import unittest

import torch
import torch.nn as nn
import torchvision

import lightly
from lightly.models import ResNetGenerator, SimCLR


def get_backbone(resnet, num_ftrs=64):
    last_conv_channels = list(resnet.children())[-1].in_features
    backbone = nn.Sequential(
        lightly.models.batchnorm.get_norm_layer(3, 0),
        *list(resnet.children())[:-1],
        nn.Conv2d(last_conv_channels, num_ftrs, 1),
        nn.AdaptiveAvgPool2d(1),
    )
    return backbone


class TestModelsSimCLR(unittest.TestCase):
    def METHOD_NAME(self):
        self.resnet_variants = ["resnet-18", "resnet-50"]
        self.batch_size = 2
        self.input_tensor = torch.rand((self.batch_size, 3, 32, 32))

    def test_create_variations_cpu(self):
        for model_name in self.resnet_variants:
            resnet = ResNetGenerator(model_name)
            model = SimCLR(get_backbone(resnet))
            self.assertIsNotNone(model)

    def test_create_variations_gpu(self):
        device = "cuda" if torch.cuda.is_available() else "cpu"
        if device == "cuda":
            for model_name in self.resnet_variants:
                resnet = ResNetGenerator(model_name)
                model = SimCLR(get_backbone(resnet)).to(device)
                self.assertIsNotNone(model)
        else:
            pass

    def test_feature_dim_configurable(self):
        device = "cuda" if torch.cuda.is_available() else "cpu"
        for model_name in self.resnet_variants:
            for num_ftrs, out_dim in zip([16, 64], [64, 256]):
                resnet = ResNetGenerator(model_name)
                model = SimCLR(
                    get_backbone(resnet, num_ftrs=num_ftrs),
                    num_ftrs=num_ftrs,
                    out_dim=out_dim,
                ).to(device)

                # check that feature vector has correct dimension
                with torch.no_grad():
                    out_features = model.backbone(self.input_tensor.to(device))
                self.assertEqual(out_features.shape[1], num_ftrs)

                # check that projection head output has right dimension
                with torch.no_grad():
                    out_projection = model.projection_head(out_features.squeeze())
                self.assertEqual(out_projection.shape[1], out_dim)
                self.assertIsNotNone(model)

    def test_variations_input_dimension(self):
        device = "cuda" if torch.cuda.is_available() else "cpu"
        for model_name in self.resnet_variants:
            for input_width, input_height in zip([32, 64], [64, 64]):
                resnet = ResNetGenerator(model_name)
                model = SimCLR(get_backbone(resnet, num_ftrs=32)).to(device)

                input_tensor = torch.rand(
                    (self.batch_size, 3, input_height, input_width)
                )
                with torch.no_grad():
                    out = model(input_tensor.to(device))

                self.assertIsNotNone(model)
                self.assertIsNotNone(out)

    def test_tuple_input(self):
        device = "cuda" if torch.cuda.is_available() else "cpu"
        resnet = ResNetGenerator("resnet-18")
        model = SimCLR(get_backbone(resnet, num_ftrs=32), out_dim=128).to(device)

        x0 = torch.rand((self.batch_size, 3, 64, 64)).to(device)
        x1 = torch.rand((self.batch_size, 3, 64, 64)).to(device)

        out = model(x0)
        self.assertEqual(out.shape, (self.batch_size, 128))

        out, features = model(x0, return_features=True)
        self.assertEqual(out.shape, (self.batch_size, 128))
        self.assertEqual(features.shape, (self.batch_size, 32))

        out0, out1 = model(x0, x1)
        self.assertEqual(out0.shape, (self.batch_size, 128))
        self.assertEqual(out1.shape, (self.batch_size, 128))

        (out0, f0), (out1, f1) = model(x0, x1, return_features=True)
        self.assertEqual(out0.shape, (self.batch_size, 128))
        self.assertEqual(out1.shape, (self.batch_size, 128))
        self.assertEqual(f0.shape, (self.batch_size, 32))
        self.assertEqual(f1.shape, (self.batch_size, 32))


if __name__ == "__main__":
    unittest.main()