package org.charsetconvert;

import java.io.BufferedReader;
import java.io.BufferedWriter;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.OutputStream;
import java.io.OutputStreamWriter;

public class CharsetConvertor {

	private String sourCharset;
	private final String destCharset;

	public CharsetConvertor(String destCharset) {
		this.destCharset = destCharset;
	}

	public CharsetConvertor(String sourCharset, String destCharset) {
		this.sourCharset = sourCharset;
		this.destCharset = destCharset;
	}

	public void convertFiles(String folderPath) {
		File folder = new File(folderPath);
		if (sourCharset == null)
			readCharsetFile(folder);
		else
			readFile(folder);
	}
	
	/**
	 * 读取目录
	 * @param folder
	 */
	private void readFile(File folder) {
		File[] files = folder.listFiles();
		for (File file : files) {
			if (file.isDirectory())
				readFile(file);//递归读取目录
			else
				convertFile(file);//转换编码
		}
	}

	/**
	 * 如果没有指定文件编码则自动获取文件编码,然后进行转码
	 * @param folder
	 */
	private void readCharsetFile(File folder) {
		File[] files = folder.listFiles();
		try {
			for (File file : files) {
				if (file.isDirectory()) {
					readCharsetFile(file);
				} else {
					//获取当前文件编码
					this.sourCharset = new CharsetDetector()
							.detectChineseCharset(new FileInputStream(file))[0];
					//如果文件已经是要转换的编码则不转码
					if(sourCharset.equals(destCharset))
						continue;
					else
						convertFile(file);
				}
			}
		} catch (IOException e) {
			e.printStackTrace();
		}
	}

	/**
	 * 按指定编码读取文件并转换编码
	 * @param file
	 */
	public void convertFile(File file) {
		InputStream input = null;
		// FileInputStream fileInput = null;
		InputStreamReader inputReader = null;
		BufferedReader buffReader = null;

		OutputStream output = null;
		// FileOutputStream fileOutput = null;
		OutputStreamWriter outputWriter = null;
		BufferedWriter buffWriter = null;
		File tempFile = null;
		try {
			// System.out.println(sourCharset);
			
			// tempFile =
			// File.createTempFile(file.getName()+"."+sourCharset+"to"+destCharset+".",
			// ".tmp", file.getParentFile());
			tempFile = File.createTempFile(file.getName() + ".", ".tmp",
					file.getParentFile());
			// System.out.println(file);
			// System.out.println(tempFile);
			// new File(file.getName() + ".tmp").createNewFile();
			
			// 创建输入输出流
			input = new FileInputStream(file);
			//以指定编码读取文件
			inputReader = new InputStreamReader(input, sourCharset);
			buffReader = new BufferedReader(inputReader);

			output = new FileOutputStream(tempFile);
			//以指定编码输出文件
			outputWriter = new OutputStreamWriter(output, destCharset);
			buffWriter = new BufferedWriter(outputWriter);

			String temp;

			// 读取文件
			while ((temp = buffReader.readLine()) != null) {
				// System.out.println("//////////////////////////////////////////");
				// System.out.println(temp);
				// temp = new String(temp.getBytes(sourCharset), destCharset);
				// System.out.println(temp);
				// 写入数据,如果读取带BOM的UTF-8编码文件,则忽略BOM头
				buffWriter.write(temp);
				buffWriter.newLine();
				// 刷新
				buffWriter.flush();
			}
		} catch (FileNotFoundException e) {
			e.printStackTrace();
		} catch (IOException e) {
			e.printStackTrace();
		} finally {
			// 关闭流
			try {
				if (output != null)
					output.close();
				if (buffWriter != null)
					buffWriter.close();
				if (outputWriter != null)
					outputWriter.close();
				if (input != null)
					input.close();
				if (buffReader != null)
					buffReader.close();
				if (inputReader != null)
					inputReader.close();
				//将源文件替换为修改后的文件
				if (file.delete()) { // 执行完buffReader.close() 之后才能删除文件
					tempFile.renameTo(file);
				}
				System.out.println("已将文件"+file+"由"+sourCharset+"编码转换为"+destCharset+"编码");
			} catch (IOException e) {
				e.printStackTrace();
			}
		}
	}

}