How we do Enums

[devxpy]

If you ever find yourself trying to define an enum but you want multiple fields for the value, use this pattern.

Start by defining a NamedTuple of your desired fields

class UpscalerModel(typing.NamedTuple):
    model_id: str
    label: str
    supports_video: bool = False
    is_bg_model: bool = False

Then inherit from both the named tuple you defined and Enum. This works because the enum constructor accepts tuples as *args

class UpscalerModels(UpscalerModel, Enum):
    gfpgan_1_4 = UpscalerModel(
        model_id="GFPGANv1.4",
        label="GFPGAN v1.4 (Tencent ARC)",
        supports_video=True,
    )
    real_esrgan_x2 = UpscalerModel(
        model_id="RealESRGAN_x2plus",
        label="Real-ESRGAN x2 (xinntao)",
        is_bg_model=True,
    )
    sd_x4 = UpscalerModel(
        model_id="stabilityai/stable-diffusion-x4-upscaler",
        label="Stable Diffusion x4 🔻 (xinntao)",
    )
    real_esrgan = UpscalerModel(
        model_id="nightmareai/real-esrgan",
        label="Real-ESRGAN 🔻 (xinntao)",
    )
    gfpgan = UpscalerModel(
        model_id="tencentarc/gfpgan",
        label="GFPGAN 🔻 (Tencent ARC)",
    )

This makes it so that you can directly access the fields of the enum from the enum without doing enum.value.field:

print(UpscalerModels.gfpgan_1_4.label)  # GFPGAN v1.4 (Tencent ARC)

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It works as expected with UI selectboxes, given you have defined a label field:

enum_multiselect(UpscalerModels, label="#### 🤗 Compare Upscalers")

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This is preferred over django's TextChoices and IntegerChoices too, just add a db_value to your tuple and provide the db_choices and from_db_value methods:

class UpscalerModel(typing.NamedTuple):
	db_value: int
    ...

class UpscalerModels(UpscalerModel, Enum):
    gfpgan_1_4 = UpscalerModel(
		db_value=1,
        ...
    )
    ...
	
    @classmethod
    def db_choices(cls):
        return [(e.db_value, e.label) for e in cls]

    @classmethod
    def from_db_value(cls, db_value: int):
        for e in cls:
            if e.db_value == db_value:
                return e
        raise ValueError(f"Invalid {cls.__name__} {db_value=}")

And then in your model:

class MyModel(models.Model):
     upscaler_model = models.IntegerField(choices=UpscalerModels.db_choices())

And to read these values from a model:

my_model = MyModel.objects.first()
print(UpscalerModels.from_db_value(my_model.upscaler_model))