package com.nuvole.util;

import com.nuvole.util.enums.FileType;

import java.io.FileInputStream;
import java.io.IOException;
import java.io.InputStream;
// @formatter:off
/**
 *                .-~~~~~~~~~-._       _.-~~~~~~~~~-.
 *            __.'  @Author     ~.   .~    代码无Bug   `.__
 *          .'//     liu.q        \./       (秘籍)      \\`.
 *        .'// [916000612@qq.com]  |   欲练神功   引刀自宫  \\`.
 *      .'// .-~"""""""~~~~-._     |    _,-~~~~"""""""~-.  \\`.
 *    .'//.-"  2019-04-24     `-.  |  .-'     15:56       "-.\\`.
 *  .'//______.============-..   \ | /   ..-============.______\\`.
 *.'______________________________\|/______________________________`.
 *
 * @Description :
 */
// @formatter:on

public class FileTypeJudge {

    private FileTypeJudge() {
    }

    /**
     * 将文件头转换成16进制字符串
     *
     * @return 16进制字符串
     */
    private static String bytesToHexString(byte[] src) {

        StringBuilder stringBuilder = new StringBuilder();
        if (src == null || src.length <= 0) {
            return null;
        }
        for (int i = 0; i < src.length; i++) {
            int v = src[i] & 0xFF;
            String hv = Integer.toHexString(v);
            if (hv.length() < 2) {
                stringBuilder.append(0);
            }
            stringBuilder.append(hv);
        }
        return stringBuilder.toString();
    }

    /**
     * 得到文件头
     *
     * @param filePath 文件路径
     * @return 文件头
     * @throws IOException
     */
    private static String getFileContent(String filePath) throws IOException {

        byte[] b = new byte[28];

        InputStream inputStream = null;

        try {
            inputStream = new FileInputStream(filePath);
            inputStream.read(b, 0, 28);
        } catch (IOException e) {
            e.printStackTrace();
            throw e;
        } finally {
            if (inputStream != null) {
                try {
                    inputStream.close();
                } catch (IOException e) {
                    e.printStackTrace();
                    throw e;
                }
            }
        }
        return bytesToHexString(b);
    }

    private static String getFileContent(InputStream inputStream){
        InputStream is = inputStream;
        byte[] b = new byte[28];
        try {
            is.read(b, 0, 28);
        } catch (IOException e) {
            e.printStackTrace();
        }
        return bytesToHexString(b);
    }

    /**
     * 判断文件类型
     *
     * @return 文件类型
     */
    public static String getType(InputStream inputStream){

        String fileHead = getFileContent(inputStream);

        if (fileHead == null || fileHead.length() == 0) {
            return null;
        }

        fileHead = fileHead.toUpperCase();

        FileType[] fileTypes = FileType.values();

        for (FileType type : fileTypes) {
            if (fileHead.startsWith(type.getValue())) {
                return type.toString();
            }
        }
        return "";
    }
}