#include "http_connection.h"

#include <iostream>
#include <algorithm>

#include <boost/bind.hpp>
#include <boost/format.hpp>
#include <boost/algorithm/string.hpp>
#include <boost/lexical_cast.hpp>
#include <boost/scoped_array.hpp>

#include <boost/filesystem/fstream.hpp>

namespace response_map_init {
	typedef std::pair<int, std::string> P;
	const P m[] = {
		P(200, "OK"),
		P(206, "Partial Content"),
		P(400, "Bad Request"),
		P(403, "Forbidden"),
		P(404, "Not Found"),
		P(416, "Requested Range Not Satisfiable"),
		P(500, "Internal Server Error"),
		P(501, "Not Implemented")
	};
	const P* begin = m;
	const P* end = m + sizeof(m) / sizeof(P);
}

const std::map<int, std::string> response_map(response_map_init::begin, response_map_init::end);

void HTTP::Connection::send_error(int code) {
	boost::asio::write(socket, boost::asio::buffer(boost::str(boost::format("HTTP/1.1 %1$d %2$s\r\n\r\n<h1>%1$d %2$s</h1>") % code % response_map.find(code)->second)));
}

void HTTP::Connection::add_header(std::string key, std::string value) {
	response_headers.push_back(std::make_pair(key, value));
}

void HTTP::Connection::send_data(const std::string& data) {
	write_headers();
	
	boost::asio::write(socket, boost::asio::buffer(data));
}

void HTTP::Connection::send_data(const void* data, std::size_t size) {
	write_headers();
	
	boost::asio::write(socket, boost::asio::buffer(data, size));
}

void HTTP::Connection::send_data(std::istream& stream) {
	char data[0x1000];
	std::streamsize size = 1;
	while(size) {
		stream.read(data, 0x1000);
		size = stream.gcount();
		if(size > 0)
			send_data(data, size);
	}
}

void HTTP::Connection::send_file(const fs::path& filename) {
	//req->add_header("Content-Type", "application/octet-stream");
	
	fs::ifstream is(filename, std::ios::in | std::ios::binary);
	is.seekg(0, std::ios::end);
	std::size_t length = is.tellg();
	is.seekg(0, std::ios::beg);
	
	// Simple Range-parser.
	// TODO: Support other formats than a single range.
	if(headers.count("Range")) {
		std::string range_str = headers["Range"];
		
		if(!boost::starts_with(range_str, "bytes=")) {
			// Broken header? We can't cope with that.
			return;
		}
		
		range_str = range_str.substr(6);
		
		std::string::iterator it = std::find(range_str.begin(), range_str.end(), '-');
		
		std::size_t begin = boost::lexical_cast<int>(std::string(range_str.begin(), it));
		std::size_t end = length;
		if(++it != range_str.end()) {
			end = boost::lexical_cast<int>(std::string(it, range_str.end()));
		}
		
		// Is the range past the end of the file?
		if(end > length) {
			end = length;
		}
		
		// Do the file contain requested range?
		if((end && end < begin) || begin > length) {
			send_error(416);
		}
		
		add_header("Content-Range", boost::str(boost::format("bytes %d-%d/%d") % begin % (end - 1) % length));
		add_header("Content-Length", boost::str(boost::format("%d") % (end - begin)));
		
		write_headers(206);
		
		is.seekg(begin);
		
		boost::scoped_array<char> buf(new char[end-begin]);
		is.read(buf.get(), end - begin);
		send_data(buf.get(), is.gcount());
	
	} else {
		add_header("Content-Length", boost::str(boost::format("%d") % length));
		send_data(is);
	}
}

HTTP::Connection::Connection(boost::asio::io_service& io_service) : socket(io_service) {
	headers_written = false;
}

void HTTP::Connection::handle_write(const boost::system::error_code& error, size_t bytes_transferred) {
}

void HTTP::Connection::handle_read(const boost::system::error_code& error, size_t bytes_transferred, Handler callback) {
	try {
		if(!parse_request(buf)) {
			// Request parse error.
			std::cout << "Request parse error." << std::endl;
			send_error(400);
			return;
		}
		
		std::cout << "Path: " << std::endl;
		for(PathList::iterator it = path.begin(); it != path.end(); it++) {
			std::cout << "  " << *it << std::endl;
		}
		
		std::cout << "Args: " << std::endl;
		for(std::map<std::string, std::string>::iterator it = args.begin(); it != args.end(); it++) {
			std::cout << "  " << it->first << " = " << it->second << std::endl;
		}
		
		std::cout << "Headers: " << std::endl;
		for(std::map<std::string, std::string>::iterator it = headers.begin(); it != headers.end(); it++) {
			std::cout << "  " << it->first << " = " << it->second << std::endl;
		}
		
		callback(shared_from_this());
	
	// Catch unhandled exceptions.
	} catch(std::exception& e) {
		std::cerr << "Unhandled exception while handling request: " << e.what() << std::endl;
		
		try {
			send_error(500);
		
		} catch(...) {
			// Ignored.
		}
	}
}

void HTTP::Connection::read_request(Handler callback) {
	boost::asio::async_read_until(socket, buf, "\r\n\r\n", boost::bind(&Connection::handle_read, shared_from_this(),
				boost::asio::placeholders::error, boost::asio::placeholders::bytes_transferred, callback));
}

std::string HTTP::Connection::pop_path_base() {
	if(!path.size()) {
		return "";
	}
	
	base_path.push_back(path.front());
	path.pop_front();
	
	return base_path.back();
}

void HTTP::Connection::write_headers(int code) {
	if(headers_written) {
		return;
	}
	headers_written = true;
	
	boost::asio::write(socket, boost::asio::buffer(boost::str(boost::format("HTTP/1.1 %d %s\r\n") % code % response_map.find(code)->second)));
	
	for(HeaderList::iterator it = response_headers.begin(); it != response_headers.end(); it++) {
		boost::asio::write(socket, boost::asio::buffer(boost::str(boost::format("%s: %s\r\n") % it->first % it->second)));
	}
	
	boost::asio::write(socket, boost::asio::buffer(std::string("\r\n")));
}