#!/bin/bash

# autoreply.sh
#
# This script sends a canned email response to those who've errone-
# ously emailed me at <amcooper@gmail.com>. Once I've manually
# tagged those emails `misdirected`, it iterates over those emails and
# responds.

set -euo pipefail

if [[ -z "$(notmuch search tag:misdirected)" ]] ; then
  echo "[autoreply.sh] Currently no emails are tagged 'misdirected'. Exiting..."
  exit 1
fi

# This weird feed-find-output-into-while-loop comes from
# https://github.com/koalaman/shellcheck/wiki/SC2044#correct-code
while IFS= read -r -d '' file ; do
  echo "[loop] Preparing the email..."

  # Make a temporary file
  temporary_file=$(mktemp /tmp/autoreply-XXXXX)
  echo "[debug] Temporary file: $temporary_file" # debug

  # Pull sender (i.e. recipient of my email), subject, and date from email
  recipient="$(perl -lane 'print if /^From:/' "$file" | cut -d' ' -f2-)" ### "Frantz Fanon <ffanon@riseup.net>"
  subject="Re: $(perl -lane 'print if /^Subject:/' "$file" | cut -d' ' -f2-)" ### "Re: Lorem ipsum baby"
  date="$(perl -lane 'print if /^Date:/' "$file" | cut -d' ' -f2-)"

  # Copy canned message to temporary file
  printf "To: $recipient\nFrom: adam@theadamcooper.com\nCc: amcooper@gmail.com\nDate: $(date +'%a, %d %b %Y %R %z')\nSubject: $subject\n\n" > "$temporary_file"
  cat /home/adam/dotfiles/bin/autoreply/misdirected_email_autoreply.txt >> "$temporary_file"
  printf "\n\nOn $date, $recipient wrote:\n" >> "$temporary_file"
  
  # Append email body to temporary file
  discard="0"
  while IFS= read -r line ; do
     if [[ $discard = "1" ]]; then
       echo "> $line" >> "$temporary_file"
     else
       if [[ -z "$line" ]]; then
         discard="1"
       fi
     fi
  done < "$file"

  # Send the email!
  printf "[debug] Outgoing email:\n$(cat "$temporary_file")\n" # debug
  echo "[loop] Sending reply to $recipient ... "
  cat "$temporary_file" | msmtp --read-envelope-from --read-recipients
  cat "$temporary_file" | notmuch insert --folder=Sent -inbox -unread +sent +misdirected-reply
  
  # Remove the misdirected tag
  notmuch tag -misdirected -- tag:misdirected

  echo "[loop] Done."

done < <(notmuch search --output=files --format=text0 tag:misdirected)

echo "[autoreply.sh] All done!"