#!/bin/sh
set -e

if [ -z "$NC_DOMAIN" ]; then
    echo "ERROR: NC_DOMAIN is not set" >&2
    exit 1
fi

LOCAL_IP=""

# Determine the server's primary LAN IP - use the source address chosen by the kernel
# for a route to a well-known public IP (1.1.1.1 is used purely to query the routing table;
# no traffic is sent there).
LOCAL_IP=$(ip route get 1.1.1.1 2>/dev/null | awk '{for(i=1;i<=NF;i++) if($i=="src") {print $(i+1); exit}}')

if [ -z "$LOCAL_IP" ]; then
    LOCAL_IP=$(hostname -I 2>/dev/null | awk '{print $1}')
fi

if [ -z "$LOCAL_IP" ]; then
    echo "ERROR: Could not determine local IP address" >&2
    exit 1
fi

echo "Nextcloud AIO dnsmasq: resolving $NC_DOMAIN -> $LOCAL_IP"
echo "Configure your router's DHCP to hand out $LOCAL_IP as the DNS server for LAN clients."

mkdir -p /etc/dnsmasq.d

cat > /etc/dnsmasq.d/nextcloud-aio.conf << EOF
# Auto-generated by Nextcloud AIO dnsmasq container.
# Resolves NC_DOMAIN (and all its subdomains) to this server's local IP.
address=/$NC_DOMAIN/$LOCAL_IP

# Bind only to the LAN interface to avoid conflicts with any system DNS resolver.
bind-interfaces
listen-address=$LOCAL_IP
EOF

exec dnsmasq --no-daemon --log-queries --conf-dir=/etc/dnsmasq.d