From 5ef33b04f8672513023dbacdd5e007a1b19a3338 Mon Sep 17 00:00:00 2001
From: Steven Baltakatei Sandoval <baltakatei@gmail.com>
Date: Sun, 28 Jun 2020 20:30:50 +0000
Subject: [PATCH] feat(unitproc):Add error codes to secondsUntilMidnight

---
 unitproc/bktemp-secondsUntilMidnight | 38 +++++++++++++++++++++++-----
 1 file changed, 32 insertions(+), 6 deletions(-)

diff --git a/unitproc/bktemp-secondsUntilMidnight b/unitproc/bktemp-secondsUntilMidnight
index e71b2fd..954afa5 100644
--- a/unitproc/bktemp-secondsUntilMidnight
+++ b/unitproc/bktemp-secondsUntilMidnight
@@ -1,14 +1,19 @@
 #!/bin/bash
-
 # Desc: Template to check that apps, files, or dirs exist.
-# Author: Steven Baltaktei Sandoval
-# License: GPLv3+
+# Author: Steven Baltaktei Sandoval; License: GPLv3+
 
 #==BEGIN Define script parameters==
 #===BEGIN Declare local script functions===
+yell() { echo "$0: $*" >&2; } # Yell, Die, Try Three-Fingered Claw technique; # Ref/Attrib: https://stackoverflow.com/a/25515370
+die() { yell "$*"; exit 111; }
+try() { "$@" || die "cannot $*"; }
 timeUntilMidnight(){
     # Desc: Report seconds until midnight
-    # Output: stdout: seconds until midnight
+    # Output: stdout: integer seconds until midnight
+    # Output: exit code 0 if stdout > 0; 1 if stdout = 0; 2 if stdout < 0
+    # Usage: timeUntilMidnight
+    # Usage: if ! myTTL="$(timeUntilMidnight)"; then yell "ERROR in if statement"; exit 1; fi
+    local returnState
     TIME_CURRENT="$(date --iso-8601=seconds)" ; # Produce `date`-parsable current timestamp with resolution of 1 second.
     TIME_CURRENT_SHORT="$(date -d "$TIME_CURRENT" +%Y%m%dT%H%M%S%z)" # Produce separator-less current timestamp with resolution 1 second.
     DATE_CURRENT="$(date -d "$TIME_CURRENT" --iso-8601=date)" ; # Produce `date`-parsable current timestamp with resolution of 1 day.
@@ -16,12 +21,33 @@ timeUntilMidnight(){
     DATE_TOMORROW="$(date -d "$TIME_CURRENT next day" --iso-8601=date)" ; # Produce timestamp of tomorrow's date (res. 1 day).
     TIME_NEXT_MIDNIGHT="$(date -d "$DATE_TOMORROW" --iso-8601=seconds)" ; # Produce `date`-parsable timestamp of closest future midnight (res. 1 second).
     SECONDS_UNTIL_NEXT_MIDNIGHT="$(( $(date +%s -d "$TIME_NEXT_MIDNIGHT") - $(date +%s -d "$TIME_CURRENT") ))" ; # Calculate seconds until closest future midnight (res. 1 second).
-    echo "$SECONDS_UNTIL_NEXT_MIDNIGHT" 2>/dev/null;
+    if [[ "$SECONDS_UNTIL_NEXT_MIDNIGHT" -gt 0 ]]; then
+	returnState="true";
+    elif [[ "$SECONDS_UNTIL_NEXT_MIDNIGHT" -eq 0 ]]; then
+	returnState="WARNING_ZERO";
+	yell "WARNING:Reported time until midnight exactly zero.";
+    elif [[ "$SECONDS_UNTIL_NEXT_MIDNIGHT" -lt 0 ]]; then
+	returnState="WARNING_NEGATIVE";
+	yell "WARNING:Reported time until midnight is negative.";
+    fi
+
+    try echo "$SECONDS_UNTIL_NEXT_MIDNIGHT"; # Report
+    
+    #===Determine function return code===
+    if [[ "$returnState" = "true" ]]; then
+	return 0;
+    elif [[ "$returnState" = "WARNING_ZERO" ]]; then
+	return 1;
+    elif [[ "$returnState" = "WARNING_NEGATIVE" ]]; then
+	return 2;
+    fi
 } # Report seconds until next midnight
 #===END Declare local script functions===
 #==END Define script parameters==
 
 
 #==BEGIN sample code==
-echo "Time until next midnight (seconds):$(timeUntilMidnight)"
+try echo "Time until next midnight (seconds):$(timeUntilMidnight)" # simple report
+
+if ! myTTL="$(timeUntilMidnight)"; then yell "ERROR in if statement for myTTL:$myTTL"; exit 1; fi # Use of exit code to exit early if time <= 0.
 #==END sample code==
-- 
2.30.2