// Licensed to the Apache Software Foundation (ASF) under one
// or more contributor license agreements.  See the NOTICE file
// distributed with this work for additional information
// regarding copyright ownership.  The ASF licenses this file
// to you under the Apache License, Version 2.0 (the
// "License"); you may not use this file except in compliance
// with the License.  You may obtain a copy of the License at
//
//   http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing,
// software distributed under the License is distributed on an
// "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
// KIND, either express or implied.  See the License for the
// specific language governing permissions and limitations
// under the License.
package com.cloud.storage.download;

import java.util.Date;

import org.apache.log4j.Level;
import org.apache.log4j.Logger;

import com.cloud.agent.api.storage.DownloadAnswer;

public abstract class DownloadState {
	public static enum DownloadEvent {DOWNLOAD_ANSWER, ABANDON_DOWNLOAD, TIMEOUT_CHECK, DISCONNECT};
	protected static final Logger s_logger = Logger.getLogger(DownloadListener.class.getName());

	private DownloadListener dl;
	
	public DownloadState(DownloadListener dl) {
		this.dl = dl;
	}
	
	protected DownloadListener getDownloadListener() {
		return dl;
	}
	
	public String handleEvent(DownloadEvent event, Object eventObj){
		if (s_logger.isTraceEnabled()) {
			getDownloadListener().log("handleEvent, event type=" + event + ", curr state=" + getName(), Level.TRACE);
		}
		switch (event) {
		case DOWNLOAD_ANSWER:
			DownloadAnswer answer=(DownloadAnswer)eventObj;
			return handleAnswer(answer);
		case ABANDON_DOWNLOAD:
			return handleAbort();
		case TIMEOUT_CHECK:
			Date now = new Date();
			long update = now.getTime() - dl.getLastUpdated().getTime();
			return handleTimeout(update);
		case DISCONNECT:
			return handleDisconnect();
		}
		return null;
	}
	
	public   void onEntry(String prevState, DownloadEvent event, Object evtObj){
		if (s_logger.isTraceEnabled()) {
			getDownloadListener().log("onEntry, event type=" + event + ", curr state=" + getName(), Level.TRACE);
		}
		if (event==DownloadEvent.DOWNLOAD_ANSWER) {
			getDownloadListener().callback((DownloadAnswer)evtObj);
		}
	}
	
	public  void onExit() {
		
	}
	
	public abstract String handleTimeout(long updateMs) ;
	
	public abstract String handleAbort();
	
	public abstract  String handleDisconnect();

	public abstract String handleAnswer(DownloadAnswer answer) ;
	
	public abstract String getName();


}
