# J621 public entry point (the "nginx" service in the compose files).
#
# Routes:
#   /api, /admin, /static, /health  -> backend:8000  (Django / gunicorn)
#   everything else                 -> frontend:80   (SPA static files)
#
# Both upstreams are variables so the same file works in all three compose
# variants: with no frontend on the network "/" answers a small JSON hint,
# with no backend the API paths answer 502 until one is configured via /setup.
# Nothing is published to the host; the Tailscale sidecar shares this
# container's network namespace and funnels to 127.0.0.1:80.

resolver 127.0.0.11 valid=10s ipv6=off;

map $http_x_forwarded_proto $j621_forwarded_proto {
    default $http_x_forwarded_proto;
    ""      $scheme;
}

server {
    listen 80;
    server_name _;

    location = /nginx-health {
        access_log off;
        return 200 "ok\n";
    }

    location ~ ^/(api|admin|static|health)(/|$) {
        set $j621_backend http://backend:8000;
        proxy_pass $j621_backend$request_uri;

        proxy_http_version 1.1;
        proxy_set_header Host $host;
        proxy_set_header X-Real-IP $remote_addr;
        proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
        proxy_set_header X-Forwarded-Host $host;
        proxy_set_header X-Forwarded-Proto $j621_forwarded_proto;

        # Uploads and client-processed files can be large; stream them.
        client_max_body_size 2048m;
        proxy_request_buffering off;
        proxy_read_timeout 600s;
        proxy_send_timeout 600s;
    }

    location / {
        set $j621_frontend http://frontend:80;
        proxy_pass $j621_frontend$request_uri;

        proxy_set_header Host $host;
        proxy_set_header X-Real-IP $remote_addr;
        proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
        proxy_set_header X-Forwarded-Host $host;
        proxy_set_header X-Forwarded-Proto $j621_forwarded_proto;

        # Backend-only deployments have no frontend: say so instead of 502.
        error_page 502 503 504 = @j621_no_frontend;
    }

    location @j621_no_frontend {
        default_type application/json;
        return 200 '{"detail":"J621 API - no frontend is attached to this deployment."}';
    }
}