server {
    listen 80;
    listen [::]:80;
    server_name app.pokedex.online localhost;

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

    # Enable gzip compression
    gzip on;
    gzip_vary on;
    gzip_min_length 1024;
    gzip_proxied any;
    gzip_comp_level 6;
    gzip_types text/plain text/css application/json application/javascript text/xml application/xml application/xml+rss text/javascript application/vnd.ms-fontobject application/x-font-ttf font/opentype image/svg+xml;

    # 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;
    add_header Referrer-Policy "strict-origin-when-cross-origin" always;
    add_header Permissions-Policy "geolocation=(), microphone=(), camera=()" always;

    # Serve static files
    location / {
        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";
        }
        
        # Don't cache HTML files
        location ~* \.(html)$ {
            expires -1;
            add_header Cache-Control "no-store, no-cache, must-revalidate, proxy-revalidate";
        }
    }

    # Proxy to backend API server (OAuth proxy + Gamemaster API)
    location /api/ {
        proxy_pass http://backend:3000/;
        proxy_http_version 1.1;
        
        # Proxy headers
        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_set_header X-Forwarded-Host $host;
        
        # WebSocket support (if needed later)
        proxy_set_header Upgrade $http_upgrade;
        proxy_set_header Connection "upgrade";
        
        # Timeout settings
        proxy_connect_timeout 10s;
        proxy_send_timeout 60s;
        proxy_read_timeout 60s;
        
        # Buffer settings
        proxy_buffering on;
        proxy_buffer_size 4k;
        proxy_buffers 8 4k;
    }

    # Proxy Challonge API requests to avoid CORS
    location /api/challonge/ {
        # Remove /api/challonge prefix and forward to Challonge API
        rewrite ^/api/challonge/(.*) /v1/$1 break;
        
        proxy_pass https://api.challonge.com;
        proxy_ssl_server_name on;
        proxy_ssl_protocols TLSv1.2 TLSv1.3;
        
        # Proxy headers
        proxy_set_header Host api.challonge.com;
        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;
        
        # CORS headers for browser requests
        add_header Access-Control-Allow-Origin $http_origin always;
        add_header Access-Control-Allow-Methods "GET, POST, PUT, DELETE, OPTIONS" always;
        add_header Access-Control-Allow-Headers "Authorization, Content-Type, Accept" always;
        add_header Access-Control-Allow-Credentials "true" always;
        
        # Handle preflight OPTIONS requests
        if ($request_method = OPTIONS) {
            add_header Access-Control-Allow-Origin $http_origin always;
            add_header Access-Control-Allow-Methods "GET, POST, PUT, DELETE, OPTIONS" always;
            add_header Access-Control-Allow-Headers "Authorization, Content-Type, Accept" always;
            add_header Access-Control-Max-Age 86400;
            add_header Content-Length 0;
            return 204;
        }
        
        # Timeout settings
        proxy_connect_timeout 10s;
        proxy_send_timeout 30s;
        proxy_read_timeout 30s;
    }

    # Health check endpoint
    location /health {
        access_log off;
        return 200 "healthy\n";
        add_header Content-Type text/plain;
    }

    # Error pages
    error_page 404 /index.html;
    error_page 500 502 503 504 /index.html;
}