# nginx/conf.d/default.conf -- SSL Termination + Reverse Proxy
# Input:  HTTPS requests on port 443, HTTP requests on port 80
# Output: Proxied requests to upstream app:8080 with TLS terminated at Nginx
#
# Replace example.com with your domain name.
# Requires valid certificates at /etc/letsencrypt/live/example.com/

# HTTP -> HTTPS redirect + ACME challenge support
server {
    listen 80;
    listen [::]:80;
    server_name example.com www.example.com;

    # Let's Encrypt ACME HTTP-01 challenge handler
    location /.well-known/acme-challenge/ {
        root /var/www/certbot;
    }

    # Redirect all other HTTP traffic to HTTPS
    location / {
        return 301 https://$host$request_uri;
    }
}

# HTTPS server with SSL termination and reverse proxy
server {
    listen 443 ssl;
    listen [::]:443 ssl;
    http2 on;  # Nginx 1.25+ syntax (replaces 'listen 443 ssl http2')
    server_name example.com www.example.com;

    # SSL certificates managed by Certbot / Let's Encrypt
    ssl_certificate     /etc/letsencrypt/live/example.com/fullchain.pem;
    ssl_certificate_key /etc/letsencrypt/live/example.com/privkey.pem;

    # Modern TLS configuration (A+ on SSL Labs)
    ssl_protocols TLSv1.2 TLSv1.3;
    ssl_ciphers ECDHE-ECDSA-AES128-GCM-SHA256:ECDHE-RSA-AES128-GCM-SHA256:ECDHE-ECDSA-AES256-GCM-SHA384:ECDHE-RSA-AES256-GCM-SHA384:ECDHE-ECDSA-CHACHA20-POLY1305:ECDHE-RSA-CHACHA20-POLY1305;
    ssl_prefer_server_ciphers off;

    # SSL session optimization
    ssl_session_cache shared:SSL:10m;
    ssl_session_timeout 1d;
    ssl_session_tickets off;

    # OCSP stapling for faster TLS handshakes
    ssl_stapling on;
    ssl_stapling_verify on;
    ssl_trusted_certificate /etc/letsencrypt/live/example.com/chain.pem;
    resolver 1.1.1.1 1.0.0.1 valid=300s;
    resolver_timeout 5s;

    # Security headers
    add_header Strict-Transport-Security "max-age=63072000; includeSubDomains; preload" always;
    add_header X-Content-Type-Options "nosniff" always;
    add_header X-Frame-Options "DENY" always;
    add_header Referrer-Policy "strict-origin-when-cross-origin" always;

    # Reverse proxy to upstream application
    location / {
        proxy_pass http://app:8080;
        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_http_version 1.1;
        proxy_set_header Upgrade $http_upgrade;
        proxy_set_header Connection "upgrade";
        proxy_read_timeout 90s;
        proxy_buffering on;
    }
}