#!/bin/sh
# busfleet-hub register.sh — Device registration endpoint
# Called with DEVICE_ID as $1. Returns JSON on stdout.
# Port pool: 2230-2299

DEVICE_ID="${1:-unknown}"
REGISTRY="/opt/busfleet-hub/port-registry.json"
PORT_POOL_START="${PORT_POOL_START:-2230}"
PORT_POOL_END="${PORT_POOL_END:-2299}"
TAILSCALE_AUTH_KEY="${TAILSCALE_AUTH_KEY:-tskey-auth-kJz8wqNVo211CNTRL-GNL5EFjp5aWQcaWPSVn2aW9TNworKUNBV}"

# Init registry if missing
if [ ! -f "$REGISTRY" ]; then
	echo '{}' > "$REGISTRY"
fi

# Check if device already registered
EXISTING_PORT=$(python3 -c "
import json
with open('$REGISTRY') as f:
    reg = json.load(f)
print(reg.get('$DEVICE_ID', {}).get('tunnel_port', ''))
" 2>/dev/null)

if [ -n "$EXISTING_PORT" ]; then
	cat <<EOF
{"device_id": "${DEVICE_ID}", "tunnel_port": ${EXISTING_PORT}, "tailscale_auth_key": "${TAILSCALE_AUTH_KEY}", "status": "existing"}
EOF
	exit 0
fi

# Find next available port
ASSIGNED_PORT=$(python3 -c "
import json
with open('$REGISTRY') as f:
    reg = json.load(f)
used = set(v['tunnel_port'] for v in reg.values())
for port in range($PORT_POOL_START, $PORT_POOL_END + 1):
    if port not in used:
        print(port)
        break
" 2>/dev/null)

if [ -z "$ASSIGNED_PORT" ]; then
	cat <<EOF
{"device_id": "${DEVICE_ID}", "error": "no ports available in pool ${PORT_POOL_START}-${PORT_POOL_END}"}
EOF
	exit 1
fi

# Record assignment
TODAY=$(date +%Y-%m-%d)
python3 -c "
import json
with open('$REGISTRY') as f:
    reg = json.load(f)
reg['$DEVICE_ID'] = {'tunnel_port': $ASSIGNED_PORT, 'assigned': '$TODAY'}
with open('$REGISTRY', 'w') as f:
    json.dump(reg, f, indent=2)
" 2>/dev/null

cat <<EOF
{"device_id": "${DEVICE_ID}", "tunnel_port": ${ASSIGNED_PORT}, "tailscale_auth_key": "${TAILSCALE_AUTH_KEY}", "status": "new"}
EOF
exit 0