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/*
 * Copyright 2017 Alibaba.com All right reserved. This software is the
 * confidential and proprietary information of Alibaba.com ("Confidential
 * Information"). You shall not disclose such Confidential Information and shall
 * use it only in accordance with the terms of the license agreement you entered
 * into with Alibaba.com.
 */
package com.alibaba.cola.extension;

import com.alibaba.cola.boot.AbstractComponentExecutor;
import com.alibaba.cola.common.ColaConstant;
import com.alibaba.cola.exception.framework.ColaException;
import com.alibaba.cola.logger.Logger;
import com.alibaba.cola.logger.LoggerFactory;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Component;

/**
 * ExtensionExecutor 
 * @author fulan.zjf 2017-11-05
 */
@Component
public class ExtensionExecutor extends AbstractComponentExecutor {

    private Logger logger = LoggerFactory.getLogger(ExtensionExecutor.class);

    @Autowired
    private ExtensionRepository extensionRepository;

    @Override
    protected  C locateComponent(Class targetClz, BizScenario bizScenario) {
        C extension = locateExtension(targetClz, bizScenario);
        logger.debug("[Located Extension]: "+extension.getClass().getSimpleName());
        return extension;
    }

    /**
     * if the bizScenarioUniqueIdentity is "ali.tmall.supermarket"
     *
     * the search path is as below:
     * 1、first try to get extension by "ali.tmall.supermarket", if get, return it.
     * 2、loop try to get extension by "ali.tmall", if get, return it.
     * 3、loop try to get extension by "ali", if get, return it.
     * 4、if not found, try the default extension
     * @param targetClz
     */
    protected  Ext locateExtension(Class targetClz, BizScenario bizScenario) {
        checkNull(bizScenario);

        Ext extension;
        String bizScenarioUniqueIdentity = bizScenario.getUniqueIdentity();
        logger.debug("BizScenario in locateExtension is : " + bizScenarioUniqueIdentity);

        // first try
        extension = firstTry(targetClz, bizScenarioUniqueIdentity);
        if (extension != null) {
            return extension;
        }

        // loop try
        extension = loopTry(targetClz, bizScenarioUniqueIdentity);
        if (extension != null) {
            return extension;
        }

        throw new ColaException("Can not find extension with ExtensionPoint: "+targetClz+" BizScenario:"+bizScenarioUniqueIdentity);
    }

    private   Ext firstTry(Class targetClz, String bizScenario) {
        return (Ext)extensionRepository.getExtensionRepo().get(new ExtensionCoordinate(targetClz.getName(), bizScenario));
    }

    private  Ext loopTry(Class targetClz, String bizScenario){
        Ext extension;
        if (bizScenario == null){
            return null;
        }
        int lastDotIndex = bizScenario.lastIndexOf(ColaConstant.DOT_SEPARATOR);
        while(lastDotIndex != -1){
            bizScenario = bizScenario.substring(0, lastDotIndex);
            extension =(Ext)extensionRepository.getExtensionRepo().get(new ExtensionCoordinate(targetClz.getName(), bizScenario));
            if (extension != null) {
                return extension;
            }
            lastDotIndex = bizScenario.lastIndexOf(ColaConstant.DOT_SEPARATOR);
        }
        return null;
    }


    private void checkNull(BizScenario bizScenario){
        if(bizScenario == null){
            throw new ColaException("BizScenario can not be null for extension");
        }
    }

}