# =============================================================================
# PolyglotAlpha — nginx reverse-proxy config for Hugging Face Spaces (W23)
# =============================================================================
# HF Spaces exposes exactly ONE port externally (the value of `app_port` in
# the README frontmatter — we use 7860). nginx fans the single ingress out
# to two backends:
#
#   /api/*, /sse/*, /trigger/*, /events/*, /leaderboard/*,
#   /operators/*, /agents/*, /health           -> uvicorn :8000  (FastAPI)
#   everything else                            -> next start  :3001 (Next.js)
#
# Two routing concerns to keep in mind:
#   1. SSE streams need `proxy_buffering off` AND a long read timeout — the
#      default 60 s would kill the lifecycle progress stream mid-event.
#   2. Next.js HMR/websocket upgrades need the Upgrade/Connection headers
#      even in `next start` (the React server channel uses them).
# -----------------------------------------------------------------------------

worker_processes 1;

events {
    worker_connections 1024;
}

http {
    include /etc/nginx/mime.types;
    default_type application/octet-stream;
    sendfile on;
    keepalive_timeout 65;
    server_tokens off;

    # Lift the default 1 MB request body limit a touch — trigger payloads
    # with mock_bids can comfortably fit in 64 kB, but 4 MB gives headroom
    # for future demo features without surprising 413s.
    client_max_body_size 4m;

    upstream polyglot_backend {
        server 127.0.0.1:8000;
    }

    upstream polyglot_frontend {
        server 127.0.0.1:3001;
    }

    server {
        listen 7860 default_server;
        listen [::]:7860 default_server;
        server_name _;

        # ─── /api/sse/ (SSE — most specific, NO buffering) ─────────────────
        # Has to come BEFORE /api/ generic so the no-buffer settings apply.
        # `rewrite ... break` strips the /api prefix before forwarding to
        # FastAPI (which serves at /sse/events).
        location ^~ /api/sse/ {
            rewrite ^/api(/.*)$ $1 break;
            proxy_pass http://polyglot_backend;
            proxy_http_version 1.1;
            proxy_buffering off;
            proxy_cache off;
            proxy_read_timeout 3600s;
            proxy_send_timeout 3600s;
            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-Proto $scheme;
            proxy_set_header Connection "";
            add_header X-Accel-Buffering no always;
        }

        # ─── /api/* — all other backend routes ─────────────────────────────
        # nginx strips the /api prefix so FastAPI's existing `/events`,
        # `/trigger`, `/leaderboard`, `/operators`, `/agents`, etc.
        # routes serve as-is. The UI's `NEXT_PUBLIC_API_BASE=/api` means
        # `fetch("/events/6")` becomes `fetch("/api/events/6")` from the
        # browser, which nginx routes here.
        #
        # WITHOUT this prefix, `/events/6` would be claimed by Next.js's
        # page router (which has its own `/events/[id]` route) — the
        # backend JSON response would never reach the UI's React tree.
        location ^~ /api/ {
            rewrite ^/api(/.*)$ $1 break;
            proxy_pass http://polyglot_backend;
            proxy_read_timeout 600s;
            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-Proto $scheme;
        }

        # Health check used by the entrypoint pre-seed loop AND by HF Spaces
        # readiness probing.
        location = /health {
            proxy_pass http://polyglot_backend;
            proxy_read_timeout 5s;
            access_log off;
        }

        location = /healthz {
            return 200 "ok\n";
            add_header Content-Type text/plain;
            access_log off;
        }

        # ---- Frontend: everything else -------------------------------------
        # Next.js handles its own routing (App Router); the websocket/upgrade
        # headers are required for streaming server components and any
        # future websocket transport.
        location / {
            proxy_pass http://polyglot_frontend;
            proxy_http_version 1.1;
            proxy_set_header Upgrade $http_upgrade;
            proxy_set_header Connection "upgrade";
            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-Proto $scheme;
            proxy_cache_bypass $http_upgrade;
            proxy_read_timeout 60s;
        }
    }
}