dotfiles/.config/shell/bin/sleep-until

#!/bin/bash
# Usage: sleep-until <time>
# Ex: sleep-until 3:00 pm

DRY="${DRY:-false}"

if [ -n "$1" ] && date --date="$*" > /dev/null 2>&1; then
   # Calculate the time in seconds to sleep by subtracting the future time from the current time
   SLEEP_TIME="$(( $(date -f - +%s- <<< "$*"$'\nnow') 0 ))"
   if [ "$SLEEP_TIME" -gt 0 ]; then
      if ! "$DRY"; then
         echo "Sleeping until:  $(date --date="$*")  (${SLEEP_TIME}s)"
         sleep "$SLEEP_TIME"
      else
         echo "$SLEEP_TIME"
      fi
   else
      echo "Error: input date '$*' is in the past" >&2
      echo "Sadly, you cannot sleep to a time in the past" >&2
      exit 1
   fi
else
   echo "Error: input date '$*' is invalid" >&2
   echo "Please input a valid date" >&2
   exit 1
fi