package cn.com.qmth.examcloud.web.upyun;

import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.InputStream;
import java.security.InvalidKeyException;
import java.security.NoSuchAlgorithmException;
import java.security.SignatureException;
import java.text.SimpleDateFormat;
import java.util.Base64;
import java.util.Calendar;
import java.util.Locale;
import java.util.Map;
import java.util.TimeZone;
import java.util.concurrent.TimeUnit;

import javax.crypto.Mac;
import javax.crypto.spec.SecretKeySpec;

import org.apache.commons.compress.utils.IOUtils;
import org.apache.commons.lang3.StringUtils;
import org.apache.http.HttpStatus;
import org.apache.http.client.config.RequestConfig;
import org.apache.http.client.methods.CloseableHttpResponse;
import org.apache.http.client.methods.HttpDelete;
import org.apache.http.client.methods.HttpPut;
import org.apache.http.entity.InputStreamEntity;
import org.apache.http.impl.client.CloseableHttpClient;
import org.apache.http.impl.client.HttpClients;
import org.apache.http.impl.conn.PoolingHttpClientConnectionManager;
import org.apache.http.util.EntityUtils;

import com.google.common.collect.Maps;

import cn.com.qmth.examcloud.commons.exception.ExamCloudRuntimeException;
import cn.com.qmth.examcloud.commons.exception.StatusException;
import cn.com.qmth.examcloud.commons.logging.ExamCloudLog;
import cn.com.qmth.examcloud.commons.logging.ExamCloudLogFactory;
import cn.com.qmth.examcloud.commons.util.MD5;

/**
 * upyun client
 *
 * @author WANGWEI
 * @date 2018年11月21日
 * @Copyright (c) 2018-? http://qmth.com.cn All Rights Reserved.
 */
public class UpYunClient {

	protected ExamCloudLog log = ExamCloudLogFactory.getLog(this.getClass());

	/**
	 * 空间名
	 */
	protected String bucketName = null;

	/**
	 * 操作员名
	 */
	protected String userName = null;

	/**
	 * 操作员密码
	 */
	protected String password = null;

	protected String md5Password = null;

	public static final String API_DOMAIN = "v0.api.upyun.com";

	private static final String MKDIR = "mkdir";

	private final String METHOD_PUT = "PUT";

	private final String METHOD_DELETE = "DELETE";

	private final String DATE = "Date";

	private final String AUTHORIZATION = "Authorization";

	private final String SEPARATOR = "/";

	private static CloseableHttpClient httpclient;

	private static RequestConfig requestConfig;

	private String domain;

	static {
		PoolingHttpClientConnectionManager cm = new PoolingHttpClientConnectionManager(10,
				TimeUnit.SECONDS);
		cm.setValidateAfterInactivity(2000);
		cm.setMaxTotal(1000);
		cm.setDefaultMaxPerRoute(1000);
		httpclient = HttpClients.custom().setConnectionManager(cm).disableAutomaticRetries()
				.build();

		requestConfig = RequestConfig.custom().setConnectionRequestTimeout(10000)
				.setSocketTimeout(10000).setConnectTimeout(10000).build();
	}

	/**
	 * 构造函数
	 *
	 * @param bucketName
	 * @param userName
	 * @param password
	 */
	public UpYunClient(String bucketName, String userName, String password, String domain) {

		this.bucketName = bucketName;
		this.userName = userName;
		this.password = password;
		this.domain = domain;
		this.md5Password = MD5.encrypt32(password);
	}

	/**
	 * 创建又拍云签名
	 *
	 * @author WANGWEI
	 * @param filePath
	 * @return
	 */
	public UpYunSign buildUpYunSign(String filePath) {
		String path = formatPath(filePath);
		String url = "https://" + API_DOMAIN + path;

		Map<String, String> headers = Maps.newHashMap();
		String date = getDate();
		String authorization = null;
		try {
			authorization = sign(userName, md5Password, METHOD_PUT, path, date, "", "");
		} catch (Exception e) {
			throw new StatusException("100005", "[upyun]. fail to build sign", e);
		}
		headers.put(AUTHORIZATION, authorization);
		headers.put(DATE, date);
		headers.put(MKDIR, "true");

		UpYunSign sign = new UpYunSign();
		sign.setUrl(url);
		sign.setHeaders(headers);

		return sign;
	}

	/**
	 * 上传文件
	 *
	 * @author WANGWEI
	 * @param filePath
	 * @param file
	 * @return
	 */
	public UpYunPathInfo writeFile(String filePath, File file) {

		InputStream in = null;
		try {
			in = new FileInputStream(file);
			return writeFile(filePath, in);
		} catch (FileNotFoundException e) {
			throw new ExamCloudRuntimeException(e);
		} finally {
			IOUtils.closeQuietly(in);
		}
	}

	/**
	 * 上传文件
	 *
	 * @author WANGWEI
	 * @param filePath
	 * @param in
	 * @return
	 */
	public UpYunPathInfo writeFile(String filePath, InputStream in) {
		String path = formatPath(filePath);
		String url = "https://" + API_DOMAIN + path;

		HttpPut httpPut = new HttpPut(url);
		httpPut.setConfig(UpYunClient.requestConfig);
		CloseableHttpResponse response = null;

		long s = System.currentTimeMillis();
		try {

			String date = getDate();
			String authorization = sign(userName, md5Password, METHOD_PUT, path, date, "", "");
			httpPut.addHeader(AUTHORIZATION, authorization);
			httpPut.addHeader(DATE, date);
			httpPut.addHeader(MKDIR, "true");

			httpPut.setEntity(new InputStreamEntity(in));
			response = httpclient.execute(httpPut);
			int statusCode = response.getStatusLine().getStatusCode();

			if (HttpStatus.SC_OK != statusCode) {
				log.error("[upyun error] " + EntityUtils.toString(response.getEntity(), "UTF-8"));
				throw new StatusException("100001", "[upyun]. fail to write file");
			}
		} catch (StatusException e) {
			throw e;
		} catch (Exception e) {
			throw new ExamCloudRuntimeException(e);
		} finally {
			IOUtils.closeQuietly(in);
			IOUtils.closeQuietly(response);
			httpPut.releaseConnection();
		}

		if (log.isDebugEnabled()) {
			log.debug("[upyun]. write file. path=" + path + "; cost "
					+ (System.currentTimeMillis() - s) + " ms.");
		}

		String fileUrl = this.domain + filePath;
		return new UpYunPathInfo(fileUrl, filePath);
	}

	/**
	 * 删除文件
	 *
	 * @author WANGWEI
	 * @param filePath
	 * @return
	 */
	public void deleteFile(String filePath) {
		String path = formatPath(filePath);
		String url = "https://" + API_DOMAIN + path;

		HttpDelete httpDelete = new HttpDelete(url);
		httpDelete.setConfig(UpYunClient.requestConfig);
		CloseableHttpResponse response = null;

		long s = System.currentTimeMillis();
		try {
			String date = getDate();
			String authorization = sign(userName, md5Password, METHOD_DELETE, path, date, "", "");
			httpDelete.addHeader(AUTHORIZATION, authorization);
			httpDelete.addHeader(DATE, date);

			response = httpclient.execute(httpDelete);
			int statusCode = response.getStatusLine().getStatusCode();

			if (HttpStatus.SC_OK != statusCode) {
				log.error("[upyun error] " + EntityUtils.toString(response.getEntity(), "UTF-8"));
				throw new StatusException("100002", "[upyun]. fail to delete file");
			}
		} catch (StatusException e) {
			throw e;
		} catch (Exception e) {
			throw new ExamCloudRuntimeException(e);
		} finally {
			IOUtils.closeQuietly(response);
			httpDelete.releaseConnection();
		}

		if (log.isDebugEnabled()) {
			log.debug("[upyun]. delete file. path=" + path + "; cost "
					+ (System.currentTimeMillis() - s) + " ms.");
		}

	}

	/**
	 * 格式化路径参数
	 * <p>
	 * 最终构成的格式："/空间名/文件路径"
	 *
	 * @param path
	 *            目录路径或文件路径
	 * @return 格式化后的路径
	 */
	private String formatPath(String path) {

		if (StringUtils.isNotBlank(path)) {

			// 去除前后的空格
			path = path.trim();

			// 确保路径以"/"开头
			if (!path.startsWith(SEPARATOR)) {
				return SEPARATOR + bucketName + SEPARATOR + path;
			}
		}

		return SEPARATOR + bucketName + path;
	}

	private String getDate() {
		Calendar calendar = Calendar.getInstance();
		SimpleDateFormat dateFormat = new SimpleDateFormat("EEE, dd MMM yyyy HH:mm:ss z",
				Locale.US);
		dateFormat.setTimeZone(TimeZone.getTimeZone("GMT"));
		return dateFormat.format(calendar.getTime());
	}

	private byte[] hashHmac(String data, String key)
			throws SignatureException, NoSuchAlgorithmException, InvalidKeyException {
		SecretKeySpec signingKey = new SecretKeySpec(key.getBytes(), "HmacSHA1");
		Mac mac = Mac.getInstance("HmacSHA1");
		mac.init(signingKey);
		return mac.doFinal(data.getBytes());
	}

	private String sign(String key, String secret, String method, String uri, String date,
			String policy, String md5) throws Exception {
		String value = method + "&" + uri + "&" + date;
		if (policy != null && policy.length() > 0) {
			value = value + "&" + policy;
		}

		if (md5 != null && md5.length() > 0) {
			value = value + "&" + md5;
		}
		byte[] hmac = hashHmac(value, secret);
		String sign = Base64.getEncoder().encodeToString(hmac);
		return "UPYUN " + key + ":" + sign;
	}

}