#!/bin/bash

# -eE         :: exit on error (do this in functions as well)
# -u          :: show (and exit) when using unset variables
# -o pipefail :: exit on error in pipes
set -eE -u -o pipefail

# shellcheck source=/dev/null
source /etc/os-release

# shellcheck source=../helpers/log.sh
source /usr/local/bin/helpers/log.sh

_log_level_is 'trace' && QUIET='-y' || QUIET='-qq'

function _pre_installation_steps() {
  _log 'info' 'Starting package installation'
  _log 'debug' 'Running pre-installation steps'

  _log 'trace' 'Updating package signatures'
  apt-get "${QUIET}" update

  _log 'trace' 'Installing packages that are needed early'
  apt-get "${QUIET}" install --no-install-recommends apt-utils 2>/dev/null

  _log 'trace' 'Upgrading packages'
  apt-get "${QUIET}" upgrade
}

function _install_postfix() {
  _log 'debug' 'Installing Postfix'

  _log 'warn' 'Applying workaround for Postfix bug (see https://github.com//issues/2023#issuecomment-855326403)'

  # Debians postfix package has a post-install script that expects a valid FQDN hostname to work:
  mv /bin/hostname /bin/hostname.bak
  echo "echo 'docker-mailserver.invalid'" >/bin/hostname
  chmod +x /bin/hostname
  apt-get "${QUIET}" install --no-install-recommends postfix
  mv /bin/hostname.bak /bin/hostname

  # Irrelevant - Debian's default `chroot` jail config for Postfix needed a separate syslog socket:
  rm /etc/rsyslog.d/postfix.conf
}

function _install_packages() {
  _log 'debug' 'Installing all packages now'

  ANTI_VIRUS_SPAM_PACKAGES=(
    amavisd-new clamav clamav-daemon
    pyzor razor spamassassin
  )

  CODECS_PACKAGES=(
    altermime arj bzip2
    cabextract cpio file
    gzip lhasa liblz4-tool
    lrzip lzop nomarch
    p7zip-full pax rpm2cpio
    unrar-free unzip xz-utils
  )

  MISCELLANEOUS_PACKAGES=(
    apt-transport-https binutils bsd-mailx
    ca-certificates curl dbconfig-no-thanks
    dumb-init gnupg iproute2 libdate-manip-perl
    libldap-common libmail-spf-perl
    libnet-dns-perl locales logwatch
    netcat-openbsd nftables rsyslog
    supervisor uuid whois
  )

  POSTFIX_PACKAGES=(
    pflogsumm postgrey postfix-ldap
    postfix-pcre postfix-policyd-spf-python postsrsd
  )

  MAIL_PROGRAMS_PACKAGES=(
    fetchmail opendkim opendkim-tools
    opendmarc libsasl2-modules sasl2-bin
  )

  # `bind9-dnsutils` provides the `dig` command
  # `iputils-ping` provides the `ping` command
  DEBUG_PACKAGES=(
    bind9-dnsutils iputils-ping less nano
  )

  apt-get "${QUIET}" --no-install-recommends install \
    "${ANTI_VIRUS_SPAM_PACKAGES[@]}" \
    "${CODECS_PACKAGES[@]}" \
    "${MISCELLANEOUS_PACKAGES[@]}" \
    "${POSTFIX_PACKAGES[@]}" \
    "${MAIL_PROGRAMS_PACKAGES[@]}" \
    "${DEBUG_PACKAGES[@]}"
}

function _install_dovecot() {
  local DOVECOT_PACKAGES=(
    dovecot-core dovecot-imapd
    dovecot-ldap dovecot-lmtpd dovecot-managesieved
    dovecot-pop3d dovecot-sieve dovecot-solr
  )

  # Dovecot packages for community supported features.
  DOVECOT_PACKAGES+=(dovecot-auth-lua)

  # Dovecot's deb community repository only provides x86_64 packages, so do not include it
  # when building for another architecture.
  if [[ ${DOVECOT_COMMUNITY_REPO} -eq 1 ]] && [[ "$(uname --machine)" == "x86_64" ]]; then
    _log 'trace' 'Using Dovecot community repository'
    curl https://repo.dovecot.org/DOVECOT-REPO-GPG | gpg --import
    gpg --export ED409DA1 > /etc/apt/trusted.gpg.d/dovecot.gpg
    echo "deb https://repo.dovecot.org/ce-2.3-latest/debian/${VERSION_CODENAME} ${VERSION_CODENAME} main" > /etc/apt/sources.list.d/dovecot.list

    _log 'trace' 'Updating Dovecot package signatures'
    apt-get "${QUIET}" update

    # Additional community package needed for Lua support if the Dovecot community repository is used.
    DOVECOT_PACKAGES+=(dovecot-lua)
  fi

  _log 'debug' 'Installing Dovecot'
  apt-get "${QUIET}" --no-install-recommends install "${DOVECOT_PACKAGES[@]}"

  # dependency for fts_xapian
  apt-get "${QUIET}" --no-install-recommends install libxapian30
}

function _install_utils() {
  _log 'debug' 'Installing utils sourced from Github'
  curl -sL https://github.com/01mf02/jaq/releases/latest/download/jaq-v1.2.0-x86_64-unknown-linux-musl -o /usr/bin/jaq && chmod +x /usr/bin/jaq
}

function _remove_data_after_package_installations() {
  _log 'debug' 'Deleting sensitive files (secrets)'
  rm /etc/postsrsd.secret

  _log 'debug' 'Deleting default logwatch cronjob'
  rm /etc/cron.daily/00logwatch
}

function _post_installation_steps() {
  _log 'debug' 'Running post-installation steps (cleanup)'
  apt-get "${QUIET}" clean
  rm -rf /var/lib/apt/lists/*

  _log 'info' 'Finished installing packages'
}

_pre_installation_steps
_install_postfix
_install_packages
_install_dovecot
_install_utils
_remove_data_after_package_installations
_post_installation_steps