#import shared
#import time
#from multiprocessing import Pool, cpu_count
import hashlib
from struct import unpack, pack
import sys
from debug import logger
from shared import config, frozen, codePath, shutdown, safeConfigGetBoolean, UISignalQueue
import openclpow
import tr
import os
import ctypes

bitmsglib = 'bitmsghash.so'
if "win32" == sys.platform:
    if ctypes.sizeof(ctypes.c_voidp) == 4:
        bitmsglib = 'bitmsghash32.dll'
    else:
        bitmsglib = 'bitmsghash64.dll'
    try:
        # MSVS
        bso = ctypes.WinDLL(os.path.join(codePath(), "bitmsghash", bitmsglib))
        logger.info("Loaded C PoW DLL (stdcall) %s", bitmsglib)
    except:
        try:
            # MinGW
            bso = ctypes.CDLL(os.path.join(codePath(), "bitmsghash", bitmsglib))
            logger.info("Loaded C PoW DLL (cdecl) %s", bitmsglib)
        except:
            bso = None
else:
    try:
        bso = ctypes.CDLL(os.path.join(codePath(), "bitmsghash", bitmsglib))
        logger.info("Loaded C PoW DLL %s", bitmsglib)
    except:
        bso = None
if bso:
    try:
        bmpow = bso.BitmessagePOW
        bmpow.restype = ctypes.c_ulonglong
    except:
        bmpow = None
else:
    bmpow = None

def _set_idle():
    if 'linux' in sys.platform:
        import os
        os.nice(20)  # @UndefinedVariable
    else:
        try:
            sys.getwindowsversion()
            import win32api,win32process,win32con  # @UnresolvedImport
            pid = win32api.GetCurrentProcessId()
            handle = win32api.OpenProcess(win32con.PROCESS_ALL_ACCESS, True, pid)
            win32process.SetPriorityClass(handle, win32process.IDLE_PRIORITY_CLASS)
        except:
            #Windows 64-bit
            pass

def _pool_worker(nonce, initialHash, target, pool_size):
    _set_idle()
    trialValue = float('inf')
    while trialValue > target:
        nonce += pool_size
        trialValue, = unpack('>Q',hashlib.sha512(hashlib.sha512(pack('>Q',nonce) + initialHash).digest()).digest()[0:8])
    return [trialValue, nonce]

def _doSafePoW(target, initialHash):
    logger.debug("Safe PoW start")
    nonce = 0
    trialValue = float('inf')
    while trialValue > target:
        nonce += 1
        trialValue, = unpack('>Q',hashlib.sha512(hashlib.sha512(pack('>Q',nonce) + initialHash).digest()).digest()[0:8])
    logger.debug("Safe PoW done")
    return [trialValue, nonce]

def _doFastPoW(target, initialHash):
    logger.debug("Fast PoW start")
    import time
    from multiprocessing import Pool, cpu_count
    try:
        pool_size = cpu_count()
    except:
        pool_size = 4
    try:
        maxCores = config.getint('bitmessagesettings', 'maxcores')
    except:
        maxCores = 99999
    if pool_size > maxCores:
        pool_size = maxCores
    pool = Pool(processes=pool_size)
    result = []
    for i in range(pool_size):
        result.append(pool.apply_async(_pool_worker, args = (i, initialHash, target, pool_size)))
    while True:
        if shutdown >= 1:
            pool.terminate()
            while True:
                time.sleep(10) # Don't let this thread return here; it will return nothing and cause an exception in bitmessagemain.py
            return
        for i in range(pool_size):
            if result[i].ready():
                result = result[i].get()
                pool.terminate()
                pool.join() #Wait for the workers to exit...
                logger.debug("Fast PoW done")
                return result[0], result[1]
        time.sleep(0.2)
        
def _doCPoW(target, initialHash):
    h = initialHash
    m = target
    out_h = ctypes.pointer(ctypes.create_string_buffer(h, 64))
    out_m = ctypes.c_ulonglong(m)
    logger.debug("C PoW start")
    nonce = bmpow(out_h, out_m)
    trialValue, = unpack('>Q',hashlib.sha512(hashlib.sha512(pack('>Q',nonce) + initialHash).digest()).digest()[0:8])
    logger.debug("C PoW done")
    return [trialValue, nonce]

def _doGPUPoW(target, initialHash):
    logger.debug("GPU PoW start")
    nonce = openclpow.do_opencl_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)
    if trialValue > target:
        deviceNames = ", ".join(gpu.name for gpu in openclpow.gpus)
        UISignalQueue.put(('updateStatusBar', tr.translateText("MainWindow",'Your GPU(s) did not calculate correctly, disabling OpenCL. Please report to the developers.')))
        logger.error("Your GPUs (%s) did not calculate correctly, disabling OpenCL. Please report to the developers.", deviceNames)
        openclpow.ctx = False
        raise Exception("GPU did not calculate correctly.")
    logger.debug("GPU PoW done")
    return [trialValue, nonce]

def run(target, initialHash):
    target = int(target)
    if safeConfigGetBoolean('bitmessagesettings', 'opencl') and openclpow.has_opencl():
#        trialvalue1, nonce1 = _doGPUPoW(target, initialHash)
#        trialvalue, nonce = _doFastPoW(target, initialHash)
#        print "GPU: %s, %s" % (trialvalue1, nonce1)
#        print "Fast: %s, %s" % (trialvalue, nonce)
#        return [trialvalue, nonce]
        try:
            return _doGPUPoW(target, initialHash)
        except:
            pass # fallback
    if bmpow:
        try:
            return _doCPoW(target, initialHash)
        except:
            pass # fallback
    try:
        return _doFastPoW(target, initialHash)
    except:
        pass #fallback
    return _doSafePoW(target, initialHash)