i++)); do
-					MILLIS=$((${STATION_ACTUAL_DEPARTURE[$i]} - STATION_NOW)); [ "$MILLIS" -lt 0 ] && MILLIS=0
-					SEKS=$((MILLIS / 1000)); MILLIS=$((MILLIS % 1000)); MINS=$((SEKS / 60)); SEKS=$((SEKS % 60))
-					MYOUTPUT[$j]="${MYOUTPUT[$j]}\
+					for ((i=0; i<"${#STATION_LINES[*]}"; i++)); do
+						MILLIS=$((${STATION_ACTUAL_DEPARTURE[$i]} - STATION_NOW)); [ "$MILLIS" -lt 0 ] && MILLIS=0
+						SEKS=$((MILLIS / 1000)); MILLIS=$((MILLIS % 1000)); MINS=$((SEKS / 60)); SEKS=$((SEKS % 60))
+						MYOUTPUT[$j]="${MYOUTPUT[$j]}\
 \t\t│$(printf "%-$((3-${#MINS}))s" "")$MINS min $(printf "%-$((2-${#SEKS}))s" "")$SEKS,$(printf "%03d" $MILLIS) s    │ $(printf "%-$((3-${#STATION_LINES[$i]}))s" "")${STATION_LINES[$i]} │ ${STATION_DESTINATIONS[$i]}$(printf "%-$((29-${#STATION_DESTINATIONS[$i]}))s" "") │\\n"
-				done
-				MYOUTPUT[$j]="${MYOUTPUT[$j]}\
+					done
+					MYOUTPUT[$j]="${MYOUTPUT[$j]}\
 \t\t└────────────────────┴─────┴───────────────────────────────┘"
+				fi
 			fi
 		done
 		draw_logo_time LOGO_AND_TIME $REALSTATION_NOW