#!/bin/bash

##
## Make sure only root can run our script
##
check_root() {
  if [[ $EUID -ne 0 ]]; then
    echo "This script must be run as root. Please sudo or log in as root first." 1>&2
    exit 1
  fi
}

##
## Do we have enough memory and disk space for Discourse?
##
check_disk_and_memory() {

  avail_mem=`free -g --si | awk ' /Mem:/  {print $2} '`
  if [ "$avail_mem" -lt 1 ]; then
    echo "WARNING: Discourse requires 1GB RAM to run. This system does not appear"
    echo "to have sufficient memory."
    echo
    echo "Your site may not work properly, or future upgrades of Discourse may not"
    echo "complete successfully."
    exit 1
  fi

  if [ "$avail_mem" -lt 2 ]; then
    total_swap=`free -g --si | awk ' /Swap:/  {print $2} '`
    if [ "$total_swap" -lt 2 ]; then
      echo "WARNING: Discourse requires at least 2GB of swap when running with less "
      echo "than 2GB of RAM. This system does not appear to have sufficient swap space."
      echo
      echo "Without sufficient swap space, your site may not work properly, and future"
      echo "upgrades of Discourse may not complete successfully."
      echo
      read -p "ENTER to create a 2GB swapfile now, or Ctrl+C to exit"

      ##
      ## derived from https://meta.discourse.org/t/13880
      ##
      install -o root -g root -m 0600 /dev/null /swapfile
      dd if=/dev/zero of=/swapfile bs=1k count=2048k
      mkswap /swapfile
      swapon /swapfile
      echo "/swapfile       swap    swap    auto      0       0" | tee -a /etc/fstab
      sysctl -w vm.swappiness=10
      echo vm.swappiness = 10 | tee -a /etc/sysctl.conf

      total_swap=`free -g --si | awk ' /Swap:/ {print $2} '`
      if [ "$total_swap" -lt 2 ]; then
        echo "Failed to create swap, sorry!"
        exit 1
      fi

    fi
  fi


  free_disk="$(df /var | tail -n 1 | awk '{print $4}')"
  if [ "$free_disk" -lt 5000 ]; then
    echo "WARNING: Discourse requires at least 5GB free disk space. This system"
    echo "does not appear to have sufficient disk space."
    echo
    echo "Insufficient disk space may result in problems running your site, and"
    echo "may not even allow Discourse installation to complete successfully."
    echo
    echo "Please free up some space, or expand your disk, before continuing."
    echo
    echo "Run \`apt-get autoremove && apt-get autoclean\` to clean up unused"
    echo "packages and \`./launcher cleanup\` to remove stale Docker containers."
    exit 1
  fi

}


##
## If we have lots of RAM or lots of CPUs, bump up the defaults to scale better
##
scale_ram_and_cpu() {

  local changelog=/tmp/changelog.$PPID
  # grab info about total system ram and physical (NOT LOGICAL!) CPU cores
  avail_gb="$(LANG=C free -g --si | grep '^Mem:' | awk '{print $2}')"
  avail_cores=`cat /proc/cpuinfo | grep "cpu cores" | uniq | awk '{print $4}'`
  echo "Found ${avail_gb}GB of memory and $avail_cores physical CPU cores"

  # db_shared_buffers: 128MB for 1GB, 256MB for 2GB, or 256MB * GB, max 4096MB
  if [ "$avail_gb" -eq "1" ]
  then
    db_shared_buffers=128
  else
    if [ "$avail_gb" -eq "2" ]
    then
      db_shared_buffers=256
    else
      db_shared_buffers=$(( 256 * $avail_gb ))
    fi
  fi
  db_shared_buffers=$(( db_shared_buffers < 4096 ? db_shared_buffers : 4096 ))

  sed -i -e "s/^  #db_shared_buffers:.*/  db_shared_buffers: \"${db_shared_buffers}MB\"/w $changelog" $config_file
  if [ -s $changelog ]
  then
    echo "setting db_shared_buffers = ${db_shared_buffers}MB"
    rm $changelog
  fi

  # UNICORN_WORKERS: 2 * GB for 2GB or less, or 2 * CPU, max 8
  if [ "$avail_gb" -le "2" ]
  then
    unicorn_workers=$(( 2 * $avail_gb ))
  else
    unicorn_workers=$(( 2 * $avail_cores ))
  fi
  unicorn_workers=$(( unicorn_workers < 8 ? unicorn_workers : 8 ))

  sed -i -e "s/^  #UNICORN_WORKERS:.*/  UNICORN_WORKERS: ${unicorn_workers}/w $changelog" $config_file
  if [ -s $changelog ]
  then
      echo "setting UNICORN_WORKERS = ${unicorn_workers}"
      rm $changelog
  fi

}


##
## standard http / https ports must not be occupied
##
check_ports() {
    check_port "80"
    check_port "443"
    echo "Ports 80 and 443 are free for use"
}


##
## check a port to see if it is already in use
##
check_port() {

  local valid=$(netstat -tln | awk '{print $4}' | grep ":${1}\$")

  if [ -n "$valid" ]; then
    echo "Port ${1} appears to already be in use."
    echo
    echo "If you are trying to run Discourse simultaneously with another web"
    echo "server like Apache or nginx, you will need to bind to a different port"
    echo
    echo "See https://meta.discourse.org/t/17247"
    exit 1
  fi
}

##
## prompt user for typical Discourse config file values
##
ask_user_for_config() {

  local changelog=/tmp/changelog.$PPID
  local hostname="discourse.example.com"
  local developer_emails="me@example.com,you@example.com"
  local smtp_address="smtp.example.com"
  local smtp_port="587"
  local smtp_user_name="postmaster@discourse.example.com"
  local smtp_password=""
  local letsencrypt_account_email="me@example.com"
  local letsencrypt_status="ENTER to skip"

  local new_value=""
  local config_ok="n"
  local update_ok="y"

  echo ""

  while [[ "$config_ok" == "n" ]]
  do
    if [ ! -z $hostname ]
    then
      read -p "Hostname for your Discourse? [$hostname]: " new_value
      if [ ! -z $new_value ]
      then
          hostname=$new_value
      fi
    fi

    if [ ! -z $developer_emails ]
    then
      read -p "Email address for admin account? [$developer_emails]: " new_value
      if [ ! -z $new_value ]
      then
          developer_emails=$new_value
      fi
    fi

    if [ ! -z $smtp_address ]
    then
      read -p "SMTP server address? [$smtp_address]: " new_value
      if [ ! -z $new_value ]
      then
        smtp_address=$new_value
      fi
    fi

    if [ ! -z $smtp_port ]
    then
      read -p "SMTP port? [$smtp_port]: " new_value
      if [ ! -z $new_value ]
      then
        smtp_port=$new_value
      fi
    fi

    ##
    ## automatically set correct user name based on common mail providers
    ##
    if [ "$smtp_address" == "smtp.sparkpostmail.com" ]
    then
    	smtp_user_name="SMTP_Injection"
    fi
    if [ "$smtp_address" == "smtp.sendgrid.net" ]
    then
	    smtp_user_name="apikey"
    fi
    if [ "$smtp_address" == "smtp.mailgun.org" ]
    then
	    smtp_user_name="postmaster@$hostname"
    fi

    if [ ! -z $smtp_user_name ]
    then
      read -p "SMTP user name? [$smtp_user_name]: " new_value
      if [ ! -z $new_value ]
      then
          smtp_user_name=$new_value
      fi
    fi

    read -p "SMTP password? [$smtp_password]: " new_value
    if [ ! -z $new_value ]
    then
        smtp_password=$new_value
    fi

    if [ ! -z $letsencrypt_account_email ]
    then
      read -p "Let's Encrypt account email? ($letsencrypt_status) [$letsencrypt_account_email]: " new_value
      if [ ! -z $new_value ]
      then
          letsencrypt_account_email=$new_value
          if [ "$new_value" == "off" ]
          then
            letsencrypt_status="ENTER to skip"
          else
            letsencrypt_status="Enter 'OFF' to disable."
          fi
      fi
    fi

    echo -e "\nDoes this look right?\n"
    echo "Hostname      : $hostname"
    echo "Email         : $developer_emails"
    echo "SMTP address  : $smtp_address"
    echo "SMTP port     : $smtp_port"
    echo "SMTP username : $smtp_user_name"
    echo "SMTP password : $smtp_password"

    if [ "$letsencrypt_status" == "Enter 'OFF' to disable." ]
    then
      echo "Let's Encrypt : $letsencrypt_account_email"
    fi

    echo ""
    read -p "ENTER to continue, 'n' to try again, Ctrl+C to exit: " config_ok
  done

  sed -i -e "s/^  DISCOURSE_HOSTNAME:.*/  DISCOURSE_HOSTNAME: $hostname/w $changelog" $config_file
  if [ -s $changelog ]
  then
    rm $changelog
  else
    echo "DISCOURSE_HOSTNAME change failed."
    update_ok="n"
  fi

  sed -i -e "s/^  DISCOURSE_DEVELOPER_EMAILS:.*/  DISCOURSE_DEVELOPER_EMAILS: \'$developer_emails\'/w $changelog" $config_file
  if [ -s $changelog ]
  then
    rm $changelog
  else
    echo "DISCOURSE_DEVELOPER_EMAILS change failed."
    update_ok="n"
  fi

  sed -i -e "s/^  DISCOURSE_SMTP_ADDRESS:.*/  DISCOURSE_SMTP_ADDRESS: $smtp_address/w $changelog" $config_file
  if [ -s $changelog ]
  then
    rm $changelog
  else
    echo "DISCOURSE_SMTP_ADDRESS change failed."
    update_ok="n"
  fi

  sed -i -e "s/^  #DISCOURSE_SMTP_PORT:.*/  DISCOURSE_SMTP_PORT: $smtp_port/w $changelog" $config_file
  if [ -s $changelog ]
  then
    rm $changelog
  else
    echo "DISCOURSE_SMTP_PORT change failed."
    update_ok="n"
  fi

  sed -i -e "s/^  #DISCOURSE_SMTP_USER_NAME:.*/  DISCOURSE_SMTP_USER_NAME: $smtp_user_name/w $changelog" $config_file
  if [ -s $changelog ]
  then
    rm $changelog
  else
    echo "DISCOURSE_SMTP_USER_NAME change failed."
    update_ok="n"
  fi

  sed -i -e "s/^  #DISCOURSE_SMTP_PASSWORD:.*/  DISCOURSE_SMTP_PASSWORD: \"${smtp_password/\//\\/}\"/w $changelog" $config_file
  if [ -s $changelog ]
  then
      rm $changelog
  else
    echo "DISCOURSE_SMTP_PASSWORD change failed."
    update_ok="n"
  fi

  if [ "$letsencrypt_status" != "ENTER to skip" ]
  then
      sed -i -e "s/^  #LETSENCRYPT_ACCOUNT_EMAIL:.*/  LETSENCRYPT_ACCOUNT_EMAIL: $letsencrypt_account_email/w $changelog" $config_file
      if [ -s $changelog ]
      then
        rm $changelog
      else
        echo "LETSENCRYPT_ACCOUNT_EMAIL change failed."
        update_ok="n"
      fi
      local src='^  #- "templates\/web.ssl.template.yml"'
      local dst='  \- "templates\/web.ssl.template.yml"'
      sed -i -e "s/$src/$dst/w $changelog" $config_file
      if [ -s $changelog ]
      then
	  echo "web.ssl.template.yml enabled"
      else
        update_ok="n"
        echo "web.ssl.template.yml NOT ENABLED--was it on already?"
      fi
      local src='^  #- "templates\/web.letsencrypt.ssl.template.yml"'
      local dst='  - "templates\/web.letsencrypt.ssl.template.yml"'

      sed -i -e "s/$src/$dst/w $changelog" $config_file
      if [ -s $changelog ]
      then
	      echo "letsencrypt.ssl.template.yml enabled"
      else
        update_ok="n"
        echo "letsencrypt.ssl.template.yml NOT ENABLED -- was it on already?"
      fi
  fi

  if [ "$update_ok" == "y" ]
  then
    echo -e "\nConfiguration file at $config_file updated successfully!\n"
  else
    echo -e "\nUnfortunately, there was an error changing $config_file\n"
    exit 1
  fi
}

##
## is our config file valid? Does it have the required fields set?
##
validate_config() {

  valid_config="y"

  for x in DISCOURSE_SMTP_ADDRESS DISCOURSE_SMTP_USER_NAME DISCOURSE_SMTP_PASSWORD \
           DISCOURSE_DEVELOPER_EMAILS DISCOURSE_HOSTNAME
  do
    config_line=`grep "^  $x:" $config_file`
    local result=$?
    local default="example.com"

    if (( result == 0 ))
    then
      if [[ $config_line = *"$default"* ]]
      then
        echo "$x left at incorrect default of example.com"
        valid_config="n"
      fi
      config_val=`echo $config_line | awk '{print $2}'`
      if [ -z $config_val ]
      then
        echo "$x was left blank"
        valid_config="n"
      fi
    else
      echo "$x not present"
      valid_config="n"
    fi
  done

  if [ "$valid_config" != "y" ]; then
    echo -e "\nSorry, these $config_file settings aren't valid -- can't continue!"
    echo "If you have unusual requirements, edit $config_file and then: "
    echo "./launcher bootstrap $app_name"
    exit 1
  fi
}


##
## template file names
##
app_name=app
template_path=samples/standalone.yml
config_file=containers/$app_name.yml
changelog=/tmp/changelog

##
## Check requirements before creating a copy of a config file we won't edit
##
check_root
check_disk_and_memory
check_ports

##
## make a copy of the simple standalone config file
##
if [ -a $config_file ]
then
  echo "The configuration file $config_file already exists!"
  echo ""
  echo "If you want to delete your old configuration file and start over:"
  echo "rm $config_file"
  exit 1
else
  cp $template_path $config_file
fi

scale_ram_and_cpu
ask_user_for_config
validate_config

##
## if we reach this point without exiting, OK to proceed
##
./launcher bootstrap $app_name && ./launcher start $app_name