//
// async_client.cpp
// ~~~~~~~~~~~~~~~~
//
// Copyright (c) 2003-2010 Christopher M. Kohlhoff (chris at kohlhoff dot com)
//
// Distributed under the Boost Software License, Version 1.0. (See accompanying
// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
 
#include <iostream>
#include <istream>
#include <ostream>
#include <string>
#include <boost/function.hpp>
#include <boost/thread/once.hpp>
#include <boost/thread.hpp>
#include <boost/asio.hpp>
#include <boost/bind.hpp>
 
using boost::asio::ip::tcp;
 
class client
{
public:
	typedef boost::function<void(client&)> on_complete_callback;
 
public:
	client(boost::asio::io_service& io_service)
		: resolver_(io_service)
		, socket_(io_service)
		, io_service_(io_service)
	{
	}
 
	~client()
	{
		io_thread_.join();
	}
 
	void navigate(const std::string& server, const std::string& path)
	{
		if (socket_.is_open()) {
			boost::system::error_code ignored_ec;
			socket_.close(ignored_ec);
		}
		std::ostream request_stream(&request_);
		request_stream << "GET " << path << " HTTP/1.0
";
		request_stream << "Host: " << server << "
";
		request_stream << "Accept: */*
";
		request_stream << "Connection: close
 
";
 
		tcp::resolver::query query(server, "http");
		resolver_.async_resolve(query,
			boost::bind(&client::handle_resolve, this,
			boost::asio::placeholders::error,
			boost::asio::placeholders::iterator));
		io_thread_.swap(boost::thread(boost::bind(&client::io_service_run, this)));
	}
 
	void regiseter_complete_callback(on_complete_callback callback)
	{
		on_complete_callback_ = callback;
	}
 
	void close_socket()
	{
		boost::system::error_code ignored_ec;
		socket_.shutdown(boost::asio::ip::tcp::socket::shutdown_both, ignored_ec);
		socket_.close(ignored_ec);
	}
 
	void io_service_run()
	{
		boost::mutex::scoped_try_lock try_lock(io_mutex_);
		if (!try_lock) {
			return ;
		}
 
 		io_service_.run();
 		io_service_.reset();
	}
 
private:
	void handle_resolve(const boost::system::error_code& err,
		tcp::resolver::iterator endpoint_iterator)
	{
		if (!err)
		{
			// Attempt a connection to the first endpoint in the list. Each endpoint
			// will be tried until we successfully establish a connection.
			tcp::endpoint endpoint = *endpoint_iterator;
			socket_.async_connect(endpoint,
				boost::bind(&client::handle_connect, this,
				boost::asio::placeholders::error, ++endpoint_iterator));
		}
		else
		{
			std::cout << "Error: " << err.message() << "\n";
		}
	}
 
	void handle_connect(const boost::system::error_code& err,
		tcp::resolver::iterator endpoint_iterator)
	{
		if (!err)
		{
			// The connection was successful. Send the request.
			boost::asio::async_write(socket_, request_,
				boost::bind(&client::handle_write_request, this,
				boost::asio::placeholders::error));
		}
		else if (endpoint_iterator != tcp::resolver::iterator())
		{
			// The connection failed. Try the next endpoint in the list.
			socket_.close();
			tcp::endpoint endpoint = *endpoint_iterator;
			socket_.async_connect(endpoint,
				boost::bind(&client::handle_connect, this,
				boost::asio::placeholders::error, ++endpoint_iterator));
		}
		else
		{
			std::cout << "Error: " << err.message() << "\n";
		}
	}
 
	void handle_write_request(const boost::system::error_code& err)
	{
		if (!err)
		{
			// Read the response status line. The response_ streambuf will
			// automatically grow to accommodate the entire line. The growth may be
			// limited by passing a maximum size to the streambuf constructor.
			boost::asio::async_read_until(socket_, response_, "
",
				boost::bind(&client::handle_read_status_line, this,
				boost::asio::placeholders::error));
		}
		else
		{
			std::cout << "Error: " << err.message() << "\n";
		}
	}
 
	void handle_read_status_line(const boost::system::error_code& err)
	{
		if (!err)
		{
			// Check that response is OK.
			std::istream response_stream(&response_);
			std::string http_version;
			response_stream >> http_version;
			unsigned int status_code;
			response_stream >> status_code;
			std::string status_message;
			std::getline(response_stream, status_message);
			if (!response_stream || http_version.substr(0, 5) != "HTTP/")
			{
				std::cout << "Invalid response\n";
				return;
			}
			if (status_code != 200)
			{
				std::cout << "Response returned with status code ";
				std::cout << status_code << "\n";
				return;
			}
 
			// Read the response headers, which are terminated by a blank line.
			boost::asio::async_read_until(socket_, response_, "
 
",
				boost::bind(&client::handle_read_headers, this,
				boost::asio::placeholders::error));
		}
		else
		{
			std::cout << "Error: " << err << "\n";
		}
	}
 
	void handle_read_headers(const boost::system::error_code& err)
	{
		if (!err)
		{
			// Process the response headers.
			std::istream response_stream(&response_);
			std::string header;
			while (std::getline(response_stream, header) && header != "\r")
				std::cout << header << "\n";
			std::cout << "\n";
 
			// Write whatever content we already have to output.
			if (response_.size() > 0)
				std::cout << &response_;
 
			// Start reading remaining data until EOF.
			boost::asio::async_read(socket_, response_,
				boost::asio::transfer_at_least(1),
				boost::bind(&client::handle_read_content, this,
				boost::asio::placeholders::error));
		}
		else
		{
			std::cout << "Error: " << err << "\n";
		}
	}
 
	void handle_read_content(const boost::system::error_code& err)
	{
		if (!err)
		{
			// Write all of the data that has been read so far.
			std::cout << &response_;
 
			// Continue reading remaining data until EOF.
			boost::asio::async_read(socket_, response_,
				boost::asio::transfer_at_least(1),
				boost::bind(&client::handle_read_content, this,
				boost::asio::placeholders::error));
		}
		else if (err != boost::asio::error::eof)
		{
			std::cout << "Error: " << err << "\n";
		}
		else
		{
			on_complete_callback_(*this);
		}
	}
 
	tcp::resolver resolver_;
	tcp::socket socket_;
	boost::asio::streambuf request_;
	boost::asio::streambuf response_;
	boost::asio::io_service& io_service_;
	boost::thread io_thread_;
	boost::mutex io_mutex_;
	on_complete_callback on_complete_callback_;
};
 
void complete(client& cli)
{
 
}
 
int main(int argc, char* argv[])
{
	try
	{
		if (argc != 3)
		{
			std::cout << "Usage: async_client <server> <path>\n";
			std::cout << "Example:\n";
			std::cout << "  async_client www.boost.org /LICENSE_1_0.txt\n";
			return 1;
		}
 
		boost::asio::io_service io_service;
		client cli(io_service);
 
		cli.regiseter_complete_callback(boost::bind(&complete, boost::ref<client>(cli)));
		cli.navigate(argv[1], argv[2]);
 
 
		std::string in;
 
		std::cout << "type 'exit' to exit.\nprompt # ";
 
		for (;;)
		{			
			char c = getchar();
			if (c == '\n' || c == EOF )
			{
 
				if (in == "exit")
				{
					io_service.post(boost::bind(&client::close_socket, &cli));
					break;
				}
				else if (in == "r") 
				{
					cli.navigate(argv[1], argv[2]);
				}
				else if(in != "")
				{
					system(in.c_str());	// std::cout << "Bad command ! \n";
				}
 
				std::cout << "prompt # ";
				in = "";
			}
			else
			{
				in += c;
			}
		}
	}
	catch (std::exception& e)
	{
		std::cout << "Exception: " << e.what() << "\n";
	}
 
	return 0;
}