import pytest

from .....src.email_composer import models

base_class = models.BaseAttachment
subclasses = base_class.__subclasses__()


class TestAttachmentSubclasses:

    must_implement_properties = ["is_b64_string", "attachment_data"]

    @pytest.mark.parametrize("subclass", subclasses)
    def test_subclass_implement_field_attachment(self, subclass):
        """Ensure that each subclass of BaseAttachment implements the
        `attachment` field.
        """
        # noinspection PyUnresolvedReferences
        field = subclass.model_fields.get("attachment")
        assert field is not None, "Subclass must have the field"
        assert field.is_required() is True, "Field must be mandatory"
        assert field.annotation == str, "Field value must be a string"

    @pytest.mark.parametrize("subclass", subclasses)
    @pytest.mark.parametrize("property_name", must_implement_properties)
    def test_subclass_implements_properties(self, subclass, property_name):
        """Ensure that each subclass of BaseAttachment implements
        the required properties.
        """
        try:
            prop = getattr(subclass, property_name)
        except AttributeError:
            pytest.fail(
                f"Subclass '{subclass.__name__}' must implement the property "
                f"'{property_name}'"
            )
        else:
            assert isinstance(prop, property), (
                f"Subclass '{subclass.__name__}' property '{property_name}' must be a"
                f" property but is not."
            )


class TestAttachmentInstances:

    @pytest.fixture
    def instance(self):
        def _(_class):
            return _class(
                file_name="test.txt", mime_type="text/plain", attachment="test"
            )

        return _

    @pytest.mark.parametrize(
        "subclass,expected",
        [
            (subclass, subclass.__name__ == models.Base64Attachment.__name__)
            for subclass in subclasses
        ],
    )
    def test_instance_is_b64_string(self, instance, subclass, expected):
        """Ensure the value returned by is_b64_string is false,
        except for Base64Attachment.
        """
        assert instance(subclass).is_b64_string == expected

    @pytest.mark.parametrize(
        "subclass,attachment,expected",
        [
            (models.Base64Attachment, "dGVzdA==", b"test"),
        ],
    )
    def test_instance_attachment_data(self, instance, subclass, attachment, expected):
        """Ensure the value returned by attachment_data is the same as the
        attachment value.
        """
        _instance = instance(subclass)
        _instance.attachment = attachment
        assert (
            _instance.attachment_data == expected
        ), "Attachment data is not correctly extracted as bytes"