package org.oxerr.chbtc.dto.valuereader;
   
   import static org.oxerr.chbtc.CHBTCClient.ENCODING;
   
   import java.io.IOException;
   import java.io.InputStream;
   
   import org.apache.commons.io.IOUtils;
   import org.slf4j.Logger;
  import org.slf4j.LoggerFactory;
  
  import com.fasterxml.jackson.core.JsonParseException;
  import com.fasterxml.jackson.databind.ObjectMapper;
  import com.fasterxml.jackson.databind.exc.UnrecognizedPropertyException;
  
  public class JsonValueReader<T> implements ValueReader<T> {
  
  	private final Logger log = LoggerFactory.getLogger(JsonValueReader.class);
  
  	private final ObjectMapper objectMapper;
  
  	private final Class<T> valueType;
  
  	public JsonValueReader(ObjectMapper objectMapper, Class<T> valueType) {
  		this.objectMapper = objectMapper;
  		this.valueType = valueType;
  	}
  
  	/**
  	 * {@inheritDoc}
  	 */
  	@Override
  	public T read(InputStream inputStream) throws IOException {
  		final String content = IOUtils.toString(inputStream, ENCODING);
  		return read(content);
  	}
  
  	protected T read(String content) throws IOException {
  		log.trace("Reading {} from \"{}\".", valueType, content);
  
  		try (InputStream in = IOUtils.toInputStream(content, ENCODING)) {
  			return objectMapper.readValue(in, valueType);
  		} catch (JsonParseException e) {
  			String msg = String.format("Parse from \"%1$s\" failed: %2$s",
  					content,
  					e.getMessage());
  			throw new JsonParseException(msg, e.getLocation(), e);
  		} catch (UnrecognizedPropertyException e) {
  			String msg = String.format("Parse from \"%1$s\" failed: %2$s",
  					content,
  					e.getMessage());
  			throw new JsonParseException(msg, e.getLocation(), e);
  		}
  	}
  
  }