#include <stdio.h>
#include <unistd.h>

#include "muduo/base/Logging.h"
#include "muduo/net/EventLoop.h"
#include "muduo/net/TcpServer.h"

using namespace muduo;
using namespace muduo::net;

void onHighWaterMark(const TcpConnectionPtr& conn, size_t len)
{
    LOG_INFO << "HighWaterMark " << len;
}

const int   kBufSize = 64 * 1024;
const char* g_file = NULL;

void onConnection(const TcpConnectionPtr& conn)
{
    LOG_INFO << "FileServer - " << conn->peerAddress().toIpPort() << " -> "
             << conn->localAddress().toIpPort() << " is "
             << (conn->connected() ? "UP" : "DOWN");
    if (conn->connected()) {
        LOG_INFO << "FileServer - Sending file " << g_file << " to "
                 << conn->peerAddress().toIpPort();
        conn->setHighWaterMarkCallback(onHighWaterMark, kBufSize + 1);

        FILE* fp = ::fopen(g_file, "rb");
        if (fp) {
            conn->setContext(fp);
            char   buf[kBufSize];
            size_t nread = ::fread(buf, 1, sizeof buf, fp);
            conn->send(buf, static_cast<int>(nread));
        } else {
            conn->shutdown();
            LOG_INFO << "FileServer - no such file";
        }
    } else {
        if (!conn->getContext().empty()) {
            FILE* fp = boost::any_cast<FILE*>(conn->getContext());
            if (fp) {
                ::fclose(fp);
            }
        }
    }
}

void onWriteComplete(const TcpConnectionPtr& conn)
{
    FILE*  fp = boost::any_cast<FILE*>(conn->getContext());
    char   buf[kBufSize];
    size_t nread = ::fread(buf, 1, sizeof buf, fp);
    if (nread > 0) {
        conn->send(buf, static_cast<int>(nread));
    } else {
        ::fclose(fp);
        fp = NULL;
        conn->setContext(fp);
        conn->shutdown();
        LOG_INFO << "FileServer - done";
    }
}

int main(int argc, char* argv[])
{
    LOG_INFO << "pid = " << getpid();
    if (argc > 1) {
        g_file = argv[1];

        EventLoop   loop;
        InetAddress listenAddr(2021);
        TcpServer   server(&loop, listenAddr, "FileServer");
        server.setConnectionCallback(onConnection);
        server.setWriteCompleteCallback(onWriteComplete);
        server.start();
        loop.loop();
    } else {
        fprintf(stderr, "Usage: %s file_for_downloading\n", argv[0]);
    }
}