tools: added error handler to timer

.local/bin/tools/timer

@@ -0,0 +1,52 @@
+#!/bin/sh
+
+help="""
+usage: timer [option] [args]
+  options:
+    -c SECONDS      Count down from given amount of seconds
+    -s              Start stopwatch
+    -h              Display this message
+"""
+
+max_seconds=86400
+
+countdown() {
+    start="$(( $(date '+%s') + $1))"
+    while [ $start -ge $(date +%s) ]; do
+        time="$(( $start - $(date +%s) ))"
+        if [ $time -ge $max_seconds ]; then
+            echo "Maximum number of seconds ($max_seconds) for countdown surpassed."
+            exit
+        fi
+        printf '%s\r' "$(date -u -d "@$time" +%H:%M:%S)"
+        sleep 0.1
+    done
+}
+
+stopwatch() {
+    start=$(date +%s)
+    while true; do
+        time="$(( $(date +%s) - $start))"
+        printf '%s\r' "$(date -u -d "@$time" +%H:%M:%S)"
+        if [ $time -ge $max_seconds ]; then
+            echo "Maximum number of seconds ($max_seconds) reached."
+            exit
+        fi
+        sleep 0.1
+    done
+}
+
+no_args="true"
+while getopts "c:sh" arg; do
+  case $arg in
+    c) countdown $OPTARG;;
+    s) stopwatch;;
+    h) echo "$help";;
+    *) echo "$help";;
+  esac
+  no_args="false"
+done
+
+if [ "$no_args" = "true" ]; then
+    echo "$help"
+fi