package com.ots.common.utils.file;
import javax.servlet.http.HttpServletRequest;
import java.io.*;
import java.net.URLEncoder;

public class FileUtils {
    public static String FILENAME_PATTERN = "[a-zA-Z0-9_\\-\\|\\.\\u4e00-\\u9fa5]+";
    
    public static void writeBytes(String filePath, OutputStream os) throws IOException {
        FileInputStream fis = null;
        try {
            File file = new File(filePath);
            if (!file.exists()) {
                throw new FileNotFoundException(filePath);
            }
            fis = new FileInputStream(file);
            byte[] b = new byte[1024];
            int length;
            while ((length = fis.read(b)) > 0) {
                os.write(b, 0, length);
            }
        } catch (IOException e) {
            throw e;
        } finally {
            if (os != null) {
                try {
                    os.close();
                } catch (IOException e1) {
                    e1.printStackTrace();
                }
            }
            if (fis != null) {
                try {
                    fis.close();
                } catch (IOException e1) {
                    e1.printStackTrace();
                }
            }
        }
    }
    
    public static boolean deleteFile(String filePath) {
        boolean flag = false;
        File file = new File(filePath);
        
        if (file.isFile() && file.exists()) {
            file.delete();
            flag = true;
        }
        return flag;
    }
    
    public static boolean isValidFilename(String filename) {
        return filename.matches(FILENAME_PATTERN);
    }
    
    public static String setFileDownloadHeader(HttpServletRequest request, String fileName) throws UnsupportedEncodingException {
        final String agent = request.getHeader("USER-AGENT");
        String filename = fileName;
        if (agent.contains("MSIE")) {
            
            filename = URLEncoder.encode(filename, "utf-8");
            filename = filename.replace("+", " ");
        } else if (agent.contains("Firefox")) {
            
            filename = new String(fileName.getBytes(), "ISO8859-1");
        } else if (agent.contains("Chrome")) {
            
            filename = URLEncoder.encode(filename, "utf-8");
        } else {
            
            filename = URLEncoder.encode(filename, "utf-8");
        }
        return filename;
    }
}