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

// Function prototypes
int make_new_item(void);
void *reader_function(void *);
void writer_function(void);

// Shared resources
char buffer;
int buffer_has_item = 0;
pthread_mutex_t mutex;
pthread_cond_t cond_buffer_empty;
pthread_cond_t cond_buffer_full;

void cleanup_resources() {
    pthread_mutex_destroy(&mutex);
    pthread_cond_destroy(&cond_buffer_empty);
    pthread_cond_destroy(&cond_buffer_full);
}

int main(int argc, char *argv[]) {
    pthread_mutexattr_t mutex_attr;
    pthread_attr_t attr;
    pthread_t reader;
    int ret;

    // Initialize mutex and condition variables
    pthread_mutexattr_init(&mutex_attr);
    pthread_mutex_init(&mutex, &mutex_attr);
    pthread_cond_init(&cond_buffer_empty, NULL);
    pthread_cond_init(&cond_buffer_full, NULL);
    pthread_attr_init(&attr);

    // Create reader thread
    pthread_create(&reader, &attr, reader_function, 0);

    // Run writer function in the main thread
    writer_function();

    // Wait for reader thread to finish
    pthread_join(reader, 0);

    // Clean up
    cleanup_resources();
    printf("Main thread finished!\n");
    return 0;
}

void writer_function(void) {
    char a = 0;

    while (a != 'q') {
        pthread_mutex_lock(&mutex);

        // Wait until the buffer is empty
        while (buffer_has_item) {
            pthread_cond_wait(&cond_buffer_empty, &mutex);
        }

        a = make_new_item();
        buffer = a;
        buffer_has_item = 1;
        printf("Thread 1: buffer: '%c'\n", a);

        // Signal the reader that the buffer is full
        pthread_cond_signal(&cond_buffer_full);
        pthread_mutex_unlock(&mutex);
    }
}

void *reader_function(void *ptr) {
    char a = 0;

    while (a != 'q') {
        pthread_mutex_lock(&mutex);

        // Wait until the buffer is full
        while (!buffer_has_item) {
            pthread_cond_wait(&cond_buffer_full, &mutex);
        }

        // Read the item from the buffer
        a = buffer;
        if (a != 'q') {
            printf("Thread 2: buffer read with '%c'\n", a);
        }
        buffer_has_item = 0;

        // Signal the producer that the buffer is empty
        pthread_cond_signal(&cond_buffer_empty);
        pthread_mutex_unlock(&mutex);
    }

    printf("Reader thread finished\n");
    return 0;
}

int make_new_item() {
    static int buffer = 'a';
    return buffer++;
}