server {
    listen 80;
    server_name localhost;
    # Allow larger uploads (default is 1MB) – must be >= backend MAX_UPLOAD_SIZE
    client_max_body_size 50m;

    # Enable gzip compression for text-based assets
    gzip on;
    gzip_vary on;
    gzip_min_length 1024;
    gzip_comp_level 6;
    gzip_types text/plain text/css text/xml text/javascript 
               application/json application/javascript application/xml+rss 
               application/atom+xml image/svg+xml text/html;
    gzip_disable "msie6";
    gzip_proxied any;

    # Static assets with aggressive caching
    location ~* \.(jpg|jpeg|png|gif|ico|svg|webp)$ {
        root /usr/share/nginx/html;
        expires 1y;
        add_header Cache-Control "public, immutable";
        access_log off;
    }

    location ~* \.(css|js)$ {
        root /usr/share/nginx/html;
        expires 1y;
        add_header Cache-Control "public, immutable";
        access_log off;
    }

    location ~* \.(woff|woff2|ttf|eot)$ {
        root /usr/share/nginx/html;
        expires 1y;
        add_header Cache-Control "public, immutable";
        access_log off;
    }

    # SEO files - proxy to backend for dynamic generation
    location = /robots.txt {
        proxy_pass http://backend:8080;
        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;
        proxy_cache_bypass $http_cache_control;
        add_header Cache-Control "public, max-age=3600";
    }

    location = /sitemap.xml {
        proxy_pass http://backend:8080;
        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;
        proxy_cache_bypass $http_cache_control;
        add_header Cache-Control "public, max-age=3600";
    }

    location / {
        root /usr/share/nginx/html;
        index index.html;
        try_files $uri $uri/ /index.html;
        
        # Cache HTML files for shorter period
        add_header Cache-Control "public, max-age=3600, must-revalidate";
    }

    # API proxy with compression
    location /api/ {
        proxy_pass http://backend:8080;
        proxy_http_version 1.1;
        proxy_set_header Upgrade $http_upgrade;
        proxy_set_header Connection 'upgrade';
        proxy_set_header Host $host;
        proxy_cache_bypass $http_upgrade;
        proxy_set_header X-Real-IP $remote_addr;
        proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
        proxy_set_header Accept-Encoding gzip;
        # Ensure Nginx accepts large uploads on this route as well
        client_max_body_size 50m;
        
        # Enable buffering for better performance
        proxy_buffering on;
        proxy_buffer_size 4k;
        proxy_buffers 8 4k;
        proxy_busy_buffers_size 8k;
    }

    # Short links and tracked redirect - must bypass SPA and hit backend
    location ^~ /s/ {
        proxy_pass http://backend:8080;
        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;
    }
    location = /r {
        proxy_pass http://backend:8080;
        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;
    }

    # Proxy backend-served assets so the frontend can use relative URLs
    location /uploads/ {
        proxy_pass http://backend:8080;
        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;
        # Allow long cache; backend may set ETag/Last-Modified
        add_header Cache-Control "public, max-age=2592000";
    }

    location /dist/ {
        proxy_pass http://backend:8080;
        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;
        add_header Cache-Control "public, max-age=2592000";
    }

    location /cache/ {
        proxy_pass http://backend:8080;
        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;
        add_header Cache-Control "public, max-age=600";
    }

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