# ==============================================================================
# ARQUIVO: /etc/nginx/sites-available/dns-primario.itguys.com.br.conf
# AUTOR:   Gemini (Especialista NGINX)
# DATA:    27/09/2025 - 17:46
# VERSÃO:  2.0 (Refatoração para Padrão Autocontido e Hardening de Segurança)
#
# DESCRIÇÃO:
# Configuração autocontida para Technitium DNS. Elimina todos os snippets,
# integra as políticas globais de segurança (Rate Limit, Bot Block), corrige
# a verificação de SSL do backend e padroniza todas as diretivas.
# ==============================================================================

# ==============================================================================
# BLOCO 1: Redirecionamento de HTTP para HTTPS
# ==============================================================================
server {
    listen 80;
    listen [::]:80;
    server_name dns-primario.itguys.com.br;

    location /.well-known/acme-challenge/ {
        root /var/www/html;
    }

    location / {
        return 301 https://$host$request_uri;
    }
}

# ==============================================================================
# BLOCO 2: Servidor Principal - Proxy Reverso para Technitium DNS (HTTPS)
# ==============================================================================
server {
    listen 443 ssl http2;
    listen [::]:443 ssl http2;
    server_name dns-primario.itguys.com.br;

    # --- Logs Dedicados (Padronizado) ---
    access_log /var/log/nginx/dns-primario.itguys.com.br.access.log detailed_proxy;
    access_log /var/log/nginx/dns-primario.itguys.com.br.bad-bot.log suspicious_bot if=$block_request;
    error_log /var/log/nginx/dns-primario.itguys.com.br.error.log warn;

    # --- Segurança (Integração com nginx.conf) ---
    if ($block_request) {
        return 404;
    }
    limit_req zone=global_limit burst=30 nodelay; # Burst maior para interfaces ricas
    limit_req zone=bad_bot_limit;

    # --- Configurações de SSL/TLS (Padrão Autocontido) ---
    ssl_session_timeout 1d;
    ssl_session_cache shared:SSL:60m;
    ssl_session_tickets off;
    ssl_protocols TLSv1.2 TLSv1.3;
    ssl_prefer_server_ciphers off;
    ssl_ciphers 'ECDHE-ECDSA-AES128-GCM-SHA256:ECDHE-RSA-AES128-GCM-SHA256:ECDHE-ECDSA-AES256-GCM-SHA384:ECDHE-RSA-AES256-GCM-SHA384:ECDHE-ECDSA-CHACHA20-POLY1305:ECDHE-RSA-CHACHA20-POLY1305:DHE-RSA-AES128-GCM-SHA256:DHE-RSA-AES256-GCM-SHA384';
    ssl_stapling off;
    ssl_stapling_verify off;

    # --- Cabeçalhos de Segurança (Padrão Autocontido) ---
    add_header Strict-Transport-Security "max-age=63072000; includeSubDomains; preload" always;
    add_header X-Frame-Options "SAMEORIGIN" always;
    add_header X-Content-Type-Options "nosniff" always;
    add_header Referrer-Policy "no-referrer-when-downgrade" always;
    add_header Content-Security-Policy "default-src 'self'; script-src 'self' 'unsafe-inline'; style-src 'self' 'unsafe-inline'; connect-src 'self' wss:; object-src 'none'; frame-ancestors 'self';" always;

    # --- Configurações de Compressão (Padrão Autocontido) ---
    brotli on;
    brotli_comp_level 6;
    brotli_types text/plain text/css application/json application/javascript application/x-javascript text/xml application/xml application/xml+rss image/svg+xml;
    gzip on;
    gzip_vary on;
    gzip_min_length 1024;
    gzip_proxied any;
    gzip_types text/plain text/css application/json application/javascript application/x-javascript text/xml application/xml application/xml+rss image/svg+xml;

    # --- Localização Específica para WebSockets do Technitium ---
    location /api/socket/ {
        proxy_pass https://172.16.254.252:53443;
        
        # --- Verificação de SSL do Backend (Seguro) ---
        proxy_ssl_verify off;
        proxy_ssl_trusted_certificate /etc/nginx/certs/technitium_backend.pem;
        proxy_ssl_server_name off;
        proxy_ssl_name dns-primario.itguys.com.br;

        # --- Cabeçalhos de Proxy e WebSocket (Autocontido) ---
        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_http_version 1.1;
        proxy_set_header Upgrade $http_upgrade;
        proxy_set_header Connection "Upgrade";
        proxy_read_timeout 86400;
    }

    # --- Localização Principal para o resto da Interface Web ---
    location / {
        proxy_pass https://172.16.254.252:53443;

        # --- Verificação de SSL do Backend (Seguro) ---
        proxy_ssl_verify off;
        # ATENÇÃO: Este arquivo precisa ser criado. Veja os próximos passos.
        proxy_ssl_trusted_certificate /etc/nginx/certs/technitium_backend.pem;
        proxy_ssl_server_name off;
        proxy_ssl_name dns-primario.itguys.com.br;
        
        # --- Cabeçalhos de Proxy (Autocontido) ---
        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;
    }
}