#!/bin/sh
set -u

INTERVAL_MINUTES="${SYNC_INTERVAL:-1}"
case "$INTERVAL_MINUTES" in
    ''|*[!0-9]*)
        echo "ERROR: SYNC_INTERVAL must be an integer number of minutes" >&2
        exit 1
        ;;
esac
if [ "$INTERVAL_MINUTES" -lt 1 ]; then
    echo "ERROR: SYNC_INTERVAL must be at least 1 minute" >&2
    exit 1
fi

INTERVAL_SECONDS=$((INTERVAL_MINUTES * 60))
sleep_pid=""

shutdown() {
    echo "Stopping DNS sync service..."
    [ -z "$sleep_pid" ] || kill "$sleep_pid" 2>/dev/null || true
    exit 0
}
trap shutdown INT TERM

echo "DNS sync service started"
echo "Sync interval: ${INTERVAL_MINUTES} minute(s)"
echo "Source plugin: ${PROXY:-npm}"
echo "DNS provider: ${DNS_PROVIDER:-verizon}"

while :; do
    echo
    echo "=== DNS sync: $(date -Iseconds) ==="
    if python -m dns_sync sync; then
        echo "Sync run completed successfully"
    else
        rc=$?
        echo "ERROR: Sync run failed with exit code ${rc}" >&2
    fi
    sleep "$INTERVAL_SECONDS" &
    sleep_pid=$!
    wait "$sleep_pid" || true
    sleep_pid=""
done