# BSD 3-Clause License

# Copyright (c) Soumith Chintala 2016,
# Copyright 2020 Huawei Technologies Co., Ltd
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.

import torch
import torch.nn as nn
import torch.nn.parallel
import torch.utils.data
from torch.autograd import Variable
import numpy as np
import torch.nn.functional as F


class STN3d(nn.Module):
    def __init__(self, device):
        super(STN3d, self).__init__()
        self.conv1 = torch.nn.Conv1d(3, 64, 1)
        self.conv2 = torch.nn.Conv1d(64, 128, 1)
        self.conv3 = torch.nn.Conv1d(128, 1024, 1)
        self.fc1 = nn.Linear(1024, 512)
        self.fc2 = nn.Linear(512, 256)
        self.fc3 = nn.Linear(256, 9)
        self.relu = nn.ReLU()

        self.bn1 = nn.BatchNorm1d(64)
        self.bn2 = nn.BatchNorm1d(128)
        self.bn3 = nn.BatchNorm1d(1024)
        self.bn4 = nn.BatchNorm1d(512)
        self.bn5 = nn.BatchNorm1d(256)

        self.device = device

    def forward(self, x):
        batchsize = x.size()[0]
        x = F.relu(self.bn1(self.conv1(x)))
        x = F.relu(self.bn2(self.conv2(x)))
        x = F.relu(self.bn3(self.conv3(x)))
        x = torch.max(x, 2, keepdim=True)[0]
        x = x.view(-1, 1024)

        x = F.relu(self.bn4(self.fc1(x)))
        x = F.relu(self.bn5(self.fc2(x)))
        x = self.fc3(x)

        iden = Variable(torch.from_numpy(np.array([1, 0, 0, 0, 1, 0, 0, 0, 1]).astype(np.float32))).view(1, 9).repeat(
            batchsize, 1)
        if self.device == 'gpu':
            iden = iden.cuda()
        elif self.device == 'npu':
            iden = iden.npu()
        else:
            iden = iden.cpu()
        x = x + iden
        x = x.view(-1, 3, 3)
        return x


class STNkd(nn.Module):
    def __init__(self, k=64, device='cpu'):
        super(STNkd, self).__init__()
        self.conv1 = torch.nn.Conv1d(k, 64, 1)
        self.conv2 = torch.nn.Conv1d(64, 128, 1)
        self.conv3 = torch.nn.Conv1d(128, 1024, 1)
        self.fc1 = nn.Linear(1024, 512)
        self.fc2 = nn.Linear(512, 256)
        self.fc3 = nn.Linear(256, k * k)
        self.relu = nn.ReLU()

        self.bn1 = nn.BatchNorm1d(64)
        self.bn2 = nn.BatchNorm1d(128)
        self.bn3 = nn.BatchNorm1d(1024)
        self.bn4 = nn.BatchNorm1d(512)
        self.bn5 = nn.BatchNorm1d(256)

        self.k = k
        self.device = device

    def forward(self, x):
        batchsize = x.size()[0]
        x = F.relu(self.bn1(self.conv1(x)))
        x = F.relu(self.bn2(self.conv2(x)))
        x = F.relu(self.bn3(self.conv3(x)))
        x = torch.max(x, 2, keepdim=True)[0]
        x = x.view(-1, 1024)

        x = F.relu(self.bn4(self.fc1(x)))
        x = F.relu(self.bn5(self.fc2(x)))
        x = self.fc3(x)

        iden = Variable(torch.from_numpy(np.eye(self.k).flatten().astype(np.float32))).view(1, self.k * self.k).repeat(
            batchsize, 1)
        if self.device == 'gpu':
            iden = iden.cuda()
        elif self.device == 'npu':
            iden = iden.npu()
        else:
            iden = iden.cpu()
        x = x + iden
        x = x.view(-1, self.k, self.k)
        return x


class PointNetfeat(nn.Module):
    def __init__(self, global_feat=True, feature_transform=False, device='cpu'):
        super(PointNetfeat, self).__init__()
        self.stn = STN3d(device)
        self.conv1 = torch.nn.Conv1d(3, 64, 1)
        self.conv2 = torch.nn.Conv1d(64, 128, 1)
        self.conv3 = torch.nn.Conv1d(128, 1024, 1)
        self.bn1 = nn.BatchNorm1d(64)
        self.bn2 = nn.BatchNorm1d(128)
        self.bn3 = nn.BatchNorm1d(1024)
        self.global_feat = global_feat
        self.feature_transform = feature_transform
        if self.feature_transform:
            self.fstn = STNkd(k=64, device=device)

    def forward(self, x):
        n_pts = x.size()[2]
        trans = self.stn(x)
        x = x.transpose(2, 1)
        x = torch.bmm(x, trans)
        x = x.transpose(2, 1)
        x = F.relu(self.bn1(self.conv1(x)))

        if self.feature_transform:
            trans_feat = self.fstn(x)
            x = x.transpose(2, 1)
            x = torch.bmm(x, trans_feat)
            x = x.transpose(2, 1)
        else:
            trans_feat = None

        pointfeat = x
        x = F.relu(self.bn2(self.conv2(x)))
        x = self.bn3(self.conv3(x))
        x = torch.max(x, 2, keepdim=True)[0]
        x = x.view(-1, 1024)
        if self.global_feat:
            return x, trans, trans_feat
        else:
            x = x.view(-1, 1024, 1).repeat(1, 1, n_pts)
            return torch.cat([x, pointfeat], 1), trans, trans_feat


class PointNetCls(nn.Module):
    def __init__(self, k=2, feature_transform=False, device='cpu'):
        super(PointNetCls, self).__init__()
        self.feature_transform = feature_transform
        self.feat = PointNetfeat(global_feat=True, feature_transform=feature_transform, device=device)
        self.fc1 = nn.Linear(1024, 512)
        self.fc2 = nn.Linear(512, 256)
        self.fc3 = nn.Linear(256, k)
        self.dropout = nn.Dropout(p=0.3)
        self.bn1 = nn.BatchNorm1d(512)
        self.bn2 = nn.BatchNorm1d(256)
        self.relu = nn.ReLU()

    def forward(self, x):
        x, trans, trans_feat = self.feat(x)
        x = F.relu(self.bn1(self.fc1(x)))
        x = F.relu(self.bn2(self.dropout(self.fc2(x))))
        x = self.fc3(x)
        return F.log_softmax(x, dim=1), trans, trans_feat


class PointNetDenseCls(nn.Module):
    def __init__(self, k=2, feature_transform=False, device='cpu'):
        super(PointNetDenseCls, self).__init__()
        self.k = k
        self.feature_transform = feature_transform
        self.feat = PointNetfeat(global_feat=False, feature_transform=feature_transform, device=device)
        self.conv1 = torch.nn.Conv1d(1088, 512, 1)
        self.conv2 = torch.nn.Conv1d(512, 256, 1)
        self.conv3 = torch.nn.Conv1d(256, 128, 1)
        self.conv4 = torch.nn.Conv1d(128, self.k, 1)
        self.bn1 = nn.BatchNorm1d(512)
        self.bn2 = nn.BatchNorm1d(256)
        self.bn3 = nn.BatchNorm1d(128)

    def forward(self, x):
        batchsize = x.size()[0]
        n_pts = x.size()[2]
        x, trans, trans_feat = self.feat(x)
        x = F.relu(self.bn1(self.conv1(x)))
        x = F.relu(self.bn2(self.conv2(x)))
        x = F.relu(self.bn3(self.conv3(x)))
        x = self.conv4(x)
        x = x.transpose(2, 1).contiguous()
        x = F.log_softmax(x.view(-1, self.k), dim=-1)
        x = x.view(batchsize, n_pts, self.k)
        return x, trans, trans_feat


def feature_transform_regularizer(trans, device):
    d = trans.size()[1]
    I = torch.eye(d)[None, :, :]
    if device == 'gpu':
        I = I.cuda()
    elif device == 'npu':
        I = I.npu()
    else:
        I = I.cpu()
    loss = torch.mean(torch.norm(torch.bmm(trans, trans.transpose(2, 1) - I), dim=(1, 2)))
    return loss


if __name__ == '__main__':
    sim_data = Variable(torch.rand(32, 3, 2500))
    trans = STN3d()
    out = trans(sim_data)
    print('stn', out.size())
    print('loss', feature_transform_regularizer(out))

    sim_data_64d = Variable(torch.rand(32, 64, 2500))
    trans = STNkd(k=64)
    out = trans(sim_data_64d)
    print('stn64d', out.size())
    print('loss', feature_transform_regularizer(out))

    pointfeat = PointNetfeat(global_feat=True)
    out, _, _ = pointfeat(sim_data)
    print('global feat', out.size())

    pointfeat = PointNetfeat(global_feat=False)
    out, _, _ = pointfeat(sim_data)
    print('point feat', out.size())

    cls = PointNetCls(k=5)
    out, _, _ = cls(sim_data)
    print('class', out.size())

    seg = PointNetDenseCls(k=3)
    out, _, _ = seg(sim_data)
    print('seg', out.size())