package Web;

import java.nio.channels.SocketChannel;
import java.util.logging.Level;
import java.util.logging.Logger;
import java.io.IOException;
import java.nio.ByteBuffer;
import java.nio.channels.AsynchronousFileChannel;
import java.nio.channels.CompletionHandler;
import java.nio.file.Files;
import java.nio.file.Path;
import java.nio.file.Paths;
import java.nio.file.attribute.BasicFileAttributeView;
import java.nio.file.attribute.BasicFileAttributes;
import java.util.concurrent.TimeUnit;

/**
 * 静态文件服务器
 *
 * @author Ma
 */
public class StaticFileServer {

 public Request request;
 public int size;
 public ByteBuffer byteBuffer;
 public SocketChannel socketChannel;
 public Path filePath;
 public String ExName;//扩展名字

 /**
 * 初始化一些东西
 *
 * @param request
 */
 public StaticFileServer(Request request) {
 this.request = request;
 String path = Options.StaticPath + this.request.Path.substring(8);
 this.filePath = Paths.get(path);
 //设置扩展名
 int index = this.request.Path.lastIndexOf(".");
 this.ExName = this.request.Path.substring(index + 1);
 }

 /**
 * 检测文件是否存在
 *
 * @return
 */
 public boolean exists() {
 return Files.exists(filePath);

 }

 /**
 * 检查文件是否需要更新还是304状态吗
 *
 * @return
 */
 public boolean update() {
 try {
 int lastTime = (int) Files.getLastModifiedTime(filePath).to(TimeUnit.SECONDS);//获取最后修改的时间戳
 Object paramTime = this.request.Header.get("If-Modified-Since");

 if ((paramTime != null) && (Integer.parseInt((String) paramTime) <= lastTime)) {
 //处理304
 Response.setStatus(304);
 Response.setContentType(Response.findContentType(this.ExName));
 Response.header("Last-Modified: " + lastTime);
 Response.header("Cache-Control:public, max-age=2592000");
 byte[] headerBytes = Response.getHeader().getBytes();
 ByteBuffer writerBuffer = ByteBuffer.allocate(headerBytes.length);
 writerBuffer.clear();
 writerBuffer.put(headerBytes);
 writerBuffer.flip();
 while (writerBuffer.hasRemaining()) {
 this.socketChannel.write(writerBuffer);
 }
 writerBuffer.clear();
 this.socketChannel.close();
 //输出debug信息
 if (Options.DEBUG || Options.ParseLine) {
 System.out.println(Response.Status + " " + this.request.Header.get("Host") + this.request.Path);
 }
 Response.finish();//清理信息
 return false;
 }
 } catch (IOException ex) {
 Logger.getLogger(StaticFileServer.class.getName()).log(Level.SEVERE, null, ex);
 }
 return true;
 }

 public void read(SocketChannel socketChannel) {
 this.socketChannel = socketChannel;
 //处理304
 if (this.update()) {
 //输出debug信息
 if (Options.DEBUG || Options.ParseLine) {
 System.out.println("Static File" + " " + this.request.Header.get("Host") + this.request.Path);
 }
 //处理200
 BasicFileAttributeView basicView = Files.getFileAttributeView(this.filePath, BasicFileAttributeView.class);

 try {
 BasicFileAttributes basicAttrs = basicView.readAttributes();
 long size = basicAttrs.size();
 if (size > 2097152) {
 //说明文件大于2M
 }
 this.size = (int) size;
 int lastTime = (int) Files.getLastModifiedTime(filePath).to(TimeUnit.SECONDS);//获取最后修改的时间戳
 this.byteBuffer = ByteBuffer.allocate((int) size);//申请缓存空间
 //开始获取通道,读取文件
 AsynchronousFileChannel afc = AsynchronousFileChannel.open(this.filePath);
 afc.read(byteBuffer, 0, lastTime, new CompletionHandlerImpl(afc));

 } catch (IOException ex) {
 //处理500错误
 Logger.getLogger(StaticFileServer.class.getName()).log(Level.SEVERE, null, ex);
 }
 }
 }

 /**
 * 成员类 处理文件完成后的操作
 */
 private class CompletionHandlerImpl implements CompletionHandler<Integer, Object> {

 AsynchronousFileChannel afc;

 public CompletionHandlerImpl(AsynchronousFileChannel afc) {
 this.afc = afc;
 }

 /**
 * 处理成功的操作
 *
 * @param result
 * @param attachment
 */
 @Override
 public void completed(Integer result, Object attachment) {

 Integer lastModifyInteger = (Integer) attachment;
 int lastModify = lastModifyInteger.intValue();
 //Header不能使用Response
 String header = "HTTP/1.1 200 OK\r\n"
 + "Content-type: " + Response.findContentType(StaticFileServer.this.ExName) + ";\r\n"
 + "Content-ength: " + StaticFileServer.this.size + "\r\n"
 + "Last-Modified: " + lastModify + "\r\n"
 + "Cache-Control:public, max-age=2592000 \r\n"
 + "Server: " + Response.Server + "\r\n\r\n";

 byte[] headerBytes = header.getBytes();
 byte[] contentBytes = StaticFileServer.this.byteBuffer.array();
 ByteBuffer writerBuffer = ByteBuffer.allocate(headerBytes.length + contentBytes.length);
 writerBuffer.clear();

 writerBuffer.put(headerBytes);
 writerBuffer.put(contentBytes);
 writerBuffer.flip();
 try {
 while (writerBuffer.hasRemaining()) {
 StaticFileServer.this.socketChannel.write(writerBuffer);
 }
 writerBuffer.clear();

 StaticFileServer.this.socketChannel.close();
 this.afc.close();
 } catch (IOException ex) {
 Logger.getLogger(StaticFileServer.class.getName()).log(Level.SEVERE, null, ex);
 }
 }

 /**
 * 处理失败的操作
 *
 * @param exc
 * @param attachment
 */
 @Override
 public void failed(Throwable exc, Object attachment) {
 System.out.println(exc.getCause());
 //@todo 处理500错误
 try {
 StaticFileServer.this.socketChannel.close();
 this.afc.close();
 } catch (IOException ex) {
 Logger.getLogger(StaticFileServer.class.getName()).log(Level.SEVERE, null, ex);
 }
 }
 }
}