#include <pthread.h>
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <semaphore.h>

#define N 10
#define PROD 5
#define CONS 3
#define PROD_MAX 500
#define DELAY 1

#define RED     "\033[31m"
#define RESET   "\033[0m"


sem_t sem_prod;
sem_t sem_cons;
sem_t sem_renderer;

int shared_buffer[N];
pthread_mutex_t lock;

void* producteur(void* args) {
    while (1) {
        sem_wait(&sem_prod);
        pthread_mutex_lock(&lock);
            int i = -1;
            while (++i < N) {
                if (shared_buffer[i] == -1) {
                    shared_buffer[i] = rand()%PROD_MAX;
                    sem_post(&sem_cons);
                    sem_post(&sem_renderer);
                    //printf("placed@%d !\n", i);
                    break;
                }
            }
            if (i >= N) {
                fprintf(stderr, "Can't place my product !\n");
                exit(1);
            }
        pthread_mutex_unlock(&lock);
        sleep(DELAY);
    }
    return NULL;
}

void* consommateur(void* args) {
    while (1) {
        sem_wait(&sem_cons);
        pthread_mutex_lock(&lock);
            int i = -1;
            while (++i < N) {
                if (shared_buffer[i] != -1) {
                    shared_buffer[i] = -1;
                    //printf("got@%d !\n", i);
                    sem_post(&sem_prod);
                    sem_post(&sem_renderer);
                    break;
                }
            }
            if (i >= N) {
                fprintf(stderr, "Can't get a product !\n");
                exit(1);
            }
        pthread_mutex_unlock(&lock);
        sleep(DELAY);
    }
    return NULL;
}

void* renderer(void* args) {
    while (1) {
        sem_wait(&sem_renderer);
        pthread_mutex_lock(&lock);
        printf("\r");
        for (int i=0; i < N; i++) {
            if (shared_buffer[i] == -1) {
                printf(RED "%3d " RESET, shared_buffer[i]);
            } else {
                printf("%3d ", shared_buffer[i]);
            }
        }
        pthread_mutex_unlock(&lock);
    }
}



int main() {
    for (int i=0; i < N; i++) {
        shared_buffer[i] = -1;
    }

    pthread_mutex_init(&lock, NULL);
    
    pthread_t tid[PROD+CONS+1];
    sem_init(&sem_prod, 0, N);
    sem_init(&sem_cons, 0, 0);
    sem_init(&sem_renderer, 0, 1);
    for (int i=0; i < PROD; i++) {
        pthread_create(&(tid[i]), NULL, &producteur, NULL);
    }

    for (int i=0; i < CONS; i++) {
        pthread_create(&(tid[i+PROD]), NULL, &consommateur, NULL);
    }

    // Additional renderer thread to display the state of the market
    pthread_create(&(tid[CONS+PROD]), NULL, &renderer, NULL);


    for (int i=0; i < PROD+CONS+1; i++) {
        pthread_join(tid[i], NULL);
    }
    sem_destroy(&sem_cons);
    sem_destroy(&sem_prod);

    return 0;
}