nginx.conf

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

events {
    worker_connections 1024;
}

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

    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;

    sendfile on;
    tcp_nopush on;
    keepalive_timeout 65;
    client_max_body_size 50m;

    # Security headers
    add_header X-Frame-Options SAMEORIGIN always;
    add_header X-Content-Type-Options nosniff always;
    add_header X-XSS-Protection "1; mode=block" always;

    gzip on;
    gzip_vary on;
    gzip_proxied any;
    gzip_comp_level 6;
    gzip_types text/plain text/css text/xml text/javascript
               application/json application/javascript application/xml+rss;

    # Rate limiting
    limit_req_zone $binary_remote_addr zone=api_limit:10m rate=10r/s;
    limit_req_zone $binary_remote_addr zone=auth_limit:10m rate=5r/s;

    # CORS origin whitelist (map to allowed origin or empty string)
    map $http_origin $cors_origin {
        default "";
        "http://localhost:5173"  $http_origin;
        "http://localhost:3000"  $http_origin;
        "http://localhost:6600"  $http_origin;
        # Add production domains here:
        # "https://your-domain.com" $http_origin;
    }

    # Upstream backend
    upstream backend {
        server backend:8000;
    }

    server {
        listen 80;
        server_name _;

        # Redirect HTTP to HTTPS in production
        # return 301 https://$server_name$request_uri;

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

        # Frontend static files
        location / {
            root /usr/share/nginx/html;
            try_files $uri $uri/ /index.html;

            # Cache static assets
            location ~* \.(js|css|png|jpg|jpeg|gif|ico|svg|woff|woff2|ttf|eot)$ {
                expires 1y;
                add_header Cache-Control "public, immutable";
            }
        }

        # API proxy - with rate limiting
        location /api/ {
            limit_req zone=api_limit burst=20 nodelay;

            proxy_pass http://backend;
            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_read_timeout 120s;
            proxy_connect_timeout 10s;

            # CORS headers (use whitelist from map block, not wildcard)
            add_header Access-Control-Allow-Origin $cors_origin always;
            add_header Access-Control-Allow-Methods "GET, POST, PUT, DELETE, PATCH, OPTIONS" always;
            add_header Access-Control-Allow-Headers "Authorization, Content-Type, X-Requested-With" always;
            add_header Access-Control-Allow-Credentials "true" always;

            # Handle OPTIONS preflight requests
            if ($request_method = OPTIONS) {
                add_header Access-Control-Allow-Origin $cors_origin;
                add_header Access-Control-Allow-Methods "GET, POST, PUT, DELETE, PATCH, OPTIONS";
                add_header Access-Control-Allow-Headers "Authorization, Content-Type, X-Requested-With";
                add_header Access-Control-Allow-Credentials "true";
                add_header Content-Length 0;
                add_header Content-Type text/plain;
                return 204;
            }
        }

        # Auth API - stricter rate limiting
        location /api/auth/ {
            limit_req zone=auth_limit burst=5 nodelay;

            proxy_pass http://backend;
            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;
        }

        # Swagger docs proxy
        location /docs {
            proxy_pass http://backend/docs;
            proxy_set_header Host $host;
        }
        location /redoc {
            proxy_pass http://backend/redoc;
            proxy_set_header Host $host;
        }
        location /openapi.json {
            proxy_pass http://backend/openapi.json;
            proxy_set_header Host $host;
        }

        # Health check endpoint
        location /health {
            proxy_pass http://backend/health;
            access_log off;
        }

        # WebSocket support for future use
        location /ws/ {
            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;
        }
    }

    # HTTPS server configuration (uncomment and configure for production)
    # server {
    #     listen 443 ssl http2;
    #     server_name your-domain.com;
    #
    #     ssl_certificate /etc/nginx/ssl/cert.pem;
    #     ssl_certificate_key /etc/nginx/ssl/key.pem;
    #     ssl_protocols TLSv1.2 TLSv1.3;
    #     ssl_ciphers HIGH:!aNULL:!MD5;
    #
    #     # ... same location blocks as above
    # }
}