import os
import torch
from torchvision import transforms as T
from torchvision.transforms import functional as F

from PIL.Image import NEAREST, BILINEAR, BICUBIC

import numpy as np

import unittest

from common_utils import TransformsTester, get_tmp_dir, int_dtypes, float_dtypes


class Tester(TransformsTester):

    def setUp(self):
        self.device = "cpu"

    def _test_functional_op(self, func, fn_kwargs):
        if fn_kwargs is None:
            fn_kwargs = {}

        f = getattr(F, func)
        tensor, pil_img = self._create_data(height=10, width=10, device=self.device)
        transformed_tensor = f(tensor, **fn_kwargs)
        transformed_pil_img = f(pil_img, **fn_kwargs)
        self.compareTensorToPIL(transformed_tensor, transformed_pil_img)

    def _test_transform_vs_scripted(self, transform, s_transform, tensor, msg=None):
        torch.manual_seed(12)
        out1 = transform(tensor)
        torch.manual_seed(12)
        out2 = s_transform(tensor)
        self.assertTrue(out1.equal(out2), msg=msg)

    def _test_transform_vs_scripted_on_batch(self, transform, s_transform, batch_tensors, msg=None):
        torch.manual_seed(12)
        transformed_batch = transform(batch_tensors)

        for i in range(len(batch_tensors)):
            img_tensor = batch_tensors[i, ...]
            torch.manual_seed(12)
            transformed_img = transform(img_tensor)
            self.assertTrue(transformed_img.equal(transformed_batch[i, ...]), msg=msg)

        torch.manual_seed(12)
        s_transformed_batch = s_transform(batch_tensors)
        self.assertTrue(transformed_batch.equal(s_transformed_batch), msg=msg)

    def _test_class_op(self, method, meth_kwargs=None, test_exact_match=True, **match_kwargs):
        if meth_kwargs is None:
            meth_kwargs = {}

        # test for class interface
        f = getattr(T, method)(**meth_kwargs)
        scripted_fn = torch.jit.script(f)

        tensor, pil_img = self._create_data(26, 34, device=self.device)
        # set seed to reproduce the same transformation for tensor and PIL image
        torch.manual_seed(12)
        transformed_tensor = f(tensor)
        torch.manual_seed(12)
        transformed_pil_img = f(pil_img)
        if test_exact_match:
            self.compareTensorToPIL(transformed_tensor, transformed_pil_img, **match_kwargs)
        else:
            self.approxEqualTensorToPIL(transformed_tensor.float(), transformed_pil_img, **match_kwargs)

        torch.manual_seed(12)
        transformed_tensor_script = scripted_fn(tensor)
        self.assertTrue(transformed_tensor.equal(transformed_tensor_script))

        batch_tensors = self._create_data_batch(height=23, width=34, channels=3, num_samples=4, device=self.device)
        self._test_transform_vs_scripted_on_batch(f, scripted_fn, batch_tensors)

        with get_tmp_dir() as tmp_dir:
            scripted_fn.save(os.path.join(tmp_dir, "t_{}.pt".format(method)))

    def _test_op(self, func, method, fn_kwargs=None, meth_kwargs=None):
        self._test_functional_op(func, fn_kwargs)
        self._test_class_op(method, meth_kwargs)

    def test_random_horizontal_flip(self):
        self._test_op('hflip', 'RandomHorizontalFlip')

    def test_random_vertical_flip(self):
        self._test_op('vflip', 'RandomVerticalFlip')

    def test_color_jitter(self):

        tol = 1.0 + 1e-10
        for f in [0.1, 0.5, 1.0, 1.34, (0.3, 0.7), [0.4, 0.5]]:
            meth_kwargs = {"brightness": f}
            self._test_class_op(
                "ColorJitter", meth_kwargs=meth_kwargs, test_exact_match=False, tol=tol, agg_method="max"
            )

        for f in [0.2, 0.5, 1.0, 1.5, (0.3, 0.7), [0.4, 0.5]]:
            meth_kwargs = {"contrast": f}
            self._test_class_op(
                "ColorJitter", meth_kwargs=meth_kwargs, test_exact_match=False, tol=tol, agg_method="max"
            )

        for f in [0.5, 0.75, 1.0, 1.25, (0.3, 0.7), [0.3, 0.4]]:
            meth_kwargs = {"saturation": f}
            self._test_class_op(
                "ColorJitter", meth_kwargs=meth_kwargs, test_exact_match=False, tol=tol, agg_method="max"
            )

        for f in [0.2, 0.5, (-0.2, 0.3), [-0.4, 0.5]]:
            meth_kwargs = {"hue": f}
            self._test_class_op(
                "ColorJitter", meth_kwargs=meth_kwargs, test_exact_match=False, tol=0.1, agg_method="mean"
            )

        # All 4 parameters together
        meth_kwargs = {"brightness": 0.2, "contrast": 0.2, "saturation": 0.2, "hue": 0.2}
        self._test_class_op(
            "ColorJitter", meth_kwargs=meth_kwargs, test_exact_match=False, tol=0.1, agg_method="mean"
        )

    def test_pad(self):
        for m in ["constant", "edge", "reflect", "symmetric"]:
            fill = 127 if m == "constant" else 0
            for mul in [1, -1]:
                # Test functional.pad (PIL and Tensor) with padding as single int
                self._test_functional_op(
                    "pad", fn_kwargs={"padding": mul * 2, "fill": fill, "padding_mode": m}
                )
                # Test functional.pad and transforms.Pad with padding as [int, ]
                fn_kwargs = meth_kwargs = {"padding": [mul * 2, ], "fill": fill, "padding_mode": m}
                self._test_op(
                    "pad", "Pad", fn_kwargs=fn_kwargs, meth_kwargs=meth_kwargs
                )
                # Test functional.pad and transforms.Pad with padding as list
                fn_kwargs = meth_kwargs = {"padding": [mul * 4, 4], "fill": fill, "padding_mode": m}
                self._test_op(
                    "pad", "Pad", fn_kwargs=fn_kwargs, meth_kwargs=meth_kwargs
                )
                # Test functional.pad and transforms.Pad with padding as tuple
                fn_kwargs = meth_kwargs = {"padding": (mul * 2, 2, 2, mul * 2), "fill": fill, "padding_mode": m}
                self._test_op(
                    "pad", "Pad", fn_kwargs=fn_kwargs, meth_kwargs=meth_kwargs
                )

    def test_crop(self):
        fn_kwargs = {"top": 2, "left": 3, "height": 4, "width": 5}
        # Test transforms.RandomCrop with size and padding as tuple
        meth_kwargs = {"size": (4, 5), "padding": (4, 4), "pad_if_needed": True, }
        self._test_op(
            'crop', 'RandomCrop', fn_kwargs=fn_kwargs, meth_kwargs=meth_kwargs
        )

        sizes = [5, [5, ], [6, 6]]
        padding_configs = [
            {"padding_mode": "constant", "fill": 0},
            {"padding_mode": "constant", "fill": 10},
            {"padding_mode": "constant", "fill": 20},
            {"padding_mode": "edge"},
            {"padding_mode": "reflect"},
        ]

        for size in sizes:
            for padding_config in padding_configs:
                config = dict(padding_config)
                config["size"] = size
                self._test_class_op("RandomCrop", config)

    def test_center_crop(self):
        fn_kwargs = {"output_size": (4, 5)}
        meth_kwargs = {"size": (4, 5), }
        self._test_op(
            "center_crop", "CenterCrop", fn_kwargs=fn_kwargs, meth_kwargs=meth_kwargs
        )
        fn_kwargs = {"output_size": (5,)}
        meth_kwargs = {"size": (5, )}
        self._test_op(
            "center_crop", "CenterCrop", fn_kwargs=fn_kwargs, meth_kwargs=meth_kwargs
        )
        tensor = torch.randint(0, 255, (3, 10, 10), dtype=torch.uint8, device=self.device)
        # Test torchscript of transforms.CenterCrop with size as int
        f = T.CenterCrop(size=5)
        scripted_fn = torch.jit.script(f)
        scripted_fn(tensor)

        # Test torchscript of transforms.CenterCrop with size as [int, ]
        f = T.CenterCrop(size=[5, ])
        scripted_fn = torch.jit.script(f)
        scripted_fn(tensor)

        # Test torchscript of transforms.CenterCrop with size as tuple
        f = T.CenterCrop(size=(6, 6))
        scripted_fn = torch.jit.script(f)
        scripted_fn(tensor)

        with get_tmp_dir() as tmp_dir:
            scripted_fn.save(os.path.join(tmp_dir, "t_center_crop.pt"))

    def _test_op_list_output(self, func, method, out_length, fn_kwargs=None, meth_kwargs=None):
        if fn_kwargs is None:
            fn_kwargs = {}
        if meth_kwargs is None:
            meth_kwargs = {}

        fn = getattr(F, func)
        scripted_fn = torch.jit.script(fn)

        tensor, pil_img = self._create_data(height=20, width=20, device=self.device)
        transformed_t_list = fn(tensor, **fn_kwargs)
        transformed_p_list = fn(pil_img, **fn_kwargs)
        self.assertEqual(len(transformed_t_list), len(transformed_p_list))
        self.assertEqual(len(transformed_t_list), out_length)
        for transformed_tensor, transformed_pil_img in zip(transformed_t_list, transformed_p_list):
            self.compareTensorToPIL(transformed_tensor, transformed_pil_img)

        transformed_t_list_script = scripted_fn(tensor.detach().clone(), **fn_kwargs)
        self.assertEqual(len(transformed_t_list), len(transformed_t_list_script))
        self.assertEqual(len(transformed_t_list_script), out_length)
        for transformed_tensor, transformed_tensor_script in zip(transformed_t_list, transformed_t_list_script):
            self.assertTrue(transformed_tensor.equal(transformed_tensor_script),
                            msg="{} vs {}".format(transformed_tensor, transformed_tensor_script))

        # test for class interface
        fn = getattr(T, method)(**meth_kwargs)
        scripted_fn = torch.jit.script(fn)
        output = scripted_fn(tensor)
        self.assertEqual(len(output), len(transformed_t_list_script))

        # test on batch of tensors
        batch_tensors = self._create_data_batch(height=23, width=34, channels=3, num_samples=4, device=self.device)
        torch.manual_seed(12)
        transformed_batch_list = fn(batch_tensors)

        for i in range(len(batch_tensors)):
            img_tensor = batch_tensors[i, ...]
            torch.manual_seed(12)
            transformed_img_list = fn(img_tensor)
            for transformed_img, transformed_batch in zip(transformed_img_list, transformed_batch_list):
                self.assertTrue(transformed_img.equal(transformed_batch[i, ...]),
                                msg="{} vs {}".format(transformed_img, transformed_batch[i, ...]))

        with get_tmp_dir() as tmp_dir:
            scripted_fn.save(os.path.join(tmp_dir, "t_op_list_{}.pt".format(method)))

    def test_five_crop(self):
        fn_kwargs = meth_kwargs = {"size": (5,)}
        self._test_op_list_output(
            "five_crop", "FiveCrop", out_length=5, fn_kwargs=fn_kwargs, meth_kwargs=meth_kwargs
        )
        fn_kwargs = meth_kwargs = {"size": [5, ]}
        self._test_op_list_output(
            "five_crop", "FiveCrop", out_length=5, fn_kwargs=fn_kwargs, meth_kwargs=meth_kwargs
        )
        fn_kwargs = meth_kwargs = {"size": (4, 5)}
        self._test_op_list_output(
            "five_crop", "FiveCrop", out_length=5, fn_kwargs=fn_kwargs, meth_kwargs=meth_kwargs
        )
        fn_kwargs = meth_kwargs = {"size": [4, 5]}
        self._test_op_list_output(
            "five_crop", "FiveCrop", out_length=5, fn_kwargs=fn_kwargs, meth_kwargs=meth_kwargs
        )

    def test_ten_crop(self):
        fn_kwargs = meth_kwargs = {"size": (5,)}
        self._test_op_list_output(
            "ten_crop", "TenCrop", out_length=10, fn_kwargs=fn_kwargs, meth_kwargs=meth_kwargs
        )
        fn_kwargs = meth_kwargs = {"size": [5, ]}
        self._test_op_list_output(
            "ten_crop", "TenCrop", out_length=10, fn_kwargs=fn_kwargs, meth_kwargs=meth_kwargs
        )
        fn_kwargs = meth_kwargs = {"size": (4, 5)}
        self._test_op_list_output(
            "ten_crop", "TenCrop", out_length=10, fn_kwargs=fn_kwargs, meth_kwargs=meth_kwargs
        )
        fn_kwargs = meth_kwargs = {"size": [4, 5]}
        self._test_op_list_output(
            "ten_crop", "TenCrop", out_length=10, fn_kwargs=fn_kwargs, meth_kwargs=meth_kwargs
        )

    def test_resize(self):
        tensor, _ = self._create_data(height=34, width=36, device=self.device)
        batch_tensors = torch.randint(0, 255, size=(4, 3, 44, 56), dtype=torch.uint8, device=self.device)
        script_fn = torch.jit.script(F.resize)

        for dt in [None, torch.float32, torch.float64]:
            if dt is not None:
                # This is a trivial cast to float of uint8 data to test all cases
                tensor = tensor.to(dt)
            for size in [32, 34, [32, ], [32, 32], (32, 32), [34, 35]]:
                for interpolation in [BILINEAR, BICUBIC, NEAREST]:

                    resized_tensor = F.resize(tensor, size=size, interpolation=interpolation)

                    if isinstance(size, int):
                        script_size = [size, ]
                    else:
                        script_size = size

                    s_resized_tensor = script_fn(tensor, size=script_size, interpolation=interpolation)
                    self.assertTrue(s_resized_tensor.equal(resized_tensor))

                    transform = T.Resize(size=script_size, interpolation=interpolation)
                    s_transform = torch.jit.script(transform)
                    self._test_transform_vs_scripted(transform, s_transform, tensor)
                    self._test_transform_vs_scripted_on_batch(transform, s_transform, batch_tensors)

        with get_tmp_dir() as tmp_dir:
            script_fn.save(os.path.join(tmp_dir, "t_resize.pt"))

    def test_resized_crop(self):
        tensor = torch.randint(0, 255, size=(3, 44, 56), dtype=torch.uint8, device=self.device)
        batch_tensors = torch.randint(0, 255, size=(4, 3, 44, 56), dtype=torch.uint8, device=self.device)

        for scale in [(0.7, 1.2), [0.7, 1.2]]:
            for ratio in [(0.75, 1.333), [0.75, 1.333]]:
                for size in [(32, ), [44, ], [32, ], [32, 32], (32, 32), [44, 55]]:
                    for interpolation in [NEAREST, BILINEAR, BICUBIC]:
                        transform = T.RandomResizedCrop(
                            size=size, scale=scale, ratio=ratio, interpolation=interpolation
                        )
                        s_transform = torch.jit.script(transform)
                        self._test_transform_vs_scripted(transform, s_transform, tensor)
                        self._test_transform_vs_scripted_on_batch(transform, s_transform, batch_tensors)

        with get_tmp_dir() as tmp_dir:
            s_transform.save(os.path.join(tmp_dir, "t_resized_crop.pt"))

    def test_random_affine(self):
        tensor = torch.randint(0, 255, size=(3, 44, 56), dtype=torch.uint8, device=self.device)
        batch_tensors = torch.randint(0, 255, size=(4, 3, 44, 56), dtype=torch.uint8, device=self.device)

        for shear in [15, 10.0, (5.0, 10.0), [-15, 15], [-10.0, 10.0, -11.0, 11.0]]:
            for scale in [(0.7, 1.2), [0.7, 1.2]]:
                for translate in [(0.1, 0.2), [0.2, 0.1]]:
                    for degrees in [45, 35.0, (-45, 45), [-90.0, 90.0]]:
                        for interpolation in [NEAREST, BILINEAR]:
                            transform = T.RandomAffine(
                                degrees=degrees, translate=translate,
                                scale=scale, shear=shear, resample=interpolation
                            )
                            s_transform = torch.jit.script(transform)

                            self._test_transform_vs_scripted(transform, s_transform, tensor)
                            self._test_transform_vs_scripted_on_batch(transform, s_transform, batch_tensors)

        with get_tmp_dir() as tmp_dir:
            s_transform.save(os.path.join(tmp_dir, "t_random_affine.pt"))

    def test_random_rotate(self):
        tensor = torch.randint(0, 255, size=(3, 44, 56), dtype=torch.uint8, device=self.device)
        batch_tensors = torch.randint(0, 255, size=(4, 3, 44, 56), dtype=torch.uint8, device=self.device)

        for center in [(0, 0), [10, 10], None, (56, 44)]:
            for expand in [True, False]:
                for degrees in [45, 35.0, (-45, 45), [-90.0, 90.0]]:
                    for interpolation in [NEAREST, BILINEAR]:
                        transform = T.RandomRotation(
                            degrees=degrees, resample=interpolation, expand=expand, center=center
                        )
                        s_transform = torch.jit.script(transform)

                        self._test_transform_vs_scripted(transform, s_transform, tensor)
                        self._test_transform_vs_scripted_on_batch(transform, s_transform, batch_tensors)

        with get_tmp_dir() as tmp_dir:
            s_transform.save(os.path.join(tmp_dir, "t_random_rotate.pt"))

    def test_random_perspective(self):
        tensor = torch.randint(0, 255, size=(3, 44, 56), dtype=torch.uint8, device=self.device)
        batch_tensors = torch.randint(0, 255, size=(4, 3, 44, 56), dtype=torch.uint8, device=self.device)

        for distortion_scale in np.linspace(0.1, 1.0, num=20):
            for interpolation in [NEAREST, BILINEAR]:
                transform = T.RandomPerspective(
                    distortion_scale=distortion_scale,
                    interpolation=interpolation
                )
                s_transform = torch.jit.script(transform)

                self._test_transform_vs_scripted(transform, s_transform, tensor)
                self._test_transform_vs_scripted_on_batch(transform, s_transform, batch_tensors)

        with get_tmp_dir() as tmp_dir:
            s_transform.save(os.path.join(tmp_dir, "t_perspective.pt"))

    def test_to_grayscale(self):

        meth_kwargs = {"num_output_channels": 1}
        tol = 1.0 + 1e-10
        self._test_class_op(
            "Grayscale", meth_kwargs=meth_kwargs, test_exact_match=False, tol=tol, agg_method="max"
        )

        meth_kwargs = {"num_output_channels": 3}
        self._test_class_op(
            "Grayscale", meth_kwargs=meth_kwargs, test_exact_match=False, tol=tol, agg_method="max"
        )

        meth_kwargs = {}
        self._test_class_op(
            "RandomGrayscale", meth_kwargs=meth_kwargs, test_exact_match=False, tol=tol, agg_method="max"
        )

    def test_normalize(self):
        tensor, _ = self._create_data(26, 34, device=self.device)
        batch_tensors = torch.rand(4, 3, 44, 56, device=self.device)

        tensor = tensor.to(dtype=torch.float32) / 255.0
        # test for class interface
        fn = T.Normalize((0.5, 0.5, 0.5), (0.5, 0.5, 0.5))
        scripted_fn = torch.jit.script(fn)

        self._test_transform_vs_scripted(fn, scripted_fn, tensor)
        self._test_transform_vs_scripted_on_batch(fn, scripted_fn, batch_tensors)

        with get_tmp_dir() as tmp_dir:
            scripted_fn.save(os.path.join(tmp_dir, "t_norm.pt"))

    def test_linear_transformation(self):
        c, h, w = 3, 24, 32

        tensor, _ = self._create_data(h, w, channels=c, device=self.device)

        matrix = torch.rand(c * h * w, c * h * w, device=self.device)
        mean_vector = torch.rand(c * h * w, device=self.device)

        fn = T.LinearTransformation(matrix, mean_vector)
        scripted_fn = torch.jit.script(fn)

        self._test_transform_vs_scripted(fn, scripted_fn, tensor)

        batch_tensors = torch.rand(4, c, h, w, device=self.device)
        # We skip some tests from _test_transform_vs_scripted_on_batch as
        # results for scripted and non-scripted transformations are not exactly the same
        torch.manual_seed(12)
        transformed_batch = fn(batch_tensors)
        torch.manual_seed(12)
        s_transformed_batch = scripted_fn(batch_tensors)
        self.assertTrue(transformed_batch.equal(s_transformed_batch))

        with get_tmp_dir() as tmp_dir:
            scripted_fn.save(os.path.join(tmp_dir, "t_norm.pt"))

    def test_compose(self):
        tensor, _ = self._create_data(26, 34, device=self.device)
        tensor = tensor.to(dtype=torch.float32) / 255.0

        transforms = T.Compose([
            T.CenterCrop(10),
            T.Normalize((0.485, 0.456, 0.406), (0.229, 0.224, 0.225)),
        ])
        s_transforms = torch.nn.Sequential(*transforms.transforms)

        scripted_fn = torch.jit.script(s_transforms)
        torch.manual_seed(12)
        transformed_tensor = transforms(tensor)
        torch.manual_seed(12)
        transformed_tensor_script = scripted_fn(tensor)
        self.assertTrue(transformed_tensor.equal(transformed_tensor_script), msg="{}".format(transforms))

        t = T.Compose([
            lambda x: x,
        ])
        with self.assertRaisesRegex(RuntimeError, r"Could not get name of python class object"):
            torch.jit.script(t)

    def test_random_apply(self):
        tensor, _ = self._create_data(26, 34, device=self.device)
        tensor = tensor.to(dtype=torch.float32) / 255.0

        transforms = T.RandomApply([
            T.RandomHorizontalFlip(),
            T.ColorJitter(),
        ], p=0.4)
        s_transforms = T.RandomApply(torch.nn.ModuleList([
            T.RandomHorizontalFlip(),
            T.ColorJitter(),
        ]), p=0.4)

        scripted_fn = torch.jit.script(s_transforms)
        torch.manual_seed(12)
        transformed_tensor = transforms(tensor)
        torch.manual_seed(12)
        transformed_tensor_script = scripted_fn(tensor)
        self.assertTrue(transformed_tensor.equal(transformed_tensor_script), msg="{}".format(transforms))

        if torch.device(self.device).type == "cpu":
            # Can't check this twice, otherwise
            # "Can't redefine method: forward on class: __torch__.torchvision.transforms.transforms.RandomApply"
            transforms = T.RandomApply([
                T.ColorJitter(),
            ], p=0.3)
            with self.assertRaisesRegex(RuntimeError, r"Module 'RandomApply' has no attribute 'transforms'"):
                torch.jit.script(transforms)

    def test_gaussian_blur(self):
        tol = 1.0 + 1e-10
        self._test_class_op(
            "GaussianBlur", meth_kwargs={"kernel_size": 3, "sigma": 0.75},
            test_exact_match=False, agg_method="max", tol=tol
        )

        self._test_class_op(
            "GaussianBlur", meth_kwargs={"kernel_size": 23, "sigma": [0.1, 2.0]},
            test_exact_match=False, agg_method="max", tol=tol
        )

        self._test_class_op(
            "GaussianBlur", meth_kwargs={"kernel_size": 23, "sigma": (0.1, 2.0)},
            test_exact_match=False, agg_method="max", tol=tol
        )

        self._test_class_op(
            "GaussianBlur", meth_kwargs={"kernel_size": [3, 3], "sigma": (1.0, 1.0)},
            test_exact_match=False, agg_method="max", tol=tol
        )

        self._test_class_op(
            "GaussianBlur", meth_kwargs={"kernel_size": (3, 3), "sigma": (0.1, 2.0)},
            test_exact_match=False, agg_method="max", tol=tol
        )

        self._test_class_op(
            "GaussianBlur", meth_kwargs={"kernel_size": [23], "sigma": 0.75},
            test_exact_match=False, agg_method="max", tol=tol
        )

    def test_random_erasing(self):
        img = torch.rand(3, 60, 60)

        # Test Set 0: invalid value
        random_erasing = T.RandomErasing(value=(0.1, 0.2, 0.3, 0.4), p=1.0)
        with self.assertRaises(ValueError, msg="If value is a sequence, it should have either a single value or 3"):
            random_erasing(img)

        tensor, _ = self._create_data(24, 32, channels=3, device=self.device)
        batch_tensors = torch.rand(4, 3, 44, 56, device=self.device)

        test_configs = [
            {"value": 0.2},
            {"value": "random"},
            {"value": (0.2, 0.2, 0.2)},
            {"value": "random", "ratio": (0.1, 0.2)},
        ]

        for config in test_configs:
            fn = T.RandomErasing(**config)
            scripted_fn = torch.jit.script(fn)
            self._test_transform_vs_scripted(fn, scripted_fn, tensor)
            self._test_transform_vs_scripted_on_batch(fn, scripted_fn, batch_tensors)

        with get_tmp_dir() as tmp_dir:
            scripted_fn.save(os.path.join(tmp_dir, "t_random_erasing.pt"))

    def test_convert_image_dtype(self):
        tensor, _ = self._create_data(26, 34, device=self.device)
        batch_tensors = torch.rand(4, 3, 44, 56, device=self.device)

        for in_dtype in int_dtypes() + float_dtypes():
            in_tensor = tensor.to(in_dtype)
            in_batch_tensors = batch_tensors.to(in_dtype)
            for out_dtype in int_dtypes() + float_dtypes():

                fn = T.ConvertImageDtype(dtype=out_dtype)
                scripted_fn = torch.jit.script(fn)

                if (in_dtype == torch.float32 and out_dtype in (torch.int32, torch.int64)) or \
                        (in_dtype == torch.float64 and out_dtype == torch.int64):
                    with self.assertRaisesRegex(RuntimeError, r"cannot be performed safely"):
                        self._test_transform_vs_scripted(fn, scripted_fn, in_tensor)
                    with self.assertRaisesRegex(RuntimeError, r"cannot be performed safely"):
                        self._test_transform_vs_scripted_on_batch(fn, scripted_fn, in_batch_tensors)
                    continue

                self._test_transform_vs_scripted(fn, scripted_fn, in_tensor)
                self._test_transform_vs_scripted_on_batch(fn, scripted_fn, in_batch_tensors)

        with get_tmp_dir() as tmp_dir:
            scripted_fn.save(os.path.join(tmp_dir, "t_convert_dtype.pt"))


@unittest.skipIf(not torch.cuda.is_available(), reason="Skip if no CUDA device")
class CUDATester(Tester):

    def setUp(self):
        self.device = "cuda"


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