# ==============================================================================
# ARQUIVO: /etc/nginx/sites-available/ns2.itguys.com.br.conf
# AUTOR:    Gemini (Especialista NGINX)
# DATA:     27/09/2025 (Consolidado e otimizado)
#
# CONTEXTO:
# Configuração de Proxy Reverso OTIMIZADA e SEGURA para Technitium DNS Server (ns2).
# Todas as configurações, incluindo SSL/TLS e segurança, foram declaradas
# diretamente neste arquivo, sem o uso de snippets.
#
# UPSTREAM: https://172.16.254.251:53443 (Observar 'proxy_ssl_verify off')
# ==============================================================================

# Define o nosso servidor Technitium como um "upstream".
# O NGINX irá se conectar a este backend usando HTTPS.
upstream technitium_backend_ns2 {
    server 172.16.254.251:53443;
    keepalive 64;
}

# ------------------------------------------------------------------------------
# BLOCO 1: Redirecionamento de HTTP (porta 80) para HTTPS
# ------------------------------------------------------------------------------
server {
    listen 80;
    listen [::]:80;
    server_name ns2.itguys.com.br;

    # Aplica o rate limiting básico (zona global_limit deve estar em nginx.conf)
    limit_req zone=global_limit burst=20 nodelay;

    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 ns2.itguys.com.br;

    # ============================================================================
    # LOGS, SEGURANÇA BÁSICA E RATE LIMITING
    # ============================================================================
    client_max_body_size 5M;
    access_log /var/log/nginx/ns2.itguys.com.br.access.log detailed_proxy;
    error_log /var/log/nginx/ns2.itguys.com.br.error.log warn;
    # Log para acessos bloqueados por bots (depende de $is_bad_bot em nginx.conf)
    access_log /var/log/nginx/ns2.itguys.com.br.bad-bot.log suspicious_bot if=$is_bad_bot;

    # Módulo de Segurança Global (Bloqueia bots e URIs suspeitas de nginx.conf)
    if ($block_request) {
        return 404;
    }

    # Rate Limiting (zona global_limit deve estar em nginx.conf)
    limit_req zone=global_limit burst=50 nodelay;

    # --- RESTRIÇÃO DE ACESSO ---
    # **INCLUIR REGRAS 'allow' e 'deny' AQUI**
    # Exemplo:
    # allow 172.16.0.0/16;
    # deny all;

    # ============================================================================
    # CONFIGURAÇÕES DE SSL/TLS (Hardening)
    # ============================================================================
    #ssl_certificate /etc/letsencrypt/live/ns2.itguys.com.br/fullchain.pem;
    #ssl_certificate_key /etc/letsencrypt/live/ns2.itguys.com.br/privkey.pem;
    #ssl_protocols TLSv1.3 TLSv1.2;
    ssl_ciphers 'TLS_AES_128_GCM_SHA256:TLS_AES_256_GCM_SHA384:TLS_CHACHA20_POLY1305_SHA256: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';
    ssl_prefer_server_ciphers on;
    ssl_ecdh_curve X25519:secp256r1:secp384r1;
    ssl_session_timeout 1d;
    ssl_dhparam /etc/nginx/dhparam.pem;
    ssl_session_tickets off;

    # OCSP Stapling
    ssl_stapling off;
    ssl_stapling_verify off;
    ssl_trusted_certificate /etc/letsencrypt/live/ns2.itguys.com.br/fullchain.pem;
    resolver 8.8.8.8 8.8.4.4 valid=300s;
    resolver_timeout 5s;

    # ============================================================================
    # HEADERS DE SEGURANÇA
    # ============================================================================
    add_header Strict-Transport-Security "max-age=63072000; includeSubDomains; preload" always;
    add_header X-Content-Type-Options "nosniff" always;
    add_header X-Frame-Options "SAMEORIGIN" always;
    add_header Referrer-Policy "no-referrer" always;
    add_header Permissions-Policy "geolocation=(), microphone=(), camera=(), payment=()" always;
    add_header Content-Security-Policy "default-src 'self'; script-src 'self' 'unsafe-inline' 'unsafe-eval'; style-src 'self' 'unsafe-inline'; img-src 'self' data:; connect-src 'self' wss:; font-src 'self'; object-src 'none';" always;
    
    # ============================================================================
    # COMPRESSÃO
    # ============================================================================
    brotli on;
    brotli_comp_level 6;
    brotli_min_length 256;
    brotli_types text/plain text/css application/json application/javascript text/xml application/xml application/xml+rss text/javascript image/svg+xml;
    gzip on;
    gzip_vary on;
    gzip_proxied any;
    gzip_comp_level 6;
    gzip_min_length 256;
    gzip_types text/plain text/css application/json application/javascript text/xml application/xml application/xml+rss text/javascript image/svg+xml;

    # ============================================================================
    # PARÂMETROS GLOBAIS DE PROXY
    # ============================================================================
    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;
    proxy_set_header X-Forwarded-Port $server_port;
    proxy_set_header User-Agent $http_user_agent;
    proxy_http_version 1.1;
    proxy_connect_timeout 60s;
    proxy_read_timeout 90s;
    proxy_send_timeout 90s;
    proxy_buffering off;
    proxy_request_buffering off;

    # IMPORTANTE: Desabilita a verificação de certificado para o backend HTTPS
    proxy_ssl_verify off;

    # ----------------------------------------------------------------------------
    # REGRAS DE ROTEAMENTO (LOCATIONS)
    # ----------------------------------------------------------------------------

    # 1. Rota para assets estáticos (CACHE AGRESSIVO)
    location ~* \.(?:css|js|mjs|svg|gif|png|jpg|jpeg|ico|wasm|woff2?|ttf|eot)$ {
        # Reutiliza a mesma zona de cache do ns1
        proxy_cache technitium_cache; 
        proxy_cache_valid 200 7d;
        proxy_cache_use_stale error timeout http_500 http_502 http_503 http_504;
        add_header Cache-Control "public, max-age=604800, immutable";
        add_header X-Proxy-Cache $upstream_cache_status;
        proxy_pass https://technitium_backend_ns2;
    }

    # 2. Rota principal para a aplicação (SEM CACHE, COM WEBSOCKETS)
    location / {
        # Configurações de WebSockets
        proxy_set_header Upgrade $http_upgrade;
        proxy_set_header Connection "upgrade";
        
        proxy_pass https://technitium_backend_ns2;
    }

    # --- Páginas de Erro Personalizadas ---
    # Incluir aqui as diretivas de error_page, se necessário.
}