user nginx;
worker_processes auto;
error_log /var/log/nginx/error.log warn;
pid /var/run/nginx.pid;

events {
    worker_connections 4096;
    use epoll;
}

http {
    include /etc/nginx/mime.types;
    default_type application/octet-stream;

    # 日志格式定义
    log_format main '$remote_addr - $remote_user [$time_local] "$request" '
                    '$status $body_bytes_sent "$http_referer" '
                    '"$http_user_agent" "$http_x_forwarded_for"';

    access_log /var/log/nginx/access.log main;

    # 性能优化
    sendfile on;
    tcp_nopush on;
    tcp_nodelay on;
    keepalive_timeout 65;
    types_hash_max_size 2048;
    client_max_body_size 100M;

    # Gzip 压缩
    gzip on;
    gzip_vary on;
    gzip_min_length 1024;
    gzip_proxied any;
    gzip_types text/plain text/css text/xml text/javascript 
               application/x-javascript application/xml+rss 
               application/rss+xml application/javascript 
               application/json application/json;

    # 上游 IM 服务定义
    upstream im_backend {
        server im_service:8000;
        keepalive 64;
    }

    # HTTP 重定向到 HTTPS
    server {
        listen 80;
        server_name _;
        
        # Let's Encrypt 验证
        location /.well-known/acme-challenge/ {
            root /var/www/certbot;
        }

        # 其他请求转发到 HTTPS
        location / {
            return 301 https://$host$request_uri;
        }
    }

    # HTTPS 服务器配置
    server {
        listen 443 ssl http2;
        server_name im.example.com;  # 替换为实际域名

        # SSL 证书配置
        ssl_certificate /etc/nginx/ssl/cert.pem;
        ssl_certificate_key /etc/nginx/ssl/key.pem;

        # SSL 协议和密码套件
        ssl_protocols TLSv1.2 TLSv1.3;
        ssl_ciphers HIGH:!aNULL:!MD5;
        ssl_prefer_server_ciphers on;
        ssl_session_cache shared:SSL:10m;
        ssl_session_timeout 10m;

        # HSTS 安全头
        add_header Strict-Transport-Security "max-age=31536000; includeSubDomains" always;
        add_header X-Frame-Options "SAMEORIGIN" always;
        add_header X-Content-Type-Options "nosniff" always;
        add_header X-XSS-Protection "1; mode=block" always;

        # 访问日志
        access_log /var/log/nginx/im_access.log main;
        error_log /var/log/nginx/im_error.log warn;

        # 静态资源缓存
        location ~* ^/(images|javascript|stylesheets|fonts)/ {
            expires max;
            add_header Cache-Control "public, immutable";
        }

        # WebSocket 支持
        location ~ ^/(api/v[0-9]+/users/websocket|api/v[0-9]+/users/[a-z0-9-_]*/(polling|typing))$ {
            proxy_pass http://im_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 86400;
        }

        # API 和业务请求
        location / {
            proxy_pass http://im_backend;
            proxy_http_version 1.1;
            proxy_set_header Connection "";
            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_connect_timeout 60s;
            proxy_send_timeout 60s;
            proxy_read_timeout 60s;
        }
    }
}