// excerpts from http://code.google.com/p/muduo/
 //
 // Use of this source code is governed by a BSD-style license
 // that can be found in the License file.
 //
 // Author: Shuo Chen (chenshuo at chenshuo dot com)
 
 #include "TcpConnection.h"
 
 #include "logging/Logging.h"
 #include "Channel.h"
 #include "EventLoop.h"
 #include "Socket.h"
 #include "SocketsOps.h"
 
 #include <boost/bind.hpp>
 
 #include <errno.h>
 #include <stdio.h>
 
 using namespace muduo;
 
 TcpConnection::TcpConnection(EventLoop* loop,
                              const std::string& nameArg,
                              int sockfd,
                              const InetAddress& localAddr,
                              const InetAddress& peerAddr)
   : loop_(CHECK_NOTNULL(loop)),
     name_(nameArg),
     state_(kConnecting),
     socket_(new Socket(sockfd)),
     channel_(new Channel(loop, sockfd)),
     localAddr_(localAddr),
     peerAddr_(peerAddr)
 {
   LOG_DEBUG << "TcpConnection::ctor[" <<  name_ << "] at " << this
             << " fd=" << sockfd;
   channel_->setReadCallback(
       boost::bind(&TcpConnection::handleRead, this, _1));
   channel_->setWriteCallback(
       boost::bind(&TcpConnection::handleWrite, this));
   channel_->setCloseCallback(
       boost::bind(&TcpConnection::handleClose, this));
   channel_->setErrorCallback(
       boost::bind(&TcpConnection::handleError, this));
 }
 
 TcpConnection::~TcpConnection()
 {
   LOG_DEBUG << "TcpConnection::dtor[" <<  name_ << "] at " << this
             << " fd=" << channel_->fd();
 }
 
+void TcpConnection::send(const std::string& message)
+{
+  if (state_ == kConnected) {
+    if (loop_->isInLoopThread()) {
+      sendInLoop(message);
+    } else {
+      loop_->runInLoop(
+          boost::bind(&TcpConnection::sendInLoop, this, message));
+    }
+  }
+}
+
+void TcpConnection::sendInLoop(const std::string& message)
+{
+  loop_->assertInLoopThread();
+  ssize_t nwrote = 0;
+  // if no thing in output queue, try writing directly
+  if (!channel_->isWriting() && outputBuffer_.readableBytes() == 0) {
+    nwrote = ::write(channel_->fd(), message.data(), message.size());
+    if (nwrote >= 0) {
+      if (implicit_cast<size_t>(nwrote) < message.size()) {
+        LOG_TRACE << "I am going to write more data";
+      }
+    } else {
+      nwrote = 0;
+      if (errno != EWOULDBLOCK) {
+        LOG_SYSERR << "TcpConnection::sendInLoop";
+      }
+    }
+  }
+
+  assert(nwrote >= 0);
+  if (implicit_cast<size_t>(nwrote) < message.size()) {
+    outputBuffer_.append(message.data()+nwrote, message.size()-nwrote);
+    if (!channel_->isWriting()) {
+      channel_->enableWriting();
+    }
+  }
+}
+
+void TcpConnection::shutdown()
+{
+  // FIXME: use compare and swap
+  if (state_ == kConnected)
+  {
+    setState(kDisconnecting);
+    // FIXME: shared_from_this()?
+    loop_->runInLoop(boost::bind(&TcpConnection::shutdownInLoop, this));
+  }
+}
+
+void TcpConnection::shutdownInLoop()
+{
+  loop_->assertInLoopThread();
+  if (!channel_->isWriting())
+  {
+    // we are not writing
+    socket_->shutdownWrite();
+  }
+}
+
 void TcpConnection::connectEstablished()
 {
   loop_->assertInLoopThread();
   assert(state_ == kConnecting);
   setState(kConnected);
   channel_->enableReading();
   connectionCallback_(shared_from_this());
 }
 
 void TcpConnection::connectDestroyed()
 {
   loop_->assertInLoopThread();
!  assert(state_ == kConnected || state_ == kDisconnecting);
   setState(kDisconnected);
   channel_->disableAll();
   connectionCallback_(shared_from_this());
 
   loop_->removeChannel(get_pointer(channel_));
 }
 
 void TcpConnection::handleRead(Timestamp receiveTime)
 {
   int savedErrno = 0;
   ssize_t n = inputBuffer_.readFd(channel_->fd(), &savedErrno);
   if (n > 0) {
     messageCallback_(shared_from_this(), &inputBuffer_, receiveTime);
   } else if (n == 0) {
     handleClose();
   } else {
     // FIXME: check savedErrno
     handleError();
   }
 }
 
 void TcpConnection::handleWrite()
 {
+  loop_->assertInLoopThread();
+  if (channel_->isWriting()) {
+    ssize_t n = ::write(channel_->fd(),
+                        outputBuffer_.peek(),
+                        outputBuffer_.readableBytes());
+    if (n > 0) {
+      outputBuffer_.retrieve(n);
+      if (outputBuffer_.readableBytes() == 0) {
+        channel_->disableWriting();
+        if (state_ == kDisconnecting) {
+          shutdownInLoop();
+        }
+      } else {
+        LOG_TRACE << "I am going to write more data";
+      }
+    } else {
+      LOG_SYSERR << "TcpConnection::handleWrite";
+      abort();  // FIXME
+    }
+  } else {
+    LOG_TRACE << "Connection is down, no more writing";
+  }
 }
 
 void TcpConnection::handleClose()
 {
   loop_->assertInLoopThread();
   LOG_TRACE << "TcpConnection::handleClose state = " << state_;
!  assert(state_ == kConnected || state_ == kDisconnecting);
   // we don't close fd, leave it to dtor, so we can find leaks easily.
   channel_->disableAll();
   // must be the last line
   closeCallback_(shared_from_this());
 }
 
 void TcpConnection::handleError()
 {
   int err = sockets::getSocketError(channel_->fd());
   LOG_ERROR << "TcpConnection::handleError [" << name_
             << "] - SO_ERROR = " << err << " " << strerror_tl(err);
 }