/**
* Written 16. November 2014 by Kai Nilsen
*/
#include <stdio.h>
#include <pthread.h>
#include <string>
#include <iostream>
#include <sstream>
using namespace std;

int const NUM_THREADS = 3;

pthread_t threads[NUM_THREADS];

int global = 0;
int globalOut = 0;

bool quit = false;

pthread_mutex_t lock = PTHREAD_MUTEX_INITIALIZER;

pthread_cond_t ready = PTHREAD_COND_INITIALIZER, work = PTHREAD_COND_INITIALIZER, print = PTHREAD_COND_INITIALIZER;

int input();

void* inFunc(void* param)
{
    int number;

    int loop = 0;

    while (quit != true)
    {
        pthread_mutex_lock(&lock);
        if (global == 0 && globalOut == 0)
        {

            number = input();

            if (number != 0)
            {
                printf("  inFunc sending %d\n", number);

                global = number;
            }
            else
            {
                global = number;
                quit = true;
            }

        }
        pthread_cond_signal(&work);
        pthread_mutex_unlock(&lock);

        loop++;
        pthread_cond_wait(&ready, &lock);
    }

    printf("inFunc looped %d\n", loop);
    pthread_exit(0);
    return 0;
}

void* workFunc(void* param)
{
    int loop = 0;
    while (quit != true)
    {

        pthread_mutex_lock(&lock);
        pthread_cond_wait(&work, &lock);
        if (global != 0 && globalOut == 0)
        {

            if (global != 0)
            {
                globalOut = global * 3;
                printf("  workFunc turning %d into %d\n", global, globalOut);
                global = 0;
            }

        }

        pthread_mutex_unlock(&lock);
        pthread_cond_signal(&print);
        loop++;
    }
    printf("workFunc looped %d\n", loop);
    pthread_exit(0);
    return 0;
}

void* outFunc(void* param)
{
    int loop = 0;
    while (quit != true)
    {

        pthread_mutex_lock(&lock);
        pthread_cond_wait(&print, &lock);

        if (globalOut != 0 && global == 0)
        {

            if (globalOut != 0)
            {
                printf("  outFunc printing %d\n", globalOut);
                globalOut = 0;
            }

        }

        pthread_mutex_unlock(&lock);
        pthread_cond_signal(&ready);
        loop++;
    }
    printf("outFunc looped %d\n", loop);
    pthread_exit(0);
    return 0;
}

int main()
{

    pthread_create(&threads[0], NULL, inFunc, NULL);
    pthread_create(&threads[1], NULL, workFunc, NULL);
    pthread_create(&threads[2], NULL, outFunc, NULL);

    for (int i = 0; i < NUM_THREADS; i++)
    {
        pthread_join(threads[i], NULL);
    }
    pthread_mutex_destroy(&lock);
    system("pause");
    return 0;
}

int input()
{
    char input[10];
    int number;
    bool validNumber = false;


    while (validNumber != true)
    {

        printf("> ");
        gets_s(input);

        for (int i = 0; i < strlen(input); i++)
        {
            if (i == 0 && input[0] == '-' && (input[1] <= '9' && input[1] >= '0'))
            {
                validNumber = true;
            }
            else if (input[i] <= '9' && input[i] >= '0')
            {
                validNumber = true;
            }
            else
            {
                validNumber = false;
                break;
            }
        }

        if (validNumber == false && input[0] == 'q' && strlen(input) == 1)
        {
            number = 0;
            validNumber = true;
        }
        else if (validNumber == true)
        {
            number = stoi(input);
        }
    }

    return number;
}