# PrimeCounter.py

# Python has multi-threading, but that doesn't take advantage of multiple cores because
# of an underlying global interpreter lock (GIL)

# the code below generates the correct answer for the threaded code, but only one processor is used

from threading import Thread as Worker
import time

class PrimeCounter(Worker):
    
    # typedef struct {
    #     int id;
    #     int N;
    #     int chunk_size;
    #     int num_threads;
    #     int count;
    # } ThreadInfo;


    def __init__ (self, id, N, chunk_size, num_threads ):
        super().__init__() 
        self.id = id
        self.N = N
        self.chunk_size = chunk_size
        self.num_threads = num_threads
        self.count = 0

    def is_prime (self, n):
        if (n < 2):
            return False
        if (n == 2):
            return True
        if (n % 2 == 0):
            return False
        for i in range (3, n, 2):
            if (n % i == 0):
                return False;
        return True                    
        
    def run (self):
        print( "running with id", self.id )

#       int start = ti->chunk_size * ti->id;
#         for (int i = start; i < ti->N; i = i + ti->chunk_size*ti->num_threads ) {
#             for (int j = 0; j < ti->chunk_size; j++) {
        start = self.chunk_size*self.id
        for i in range( start, self.N, self.chunk_size*self.num_threads):
            for j in range(0, self.chunk_size ):
                if self.is_prime(i+j):
                    self.count += 1      
        return 0       
    
    def getCount (self):
        return self.count
        

def main ():
    N = 100000
    NUM_THREADS = 8

    pc = []
    for i in range(NUM_THREADS):
        pc.append( PrimeCounter( id=i, N=N, chunk_size=100, num_threads=NUM_THREADS) )

    pc0 = PrimeCounter( id=0, N=N, chunk_size=N, num_threads=1)

    t1 = time.time()
    
    for i in range(NUM_THREADS):
        pc[i].start()
       
    for i in range(NUM_THREADS):
        pc[i].join()
    
    count = 0
    for i in range(NUM_THREADS):
        count += pc[i].getCount()
        
    t2 = time.time()
    
    print("multi-thread count ", count, " primes")
    print("time is ", t2 - t1)
    
    t1 = time.time()
    
    pc0.start()
    pc0.join()
    
    t2 = time.time()
    
    print("1 thread count ", pc0.getCount(), " primes")
    print("time is ", t2 - t1)
    
    
if __name__ == "__main__":
    main()