#!/usr/bin/with-contenv bash

mkdir -p /config/{templates,coredns}

# install headers and wireguard
apt-get update
if apt-cache show linux-headers-$(uname -r) 2&>1 >/dev/null; then
  apt-get install -y \
    linux-headers-$(uname -r) \
    wireguard
elif (uname -r | grep -q 'v7+') || (uname -r | grep -q 'v7l+'); then
  echo "Raspbian kernel naming convention detected, attempting to install raspbian kernel headers"
  curl -s http://archive.raspberrypi.org/debian/raspberrypi.gpg.key | apt-key add -
  echo -e \
    "deb http://archive.raspberrypi.org/debian/ buster main\ndeb-src http://archive.raspberrypi.org/debian/ buster main" \
    > /etc/apt/sources.list.d/raspbian.list
  apt-get update
  apt-get install -y \
    raspberrypi-kernel-headers \
    wireguard
elif uname -v | grep -q 'Ubuntu'; then
  echo "Attempting to install kernel headers from Ubuntu Xenial repo"
  curl -s http://archive.ubuntu.com/ubuntu/dists/xenial/Release.gpg | apt-key add -
  echo -e \
    "deb http://archive.ubuntu.com/ubuntu/ xenial main restricted\ndeb-src http://archive.ubuntu.com/ubuntu/ xenial main restricted\n\ndeb http://archive.ubuntu.com/ubuntu/ xenial-updates main restricted\ndeb-src http://archive.ubuntu.com/ubuntu/ xenial-updates main restricted" \
    > /etc/apt/sources.list.d/xenial.list
  apt-get update
  if apt-cache show linux-headers-$(uname -r) 2&>1 >/dev/null; then
    apt-get install -y \
      linux-headers-$(uname -r) \
      wireguard
  else
    echo "No kernel headers found in the Ubuntu repos!! Will try the headers from host (if mapped), may or may not work"
    apt-get install -y \
      wireguard
  fi
elif uname -v | grep -q 'Debian'; then
  echo "Debian host detected, attempting to install kernel headers from Debian Buster repo"
  curl -s https://ftp-master.debian.org/keys/archive-key-10.asc | apt-key add -
  echo -e \
    "deb http://deb.debian.org/debian buster main contrib non-free\ndeb-src http://deb.debian.org/debian buster main contrib non-free" \
    > /etc/apt/sources.list.d/debian.list
  apt-get update
  if apt-cache show linux-headers-$(uname -r) 2&>1 >/dev/null; then
    apt-get install -y \
      linux-headers-$(uname -r) \
      wireguard
  else
    echo "Attempting to install kernel headers from the Debian Stretch repo"
    curl -s https://ftp-master.debian.org/keys/archive-key-9.asc | apt-key add -
    sed -i 's/buster/stretch/g' /etc/apt/sources.list.d/debian.list
    apt-get update
    if apt-cache show linux-headers-$(uname -r) 2&>1 >/dev/null; then
      apt-get install -y \
        linux-headers-$(uname -r) \
        wireguard
    else
      echo "No kernel headers found in Debian repos!! Will try the headers from host (if mapped), may or may not work"
      apt-get install -y \
        wireguard
    fi
  fi
else
  echo "No kernel headers found in the Ubuntu or Debian repos!! Will try the headers from host (if mapped), may or may not work"
  apt-get install -y \
    wireguard
fi

# prepare symlinks
rm -rf /etc/wireguard
mkdir -p /etc/wireguard
ln -s /config/wg0.conf /etc/wireguard/wg0.conf
# prepare templates
[[ ! -f /config/templates/server.conf ]] && \
  cp /defaults/server.conf /config/templates/server.conf
[[ ! -f /config/templates/peer.conf ]] && \
  cp /defaults/peer.conf /config/templates/peer.conf

generate_confs () {
  mkdir -p /config/server
  if [ ! -f /config/server/privatekey-server ]; then
    umask 077
    wg genkey | tee /config/server/privatekey-server | wg pubkey > /config/server/publickey-server
  fi
  eval "`printf %s`
  cat <<DUDE > /config/wg0.conf
`cat /config/templates/server.conf`

DUDE"
  for i in $(seq 1 $PEERS); do
    mkdir -p /config/peer${i}
    if [ ! -f "/config/peer${i}/privatekey-peer${i}" ]; then
      umask 077
      wg genkey | tee /config/peer${i}/privatekey-peer${i} | wg pubkey > /config/peer${i}/publickey-peer${i}
    fi
    eval "`printf %s`
    cat <<DUDE > /config/peer${i}/peer${i}.conf
`cat /config/templates/peer.conf`
DUDE"
    cat <<DUDE >> /config/wg0.conf
[Peer]
PublicKey = $(cat /config/peer${i}/publickey-peer${i})
AllowedIPs = ${INTERFACE}.$(( $i + 1 ))/32

DUDE
    echo "PEER ${i} QR code:"
    qrencode -t ansiutf8 < /config/peer${i}/peer${i}.conf
    qrencode -o /config/peer${i}/peer${i}.png < /config/peer${i}/peer${i}.conf
  done
}

save_vars () {
  cat <<DUDE > /config/.donoteditthisfile
ORIG_SERVERURL=$SERVERURL
ORIG_SERVERPORT=$SERVERPORT
ORIG_PEERDNS=$PEERDNS
ORIG_PEERS=$PEERS
ORIG_INTERFACE=$INTERFACE
DUDE
}

if [ -n "$PEERS" ]; then
  echo "Server mode is selected"
  if ! [[ "$PEERS" =~ ^[0-9]+$ ]]; then
    echo "PEERS is not set to an integer, setting it to 1"
    PEERS="1"
  fi
  if [ -z "$SERVERURL" ] || [ "$SERVERURL" = "auto" ]; then
    SERVERURL=$(curl icanhazip.com)
    echo "SERVERURL var is either not set or is set to \"auto\", setting external IP to auto detected value of $SERVERURL"
  else
    echo "External server address is set to $SERVERURL"
  fi
  SERVERPORT=${SERVERPORT:-51820}
  echo "External server port is set to ${SERVERPORT}. Make sure that port is properly forwarded to port 51820 inside this container"
  INTERNAL_SUBNET=${INTERNAL_SUBNET:-10.13.13.0}
  echo "Internal subnet is set to $INTERNAL_SUBNET"
  INTERFACE=$(echo "$INTERNAL_SUBNET" | awk 'BEGIN{FS=OFS="."} NF--')
  if [ -z "$PEERDNS" ] || [ "$PEERDNS" = "auto" ]; then
    PEERDNS="${INTERFACE}.1"
    echo "PEERDNS var is either not set or is set to \"auto\", setting peer DNS to ${INTERFACE}.1 to use wireguard docker host's DNS."
  else
    echo "Peer DNS servers will be set to $PEERDNS"
  fi
  if [ ! -f /config/wg0.conf ]; then
    echo "No found wg0.conf found (maybe an initial install), generating 1 server and $PEERS peer/client confs"
    generate_confs
    save_vars
  else
    echo "Server mode is selected"
    [[ -f /config/.donoteditthisfile ]] && \
      . /config/.donoteditthisfile
    if [ "$SERVERURL" != "$ORIG_SERVERURL" ] || [ "$SERVERPORT" != "$ORIG_SERVERPORT" ] || [ "$PEERDNS" != "$ORIG_PEERDNS" ] || [ "$PEERS" != "$ORIG_PEERS" ] || [ "$INTERFACE" != "$ORIG_INTERFACE" ]; then
      echo "Server related environment variables changed, regenerating 1 server and $PEERS peer/client confs"
      generate_confs
      save_vars
    else
      echo "No changes to parameters. Existing configs are used."
    fi
  fi
else
  echo "Client mode selected."
  if [ ! -f /config/wg0.conf ]; then
    "No client conf found. Provide your own client conf as \"/config/wg0.conf\" and restart the container."
    sleep infinity
  fi
fi

# set up CoreDNS
[[ ! -f /config/coredns/Corefile ]] && \
  cp /defaults/Corefile /config/coredns/Corefile

# permissions
chown -R abc:abc \
	/config