# Frontend nginx config
# - Serves the built SPA from /usr/share/nginx/html
# - Proxies /api/* to the backend service (Docker compose network name: api)

server {
    listen 80;
    server_name _;

    root /usr/share/nginx/html;
    index index.html;

    # حداکثر حجم فایل‌های آپلودی (فاکتور/پیش‌فاکتور) — پیش‌فرض nginx فقط ۱ مگابایت
    # است و آپلودهای بزرگ‌تر با خطای 413 رد می‌شوند.
    client_max_body_size 50m;

    # API reverse proxy -> FastAPI backend (port 8000)
    # NOTE: upstream is resolved at REQUEST time through Docker's embedded DNS
    # (127.0.0.11). A plain `proxy_pass http://api:8000` caches the container
    # IP at nginx startup, so after the api container restarts and gets a new
    # IP, nginx keeps proxying to the stale address (which may belong to
    # another service) until this container is restarted too.
    location /api/ {
        resolver 127.0.0.11 valid=10s ipv6=off;
        set $api_upstream http://api:8000;
        proxy_pass $api_upstream;
        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 — all client-side routes go to index.html
    location / {
        try_files $uri $uri/ /index.html;
    }

    # Static assets cache
    location /assets/ {
        expires 30d;
        add_header Cache-Control "public, immutable";
    }
}