upstream crm_backend {
    server 127.0.0.1:7100;
}

# Rate limiting zones
limit_req_zone $binary_remote_addr zone=general:10m rate=10r/s;
limit_req_zone $binary_remote_addr zone=auth:10m    rate=1r/s;
limit_req_zone $binary_remote_addr zone=upload:10m  rate=5r/s;

server {
    listen 80;
    listen [::]:80;
    server_name pn.letsbe.solutions;

    # Allow certbot ACME challenges
    location /.well-known/acme-challenge/ {
        root /var/www/certbot;
    }

    # Security headers
    add_header X-Content-Type-Options "nosniff" always;
    add_header X-Frame-Options "DENY" always;
    add_header X-XSS-Protection "0" always;
    add_header Referrer-Policy "strict-origin-when-cross-origin" always;
    add_header Permissions-Policy "camera=(), microphone=(), geolocation=()" always;

    # Client body size limit (50MB for file uploads)
    client_max_body_size 50m;

    # URL length limit
    large_client_header_buffers 4 8k;

    # Gzip compression
    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 application/atom+xml
               image/svg+xml;

    # Auth endpoints - strict rate limit
    location ~ ^/api/auth/ {
        limit_req zone=auth burst=5 nodelay;
        limit_req_status 429;
        proxy_pass http://crm_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;
        proxy_set_header Connection "";
        proxy_cache_bypass $http_upgrade;
        proxy_read_timeout 60s;
        proxy_send_timeout 60s;
        proxy_connect_timeout 10s;
    }

    # File upload endpoints - dedicated rate limit
    location ~ ^/api/v1/files {
        limit_req zone=upload burst=10 nodelay;
        limit_req_status 429;
        client_max_body_size 50m;
        proxy_pass http://crm_backend;
        proxy_request_buffering off;
        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_set_header Connection "";
        proxy_cache_bypass $http_upgrade;
        proxy_read_timeout 60s;
        proxy_send_timeout 60s;
        proxy_connect_timeout 10s;
    }

    # WebSocket upgrade for Socket.io
    location /socket.io/ {
        limit_req zone=general burst=20 nodelay;
        proxy_pass http://crm_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;
        proxy_read_timeout 86400s;
        proxy_send_timeout 86400s;
    }

    # All other traffic - general rate limit
    location / {
        limit_req zone=general burst=20 nodelay;
        limit_req_status 429;
        proxy_pass http://crm_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;
        proxy_set_header Connection "";
        proxy_cache_bypass $http_upgrade;
        proxy_read_timeout 60s;
        proxy_send_timeout 60s;
        proxy_connect_timeout 10s;
    }
}