#include <sys/types.h>
#include <sys/ipc.h>
#include <sys/msg.h>
#include <unistd.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <signal.h>
#define MSG_SZ_MAX 255

struct message{
	long mtype;
	pid_t pid;
	char mtext[MSG_SZ_MAX];
};

int descr;
struct message sendMsg, recieveMsg;

static void sigHandle(int signum);


void main(){
	descr = msgget(10, IPC_CREAT|0666);
	printf("descriptor : %d\n", descr);
	printf("PID : %d\n", getpid());

	if(signal(SIGINT, sigHandle) == SIG_ERR){
		perror("Can't handle a signal SIGINT.");
		exit(1);
	}
	if(signal(SIGUSR1, sigHandle) == SIG_ERR){
		perror("Can't handle a signal SIGUSR1.");
		exit(1);
	}
	if(signal(SIGTERM, sigHandle) == SIG_ERR){
		perror("Can't handle a signal SIGTERM.");
		exit(1);
	}

	printf("Receiver's PID : ");
	pid_t pidRes;
	scanf("%d", &pidRes);

	sendMsg.mtype = pidRes;
	sendMsg.pid = getpid();
	recieveMsg.mtype = getpid();
	

	if(descr==-1){
		perror("msgget");
	}

	while(1){
		
		strcpy(sendMsg.mtext, "[");
		//strcat(sendMsg.mtext, (char*)getpid);
		char senderpid[10];
		snprintf(senderpid, 10, "%ld", (long)getpid());
		strcat(sendMsg.mtext, senderpid);
		strcat(sendMsg.mtext, "] : ");

		/*
		*sendMsg.mtext += sprintf(sendMsg.mtext, "%s", "[");
		*sendMsg.mtext += sprintf(sendMsg.mtext, "%ld", (long)getpid());
		*sendMsg.mtext += sprintf(sendMsg.mtext, "%s", "] : ");*/

		char buf[MSG_SZ_MAX];
		/**
		*INPUT
		*/
		scanf("%s", buf);
		strcat(sendMsg.mtext, buf);
		//fgets(buf, MSG_SZ_MAX, stdin);
		//*sendMsg.mtext += sprintf(sendMsg.mtext, "%s", buf);

		if(msgsnd(descr, &sendMsg, sizeof(struct message), 0) == -1){
			perror("msgsnd");
			exit(2);
		}

		while(1){
			if(msgrcv(descr, &recieveMsg, sizeof(struct message), getpid(), IPC_NOWAIT) != -1){
				printf("%s\n", recieveMsg.mtext);
			} else break;
		}
	}
}

static void sigHandle(int signum){
	if(signum == SIGUSR1){
		printf("\nOther process has been terminated.\n");
		exit(0);
	}
	if(signum == SIGINT){
		kill(recieveMsg.pid, SIGUSR1);
		msgctl(descr, IPC_RMID, 0);
		exit(0);
	}
	if(signum == SIGTERM){
		printf("\nSIGTERM has been received, terminated.\n");
		kill(recieveMsg.pid, SIGUSR1);
		msgctl(descr, IPC_RMID, 0);
		exit(0);
	}
}