package strategy;

import java.util.List;
import java.util.ArrayList;

public class StrategyFactory {
    private final List<CrawlerStrategy> STRATEGIES = new ArrayList<>();
        
    public StrategyFactory() {
        STRATEGIES.add(new CNKIStrategy());
        STRATEGIES.add(new IEEEStrategy());
        STRATEGIES.add(new ACMDigitalLibraryStrategy());
        STRATEGIES.add(new SpringerLinkStrategy());
        STRATEGIES.add(new ScienceDirectStrategy());
        STRATEGIES.add(new ArXivStrategy());
        STRATEGIES.add(new SemanticScholarStrategy());
    }

    /**
     * 根据URL创建对应的爬虫策略
     * @param url 要创建策略的URL
     * @return 对应的爬虫策略，如果URL不支持任何策略则返回null
     */
    public CrawlerStrategy createCrawlerByUrl(String url) {
        for (CrawlerStrategy strategy : STRATEGIES) {
            if (strategy.supportsUrl(url)) {
                return strategy;
            }
        }
        return null;
    }
    
    public int getPlatformCount() {
        return STRATEGIES.size();
    }
    
    public List<CrawlerStrategy> getAllStrategies() {
        return STRATEGIES;
    }
}