#!/usr/bin/with-contenv bash
# https://github.com/arankaren/docker-wireguard/blob/master/root/etc/s6-overlay/s6-rc.d/init-wireguard-confs/run

# 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
# add preshared key to user templates (backwards compatibility)
if ! grep -q 'PresharedKey' /config/templates/peer.conf; then
  sed -i 's|^Endpoint|PresharedKey = \$\(cat /config/\${PEER_ID}/presharedkey-\${PEER_ID}\)\nEndpoint|' /config/templates/peer.conf
fi

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 ${PEERS_ARRAY[@]}; do
    if [[ ! "${i}" =~ ^[[:alnum:]]+$ ]]; then
      echo "**** Peer ${i} contains non-alphanumeric characters and thus will be skipped. No config for peer ${i} will be generated. ****"
    else
      if [[ "${i}" =~ ^[0-9]+$ ]]; then
        PEER_ID="peer${i}"
      else
        PEER_ID="peer_${i}"
      fi
      mkdir -p /config/${PEER_ID}
      if [ ! -f "/config/${PEER_ID}/privatekey-${PEER_ID}" ]; then
        umask 077
        wg genkey | tee /config/${PEER_ID}/privatekey-${PEER_ID} | wg pubkey > /config/${PEER_ID}/publickey-${PEER_ID}
        wg genpsk > /config/${PEER_ID}/presharedkey-${PEER_ID}
      fi
      if [ -f "/config/${PEER_ID}/${PEER_ID}.conf" ]; then
        CLIENT_IPV4=$(cat /config/${PEER_ID}/${PEER_ID}.conf | grep "Address" | awk '{print substr($3, 1, length($3)-1)}')
        if [ -n "${ORIG_INTERFACE_IPV4}" ] && [ "${INTERFACE_IPV4}" != "${ORIG_INTERFACE_IPv4}" ]; then
          CLIENT_IPV4=$(echo "${CLIENT_IPV4}" | sed "s|${ORIG_INTERFACE_IPV4}|${INTERFACE_IPV4}|")
        fi
        CLIENT_IPV6=$(cat /config/${PEER_ID}/${PEER_ID}.conf | grep "Address" | awk '{print $NF}')
        if [ -n "${ORIG_INTERFACE_IPV6}" ] && [ "${INTERFACE_IPV6}" != "${ORIG_INTERFACE_IPV6}" ]; then
          CLIENT_IPV6=$(echo "${CLIENT_IPV6}" | sed "s|${ORIG_INTERFACE_IPV6}|${INTERFACE_IPV6}|")
        fi
      else
        for idx in {2..254}; do
          PROPOSED_IPV4="${INTERFACE_IPV4}.${idx}"
          if ! grep -q -R "${PROPOSED_IPV4}" /config/peer*/*.conf 2>/dev/null && ([ -z "${ORIG_INTERFACE}" ] || ! grep -q -R "${ORIG_INTERFACE}.${idx}" /config/peer*/*.conf 2>/dev/null); then
            CLIENT_IPV4="${PROPOSED_IPV4}"
            break
          fi
        done
        for idx in {2..254}; do
          PROPOSED_IPV6="${INTERFACE_IPV6}:${idx}"
          if ! grep -q -R "${PROPOSED_IPV6}" /config/peer*/*.conf 2>/dev/null && ([ -z "${ORIG_INTERFACE}" ] || ! grep -q -R "${ORIG_INTERFACE}.${idx}" /config/peer*/*.conf 2>/dev/null); then
            CLIENT_IPV6="${PROPOSED_IPV6}"
            break
          fi
        done
      fi
      if [ -f "/config/${PEER_ID}/presharedkey-${PEER_ID}" ]; then
        # create peer conf with presharedkey
        eval "`printf %s`
        cat <<DUDE > /config/${PEER_ID}/${PEER_ID}.conf
`cat /config/templates/peer.conf`
DUDE"
        # add peer info to server conf with presharedkey
        cat <<DUDE >> /config/wg0.conf
[Peer]
# ${PEER_ID}
PublicKey = $(cat /config/${PEER_ID}/publickey-${PEER_ID})
PresharedKey = $(cat /config/${PEER_ID}/presharedkey-${PEER_ID})
DUDE
      else
        echo "**** Existing keys with no preshared key found for ${PEER_ID}, creating confs without preshared key for backwards compatibility ****"
        # create peer conf without presharedkey
        eval "`printf %s`
        cat <<DUDE > /config/${PEER_ID}/${PEER_ID}.conf
`cat /config/templates/peer.conf | sed '/PresharedKey/d'`
DUDE"
        # add peer info to server conf without presharedkey
        cat <<DUDE >> /config/wg0.conf
[Peer]
# ${PEER_ID}
PublicKey = $(cat /config/${PEER_ID}/publickey-${PEER_ID})
DUDE
      fi
      SERVER_ALLOWEDIPS=SERVER_ALLOWEDIPS_PEER_${i}
      # add peer's allowedips to server conf
      if [ -n "${!SERVER_ALLOWEDIPS}" ]; then
        echo "Adding ${!SERVER_ALLOWEDIPS} to wg0.conf's AllowedIPs for peer ${i}"
        cat <<DUDE >> /config/wg0.conf
AllowedIPs = ${CLIENT_IPV4}/32,${!SERVER_ALLOWEDIPS}

DUDE
    else
      cat <<DUDE >> /config/wg0.conf
AllowedIPs = ${CLIENT_IPV4}/32,${CLIENT_IPV6}/128

DUDE
      fi
      if [ -z "${LOG_CONFS}" ] || [ "${LOG_CONFS}" = "true" ]; then
        echo "PEER ${i} QR code:"
        qrencode -t ansiutf8 < /config/${PEER_ID}/${PEER_ID}.conf
      else
        echo "PEER ${i} conf and QR code png saved in /config/${PEER_ID}"
      fi
      qrencode -o /config/${PEER_ID}/${PEER_ID}.png < /config/${PEER_ID}/${PEER_ID}.conf
    fi
  done
}

save_vars () {
  cat <<DUDE > /config/.donoteditthisfile
ORIG_SERVERURL="$SERVERURL"
ORIG_SERVERPORT="$SERVERPORT"
ORIG_PEERDNS="$PEERDNS"
ORIG_PEERS="$PEERS"
ORIG_INTERFACE_IPV4="$INTERFACE_IPV4"
ORIG_INTERFACE_IPV6="$INTERFACE_IPV6"
ORIG_ALLOWEDIPS="$ALLOWEDIPS"
DUDE
}

if [ -n "$PEERS" ]; then
  echo "**** Server mode is selected ****"
  if [[ "$PEERS" =~ ^[0-9]+$ ]] && ! [[ "$PEERS" =~ *,* ]]; then
    PEERS_ARRAY=($(seq 1 $PEERS))
  else
    PEERS_ARRAY=($(echo "$PEERS" | tr ',' ' '))
  fi
  PEERS_COUNT=$(echo "${#PEERS_ARRAY[@]}")
  if [ -z "$SERVERURL" ] || [ "$SERVERURL" = "auto" ]; then
    SERVERURL=$(curl -s 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 ${SERVERPORT}. Make sure that port is properly forwarded to port 51820 inside this container ****"
  INTERNAL_SUBNET_IPV4=${INTERNAL_SUBNET_IPV4:-10.13.13.0}
  echo "**** Internal subnet is set to $INTERNAL_SUBNET_IPV4 ****"
  INTERFACE_IPV4=$(echo "$INTERNAL_SUBNET_IPV4" | awk 'BEGIN{FS=OFS="."} NF--')
  INTERNAL_SUBNET_IPV6=${INTERNAL_SUBNET_IPV6:-fd42:42:42::0}
  echo "**** Internal subnet is set to $INTERNAL_SUBNET_IPV6 ****"
  INTERFACE_IPV6=$(echo "$INTERNAL_SUBNET_IPV6" | awk 'BEGIN{FS=OFS="::"} NF--')
  ALLOWEDIPS=${ALLOWEDIPS:-0.0.0.0/0, ::/0}
  echo "**** AllowedIPs for peers $ALLOWEDIPS ****"
  if [ -z "$PEERDNS" ] || [ "$PEERDNS" = "auto" ]; then
    PEERDNS="${INTERFACE_IPV4}.1, ${INTERFACE_IPV6}::1"
    echo "**** PEERDNS var is either not set or is set to \"auto\", setting peer DNS to ${INTERFACE_IPV4}.1 and ${INTERFACE_IPV6}::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 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_IPV4" != "$ORIG_INTERFACE_IPV4" ] || [ "$INTERFACE_IPV6" != "$ORIG_INTERFACE_IPV6" ] || [ "$ALLOWEDIPS" != "$ORIG_ALLOWEDIPS" ]; 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
    echo "**** No client conf found. Provide your own client conf as \"/config/wg0.conf\" and restart the container. ****"
    sleep infinity
  fi
  printf "false" > /run/s6/container_environment/USE_COREDNS
fi

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

# permissions
chown -R abc:abc \
  /config