package com.soa.bus;

import com.soa.service.Service;
import org.apache.logging.log4j.LogManager;
import org.apache.logging.log4j.Logger;
import java.util.Map;
import java.util.concurrent.ConcurrentHashMap;

/**
 * 服务总线 - 负责服务的注册、发现和路由
 */
public class ServiceBus {
    private static final Logger logger = LogManager.getLogger(ServiceBus.class);
    private static ServiceBus instance;
    private final Map<String, Service> serviceRegistry = new ConcurrentHashMap<>();
    
    private ServiceBus() {}
    
    /**
     * 获取服务总线单例
     */
    public static synchronized ServiceBus getInstance() {
        if (instance == null) {
            instance = new ServiceBus();
        }
        return instance;
    }
    
    /**
     * 注册服务
     */
    public void registerService(Service service) {
        String serviceName = service.getName();
        serviceRegistry.put(serviceName, service);
        logger.info("Service registered: {}", serviceName);
    }
    
    /**
     * 注销服务
     */
    public void unregisterService(String serviceName) {
        serviceRegistry.remove(serviceName);
        logger.info("Service unregistered: {}", serviceName);
    }
    
    /**
     * 调用服务
     */
    public String callService(String serviceName, String request) {
        Service service = serviceRegistry.get(serviceName);
        if (service == null) {
            logger.error("Service not found: {}", serviceName);
            return "Error: Service not found - " + serviceName;
        }
        
        if (!service.isAvailable()) {
            logger.error("Service not available: {}", serviceName);
            return "Error: Service not available - " + serviceName;
        }
        
        logger.info("Routing request to service: {}", serviceName);
        return service.execute(request);
    }
    
    /**
     * 检查服务是否可用
     */
    public boolean isServiceAvailable(String serviceName) {
        Service service = serviceRegistry.get(serviceName);
        return service != null && service.isAvailable();
    }
    
    /**
     * 获取已注册的服务数量
     */
    public int getRegisteredServiceCount() {
        return serviceRegistry.size();
    }
}