# Copyright (c) OpenMMLab. All rights reserved.
from unittest import TestCase

import torch
from torch.nn.modules.batchnorm import _BatchNorm

from mmpose.models.backbones import LiteHRNet
from mmpose.models.backbones.litehrnet import LiteHRModule
from mmpose.models.backbones.resnet import Bottleneck


class TestLiteHrnet(TestCase):

    @staticmethod
    def is_norm(modules):
        """Check if is one of the norms."""
        if isinstance(modules, (_BatchNorm, )):
            return True
        return False

    @staticmethod
    def all_zeros(modules):
        """Check if the weight(and bias) is all zero."""
        weight_zero = torch.equal(modules.weight.data,
                                  torch.zeros_like(modules.weight.data))
        if hasattr(modules, 'bias'):
            bias_zero = torch.equal(modules.bias.data,
                                    torch.zeros_like(modules.bias.data))
        else:
            bias_zero = True

        return weight_zero and bias_zero

    def test_litehrmodule(self):
        # Test LiteHRModule forward
        block = LiteHRModule(
            num_branches=1,
            num_blocks=1,
            in_channels=[
                40,
            ],
            reduce_ratio=8,
            module_type='LITE')

        x = torch.randn(2, 40, 56, 56)
        x_out = block([[x]])
        self.assertEqual(x_out[0][0].shape, torch.Size([2, 40, 56, 56]))

        block = LiteHRModule(
            num_branches=1,
            num_blocks=1,
            in_channels=[
                40,
            ],
            reduce_ratio=8,
            module_type='NAIVE')

        x = torch.randn(2, 40, 56, 56)
        x_out = block([x])
        self.assertEqual(x_out[0].shape, torch.Size([2, 40, 56, 56]))

        with self.assertRaises(ValueError):
            block = LiteHRModule(
                num_branches=1,
                num_blocks=1,
                in_channels=[
                    40,
                ],
                reduce_ratio=8,
                module_type='none')

    def test_litehrnet_backbone(self):
        extra = dict(
            stem=dict(stem_channels=32, out_channels=32, expand_ratio=1),
            num_stages=3,
            stages_spec=dict(
                num_modules=(2, 4, 2),
                num_branches=(2, 3, 4),
                num_blocks=(2, 2, 2),
                module_type=('LITE', 'LITE', 'LITE'),
                with_fuse=(True, True, True),
                reduce_ratios=(8, 8, 8),
                num_channels=(
                    (40, 80),
                    (40, 80, 160),
                    (40, 80, 160, 320),
                )),
            with_head=True)

        model = LiteHRNet(extra, in_channels=3)

        imgs = torch.randn(2, 3, 224, 224)
        feat = model(imgs)
        self.assertIsInstance(feat, tuple)
        self.assertEqual(feat[-1].shape, torch.Size([2, 40, 56, 56]))

        # Test HRNet zero initialization of residual
        model = LiteHRNet(extra, in_channels=3)
        model.init_weights()
        for m in model.modules():
            if isinstance(m, Bottleneck):
                self.assertTrue(self.all_zeros(m.norm3))
        model.train()

        imgs = torch.randn(2, 3, 224, 224)
        feat = model(imgs)
        self.assertIsInstance(feat, tuple)
        self.assertEqual(feat[-1].shape, torch.Size([2, 40, 56, 56]))

        extra = dict(
            stem=dict(stem_channels=32, out_channels=32, expand_ratio=1),
            num_stages=3,
            stages_spec=dict(
                num_modules=(2, 4, 2),
                num_branches=(2, 3, 4),
                num_blocks=(2, 2, 2),
                module_type=('NAIVE', 'NAIVE', 'NAIVE'),
                with_fuse=(True, True, True),
                reduce_ratios=(8, 8, 8),
                num_channels=(
                    (40, 80),
                    (40, 80, 160),
                    (40, 80, 160, 320),
                )),
            with_head=True)

        model = LiteHRNet(extra, in_channels=3)

        imgs = torch.randn(2, 3, 224, 224)
        feat = model(imgs)
        self.assertIsInstance(feat, tuple)
        self.assertEqual(feat[-1].shape, torch.Size([2, 40, 56, 56]))

        # Test HRNet zero initialization of residual
        model = LiteHRNet(extra, in_channels=3)
        model.init_weights()
        for m in model.modules():
            if isinstance(m, Bottleneck):
                self.assertTrue(self.all_zeros(m.norm3))
        model.train()

        imgs = torch.randn(2, 3, 224, 224)
        feat = model(imgs)
        self.assertIsInstance(feat, tuple)
        self.assertEqual(feat[-1].shape, torch.Size([2, 40, 56, 56]))