# nginx vhost for the RFC app — single-process FastAPI behind nginx,
# frontend served as static files from the Vite build output.
#
# Install:
#   sudo cp deploy/nginx/ohm.wiggleverse.org.conf \
#       /etc/nginx/sites-available/ohm.wiggleverse.org
#   sudo ln -s /etc/nginx/sites-available/ohm.wiggleverse.org \
#       /etc/nginx/sites-enabled/
#   sudo nginx -t && sudo systemctl reload nginx
#
# Then add the Let's Encrypt cert:
#   sudo certbot --nginx -d ohm.wiggleverse.org
# Certbot will rewrite this file to add the 443 listener and certificate
# directives; the rest of the config below stays as written.

server {
    listen 80;
    listen [::]:80;
    server_name ohm.wiggleverse.org;

    # v0.25.0 security hardening (audit 0026 M2/L8)
    #
    # NOTE: certbot promotes THIS server block to the HTTPS listener
    # (`listen 443 ssl`) and adds a separate port-80 → 443 redirect
    # block (see the install comment above). These response headers
    # therefore ride into the HTTPS server block on the VM. They use
    # `add_header ... always` so they also apply to nginx-generated
    # error responses (4xx/5xx), not just 200s.
    #
    # `server_tokens off` (L8) — suppress the nginx version in the
    # Server header and on error pages so we don't advertise the
    # build to scanners.
    server_tokens off;

    add_header Strict-Transport-Security "max-age=31536000; includeSubDomains" always;
    add_header X-Frame-Options "DENY" always;
    add_header X-Content-Type-Options "nosniff" always;
    add_header Referrer-Policy "strict-origin-when-cross-origin" always;

    # Content-Security-Policy (M2). Tuned to what the SPA actually loads:
    #   - default-src 'self': everything not called out below is same-origin.
    #   - script-src 'self' + challenges.cloudflare.com: the only external
    #     <script> tag the app injects is the CloudFlare Turnstile widget
    #     (frontend/src/components/TurnstileWidget.jsx). Amplitude and
    #     mermaid are BUNDLED (dynamic `import()` from node_modules, served
    #     from 'self'), so they need no extra script origin — *.amplitude.com
    #     is listed defensively in case a future SDK build script-injects.
    #     script-src DELIBERATELY OMITS 'unsafe-inline' — no inline <script>
    #     is used, so we keep XSS-via-inline-script blocked.
    #   - style-src 'unsafe-inline' IS REQUIRED by the current build: the
    #     JSX uses inline `style={...}` attributes throughout and mermaid
    #     injects <style> blocks at render time. Removing it would break
    #     layout; tightening this is a future build-side change (nonce/hash).
    #   - img-src 'self' data: https: — markdown/RFC bodies may embed remote
    #     images and data: URIs; svg/mermaid output uses data: too.
    #   - font-src 'self' data: — bundled fonts plus data: webfonts.
    #   - connect-src 'self' + *.amplitude.com + challenges.cloudflare.com:
    #     the app's API/auth/SSE are same-origin (nginx proxy); Amplitude
    #     Analytics + Session Replay (shipped at sampleRate 1) POST to
    #     *.amplitude.com; Turnstile verifies via challenges.cloudflare.com.
    #   - worker-src 'self' blob: — Amplitude Session Replay spins up a
    #     Web Worker from a blob: URL for capture/compression; without
    #     blob: here session replay breaks for every consenting user.
    #   - frame-src challenges.cloudflare.com — the Turnstile challenge
    #     renders in an iframe from that origin.
    #   - frame-ancestors 'none' — clickjacking defense, pairs with
    #     X-Frame-Options DENY for older agents.
    #   - base-uri 'self'; object-src 'none' — lock down <base>/<object>.
    add_header Content-Security-Policy "default-src 'self'; script-src 'self' https://challenges.cloudflare.com https://*.amplitude.com; style-src 'self' 'unsafe-inline'; img-src 'self' data: https:; font-src 'self' data:; connect-src 'self' https://*.amplitude.com https://challenges.cloudflare.com; worker-src 'self' blob:; frame-src https://challenges.cloudflare.com; frame-ancestors 'none'; base-uri 'self'; object-src 'none'" always;

    # Static SPA assets live in the Vite build output. The systemd unit
    # runs as user `rfc-app`; make sure nginx (usually `www-data`) can
    # read this path. Either group-add www-data into rfc-app's group, or
    # chmod o+r on the dist/ tree.
    root /opt/rfc-app/frontend/dist;
    index index.html;

    # API routes are proxied to the FastAPI process. SSE chat streams
    # need proxy_buffering off so chunks reach the browser immediately;
    # the long read_timeout matches a slow LLM turn.
    location /api/ {
        proxy_pass http://127.0.0.1:8000;
        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-Proto $scheme;
        proxy_buffering off;
        proxy_cache off;
        proxy_read_timeout 1h;
    }

    location /auth/ {
        proxy_pass http://127.0.0.1:8000;
        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-Proto $scheme;
    }

    # SPA fallback — any non-asset path falls back to index.html so
    # React Router can take over.
    location / {
        try_files $uri $uri/ /index.html;
    }

    # Cache the hashed JS/CSS bundles aggressively; Vite includes a
    # content-hash in the filename so updates bust the cache for free.
    location ~* \.(js|css|woff2?|ttf|otf|eot|png|jpg|jpeg|gif|svg|ico)$ {
        try_files $uri =404;
        expires 1y;
        add_header Cache-Control "public, immutable";
    }

    # Reasonable upload cap. Adjust if RFC bodies grow large.
    client_max_body_size 4M;
}