# Honor a reverse proxy's X-Forwarded-Proto (e.g. traefik terminating TLS) so the API sees
# https and builds https OAuth redirects; fall back to the connection scheme for direct access.
map $http_x_forwarded_proto $fwd_proto {
    default $scheme;
    https   https;
    http    http;
}

server {
    listen 80;
    server_name _;
    root /usr/share/nginx/html;
    index index.html;

    # AUDIT M-2: security headers on the SPA. script-src 'self' works because the theme
    # bootstrap lives in /theme-init.js (no inline scripts); style-src needs 'unsafe-inline'
    # for React/Chart.js/grid-layout inline style attributes (low risk with script-src locked).
    add_header Content-Security-Policy "default-src 'self'; script-src 'self'; style-src 'self' 'unsafe-inline'; img-src 'self' data:; font-src 'self'; connect-src 'self'; object-src 'none'; base-uri 'self'; form-action 'self'; frame-ancestors 'none'" always;
    add_header X-Content-Type-Options "nosniff" always;
    add_header X-Frame-Options "DENY" always;
    add_header Referrer-Policy "no-referrer" always;

    # Compress the SPA bundle (AUDIT perf note: ~680 KB JS).
    gzip on;
    gzip_types text/css application/javascript application/json image/svg+xml;
    gzip_min_length 1024;

    # SPA fallback.
    location / {
        try_files $uri $uri/ /index.html;
    }

    # Proxy API + auth calls to the backend container.
    location /api/ {
        proxy_pass http://api:8080;
        proxy_set_header Host $http_host;
        proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
        proxy_set_header X-Forwarded-Proto $fwd_proto;
        proxy_set_header X-Forwarded-Host $http_host;
        proxy_set_header Cookie $http_cookie;
    }

    # Google OAuth2 callback + sign-out land here (not under /api) and must
    # reach the backend so the cookie session is established same-origin.
    location ~ ^/(signin-google|signout-google) {
        proxy_pass http://api:8080;
        proxy_set_header Host $http_host;
        proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
        proxy_set_header X-Forwarded-Proto $fwd_proto;
        proxy_set_header X-Forwarded-Host $http_host;
        proxy_set_header Cookie $http_cookie;
    }
}