package com.soa.gateway;

import com.soa.bus.ServiceBus;
import org.apache.logging.log4j.LogManager;
import org.apache.logging.log4j.Logger;

/**
 * 服务网关 - 负责请求的路由、认证、限流等
 */
public class ServiceGateway {
    private static final Logger logger = LogManager.getLogger(ServiceGateway.class);
    private final ServiceBus serviceBus;
    
    public ServiceGateway() {
        this.serviceBus = ServiceBus.getInstance();
    }
    
    /**
     * 处理请求
     */
    public String handleRequest(String serviceName, String request, String apiKey) {
        // 1. 验证API Key
        if (!validateApiKey(apiKey)) {
            logger.warn("Invalid API Key: {}", apiKey);
            return "Error: Unauthorized access - Invalid API Key";
        }
        
        // 2. 日志请求
        logger.info("Request received for service: {}, with API Key ending in: {}", 
                serviceName, apiKey.substring(apiKey.length() - 4));
        
        // 3. 检查限流（简单实现）
        if (!checkRateLimit(apiKey)) {
            logger.warn("Rate limit exceeded for API Key: {}", apiKey);
            return "Error: Rate limit exceeded";
        }
        
        // 4. 路由到服务总线
        return serviceBus.callService(serviceName, request);
    }
    
    /**
     * 验证API Key
     */
    private boolean validateApiKey(String apiKey) {
        // 简化实现 - 实际应该从数据库或配置中验证
        return apiKey != null && apiKey.startsWith("valid_");
    }
    
    /**
     * 检查限流
     */
    private boolean checkRateLimit(String apiKey) {
        // 简化实现 - 实际应该使用令牌桶或漏桶算法
        return true;
    }
    
    /**
     * 获取服务状态
     */
    public String getServiceStatus(String serviceName) {
        boolean available = serviceBus.isServiceAvailable(serviceName);
        return "Service: " + serviceName + " - Status: " + (available ? "Available" : "Unavailable");
    }
}