package com.foxinmy.weixin4j.http.message;
   
   import java.io.IOException;
   import java.io.InputStream;
   import java.nio.charset.Charset;
   import java.util.ArrayList;
   import java.util.Arrays;
   import java.util.Collections;
   import java.util.List;
  
  import com.foxinmy.weixin4j.http.HttpResponse;
  import com.foxinmy.weixin4j.http.MimeType;
  import com.foxinmy.weixin4j.util.Consts;
  
  public abstract class AbstractMessageConverter implements MessageConverter {
  
  	protected Charset charset = Consts.UTF_8;
  
  	private List<MimeType> supportedMimeTypes;
  
  	protected AbstractMessageConverter() {
  		this.supportedMimeTypes = Collections.emptyList();
  	}
  
  	protected AbstractMessageConverter(MimeType supportedMimeType) {
  		setSupportedMediaTypes(Collections.singletonList(supportedMimeType));
  	}
  
  	protected AbstractMessageConverter(MimeType... supportedMimeTypes) {
  		setSupportedMediaTypes(Arrays.asList(supportedMimeTypes));
  	}
  
  	public void setSupportedMediaTypes(List<MimeType> supportedMimeTypes) {
  		this.supportedMimeTypes = new ArrayList<MimeType>(supportedMimeTypes);
  	}
  
  	public Charset getCharset() {
  		return charset;
  	}
  
  	public void setCharset(Charset charset) {
  		this.charset = charset;
  	}
  
  	@Override
  	public List<MimeType> supportedMimeTypes() {
  		return Collections.unmodifiableList(this.supportedMimeTypes);
  	}
  
  	@Override
  	public boolean canConvert(Class<?> clazz, HttpResponse response) {
  		MimeType mimeType = MimeType.valueOf(response.getHeaders().getContentType());
  		byte[] content = response.getContent();
  		return supports(clazz, mimeType) || supports(clazz, content);
  	}
  
  	/**
  	 * 满足其中一个supports
  	 * 
  	 * @param clazz
  	 *            转换类型
  	 * @param mimeType
  	 *            媒体类型
  	 * @return 支持标识
  	 */
  	protected boolean supports(Class<?> clazz, MimeType mimeType) {
  		if (mimeType == null) {
  			return true;
  		}
  		for (MimeType supportedMediaType : supportedMimeTypes()) {
  			if (supportedMediaType.includes(mimeType)) {
  				return true;
  			}
  		}
  		return false;
  	}
  
  	/**
  	 * 满足其中一个supports
  	 * 
  	 * @param clazz
  	 *            转换类型
  	 * @param content
  	 *            内容数据
  	 * @return 支持标识
  	 */
  	protected abstract boolean supports(Class<?> clazz, byte[] content);
  
  	@Override
  	public <T> T convert(Class<? extends T> clazz, HttpResponse response) throws IOException {
  		return convertInternal(clazz, response.getBody());
  	}
  
  	protected abstract <T> T convertInternal(Class<? extends T> clazz, InputStream body) throws IOException;
  }