#include<stdio.h>
#include<stdlib.h>
#include<string.h>
#include<unistd.h>
#include<arpa/inet.h>
#include<sys/types.h>
#include<sys/socket.h>
#include<pthread.h>
#define BUFF_SIZE 1024
int thread_num[25];	//스레드 번호 (해당 스레드 활성화시 번호 값 + 1, 비활성화시 0)
			//ex) thread_num[스레드 번호]==스레드 번호+1
int client_socket_array[25];	//클라이언트 소캣, 각 스레드 마다 자신의 번호에 해당하는 소캣 사용
				//ex) 스레드가 사용 중인 소캣 == client_socket_array[스레드 번호]
char id[100][256];
char password[100][256];
char id_state[100];
int id_num;
char chat[100][BUFF_SIZE+5];
char chat_s[100], chat_e;
void* rutine(void* data)//data = &thread_num[스레드 번호]
{
	int t_num,i_num;//스레드 번호, 아이디 번호
	int client_socket;
	char buff_rcv[BUFF_SIZE+5],buff_snd[BUFF_SIZE+5];
	int rcv;
	int i,j;
	t_num=*((int*)data);
	//사용자가 이해하기 쉽도록 스레드 번호에 +1 값을 쓰도록 한다.
	client_socket=client_socket_array[t_num-1];
	//코드의 간결화를 위해 값을 복사한다.
	recv(client_socket, buff_rcv,BUFF_SIZE,0);
	sprintf(buff_snd,"test\n");
	send(client_socket, buff_snd, strlen(buff_snd)+1,0);
	printf("%dth client connected\n",t_num);
	//접속 검사 코드
	//로그인 루프
	while(1)
	{
		if(recv(client_socket, buff_rcv,BUFF_SIZE,0)<=0)
		{
			printf("%dth client disconnected\n",t_num);
			close(client_socket);
			thread_num[t_num-1]=0;
			client_socket_array[t_num-1]=0;
			//스레드가 비활성화 되었으므로 thread_num을 0으로 초기화한다.
			return;
		}
		if(buff_rcv[0]=='n' || buff_rcv[0]=='l')
		{
			sprintf(buff_snd,"a\n");
			send(client_socket, buff_snd, strlen(buff_snd)+1,0);
			break;
		}
		else
		{
			printf("wrong data\n");
			sprintf(buff_snd,"c\n");
			send(client_socket, buff_snd, strlen(buff_snd)+1,0);
		}
	}
	if(buff_rcv[0]=='n')//새 계정 생성
	{
		printf("client try to make ID\n");
		while(1)
		{
			sprintf(buff_snd,"i\n");
			send(client_socket, buff_snd, strlen(buff_snd)+1,0);//id 요구
			if(recv(client_socket, buff_rcv,BUFF_SIZE,0)<=0)
			{
				printf("%dth client disconnected\n",t_num);
				close(client_socket);
				thread_num[t_num-1]=0;
				client_socket_array[t_num-1]=0;
				//스레드가 비활성화 되었으므로 thread_num을 0으로 초기화한다.
				return;
			}
			sprintf(id[id_num],"%s",buff_rcv);
			for(i=0;i<id_num;i++)
			{
				for(j=0;id[i][j];j++)
				{
					if(id[i][j]!=buff_rcv[j])
						break;
				}
				if(!id[i][j])
					break;
			}
			if(i==id_num)
			{
				break;
			}
		}
		sprintf(buff_snd,"p\n");
		send(client_socket, buff_snd, strlen(buff_snd)+1,0);//password 요구
		if(recv(client_socket, buff_rcv,BUFF_SIZE,0)<=0)
		{
			printf("%dth client disconnected\n",t_num);
			close(client_socket);
			thread_num[t_num-1]=0;
			client_socket_array[t_num-1]=0;
			//스레드가 비활성화 되었으므로 thread_num을 0으로 초기화한다.
			return;
		}
		printf("%dth client's password : %s\n",t_num,buff_rcv);
		sprintf(password[id_num],"%s",buff_rcv);
		i_num=id_num;
		id_num++;
		printf("%dth client made new ID\n",t_num);
		sprintf(buff_snd,"a\n");
		send(client_socket, buff_snd, strlen(buff_snd)+1,0);//접속 확인
	}
	else
	{
		printf("client try to login\n");
		while(1)
		{			
			sprintf(buff_snd,"i\n");
			send(client_socket, buff_snd, strlen(buff_snd)+1,0);//id 요구
			if(recv(client_socket, buff_rcv,BUFF_SIZE,0)<=0)
			{
				printf("%dth client disconnected\n",t_num);
				close(client_socket);
				thread_num[t_num-1]=0;
				client_socket_array[t_num-1]=0;
				//스레드가 비활성화 되었으므로 thread_num을 0으로 초기화한다.
				return;
			}
			for(i=0;i<id_num;i++)
			{
				for(j=0;id[i][j];j++)
				{
					if(id[i][j]!=buff_rcv[j])
						break;
				}
				if(!id[i][j])
					break;
			}
			if(i==id_num)
				continue;
			else
				if(id_state[i])
					continue;
			sprintf(buff_snd,"p\n");
			send(client_socket, buff_snd, strlen(buff_snd)+1,0);//password 요구
			if(recv(client_socket, buff_rcv,BUFF_SIZE,0)<=0)
			{
				printf("%dth client disconnected\n",t_num);
				close(client_socket);
				thread_num[t_num-1]=0;
				client_socket_array[t_num-1]=0;
				//스레드가 비활성화 되었으므로 thread_num을 0으로 초기화한다.
				return;
			}
			for(j=0;password[i][j]!='\n';j++)
			{
				if(password[i][j]!=buff_rcv[j])
					break;
			}
			if(!password[i][j])
				printf("%dth client's password : %s\n",t_num,buff_rcv);
			else
				continue;
			printf("%dth client logined\n",t_num);
			sprintf(buff_snd,"a\n");
			send(client_socket, buff_snd, strlen(buff_snd)+1,0);//접속 확인
			i_num=i;
			break;
		}
	}
	sprintf(buff_snd,"%s has joined",id[i_num]);
	for(i=0;i<20;i++)
	{
		if(thread_num[i])
			send(client_socket_array[i],buff_snd,strlen(buff_snd)+1,0);
	}
	id_state[i_num]=1;
	for(;chat_s[i_num]!=chat_e;chat_s[i_num]++)
	{
		sprintf(buff_snd,"%s\n",chat[chat_s[i_num]]);
		send(client_socket, buff_snd, strlen(buff_snd)+1,0);
	}
	while(1)
	{
		rcv=recv(client_socket,buff_rcv,BUFF_SIZE,0);
		if(rcv>0)
		{
			printf("received\n");
			sprintf(buff_snd,"%s : %s",id[i_num],buff_rcv);
			for(i=0;i<20;i++)
			{
				if(thread_num[i])
					send(client_socket_array[i],buff_snd,strlen(buff_snd)+1,0);
			}
			sprintf(chat[chat_e],"%s",buff_snd);
			chat_e++;
			chat_e%=100;
			for(i=0;i<100;i++)
				if(id_state[i] || i>=id_num)
					chat_s[i]=chat_e;
		}
		else
		{
			break;
		}
	}
	printf("disconnected\n");
	sprintf(buff_snd,"%s has left",id[i_num]);
	for(i=0;i<20;i++)
	{
		if(thread_num[i])
			send(client_socket_array[i],buff_snd,strlen(buff_snd)+1,0);
	}
	printf("disconnected\n");
	close(client_socket);
	thread_num[t_num-1]=0;
	client_socket_array[t_num-1]=0;
	//스레드가 비활성화 되었으므로 thread_num을 0으로 초기화한다.
	id_state[i_num]=0;
}
int main()
{
	int server_socket;
	pthread_t p_thread[25];
	struct sockaddr_in server_addr;
	struct sockaddr_in client_addr;
	int client_addr_size;
	int i;
	server_socket=socket(PF_INET, SOCK_STREAM, 0);
	if(server_socket==-1)
	{
		printf("socket error\n");
		exit(1);
	}
	memset(&server_addr,0,sizeof(server_addr));
	server_addr.sin_family	=AF_INET;
	server_addr.sin_port	=htons(4000);
	server_addr.sin_addr.s_addr=htonl(INADDR_ANY);
	if(-1==bind(server_socket,(struct sockaddr*)&server_addr,sizeof(server_addr)))
	{
		printf("bind error\n");
		exit(1);
	}
	printf("server started\n");
	for(i=0;i<20;i++)
		thread_num[i]=0;
	while(1)
	{
		if(-1==listen(server_socket,5))
		{
			printf("listen error\n");
			exit(1);
		}
		for(i=0;i<20;i++)
		{
			if(!thread_num[i])
			{
				client_addr_size= sizeof(client_addr);
				client_socket_array[i] = accept(server_socket, (struct sockaddr*)&client_addr,&client_addr_size);
				thread_num[i]=i+1;
				memset(&p_thread[i],0,sizeof(p_thread[i]));
				pthread_create(&p_thread[i],NULL,rutine,(void *)&thread_num[i]);
				break;
			}
		}
		if(i==20)
			printf("error : Too many clients connected");
	}
	close(server_socket);
	return 0;
}