#!/bin/bash

# version  0.1.0
#
# <INSERT TASK HERE>

# shellcheck source=/dev/null
. /usr/local/bin/helper_functions.sh

LOG_DATE=$(date +"%Y-%m-%d %H:%M:%S ")
echo "${LOG_DATE} Start check-for-changes script."

# ? Checks ------------------------------------------------

cd /tmp/docker-mailserver || exit 1

# Check postfix-accounts.cf exist else break
if [[ ! -f postfix-accounts.cf ]]
then
  echo "${LOG_DATE} postfix-accounts.cf is missing! This should not run! Exit!"
  exit
fi

# Verify checksum file exists; must be prepared by start-mailserver.sh
if [[ ! -f ${CHKSUM_FILE} ]]
then
  echo "${LOG_DATE} ${CHKSUM_FILE} is missing! Start script failed? Exit!"
  exit
fi

# ? Actual script begins ----------------------------------

# Determine postmaster address, duplicated from start-mailserver.sh
# This script previously didn't work when POSTMASTER_ADDRESS was empty
if [[ -n ${OVERRIDE_HOSTNAME} ]]
then
  DOMAINNAME="${OVERRIDE_HOSTNAME#*.}"
else
  DOMAINNAME="$(hostname -d)"
fi
PM_ADDRESS="${POSTMASTER_ADDRESS:=postmaster@${DOMAINNAME}}"
echo "${LOG_DATE} Using postmaster address ${PM_ADDRESS}"
sleep 10

while true
do
  LOG_DATE=$(date +"%Y-%m-%d %H:%M:%S ")

  # get chksum and check it, no need to lock config yet
  _monitored_files_checksums >"${CHKSUM_FILE}.new"

  if ! cmp --silent -- "${CHKSUM_FILE}" "${CHKSUM_FILE}.new"
  then
    echo "${LOG_DATE} Change detected"
    changed=$(grep -Fxvf "${CHKSUM_FILE}" "${CHKSUM_FILE}.new" | sed 's/^[^ ]\+  //')
    mv "${CHKSUM_FILE}.new" "${CHKSUM_FILE}"

    # Bug alert! This overwrites the alias set by start-mailserver.sh
    # Take care that changes in one script are propagated to the other

    # ! NEEDS FIX -----------------------------------------
    # TODO FIX --------------------------------------------
    # ! NEEDS EXTENSIONS ----------------------------------
    # TODO Perform updates below conditionally too --------
    # Also note that changes are performed in place and are not atomic
    # We should fix that and write to temporary files, stop, swap and start
    # Lock configuration while working
    (
      flock -e 200

      for file in ${changed}
      do
        case ${file} in
          /etc/letsencrypt/acme.json)
            for certdomain in ${SSL_DOMAIN} ${HOSTNAME} ${DOMAINNAME}
            do
              if _extract_certs_from_acme "${certdomain}"
              then
                break
              fi
            done
            ;;
          * ) _notify 'warn' 'file not found for certificate in check_for_changes.sh' ;;
        esac
      done

      # regenerate postix aliases
      echo "root: ${PM_ADDRESS}" >/etc/aliases
      if [[ -f /tmp/docker-mailserver/postfix-aliases.cf ]]
      then
        cat /tmp/docker-mailserver/postfix-aliases.cf >>/etc/aliases
      fi
      postalias /etc/aliases

      # regenerate postfix accounts
      echo -n >/etc/postfix/vmailbox
      echo -n >/etc/dovecot/userdb

      if [[ -f /tmp/docker-mailserver/postfix-accounts.cf ]] && [[ ${ENABLE_LDAP} -ne 1 ]]
      then
        sed -i 's/\r//g' /tmp/docker-mailserver/postfix-accounts.cf
        echo "# WARNING: this file is auto-generated. Modify config/postfix-accounts.cf to edit user list." >/etc/postfix/vmailbox

        # Checking that /tmp/docker-mailserver/postfix-accounts.cf ends with a newline
        # shellcheck disable=SC1003
        sed -i -e '$a\' /tmp/docker-mailserver/postfix-accounts.cf
        chown dovecot:dovecot /etc/dovecot/userdb
        chmod 640 /etc/dovecot/userdb
        sed -i -e '/\!include auth-ldap\.conf\.ext/s/^/#/' /etc/dovecot/conf.d/10-auth.conf
        sed -i -e '/\!include auth-passwdfile\.inc/s/^#//' /etc/dovecot/conf.d/10-auth.conf

        # rebuild relay host
        if [[ -n ${RELAY_HOST} ]]
        then
          # keep old config
          echo -n >/etc/postfix/sasl_passwd
          if [[ -n ${SASL_PASSWD} ]]
          then
            echo "${SASL_PASSWD}" >>/etc/postfix/sasl_passwd
          fi

          # add domain-specific auth from config file
          if [[ -f /tmp/docker-mailserver/postfix-sasl-password.cf ]]
          then
            (grep -v "^\s*$\|^\s*\#" /tmp/docker-mailserver/postfix-sasl-password.cf || true) | while read -r line
            do
              if ! echo "${line}" | grep -q -e "\s*#"
              then
                echo "${line}" >>/etc/postfix/sasl_passwd
              fi
            done
          fi

          # add default relay
          if [[ -n "${RELAY_USER}" ]] && [[ -n "${RELAY_PASSWORD}" ]]
          then
            echo "[${RELAY_HOST}]:${RELAY_PORT}		${RELAY_USER}:${RELAY_PASSWORD}" >>/etc/postfix/sasl_passwd
          fi
        fi

        # creating users ; 'pass' is encrypted
        # comments and empty lines are ignored
        grep -v "^\s*$\|^\s*\#" /tmp/docker-mailserver/postfix-accounts.cf | while IFS=$'|' read -r login pass
        do
          user=$(echo "${login}" | cut -d @ -f1)
          domain=$(echo "${login}" | cut -d @ -f2)

          user_attributes=""
          # test if user has a defined quota
          if [[ -f /tmp/docker-mailserver/dovecot-quotas.cf ]]
          then
            declare -a USER_QUOTA
            IFS=':' ; read -r -a USER_QUOTA < <(grep "${user}@${domain}:" -i /tmp/docker-mailserver/dovecot-quotas.cf)
            unset IFS

            [[ ${#USER_QUOTA[@]} -eq 2 ]] && user_attributes="${user_attributes}userdb_quota_rule=*:bytes=${USER_QUOTA[1]}"
          fi

          echo "${login} ${domain}/${user}/" >>/etc/postfix/vmailbox

          # user database for dovecot has the following format:
          # user:password:uid:gid:(gecos):home:(shell):extra_fields
          # example :
          # ${login}:${pass}:5000:5000::/var/mail/${domain}/${user}::userdb_mail=maildir:/var/mail/${domain}/${user}
          echo "${login}:${pass}:5000:5000::/var/mail/${domain}/${user}::${user_attributes}" >>/etc/dovecot/userdb
          mkdir -p "/var/mail/${domain}/${user}"

          if [[ -e /tmp/docker-mailserver/${login}.dovecot.sieve ]]
          then
            cp "/tmp/docker-mailserver/${login}.dovecot.sieve" "/var/mail/${domain}/${user}/.dovecot.sieve"
          fi

          echo "${domain}" >>/tmp/vhost.tmp
        done
      fi

      [[ -n ${RELAY_HOST} ]] && _populate_relayhost_map


      if [[ -f /etc/postfix/sasl_passwd ]]
      then
        chown root:root /etc/postfix/sasl_passwd
        chmod 0600 /etc/postfix/sasl_passwd
      fi

      if [[ -f postfix-virtual.cf ]]
      then
        # regenerate postfix aliases
        echo -n >/etc/postfix/virtual
        echo -n >/etc/postfix/regexp

        if [[ -f /tmp/docker-mailserver/postfix-virtual.cf ]]
        then
          cp -f /tmp/docker-mailserver/postfix-virtual.cf /etc/postfix/virtual

          # the `to` seems to be important; don't delete it
          # shellcheck disable=SC2034
          (grep -v "^\s*$\|^\s*\#" /tmp/docker-mailserver/postfix-virtual.cf || true) | while read -r from to
          do
            uname=$(echo "${from}" | cut -d @ -f1)
            domain=$(echo "${from}" | cut -d @ -f2)

            # if they are equal it means the line looks like: "user1	 other@domain.tld"
            [ "${uname}" != "${domain}" ] && echo "${domain}" >>/tmp/vhost.tmp
          done
        fi

        if [[ -f /tmp/docker-mailserver/postfix-regexp.cf ]]
        then
          cp -f /tmp/docker-mailserver/postfix-regexp.cf /etc/postfix/regexp
          sed -i -e '/^virtual_alias_maps/{
s/ regexp:.*//
s/$/ regexp:\/etc\/postfix\/regexp/
}' /etc/postfix/main.cf
        fi
      fi

      if [[ -f /tmp/vhost.tmp ]]
      then
        # shellcheck disable=SC2002
        cat /tmp/vhost.tmp | sort | uniq >/etc/postfix/vhost && rm /tmp/vhost.tmp
      fi

      if [[ $(find /var/mail -maxdepth 3 -a \( \! -user 5000 -o \! -group 5000 \) | grep -c .) -ne 0 ]]
      then
        chown -R 5000:5000 /var/mail
      fi

      supervisorctl restart postfix

      # prevent restart of dovecot when smtp_only=1
      [[ ${SMTP_ONLY} -ne 1 ]] && supervisorctl restart dovecot
    ) 200<postfix-accounts.cf # end lock
  fi

  sleep 1
done