package org.argeo.cms.integration;
   
   import java.io.IOException;
   import java.io.Writer;
   import java.util.ArrayList;
   import java.util.List;
   
   import javax.servlet.http.HttpServletResponse;
   
  import org.apache.commons.logging.Log;
  import org.apache.commons.logging.LogFactory;
  
  import com.fasterxml.jackson.core.JsonGenerator;
  import com.fasterxml.jackson.core.JsonProcessingException;
  import com.fasterxml.jackson.databind.ObjectMapper;
  
  /** Serialisable wrapper of a {@link Throwable}. */
  public class CmsExceptionsChain {
  	public final static Log log = LogFactory.getLog(CmsExceptionsChain.class);
  
  	private List<SystemException> exceptions = new ArrayList<>();
  
  	public CmsExceptionsChain() {
  		super();
  	}
  
  	public CmsExceptionsChain(Throwable exception) {
  		writeException(exception);
  		if (log.isDebugEnabled())
  			log.error("Exception chain", exception);
  	}
  
  	public String toJsonString(ObjectMapper objectMapper) {
  		try {
  			return objectMapper.writerWithDefaultPrettyPrinter().writeValueAsString(this);
  		} catch (JsonProcessingException e) {
  			throw new IllegalStateException("Cannot write system exceptions " + toString(), e);
  		}
  	}
  
  	public void writeAsJson(ObjectMapper objectMapper, Writer writer) {
  		try {
  			JsonGenerator jg = objectMapper.writerWithDefaultPrettyPrinter().getFactory().createGenerator(writer);
  			jg.writeObject(this);
  		} catch (IOException e) {
  			throw new IllegalStateException("Cannot write system exceptions " + toString(), e);
  		}
  	}
  
  	public void writeAsJson(ObjectMapper objectMapper, HttpServletResponse resp) {
  		try {
  			resp.setContentType("application/json");
  			resp.setStatus(500);
  			writeAsJson(objectMapper, resp.getWriter());
  		} catch (IOException e) {
  			throw new IllegalStateException("Cannot write system exceptions " + toString(), e);
  		}
  	}
  
  	/** recursive */
  	protected void writeException(Throwable exception) {
  		SystemException systemException = new SystemException(exception);
  		exceptions.add(systemException);
  		Throwable cause = exception.getCause();
  		if (cause != null)
  			writeException(cause);
  	}
  
  	public List<SystemException> getExceptions() {
  		return exceptions;
  	}
  
  	public void setExceptions(List<SystemException> exceptions) {
  		this.exceptions = exceptions;
  	}
  
  	/** An exception in the chain. */
  	public static class SystemException {
  		private String type;
  		private String message;
  		private List<String> stackTrace;
  
  		public SystemException() {
  		}
  
  		public SystemException(Throwable exception) {
  			this.type = exception.getClass().getName();
  			this.message = exception.getMessage();
  			this.stackTrace = new ArrayList<>();
  			StackTraceElement[] elems = exception.getStackTrace();
  			for (int i = 0; i < elems.length; i++)
  				stackTrace.add("at " + elems[i].toString());
  		}
  
  		public String getType() {
  			return type;
  		}
  
  		public void setType(String type) {
 			this.type = type;
 		}
 
 		public String getMessage() {
 			return message;
 		}
 
 		public void setMessage(String message) {
 			this.message = message;
 		}
 
 		public List<String> getStackTrace() {
 			return stackTrace;
 		}
 
 		public void setStackTrace(List<String> stackTrace) {
 			this.stackTrace = stackTrace;
 		}
 
 		@Override
 		public String toString() {
 			return "System exception: " + type + ", " + message + ", " + stackTrace;
 		}
 
 	}
 
 	@Override
 	public String toString() {
 		return exceptions.toString();
 	}
 
 //	public static void main(String[] args) throws Exception {
 //		try {
 //			try {
 //				try {
 //					testDeeper();
 //				} catch (Exception e) {
 //					throw new Exception("Less deep exception", e);
 //				}
 //			} catch (Exception e) {
 //				throw new RuntimeException("Top exception", e);
 //			}
 //		} catch (Exception e) {
 //			CmsExceptionsChain vjeSystemErrors = new CmsExceptionsChain(e);
 //			ObjectMapper objectMapper = new ObjectMapper();
 //			System.out.println(objectMapper.writerWithDefaultPrettyPrinter().writeValueAsString(vjeSystemErrors));
 //			System.out.println(objectMapper.writerWithDefaultPrettyPrinter().writeValueAsString(e));
 //			e.printStackTrace();
 //		}
 //	}
 //
 //	static void testDeeper() throws Exception {
 //		throw new IllegalStateException("Deep exception");
 //	}
 
 }