package com.hotent.im.network;

import org.springframework.web.multipart.MultipartFile;

import java.io.*;
import java.net.HttpURLConnection;
import java.net.URL;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

/**
 * HttpURLConnection发送Post请求工具类
 *
 * @author yanhongliang
 */
public abstract class AbstractHttpPost {

    /**
     * 网络请求回调
     * 抽象方法
     * @param response
     */
    public abstract void complete(Response response);

    /**
     * post 网络请求
     * @param actionUrl 网络请求地址
     * @param params 常规参数
     * @param files 文件参数
     */
    public void post(
            final String actionUrl,
            final Map<String, Object> params,
            final HashMap<String, MultipartFile> files) {

        sendRequest(actionUrl, params, files);
    }


    /**
     * 通过拼接的方式构造请求内容，实现参数传输以及文件传输
     *
     * @param actionUrl
     *            访问的服务器URL
     * @param params
     *            普通参数
     * @param files
     *            文件参数
     */
    private void sendRequest(
            String actionUrl,
            Map<String, Object> params,
            HashMap<String, MultipartFile> files) {

        if (actionUrl == null || actionUrl.isEmpty()) {
            return;
        }

        Response response = new Response(0);

        HttpURLConnection conn = null;
        InputStreamReader in = null;
        try {

            String boundary = java.util.UUID.randomUUID().toString();
            String prefix = "--", linend = "\r\n";
            String multipartFromData = "multipart/form-data";
            String charset = "UTF-8";

            URL uri = new URL(actionUrl);
            conn = (HttpURLConnection) uri.openConnection();
            // 缓存的最长时间
            conn.setReadTimeout(30 * 1000);
            // 允许输入
            conn.setDoInput(true);
            // 允许输出
            conn.setDoOutput(true);
            // 不允许使用缓存
            conn.setUseCaches(false);
            conn.setRequestMethod("POST");
            conn.setRequestProperty("connection", "keep-alive");
            conn.setRequestProperty("Charsert", "UTF-8");
            conn.setRequestProperty("Content-Type", multipartFromData + ";boundary=" + boundary);

            DataOutputStream outStream = new DataOutputStream(conn.getOutputStream());

            // 首先组拼文本类型的参数------start------
            if (params != null){
                StringBuilder text = new StringBuilder();
                for (Map.Entry<String, Object> entry : params.entrySet()) {
                    text.append(prefix);
                    text.append(boundary);
                    text.append(linend);
                    text.append("Content-Disposition: form-data; name=\"")
                            .append(entry.getKey())
                            .append("\"")
                            .append(linend);

                    text.append("Content-Type: text/plain; charset=")
                            .append(charset)
                            .append(linend);

                    text.append("Content-Transfer-Encoding: 8bit")
                            .append(linend);

                    text.append(linend);
                    text.append(entry.getValue());
                    text.append(linend);
                }

                outStream.write(text.toString().getBytes());
            }

            // 首先组拼文本类型的参数------end------

            // 发送文件数据--------------start-----
            if (files != null) {
                for (HashMap.Entry<String, MultipartFile> file : files.entrySet()) {
                    StringBuilder fileBuilder = new StringBuilder();
                    fileBuilder.append(prefix);
                    fileBuilder.append(boundary);
                    fileBuilder.append(linend);
                    // name是post中传参的键 filename是文件的名称
                    fileBuilder.append("Content-Disposition: form-data; name=\"file\"; filename=\"")
                            .append(file.getKey())
                            .append("\"")
                            .append(linend);

                    fileBuilder.append("Content-Type: application/octet-stream; charset=")
                            .append(charset)
                            .append(linend);

                    fileBuilder.append(linend);
                    outStream.write(fileBuilder.toString().getBytes());

                    InputStream is = file.getValue().getInputStream();
                    byte[] buffer = new byte[1024];
                    int len = 0;
                    while ((len = is.read(buffer)) != -1) {
                        outStream.write(buffer, 0, len);
                    }

                    is.close();
                    outStream.write(linend.getBytes());
                }

            }
            // 发送文件数据--------------start-----

            // 请求结束标志
            byte[] endData = (prefix + boundary + prefix + linend).getBytes();
            outStream.write(endData);
            outStream.flush();
            outStream.close();

            long timestamp = System.currentTimeMillis();
            response.timestamp = conn.getHeaderFieldDate("Date", 0);
            if (response.timestamp != 0) {
                response.timestamp += System.currentTimeMillis() - timestamp;
            }

            // 得到响应码
            response.state = conn.getResponseCode();

            if (response.state == 200) {

                in = new InputStreamReader(conn.getInputStream(), "UTF-8");

                // 读取返回数据
                BufferedReader reader = new BufferedReader(in);

                StringBuilder strBuilder = new StringBuilder();
                String line = null;
                while ((line = reader.readLine()) != null && !cancel) {
                    //$NON-NLS-1$
                    strBuilder.append(line).append("\n");
                }
                reader.close();

                response.content = strBuilder.toString();

            }

        }catch (Exception e){
            response.content = e.getLocalizedMessage();
            error(e);
        }finally {
            if (in != null) {
                try {
                    in.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
            if (conn != null){
                conn.disconnect();
            }
            response.cancel = cancel;
            cancel = false;
            complete(response);
        }

    }

    /**
     * 取消网络请求
     */
    private boolean cancel = false;
    public void cancel() {
        cancel = true;
    }

    /**
     * 异常输出
     * @param e 异常
     */
    private void error(Exception e){
        e.printStackTrace();
    }

}