#ifdef Posix_compile
#include <unistd.h>
#include <errno.h>
#include <signal.h>
#include <pthread.h>
#include <sys/types.h>
#include <sys/ipc.h>
#include <sys/mman.h>
#include <sys/sem.h>
#include <semaphore.h>
#include <fcntl.h>
#else
#include <windows.h>
#endif

#include <stdio.h>
#include <stdlib.h>
#include <string.h>


typedef struct _thread {
	pthread_t tid;
	char my_str[1024];
	int occ;
} thread;


char buffer[1024];
FILE *file;
thread *list;
int N, sem_m, sem_th;
struct sembuf oper_m;


void error_handler(char *message) {
	fprintf(stderr, "%s\n", message);
	perror("ERROR");
	exit(EXIT_FAILURE);
}


void SIGINT_handler(int a, siginfo_t *b, void *c) {
	int i;
	printf("\n");
	for (i = 0; i < N; i++) {
		printf("Thread %ld has %d occurrences\n",list[i].tid, list[i].occ);
	}
}


void *run(void *index) {
	list[(long)index].tid = pthread_self();
	list[(long)index].occ = 0;
	struct sembuf oper_t;
	int ret;

	oper_t.sem_num = (long)index;
	oper_t.sem_op = -1;
	oper_t.sem_flg = 0;

	while(1) {
	semop1:	ret = semop(sem_th, &oper_t, 1);
		if (ret == -1) {
			if (errno == EINTR)
				goto semop1;
			error_handler("Semaphore operation failed");
		}
		if (strstr(list[(long)index].my_str, buffer) != NULL) {
			printf("Thread %ld has found a new occurrence\n",list[(long)index].tid);
			ret = fprintf(file, "%s\n", buffer);
			fflush(file);
			if (ret < 0) {
				error_handler("File write has failed");
			}
			list[(long)index].occ += 1;
		}
		oper_m.sem_num = 0;
		oper_m.sem_op = 1;
		oper_m.sem_flg = 0;

	semop2:	ret = semop(sem_m, &oper_m, 1);
		if (ret == -1) {
			error_handler("Semaphore operation has failed");
			if(errno == EINTR)
				goto semop2;
		}
	}
}


int main(int argc,char *argv[]) {

	int ret;
	long i;
	pthread_t tid;
	sigset_t set;
	struct sigaction act;
	struct sembuf oper_t;

	if(argc < 3) {
		error_handler("Not valid input");
	}
	N = argc - 2;
	file = fopen(argv[1], "w+");
	if (file == NULL) {
		error_handler("Unable to open the file");
	}
	list = malloc(N*sizeof(thread*));
	sem_m = semget(IPC_PRIVATE, 1, IPC_CREAT|0666);
	if (sem_m == -1) {
		error_handler("Unable to get a semaphore");
	}
	sem_th = semget(IPC_PRIVATE, N, IPC_CREAT|0666);
	if (sem_th == -1) {
		error_handler("Unable to get a semaphore");
	}
	ret = semctl(sem_m, 0, SETVAL, N);
	if (ret == -1) {
		error_handler("semctl has failed");
	}
	for (i = 0; i < N; i++) {
		ret = semctl(sem_th, i, SETVAL, 0);
		if (ret == -1) {
			error_handler("semctl has failed");
		}
	}
	for (i = 0; i < N; i++) {
		strcpy(list[i].my_str, argv[i+2]);
		ret = pthread_create(&tid, NULL, run, (void *)i);
		if (ret != 0) {
			error_handler("Creation thread has failed");
		}
	}
	ret = sigfillset(&set);
	act.sa_sigaction = SIGINT_handler;
	act.sa_mask = set;
	act.sa_flags = 0;

	sigaction(SIGINT, &act, NULL);

	oper_m.sem_num = 0;
	oper_m.sem_op = -N;
	oper_m.sem_flg = 0;

	printf("Main thread is ready to receive strings\n");
	while(1) {
	step1:	ret = semop(sem_m, &oper_m, 1);
		if (ret == -1) {
			if (errno == EINTR)
				goto step1;
			error_handler("Semaphore operation failed");
		}
	step2:	ret = scanf("%s", buffer);
		if (ret == -1) {
			if (errno == EINTR)
				goto step2;
			error_handler("scanf has failed");
		}
		if (ret == 0) {
			while(getchar() != '\n') {}
			printf("Not valid input. Retry\n");
			goto step2;
		}
		oper_t.sem_op = 1;
		oper_t.sem_flg = 0;
		for (i = 0; i < N; i++) {
			oper_t.sem_num = i;
		step3:	ret = semop(sem_th, &oper_t, 1);
			if (ret == -1) {
				if (errno == EINTR)
					goto step3;
				error_handler("Semaphore operation failed");
			}
		}
	}
}