#include <iostream>
#include <string.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <unistd.h>
#include <netinet/in.h>
#include <errno.h>
#include <fcntl.h>
#include <utf8/utf8.h>
#include "server.h"
#include "string_functions.h"



Server::Server()
{
	main_socket  = -1;
	close_server = false;
}

Server::~Server()
{
	Close();
}


void Server::CloseMainSocket()
{
	if( main_socket != -1 )
	{
		close(main_socket);
		main_socket = -1;
	}
}


void Server::CloseClientSockets()
{
	for(size_t i=0 ; i<client_tab.size() ; ++i)
		close(client_tab[i].socket);

	client_tab.clear();
}


void Server::Close()
{
	CloseMainSocket();
	CloseClientSockets();
}






void Server::PrepareMainSocket()
{
	CloseMainSocket();

	main_socket = socket(PF_INET, SOCK_STREAM | SOCK_NONBLOCK, 0);

	if( main_socket < 0 )
	{
		std::cout << "I cannot create a socket" << std::endl;
		return;
	}

	int optval = 1;

	if( setsockopt(main_socket, SOL_SOCKET, SO_REUSEPORT, &optval, sizeof(optval)) < 0 )
	{
		std::cout << "I cannot setsockopt " << std::endl;
		return;
	}


	struct sockaddr_in addr;

	memset(&addr, 0, sizeof(addr));

	addr.sin_len         = sizeof(addr);
	addr.sin_family      = PF_INET;
	addr.sin_addr.s_addr = INADDR_ANY;
	addr.sin_port        = htons(3012);

	socklen_t len = sizeof(addr);

	if( bind(main_socket, (struct sockaddr*)&addr, len) < 0 )
	{
		std::cout << "bind failed: " << std::endl;
		return;
	}


	if( listen(main_socket, 100) < 0 )
	{
		std::cout << "listen failed" << std::endl;
		return;
	}
}



void Server::Wait()
{
	while( !close_server )
	{
		int fd_max = AddSocketsToSet();
		int ready_fd = select(fd_max + 1, &read_set, &write_set, 0, 0);

		if( ready_fd < 0 )
		{
			std::cout << "select failed" << std::endl;
			return;
		}

		if( ready_fd > 0 )
		{
			if( FD_ISSET(main_socket, &read_set) )
			{
				AddNewClient();
			}
			else
			{
				ReadWriteToClients();
			}
		}
	}
}



int Server::AddSocketsToSet()
{
	FD_ZERO(&read_set);
	FD_ZERO(&write_set);

	int fd_max = 0;

	if( main_socket >= 0 )
	{
		FD_SET(main_socket, &read_set);
		fd_max = main_socket;

		for(size_t i=0 ; i<client_tab.size() ; ++i)
		{
			FD_SET(client_tab[i].socket, &read_set);

			if( client_tab[i].answer_generated && !client_tab[i].output_buffer.empty() )
				FD_SET(client_tab[i].socket, &write_set);

			if( client_tab[i].socket > fd_max )
				fd_max = client_tab[i].socket;
		}
	}
	else
	{
		std::cout << "there is no main socket" << std::endl;
	}

	return fd_max;
}



void Server::AddNewClient()
{
struct sockaddr_in client_addr;
socklen_t len;
int client_socket;
//int optval;

	memset(&client_addr, 0, sizeof(client_addr));
	len = sizeof(client_addr);

	client_socket = accept(main_socket, (struct sockaddr*)&client_addr, &len);

	if( client_socket < 0 )
	{
		std::cout << "accept failed" << std::endl;
	}
	else
	{
		int opt = fcntl(client_socket, F_GETFL);

		if( opt >= 0 )
		{
			opt = opt | O_NONBLOCK;

			if( fcntl(client_socket, F_SETFL, opt) >= 0 )
			{
				Client c;

				c.socket = client_socket;
				c.close_connection = false;

				client_tab.push_back(c);
				client_tab.back().PrepareToNewRequest();
			}
			else
			{
				std::cout << "I cannot fcntl (O_NONBLOCK)" << std::endl;
			}
		}
	}
}


void Server::ReadWriteToClients()
{
	size_t i = 0;

	while( i < client_tab.size() )
	{
		if( FD_ISSET(client_tab[i].socket, &read_set))
		{
			ReadInputFromClient(client_tab[i]);
		}

		if( client_tab[i].answer_generated && FD_ISSET(client_tab[i].socket, &write_set) )
		{
			WriteOutputToClient(client_tab[i]);
		}

		if( client_tab[i].output_buffer.empty() && client_tab[i].close_connection )
		{
			std::cout << "closing connection for client nr " << client_tab[i].socket << std::endl;

			close(client_tab[i].socket);
			client_tab.erase(client_tab.begin() + i);
		}
		else
		{
			i += 1;
		}
	}
}






void Server::ReadInputFromClient(Client & client)
{
	std::cout << "trying read something from client number: " << client.socket << std::endl;

	// we need at least one char more (for terminating zero for logging/debugging)

	if( client.in_buffer_max_len - client.in_buffer_len < 2 )
	{
		client.input_buffer.append(client.in_buffer, client.in_buffer_len);
		client.in_buffer_len = 0;
	}

	char * old_pointer = client.in_buffer + client.in_buffer_len;

	// after adding to client.input_buffer we set in_buffer_len to 0
	// so here is sufficient client.in_buffer (without adding client.in_buffer_len)
	int read_len = read(client.socket, client.in_buffer + client.in_buffer_len, client.in_buffer_max_len - client.in_buffer_len - 1);

	if( read_len < 0 )
	{
		// read failed, we do not parse this request

		std::cout << "read failed" << std::endl;
		client.close_connection = true;
	}
	else
	if( read_len == 0 )
	{
		// end

		if( client.in_buffer_len > 0 )
		{
			client.input_buffer.append(client.in_buffer, client.in_buffer_len);
			client.in_buffer_len = 0;
		}

		std::cout << "------------------------------ client: " << client.socket << " calosc komunikatu " << std::endl;
		std::cout << client.input_buffer;
		std::cout << "----------------------------------------" << std::endl;

		// the client has terminated connection
		client.close_connection = true;
	}
	else
	{
		client.in_buffer_len += read_len;

		size_t input_buffer_index = client.input_buffer.size();

		client.input_buffer.append(client.in_buffer, client.in_buffer_len);
		client.in_buffer_len = 0;

		if( client.parsing_headers )
			CheckHeaders(client, input_buffer_index);



		client.in_buffer[client.in_buffer_len] = 0; // only for logging (we have at least one character more for terminating zero)

		std::cout << "------------------------------ client: " << client.socket << std::endl;
		std::cout << old_pointer;
		std::cout << "----------------------------------------" << std::endl;
	}
}



void Server::WriteOutputToClient(Client & client)
{
	std::cout << "writing to client nr " << client.socket << std::endl;

	const char * data = client.output_buffer.c_str() + client.output_buffer_sent;
	size_t how_many_to_send = client.output_buffer.size() - client.output_buffer_sent;

	if( how_many_to_send > 0 )
	{
		int len = send(client.socket, data, how_many_to_send, 0);

		if( len < 0 )
		{
			std::cout << "writing failed" << std::endl;
		}
		else
		{
			client.output_buffer_sent += len;

			if( client.output_buffer_sent == client.output_buffer.size() )
			{
				client.PrepareToNewRequest();
			}
		}
	}
}




void Server::CheckHeaders(Client & client, size_t input_buffer_index)
{
	// at least 3 bytes before

	if( input_buffer_index > 3 )
		input_buffer_index -= 3;
	else
		input_buffer_index = 0;

	for( ; input_buffer_index + 3 < client.input_buffer.size() ; ++input_buffer_index)
	{
		if( headers_parser.IsHeadersEnding(client.input_buffer.c_str() + input_buffer_index) )
		{
			headers_parser.ParseHeaders(client);

			if( !SelectMethodName(client, client.http_method_str) )
			{
				std::cout << "unsupported http method" << std::endl;
				client.close_connection = true;
			}

			client.parsing_headers = false;
			client.input_buffer.erase(0, input_buffer_index + 4);


			// temporarily we are using only get method with http 1.0 (closing connection after answering)
			if( client.http_method == http_method_get )
			{
				CreateAnswer(client);
				client.answer_generated = true;

				if( client.http_version == http_version_1_0 )
				{
					std::cout << "answer generated, closing connection for http 1.0" << std::endl;
					client.close_connection = true;
				}
			}

			if( client.http_method != http_method_get )
			{
				// at the moment only get method
				client.close_connection = true;
			}

			break;
		}
	}
}






bool Server::SelectMethodName(Client & client, const std::wstring & method_name)
{
	client.http_method = http_method_unsupported;

	if( CompareNoCase(method_name, L"get") )
	{
		client.http_method = http_method_get;
	}
	else
	if( CompareNoCase(method_name, L"put") )
	{
		client.http_method = http_method_put;
	}
	else
	if( CompareNoCase(method_name, L"post") )
	{
		client.http_method = http_method_post;
	}
	else
	if( CompareNoCase(method_name, L"delete") )
	{
		client.http_method = http_method_delete;
	}
	else
	if( CompareNoCase(method_name, L"options") )
	{
		client.http_method = http_method_options;
	}

	return client.http_method != http_method_unsupported;
}






//void Server::RemoveClientSocket(int client_socket)
//{
//	for(size_t i=0 ; i<client_tab.size() ; ++i)
//	{
//		if( client_tab[i].socket == client_socket )
//		{
//			close(client_socket);
//			client_tab.erase(client_tab.begin() + i);
//
//			// warning: in ReadWriteToClients we have a loop through client_tab
//			// (next item will be skipped by ++i)
//			break;
//		}
//	}
//}




void Server::CreateAnswer(Client & client)
{
	std::wstring a, c;

	c = L"hello world from my webserver, your requested: " + client.url;
	c += L"\r\n";

	if( client.url == L"/quit" )
	{
		c += L"<br><br>bye bye";
		close_server = true;
	}

	std::string c_ascii;
	PT::WideToUTF8(c,c_ascii);


	a = L"HTTP/";

	if( client.http_version == http_version_1_0 )
		a += L"1.0";
	else
		a += L"1.1";

	a += L" 200 OK\r\n";
	a += L"Content-Type: text/html; charset=UTF-8\r\n";



	wchar_t buf[32];
	swprintf(buf, sizeof(buf)/sizeof(wchar_t), L"%d", c_ascii.size());

	a += L"Content-Length: ";
	a += buf;
	a += L"\r\n";
	a += L"\r\n";


	PT::WideToUTF8(a, client.output_buffer);
	client.output_buffer += c_ascii;
}