import copy
import csv
import functools
import glob
import math
import os
import random

from collections import namedtuple

import SimpleITK as sitk
import numpy as np

import torch
import torch.cuda
import torch.nn.functional as F
from torch.utils.data import Dataset

from util.disk import getCache
from util.util import XyzTuple, xyz2irc
from util.logconf import logging

log = logging.getLogger(__name__)
# log.setLevel(logging.WARN)
# log.setLevel(logging.INFO)
log.setLevel(logging.DEBUG)

raw_cache = getCache('part2ch12_raw')

NoduleInfoTuple = namedtuple('NoduleInfoTuple', 'isMalignant_bool, diameter_mm, series_uid, center_xyz')

@functools.lru_cache(1)
def getNoduleInfoList(requireDataOnDisk_bool=True):
    # We construct a set with all series_uids that are present on disk.
    # This will let us use the data, even if we haven't downloaded all of
    # the subsets yet.
    mhd_list = glob.glob('data-unversioned/part2/luna/subset*/*.mhd')
    dataPresentOnDisk_set = {os.path.split(p)[-1][:-4] for p in mhd_list}

    diameter_dict = {}
    with open('data/part2/luna/annotations.csv', "r") as f:
        for row in list(csv.reader(f))[1:]:
            series_uid = row[0]
            annotationCenter_xyz = tuple([float(x) for x in row[1:4]])
            annotationDiameter_mm = float(row[4])

            diameter_dict.setdefault(series_uid, []).append((annotationCenter_xyz, annotationDiameter_mm))

    noduleInfo_list = []
    with open('data/part2/luna/candidates.csv', "r") as f:
        for row in list(csv.reader(f))[1:]:
            series_uid = row[0]

            if series_uid not in dataPresentOnDisk_set and requireDataOnDisk_bool:
                continue

            isMalignant_bool = bool(int(row[4]))
            candidateCenter_xyz = tuple([float(x) for x in row[1:4]])

            candidateDiameter_mm = 0.0
            for annotationCenter_xyz, annotationDiameter_mm in diameter_dict.get(series_uid, []):
                for i in range(3):
                    delta_mm = abs(candidateCenter_xyz[i] - annotationCenter_xyz[i])
                    if delta_mm > annotationDiameter_mm / 4:
                        break
                else:
                    candidateDiameter_mm = annotationDiameter_mm
                    break

            noduleInfo_list.append(NoduleInfoTuple(isMalignant_bool, candidateDiameter_mm, series_uid, candidateCenter_xyz))

    noduleInfo_list.sort(reverse=True)
    return noduleInfo_list

class Ct(object):
    def __init__(self, series_uid):
        mhd_path = glob.glob('data-unversioned/part2/luna/subset*/{}.mhd'.format(series_uid))[0]

        ct_mhd = sitk.ReadImage(mhd_path)
        ct_a = np.array(sitk.GetArrayFromImage(ct_mhd), dtype=np.float32)

        # CTs are natively expressed in https://en.wikipedia.org/wiki/Hounsfield_scale
        # HU are scaled oddly, with 0 g/cc (air, approximately) being -1000 and 1 g/cc (water) being 0.
        # This gets rid of negative density stuff used to indicate out-of-FOV
        ct_a[ct_a < -1000] = -1000

        # This nukes any weird hotspots and clamps bone down
        ct_a[ct_a > 1000] = 1000

        self.series_uid = series_uid
        self.hu_a = ct_a

        self.origin_xyz = XyzTuple(*ct_mhd.GetOrigin())
        self.vxSize_xyz = XyzTuple(*ct_mhd.GetSpacing())
        self.direction_tup = tuple(int(round(x)) for x in ct_mhd.GetDirection())

    def getRawNodule(self, center_xyz, width_irc):
        center_irc = xyz2irc(center_xyz, self.origin_xyz, self.vxSize_xyz, self.direction_tup)

        slice_list = []
        for axis, center_val in enumerate(center_irc):
            start_ndx = int(round(center_val - width_irc[axis]/2))
            end_ndx = int(start_ndx + width_irc[axis])

            assert center_val >= 0 and center_val < self.hu_a.shape[axis], repr([self.series_uid, center_xyz, self.origin_xyz, self.vxSize_xyz, center_irc, axis])

            if start_ndx < 0:
                # log.warning("Crop outside of CT array: {} {}, center:{} shape:{} width:{}".format(
                #     self.series_uid, center_xyz, center_irc, self.hu_a.shape, width_irc))
                start_ndx = 0
                end_ndx = int(width_irc[axis])

            if end_ndx > self.hu_a.shape[axis]:
                # log.warning("Crop outside of CT array: {} {}, center:{} shape:{} width:{}".format(
                #     self.series_uid, center_xyz, center_irc, self.hu_a.shape, width_irc))
                end_ndx = self.hu_a.shape[axis]
                start_ndx = int(self.hu_a.shape[axis] - width_irc[axis])

            slice_list.append(slice(start_ndx, end_ndx))

        ct_chunk = self.hu_a[tuple(slice_list)]

        return ct_chunk, center_irc


@functools.lru_cache(1, typed=True)
def getCt(series_uid):
    return Ct(series_uid)

@raw_cache.memoize(typed=True)
def getCtRawNodule(series_uid, center_xyz, width_irc):
    ct = getCt(series_uid)
    ct_chunk, center_irc = ct.getRawNodule(center_xyz, width_irc)
    return ct_chunk, center_irc

def getCtAugmentedNodule(
        augmentation_dict,
        series_uid, center_xyz, width_irc,
        use_cache=True):
    if use_cache:
        ct_chunk, center_irc = getCtRawNodule(series_uid, center_xyz, width_irc)
    else:
        ct = getCt(series_uid)
        ct_chunk, center_irc = ct.getRawNodule(center_xyz, width_irc)

    ct_t = torch.tensor(ct_chunk).unsqueeze(0).unsqueeze(0).to(torch.float32)

    transform_t = torch.eye(4).to(torch.float64)
    # ... <1>

    for i in range(3):
        if 'flip' in augmentation_dict:
            if random.random() > 0.5:
                transform_t[i,i] *= -1

        if 'offset' in augmentation_dict:
            offset_float = augmentation_dict['offset']
            random_float = (random.random() * 2 - 1)
            transform_t[3,i] = offset_float * random_float

        if 'scale' in augmentation_dict:
            scale_float = augmentation_dict['scale']
            random_float = (random.random() * 2 - 1)
            transform_t[i,i] *= 1.0 + scale_float * random_float


    if 'rotate' in augmentation_dict:
        angle_rad = random.random() * math.pi * 2
        s = math.sin(angle_rad)
        c = math.cos(angle_rad)

        rotation_t = torch.tensor([
            [c, -s, 0, 0],
            [s, c, 0, 0],
            [0, 0, 1, 0],
            [0, 0, 0, 1],
        ], dtype=torch.float64)

        transform_t @= rotation_t

    affine_t = F.affine_grid(
            transform_t[:3].unsqueeze(0).to(torch.float32),
            ct_t.size(),
        )

    augmented_chunk = F.grid_sample(
            ct_t,
            affine_t,
            padding_mode='border'
        ).to('cpu')

    if 'noise' in augmentation_dict:
        noise_t = torch.randn_like(augmented_chunk)
        noise_t *= augmentation_dict['noise']

        augmented_chunk += noise_t

    return augmented_chunk[0], center_irc


class LunaDataset(Dataset):
    def __init__(self,
                 val_stride=0,
                 isValSet_bool=None,
                 series_uid=None,
                 sortby_str='random',
                 ratio_int=0,
                 augmentation_dict=None,
                 noduleInfo_list=None,
            ):
        self.ratio_int = ratio_int
        self.augmentation_dict = augmentation_dict

        if noduleInfo_list:
            self.noduleInfo_list = copy.copy(noduleInfo_list)
            self.use_cache = False
        else:
            self.noduleInfo_list = copy.copy(getNoduleInfoList())
            self.use_cache = True

        if series_uid:
            self.noduleInfo_list = [x for x in self.noduleInfo_list if x.series_uid == series_uid]

        if isValSet_bool:
            assert val_stride > 0, val_stride
            self.noduleInfo_list = self.noduleInfo_list[::val_stride]
            assert self.noduleInfo_list
        elif val_stride > 0:
            del self.noduleInfo_list[::val_stride]
            assert self.noduleInfo_list

        if sortby_str == 'random':
            random.shuffle(self.noduleInfo_list)
        elif sortby_str == 'series_uid':
            self.noduleInfo_list.sort(key=lambda x: (x.series_uid, x.center_xyz))
        elif sortby_str == 'malignancy_size':
            pass
        else:
            raise Exception("Unknown sort: " + repr(sortby_str))

        self.benign_list = [nt for nt in self.noduleInfo_list if not nt.isMalignant_bool]
        self.malignant_list = [nt for nt in self.noduleInfo_list if nt.isMalignant_bool]

        log.info("{!r}: {} {} samples, {} ben, {} mal, {} ratio".format(
            self,
            len(self.noduleInfo_list),
            "validation" if isValSet_bool else "training",
            len(self.benign_list),
            len(self.malignant_list),
            '{}:1'.format(self.ratio_int) if self.ratio_int else 'unbalanced'
        ))

    def shuffleSamples(self):
        if self.ratio_int:
            random.shuffle(self.benign_list)
            random.shuffle(self.malignant_list)

    def __len__(self):
        if self.ratio_int:
            return 20000
            return 200000
        else:
            return len(self.noduleInfo_list) // 20

    def __getitem__(self, ndx):
        if self.ratio_int:
            malignant_ndx = ndx // (self.ratio_int + 1)

            if ndx % (self.ratio_int + 1):
                benign_ndx = ndx - 1 - malignant_ndx
                benign_ndx %= len(self.benign_list)
                nodule_tup = self.benign_list[benign_ndx]
            else:
                malignant_ndx %= len(self.malignant_list)
                nodule_tup = self.malignant_list[malignant_ndx]
        else:
            nodule_tup = self.noduleInfo_list[ndx]

        width_irc = (32, 48, 48)

        if self.augmentation_dict:
            nodule_t, center_irc = getCtAugmentedNodule(
                self.augmentation_dict,
                nodule_tup.series_uid,
                nodule_tup.center_xyz,
                width_irc,
                self.use_cache,
            )
        elif self.use_cache:
            nodule_a, center_irc = getCtRawNodule(
                nodule_tup.series_uid,
                nodule_tup.center_xyz,
                width_irc,
            )
            nodule_t = torch.from_numpy(nodule_a).to(torch.float32)
            nodule_t = nodule_t.unsqueeze(0)
        else:
            ct = getCt(nodule_tup.series_uid)
            nodule_a, center_irc = ct.getRawNodule(
                nodule_tup.center_xyz,
                width_irc,
            )
            nodule_t = torch.from_numpy(nodule_a).to(torch.float32)
            nodule_t = nodule_t.unsqueeze(0)

        malignant_t = torch.tensor([
                not nodule_tup.isMalignant_bool,
                nodule_tup.isMalignant_bool
            ],
            dtype=torch.long,
        )

        return nodule_t, malignant_t, nodule_tup.series_uid, torch.tensor(center_irc)