# -*- coding: utf-8 -*-
r"""
Initialization code of pyopencl.
"""
__author__ = "Konstantin Klementiev, Roman Chernikov"
__date__ = "19 Mar 2017"
import numpy as np
import os
#import time
from .. import raycing
try:
    import pyopencl as cl
    os.environ['PYOPENCL_COMPILER_OUTPUT'] = '1'
    isOpenCL = True
except ImportError:
    isOpenCL = False

__fdir__ = os.path.dirname(__file__)
_DEBUG = 20


class XRT_CL(object):
    def __init__(self, filename=None, targetOpenCL=raycing.targetOpenCL,
                 precisionOpenCL=raycing.precisionOpenCL, kernelsource=None):
        self.kernelsource = kernelsource
        self.cl_filename = filename
        self.lastTargetOpenCL = None
        self.lastPrecisionOpenCL = None
        self.set_cl(targetOpenCL, precisionOpenCL)
        self.cl_is_blocking = True

    def set_cl(self, targetOpenCL=raycing.targetOpenCL,
               precisionOpenCL=raycing.precisionOpenCL):
        if (targetOpenCL == self.lastTargetOpenCL) and\
                (precisionOpenCL == self.lastPrecisionOpenCL):
            return
        self.lastTargetOpenCL = targetOpenCL
        self.lastPrecisionOpenCL = precisionOpenCL
        if not isOpenCL:
            raise EnvironmentError("pyopencl is not available!")
        else:
            try:
                cl_platforms = cl.get_platforms()
            except:
                targetOpenCL = None
                raise EnvironmentError("Unknown error. OpenCL disabled")
            if isinstance(targetOpenCL, (tuple, list)):
                iDevice = []
                targetOpenCL = list(targetOpenCL)
                if isinstance(targetOpenCL[0], int):
                    nPlatform, nDevice = targetOpenCL
                    platform = cl_platforms[nPlatform]
                    try:
                        dev = platform.get_devices()[nDevice]
                        iDevice.extend([dev])
                    except:
                        pass
                else:
                    for target in targetOpenCL:
                        if isinstance(target, (tuple, list)):
                            target = list(target)
                            if len(target) > 1:
                                nPlatform, nDevice = target
                                platform = cl_platforms[nPlatform]
                                try:
                                    iDevice.extend(
                                        [platform.get_devices()[nDevice]])
                                except:
                                    pass
                            else:
                                nPlatform = target[0]
                                platform = cl_platforms[nPlatform]
                                try:
                                    iDevice.extend(platform.get_devices())
                                except:
                                    pass
            elif isinstance(targetOpenCL, int):
                nPlatform = targetOpenCL
                platform = cl_platforms[nPlatform]
                try:
                    iDevice = platform.get_devices()
                except:
                    pass
            elif isinstance(targetOpenCL, str):
                iDeviceCPU = []
                iDeviceGPU = []
                iDeviceAcc = []
                iDevice = []
                for platform in cl_platforms:
                    if 'mesa' in platform.vendor.lower():
                        continue  # for new Linuxes Mesa provides OpenCL 1.1
                    CPUdevices = []
                    GPUdevices = []
                    AccDevices = []
                    try:  # at old pyopencl versions:
                        CPUdevices =\
                            platform.get_devices(
                                device_type=cl.device_type.CPU)
                        GPUdevices =\
                            platform.get_devices(
                                device_type=cl.device_type.GPU)
                        AccDevices =\
                            platform.get_devices(
                                device_type=cl.device_type.ACCELERATOR)
                    except cl.RuntimeError:
                        pass

                    if len(CPUdevices) > 0:
                        if len(iDeviceCPU) > 0:
                            if CPUdevices[0].vendor == \
                                    CPUdevices[0].platform.vendor:
                                try:
                                    tmpctx = cl.Context(devices=CPUdevices)
                                    iDeviceCPU = CPUdevices
                                except:
                                    pass
                        else:
                            try:
                                tmpctx = cl.Context(devices=CPUdevices)
                                iDeviceCPU.extend(CPUdevices)
                            except:
                                pass
                    for GPUDevice in GPUdevices:
                        try:
                            if ('graphics' in GPUDevice.name.lower() and
                                    'intel' in GPUDevice.vendor.lower()):
                                continue
                            tmpctx = cl.Context(devices=[GPUDevice])
                            if GPUDevice.double_fp_config > 0:
                                iDeviceGPU.extend([GPUDevice])
                        except:
                            pass
                    iDeviceAcc.extend(AccDevices)
                if _DEBUG > 10:
                    print("OpenCL: bulding {0} ...".format(self.cl_filename))
                    print("OpenCL: found {0} CPU{1}".format(
                          len(iDeviceCPU) if len(iDeviceCPU) > 0 else 'none',
                          's' if len(iDeviceCPU) > 1 else ''))
                    print("OpenCL: found {0} GPU{1}".format(
                          len(iDeviceGPU) if len(iDeviceGPU) > 0 else 'none',
                          's' if len(iDeviceGPU) > 1 else ''))
                    print("OpenCL: found {0} other accelerator{1}".format(
                          len(iDeviceAcc) if len(iDeviceAcc) > 0 else 'none',
                          's' if len(iDeviceAcc) > 1 else ''))

                if targetOpenCL.upper().startswith('GPU'):
                    iDevice.extend(iDeviceGPU)
                elif targetOpenCL.upper().startswith('CPU'):
                    iDevice.extend(iDeviceCPU)
                elif targetOpenCL.upper().startswith('ALL'):
                    iDevice.extend(iDeviceGPU)
                    iDevice.extend(iDeviceCPU)
                    iDevice.extend(iDeviceAcc)
                else:  # auto
                    if len(iDeviceGPU) > 0:
                        iDevice = iDeviceGPU
                    elif len(iDeviceAcc) > 0:
                        iDevice = iDeviceAcc
                    else:
                        iDevice = iDeviceCPU
                if len(iDevice) == 0:
                    targetOpenCL = None
                    self.lastTargetOpenCL = targetOpenCL
            else:  # None
                targetOpenCL = None
                self.lastTargetOpenCL = targetOpenCL
        if targetOpenCL is not None:
            if _DEBUG > 10:
                autoStr = "Autos" if isinstance(targetOpenCL, str) else "S"
                for idn, idv in enumerate(iDevice):
                    print("OpenCL for {0}: {1}elected device {2}: {3}".format(
                        self.cl_filename, autoStr, idn, idv.name))

            if self.kernelsource is None:
                cl_file = os.path.join(os.path.dirname(__file__),
                                       self.cl_filename)
                with open(cl_file, 'r') as f:
                    kernelsource = f.read()
            else:
                kernelsource = self.kernelsource
            if precisionOpenCL == 'auto':
                try:
                    for device in iDevice:
                        if device.double_fp_config == 63:
                            precisionOpenCL = 'float64'
                        else:
                            raise AttributeError
                except AttributeError:
                    precisionOpenCL = 'float32'
            if _DEBUG > 10:
                print('precisionOpenCL = {0}'.format(precisionOpenCL))
            if precisionOpenCL == 'float64':
                self.cl_precisionF = np.float64
                self.cl_precisionC = np.complex128
                kernelsource = kernelsource.replace('float', 'double')
            elif precisionOpenCL == 'float32':
                self.cl_precisionF = np.float32
                self.cl_precisionC = np.complex64
            else:
                raise ValueError("Unknown precision")
            self.cl_queue = []
            self.cl_ctx = []
            self.cl_program = []
            for device in iDevice:
                cl_ctx = cl.Context(devices=[device])
                self.cl_queue.extend([cl.CommandQueue(cl_ctx, device)])
                self.cl_program.extend(
                    [cl.Program(cl_ctx, kernelsource).build(
                        options=['-I', __fdir__])])
                self.cl_ctx.extend([cl_ctx])

            self.cl_mf = cl.mem_flags

    def run_parallel(self, kernelName='', scalarArgs=None,
                     slicedROArgs=None, nonSlicedROArgs=None,
                     slicedRWArgs=None, nonSlicedRWArgs=None, dimension=0):

        # t0 = time.time()
        ka_offset = len(scalarArgs) if scalarArgs is not None else 0
        ro_offset = len(slicedROArgs) if slicedROArgs is not None else 0
        ns_offset = len(nonSlicedROArgs) if nonSlicedROArgs is not None else 0
        rw_offset = len(slicedRWArgs) if slicedRWArgs is not None else 0
        rw_pos = ka_offset + ro_offset + ns_offset
        nsrw_pos = ka_offset + ro_offset + ns_offset + rw_offset

        kernel_bufs = []
        global_size = []
        ev_h2d = []
        ev_run = []
        nCU = []
        ndstart = []
        ndslice = []
        ndsize = []
        minWGS = 1e20

        for ictx, ctx in enumerate(self.cl_ctx):
            nCUw = 1
            nCU.extend([nCUw])
            tmpWGS = ctx.devices[0].max_work_group_size
            if tmpWGS < minWGS:
                minWGS = tmpWGS
            # nCU.extend([ctx.devices[0].max_compute_units*nCUw])

        totalCUs = np.sum(nCU)
        minWGS = 256
        divider = minWGS * totalCUs
        n2f = np.remainder(dimension, divider)
        needResize = False
        # odd dimension performance fix
        if n2f != 0 and dimension > divider:
            oldSize = dimension
            dimension = (np.trunc(dimension/divider) + 1) * divider
            nDiff = int(dimension - oldSize)
            needResize = True

        work_cl_ctx = self.cl_ctx if dimension > totalCUs else [self.cl_ctx[0]]
        nctx = len(work_cl_ctx)

        for ictx, ctx in enumerate(work_cl_ctx):
            ev_h2d.extend([[]])
            kernel_bufs.extend([[]])
            if scalarArgs is not None:
                kernel_bufs[ictx].extend(scalarArgs)
            ndstart.extend([sum(ndsize)])

            if dimension > 1:
                if ictx < nctx - 1:
                    ndsize.extend([np.floor(dimension*nCU[ictx]/totalCUs)])
                else:
                    ndsize.extend([dimension-ndstart[ictx]])
                ndslice.extend([slice(ndstart[ictx],
                                      ndstart[ictx]+ndsize[ictx])])
            else:
                ndslice.extend([0])
# In case each photon has an array of input/output data we define a second
# dimension
            if slicedROArgs is not None and dimension > 1:
                for iarg, arg in enumerate(slicedROArgs):
                    newArg = np.concatenate([arg, arg[:nDiff]]) if needResize\
                        else arg
                    secondDim = np.int(len(newArg) / dimension)
                    iSlice = slice(int(ndstart[ictx]*secondDim),
                                   int((ndstart[ictx]+ndsize[ictx])*secondDim))
                    kernel_bufs[ictx].extend([cl.Buffer(
                        self.cl_ctx[ictx], self.cl_mf.READ_ONLY |
                        self.cl_mf.COPY_HOST_PTR, hostbuf=newArg[iSlice])])

            if nonSlicedROArgs is not None:
                for iarg, arg in enumerate(nonSlicedROArgs):
                    kernel_bufs[ictx].extend([cl.Buffer(
                        self.cl_ctx[ictx], self.cl_mf.READ_ONLY |
                        self.cl_mf.COPY_HOST_PTR, hostbuf=arg)])

            if slicedRWArgs is not None:
                for iarg, arg in enumerate(slicedRWArgs):
                    newArg = np.concatenate([arg, arg[:nDiff]]) if needResize\
                        else arg
                    secondDim = np.int(len(newArg) / dimension)
                    iSlice = slice(int(ndstart[ictx]*secondDim),
                                   int((ndstart[ictx]+ndsize[ictx])*secondDim))
                    kernel_bufs[ictx].extend([cl.Buffer(
                        self.cl_ctx[ictx], self.cl_mf.READ_WRITE |
                        self.cl_mf.COPY_HOST_PTR, hostbuf=newArg[iSlice])])
                global_size.extend([(np.int(ndsize[ictx]),)])
            if nonSlicedRWArgs is not None:
                for iarg, arg in enumerate(nonSlicedRWArgs):
                    kernel_bufs[ictx].extend([cl.Buffer(
                        self.cl_ctx[ictx], self.cl_mf.READ_WRITE |
                        self.cl_mf.COPY_HOST_PTR, hostbuf=arg)])
                global_size.extend([np.array([1]).shape])

        local_size = None
        for ictx, ctx in enumerate(work_cl_ctx):
            kernel = getattr(self.cl_program[ictx], kernelName)
            ev_run.extend([kernel(
                self.cl_queue[ictx],
                global_size[ictx],
                local_size,
                *kernel_bufs[ictx])])

        for iev, ev in enumerate(ev_run):
            status = cl.command_execution_status.to_string(
                ev.command_execution_status)
            if _DEBUG > 20:
                print("ctx status {0} {1}".format(iev, status))

        ret = ()

        if slicedRWArgs is not None:
            for ictx, ctx in enumerate(work_cl_ctx):
                for iarg, arg in enumerate(slicedRWArgs):
                    newArg = np.concatenate([arg, arg[:nDiff]]) if needResize\
                        else arg
                    secondDim = np.int(len(newArg) / dimension)
                    iSlice = slice(int(ndstart[ictx]*secondDim),
                                   int((ndstart[ictx]+ndsize[ictx])*secondDim))
                    cl.enqueue_copy(self.cl_queue[ictx],
                                    slicedRWArgs[iarg][iSlice],
                                    kernel_bufs[ictx][iarg + rw_pos],
                                    is_blocking=self.cl_is_blocking)
            if needResize:
                for arg in slicedRWArgs:
                    arg = arg[:oldSize]
            ret += tuple(slicedRWArgs)

        if nonSlicedRWArgs is not None:
            for ictx, ctx in enumerate(work_cl_ctx):
                for iarg, arg in enumerate(nonSlicedRWArgs):
                    cl.enqueue_copy(self.cl_queue[ictx],
                                    nonSlicedRWArgs[iarg],
                                    kernel_bufs[ictx][iarg + nsrw_pos],
                                    is_blocking=self.cl_is_blocking)
            if needResize:
                for arg in nonSlicedRWArgs:
                    arg = arg[:oldSize]
            ret += tuple(nonSlicedRWArgs)
#        print("Total CL execution time:", time.time() - t0, "s")
        return ret
