server {
    listen 80;
    server_name _;
    root /usr/share/nginx/html;
    index index.html;

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

    # 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 "no-referrer-when-downgrade" always;

    # API proxy - forward all /api requests to backend service
    # Strip /api prefix so /api/v1/health becomes /v1/health
    location /api/ {
        proxy_pass http://backend:3000/;
        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;
        proxy_cache_bypass $http_upgrade;

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

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

    # Don't cache index.html
    location = /index.html {
        expires -1;
        add_header Cache-Control "no-store, no-cache, must-revalidate, proxy-revalidate, max-age=0";
    }

    # SPA routing - serve index.html for all routes
    location / {
        try_files $uri $uri/ /index.html;
    }

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

    # Hide nginx version
    server_tokens off;

    # Custom error pages
    error_page 404 /index.html;
    error_page 500 502 503 504 /50x.html;
    location = /50x.html {
        root /usr/share/nginx/html;
    }
}