#import shared
#import time
#from multiprocessing import Pool, cpu_count
import hashlib
from struct import unpack, pack
import sys
import time
from debug import logger
import shared
import openclpow
import tr
import os
import ctypes

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 and shared.shutdown == 0:
        nonce += 1
        trialValue, = unpack('>Q',hashlib.sha512(hashlib.sha512(pack('>Q',nonce) + initialHash).digest()).digest()[0:8])
    if shared.shutdown != 0:
        raise StopIteration("Interrupted")
    logger.debug("Safe PoW done")
    return [trialValue, nonce]

def _doFastPoW(target, initialHash):
    logger.debug("Fast PoW start")
    from multiprocessing import Pool, cpu_count
    try:
        pool_size = cpu_count()
    except:
        pool_size = 4
    try:
        maxCores = shared.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 shared.shutdown > 0:
            try:
                pool.terminate()
                pool.join()
            except:
                pass
            raise StopIteration("Interrupted")
        for i in range(pool_size):
            if result[i].ready():
                try:
                    result[i].successful()
                except AssertionError:
                    pool.terminate()
                    pool.join()
                    raise StopIteration("Interrupted")
                result = result[i].get()
                pool.terminate()
                pool.join()
                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])
    if shared.shutdown != 0:
        raise StopIteration("Interrupted")
    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)
        shared.UISignalQueue.put(('updateStatusBar', tr._translate("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.")
    if shared.shutdown != 0:
        raise StopIteration("Interrupted")
    logger.debug("GPU PoW done")
    return [trialValue, nonce]
    
def estimate(difficulty, format = False):
    ret = difficulty / 10
    if ret < 1:
        ret = 1
    if format:
        out = str(int(ret)) + " seconds"
        if ret > 60:
            ret /= 60
            out = str(int(ret)) + " minutes"
        if ret > 60:
            ret /= 60
            out = str(int(ret)) + " hours"
        if ret > 24:
            ret /= 24
            out = str(int(ret)) + " days"
        if ret > 7:
            out = str(int(ret)) + " weeks"
        if ret > 31:
            out = str(int(ret)) + " months"
        if ret > 366:
            ret /= 366
            out = str(int(ret)) + " years"
    else:
        return ret

def getPowType():
    if shared.safeConfigGetBoolean('bitmessagesettings', 'opencl') and openclpow.has_opencl():
        return "OpenCL"
    if bmpow:
        return "C"
    return "python"

def run(target, initialHash):
    if shared.shutdown != 0:
        raise
    target = int(target)
    if shared.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 StopIteration:
            raise
        except:
            pass # fallback
    if bmpow:
        try:
            return _doCPoW(target, initialHash)
        except StopIteration:
            raise
        except:
            pass # fallback
    if shared.frozen == "macosx_app" or not shared.frozen:
        # on my (Peter Surda) Windows 10, Windows Defender
        # does not like this and fights with PyBitmessage
        # over CPU, resulting in very slow PoW
        # added on 2015-11-29: multiprocesing.freeze_support() doesn't help
        try:
            return _doFastPoW(target, initialHash)
        except StopIteration:
            logger.error("Fast PoW got StopIteration")
            raise
        except:
            logger.error("Fast PoW got exception:", exc_info=True)
            pass #fallback
    try:
        return _doSafePoW(target, initialHash)
    except StopIteration:
        raise
    except:
        pass #fallback

# init
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(shared.codePath(), "bitmsghash", bitmsglib))
        logger.info("Loaded C PoW DLL (stdcall) %s", bitmsglib)
        bmpow = bso.BitmessagePOW
        bmpow.restype = ctypes.c_ulonglong
        _doCPoW(2**63, "")
        logger.info("Successfully tested C PoW DLL (stdcall) %s", bitmsglib)
    except:
        logger.error("C PoW test fail.", exc_info=True)
        try:
            # MinGW
            bso = ctypes.CDLL(os.path.join(shared.codePath(), "bitmsghash", bitmsglib))
            logger.info("Loaded C PoW DLL (cdecl) %s", bitmsglib)
            bmpow = bso.BitmessagePOW
            bmpow.restype = ctypes.c_ulonglong
            _doCPoW(2**63, "")
            logger.info("Successfully tested C PoW DLL (cdecl) %s", bitmsglib)
        except:
            logger.error("C PoW test fail.", exc_info=True)
            bso = None
else:
    try:
        bso = ctypes.CDLL(os.path.join(shared.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