#!/usr/bin/with-contenv bash
# shellcheck shell=bash
# shellcheck disable=SC2016,SC1091,SC2183

# prepare symlinks
rm -rf /etc/wireguard
mkdir -p /etc/wireguard
ln -s /config/wg0.conf /etc/wireguard/wg0.conf
# prepare templates
if [[ ! -f /config/templates/server.conf ]]; then
    cp /defaults/server.conf /config/templates/server.conf
fi
if [[ ! -f /config/templates/peer.conf ]]; then
    cp /defaults/peer.conf /config/templates/peer.conf
fi
# 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}/${PEER_ID}.conf" ]]; then
        CLIENT_IP=$(grep "Address" "/config/${PEER_ID}/${PEER_ID}.conf" | awk '{print $NF}')
        if [[ -n "${ORIG_INTERFACE}" ]] && [[ "${INTERFACE}" != "${ORIG_INTERFACE}" ]]; then
          CLIENT_IP="${CLIENT_IP//${ORIG_INTERFACE}/${INTERFACE}}"
        fi
      else
        for idx in {2..254}; do
          PROPOSED_IP="${INTERFACE}.${idx}"
          if ! grep -q -R "${PROPOSED_IP}" /config/peer*/*.conf 2>/dev/null && ([[ -z "${ORIG_INTERFACE}" ]] || ! grep -q -R "${ORIG_INTERFACE}.${idx}" /config/peer*/*.conf 2>/dev/null); then
            CLIENT_IP="${PROPOSED_IP}"
            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
$(sed '/PresharedKey/d' "/config/templates/peer.conf")
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 = ${CLIENT_IP}/32,${!SERVER_ALLOWEDIPS}
DUDE
      else
        cat <<DUDE >> /config/wg0.conf
AllowedIPs = ${CLIENT_IP}/32
DUDE
      fi
      # add PersistentKeepalive if the peer is specified
      if [[ -n "${PERSISTENTKEEPALIVE_PEERS_ARRAY}" ]] && ([[ "${PERSISTENTKEEPALIVE_PEERS_ARRAY[0]}" = "all" ]] || printf '%s\0' "${PERSISTENTKEEPALIVE_PEERS_ARRAY[@]}" | grep -Fxqz -- "${i}"); then
        cat <<DUDE >> /config/wg0.conf
PersistentKeepalive = 25

DUDE
      else
        cat <<DUDE >> /config/wg0.conf

DUDE
      fi
      if [[ -z "${LOG_CONFS}" ]] || [[ "${LOG_CONFS}" = "true" ]]; then
        echo "PEER ${i} QR code (conf file is saved under /config/${PEER_ID}):"
        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="$INTERFACE"
ORIG_ALLOWEDIPS="$ALLOWEDIPS"
ORIG_PERSISTENTKEEPALIVE_PEERS="$PERSISTENTKEEPALIVE_PEERS"
DUDE
}

if [[ -n "$PEERS" ]]; then
    echo "**** Server mode is selected ****"
    if [[ "$PEERS" =~ ^[0-9]+$ ]] && ! [[ "$PEERS" = *,* ]]; then
        mapfile -t PEERS_ARRAY < <(seq 1 "${PEERS}")
    else
        mapfile -t PEERS_ARRAY < <(echo "${PEERS}" | tr ',' '\n')
    fi
    if [[ -n "${PERSISTENTKEEPALIVE_PEERS}" ]]; then
        echo "**** PersistentKeepalive will be set for: ${PERSISTENTKEEPALIVE_PEERS/,/ } ****"
        mapfile -t PERSISTENTKEEPALIVE_PEERS_ARRAY < <(echo "${PERSISTENTKEEPALIVE_PEERS}" | tr ',' '\n')
    fi
    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 ${SERVERPORT}. Make sure that port is properly forwarded to port 51820 inside this container ****"
    INTERNAL_SUBNET=${INTERNAL_SUBNET:-10.13.13.0}
    echo "**** Internal subnet is set to $INTERNAL_SUBNET ****"
    INTERFACE=$(echo "$INTERNAL_SUBNET" | awk 'BEGIN{FS=OFS="."} NF--')
    ALLOWEDIPS=${ALLOWEDIPS:-0.0.0.0/0, ::/0}
    echo "**** AllowedIPs for peers $ALLOWEDIPS ****"
    if [[ -z "$PEERDNS" ]] || [[ "$PEERDNS" = "auto" ]]; then
        PEERDNS="${INTERFACE}.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 wg0.conf found (maybe an initial install), generating 1 server and ${PEERS} peer/client confs ****"
        generate_confs
        save_vars
    else
      echo "**** Server mode is selected ****"
      if [[ -f /config/.donoteditthisfile ]]; then
          . /config/.donoteditthisfile
      fi
      if [[ "$SERVERURL" != "$ORIG_SERVERURL" ]] || [[ "$SERVERPORT" != "$ORIG_SERVERPORT" ]] || [[ "$PEERDNS" != "$ORIG_PEERDNS" ]] || [[ "$PEERS" != "$ORIG_PEERS" ]] || [[ "$INTERFACE" != "$ORIG_INTERFACE" ]] || [[ "$ALLOWEDIPS" != "$ORIG_ALLOWEDIPS" ]] || [[ "$PERSISTENTKEEPALIVE_PEERS" != "$ORIG_PERSISTENTKEEPALIVE_PEERS" ]]; then
          echo "**** Server related environment variables changed, regenerating 1 server and ${PEERS} peer/client confs ****"
          generate_confs
          save_vars
      else
          echo "**** No changes to parameters. Existing configs are used. ****"
      fi
    fi
else
    echo "**** Client mode selected. ****"
    if [[ ! -f /config/wg0.conf ]]; then
        echo "**** No client conf found. Provide your own client conf as \"/config/wg0.conf\" and restart the container. ****"
        sleep infinity
    fi
    printf %s "${USE_COREDNS,,:-false}" > /run/s6/container_environment/USE_COREDNS
fi

# set up CoreDNS
if [[ ! -f /config/coredns/Corefile ]]; then
    cp /defaults/Corefile /config/coredns/Corefile
fi

# permissions
lsiown -R abc:abc \
    /config