import numpy
from struct import pack, unpack
import time
import hashlib
import pyopencl as cl

hash_dt = numpy.dtype([('target', numpy.uint64), ('v', numpy.str_, 73)])
ctx = False
queue = False
program = False

try:
        if (len(cl.get_platforms()) > 0):
		ctx = cl.create_some_context()
		queue = cl.CommandQueue(ctx)

		f = open('kernel.cl', 'r')
		fstr = ''.join(f.readlines())
		program = cl.Program(ctx, fstr).build()
except: 
	ctx = False

def has_opencl():
	return (ctx != False)

def do_opencl_pow(hash, target):
	output = numpy.zeros(1, dtype=[('v', numpy.uint64, 1)])
	if (ctx == False):
		return output[0][0]
	
	data = numpy.zeros(1, dtype=hash_dt, order='C')
	data[0]['v'] = ("0000000000000000" + hash).decode("hex")
	data[0]['target'] = target
	
	hash_buf = cl.Buffer(ctx, cl.mem_flags.READ_ONLY | cl.mem_flags.COPY_HOST_PTR, hostbuf=data)
	dest_buf = cl.Buffer(ctx, cl.mem_flags.WRITE_ONLY, output.nbytes)
	
	kernel = program.kernel_sha512
	worksize = kernel.get_work_group_info(cl.kernel_work_group_info.WORK_GROUP_SIZE, cl.get_platforms()[0].get_devices()[0])

	kernel.set_arg(0, hash_buf)
	kernel.set_arg(1, dest_buf)

	start = time.time()
	startpos = 0
	globamt = worksize*2000

	while output[0][0] == 0:
		kernel.set_arg(2, pack("<Q", startpos))
		cl.enqueue_nd_range_kernel(queue, kernel, (globamt,), (worksize,))
		cl.enqueue_read_buffer(queue, dest_buf, output)
		queue.finish()
		startpos += globamt
		sofar = time.time() - start
		print sofar, startpos / sofar, "hashes/sec"
	taken = time.time() - start
	print startpos, taken
	return output[0][0]

if __name__ == "__main__":
	target = 54227212183L
	initialHash = "3758f55b5a8d902fd3597e4ce6a2d3f23daff735f65d9698c270987f4e67ad590b93f3ffeba0ef2fd08a8dc2f87b68ae5a0dc819ab57f22ad2c4c9c8618a43b3".decode("hex")
	nonce = do_pow(initialHash.encode("hex"), target)
	trialValue, = unpack('>Q',hashlib.sha512(hashlib.sha512(pack('>Q',nonce) + initialHash).digest()).digest()[0:8])
	print "{} - value {} < {}".format(nonce, trialValue, target)