# ServerKit Production Nginx Configuration
#
# This is the reference all-in-one nginx config. It assumes TLS terminates at
# this server. If you use Cloudflare in front, prefer the split design in
# nginx/sites-available/serverkit.conf, which supports Cloudflare Origin CA
# certificates and documents the Cloudflare dashboard settings that make the
# end-user experience painless (Always Use HTTPS, HSTS, Minimum TLS 1.2).

user nginx;
worker_processes auto;
error_log /var/log/nginx/error.log warn;
pid /var/run/nginx.pid;

events {
    worker_connections 1024;
    use epoll;
    multi_accept on;
}

http {
    include /etc/nginx/mime.types;
    default_type application/octet-stream;

    # Logging format
    log_format main '$remote_addr - $remote_user [$time_local] "$request" '
                    '$status $body_bytes_sent "$http_referer" '
                    '"$http_user_agent" "$http_x_forwarded_for"';

    access_log /var/log/nginx/access.log main;

    # Performance settings
    sendfile on;
    tcp_nopush on;
    tcp_nodelay on;
    keepalive_timeout 65;
    types_hash_max_size 2048;
    client_max_body_size 100m;

    # Gzip compression
    gzip on;
    gzip_vary on;
    gzip_proxied any;
    gzip_comp_level 6;
    gzip_types text/plain text/css text/xml application/json application/javascript
               application/xml+rss application/atom+xml image/svg+xml;

    # Rate limiting zones
    limit_req_zone $binary_remote_addr zone=api_limit:10m rate=100r/m;
    limit_req_zone $binary_remote_addr zone=auth_limit:10m rate=5r/m;
    limit_conn_zone $binary_remote_addr zone=conn_limit:10m;

    # Upstream servers
    # Backend runs on host, not in Docker
    upstream backend {
        server 127.0.0.1:5000;
        keepalive 32;
    }

    # Frontend runs in Docker
    upstream frontend {
        server host.docker.internal:8080;
    }

    # HTTP server - redirect to HTTPS
    server {
        listen 80;
        server_name _;

        # Allow Let's Encrypt verification
        location /.well-known/acme-challenge/ {
            root /var/www/certbot;
        }

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

    # HTTPS server
    server {
        listen 443 ssl http2;
        server_name _;

        # SSL Configuration
        # For Cloudflare Origin CA, replace these paths with your origin cert/key.
        ssl_certificate /etc/nginx/ssl/fullchain.pem;
        ssl_certificate_key /etc/nginx/ssl/privkey.pem;
        ssl_session_timeout 1d;
        ssl_session_cache shared:SSL:50m;
        ssl_session_tickets off;

        # Modern SSL configuration
        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;
        ssl_prefer_server_ciphers off;

        # OCSP stapling (optional)
        # ssl_stapling on;
        # ssl_stapling_verify on;
        # ssl_trusted_certificate /etc/nginx/ssl/chain.pem;

        # HSTS
        add_header Strict-Transport-Security "max-age=63072000; includeSubDomains; preload" always;

        # Security headers
        add_header X-Frame-Options "DENY" always;
        add_header X-Content-Type-Options "nosniff" always;
        add_header X-XSS-Protection "1; mode=block" always;
        add_header Referrer-Policy "strict-origin-when-cross-origin" always;
        add_header Permissions-Policy "geolocation=(), microphone=(), camera=()" always;

        # Content Security Policy
        add_header Content-Security-Policy "default-src 'self'; script-src 'self' 'unsafe-inline' 'unsafe-eval'; style-src 'self' 'unsafe-inline'; img-src 'self' data: https:; font-src 'self'; connect-src 'self' ws: wss:; frame-ancestors 'none'; base-uri 'self'; form-action 'self' https://github.com;" always;

        # Connection limits
        limit_conn conn_limit 20;

        # Root location - serve frontend
        location / {
            proxy_pass http://frontend;
            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;
        }

        # Auth endpoints - strict rate limiting
        location /api/v1/auth {
            limit_req zone=auth_limit burst=3 nodelay;

            proxy_pass http://backend;
            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;
        }

        # API endpoints
        location /api {
            limit_req zone=api_limit burst=20 nodelay;

            proxy_pass http://backend;
            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;

            # Timeouts
            proxy_connect_timeout 60s;
            proxy_send_timeout 60s;
            proxy_read_timeout 60s;
        }

        # WebSocket support for socket.io
        location /socket.io {
            proxy_pass http://backend;
            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;

            # WebSocket specific timeouts
            proxy_connect_timeout 7d;
            proxy_send_timeout 7d;
            proxy_read_timeout 7d;
        }

        # Deny access to sensitive files
        location ~ /\. {
            deny all;
        }

        location ~* \.(env|git|gitignore|dockerignore)$ {
            deny all;
        }
    }
}