#include "stdio.h"
#include "unistd.h"
#include "pthread.h"
#include "stdlib.h"
#include "errno.h"
#include "limits.h"
#include "math.h"
#include "semaphore.h"
#include "string.h"

#define BUFFER_SIZE 100

#define PREFIX "MARCIN"

sem_t wr, rd1, rd2, rd3;

void emptyBuffer( char* buff);
void *threadCzytelnik(void *arg);





struct targs{
    int numWatku;
};
char common[BUFFER_SIZE];
int koniecPliku = 0;
int main()
{
    FILE *fp;

    emptyBuffer(common);
    sem_init(&wr, 0, 1);
    sem_init(&rd1, 0, 0);
    sem_init(&rd2, 0, 0);
    sem_init(&rd3, 0, 0);
    pthread_attr_t attrs;
    pthread_attr_init(&attrs);
    //pthread_attr_setdetachstate(&attrs, PTHREAD_CREATE_DETACHED );

    pthread_t threadId[3];
    fp = fopen("/etc/passwd","r");
    struct targs watki[3];
    {
        int i = 0;
        for(;i < 3; i++)
        {
            watki[i].numWatku = i+1;
            pthread_create(&threadId[i], &attrs, threadCzytelnik, &watki[i]);
            pthread_detach(threadId[i]);
        }
    }
    char *l;
    while( 1 ) {
        sem_wait(&wr);
        l = fgets(common, BUFFER_SIZE, fp);
        if(l==0) break;
        sem_post(&rd1);

    }
    fclose(fp);
    koniecPliku = 1;
    sem_post(&rd1);
}

void emptyBuffer( char* buff)
{
    {
        int i = 0;
        for(;i<BUFFER_SIZE;i++)
        {
            buff[i] = 0;
        }
    }
}


void *threadCzytelnik(void *arg)
{

    struct targs *argptr = (struct targs*) arg;

    char nazwaPliku[80];
    snprintf(nazwaPliku, 80, "./MATEUSZ%d", argptr->numWatku);
    FILE *fp = fopen(nazwaPliku, "w");
    while(1)
    {
        if(argptr->numWatku==1) sem_wait(&rd1);
        if(argptr->numWatku==2) sem_wait(&rd2);
        if(argptr->numWatku==3) sem_wait(&rd3);
            if(koniecPliku)
            {
                fflush(fp);
                fclose(fp);
                pthread_exit(0);
            }
            fwrite(common, sizeof(char), strlen(common), fp);
            printf("%d-%s\n", argptr->numWatku, common);
            fflush(stdout);
        if(argptr->numWatku==1) sem_post(&rd2);
        if(argptr->numWatku==2) sem_post(&rd3);
        if(argptr->numWatku==3) sem_post(&wr);
    }
}