feat: added promocode creation and view

solution/apps/promo/validators.py

@@ -0,0 +1,82 @@
+from django.core.exceptions import ValidationError
+from django.core.validators import BaseValidator
+from django.utils.deconstruct import deconstructible
+
+MAX_CATEGORIES_LIST_LEN = 20
+MIN_CATEGORY_LEN = 2
+MAX_CATEGORY_LEN = 20
+
+MIN_UNIQUE_PROMOCODES_LIST_LEN = 1
+MAX_UNIQUE_PROMOCODES_LIST_LEN = 5000
+MIN_UNIQUE_PROMOCODE_LEN = 3
+MAX_UNIQUE_PROMOCODE_LEN = 30
+
+
+class TargetAgeValidator:
+    def __call__(self, instance) -> None:  # noqa: ANN001
+        if (
+            instance.age_from is not None
+            and instance.age_until is not None
+            and instance.age_from > instance.age_until
+        ):
+            err = "age_from can't be greater than age_until"
+            raise ValidationError(err)
+
+
+class PromocodeDurationValidator:
+    def __call__(self, instance) -> None:  # noqa: ANN001
+        if (
+            instance.active_from is not None
+            and instance.active_until is not None
+            and instance.active_from > instance.active_until
+        ):
+            err = "active_from can't be greater than active_until"
+            raise ValidationError(err)
+
+
+@deconstructible
+class TargetCategoriesValidator(BaseValidator):
+    def __init__(self) -> None:
+        pass
+
+    def __call__(self, categories: list) -> None:
+        if not isinstance(categories, list):
+            err = "categories must be a list"
+            raise ValidationError(err)
+
+        if len(categories) > MAX_CATEGORIES_LIST_LEN:
+            err = "max. categories length is 20"
+            raise ValidationError(err)
+
+        for category in categories:
+            if not (MIN_CATEGORY_LEN <= len(category) <= MAX_CATEGORY_LEN):
+                err = "category name length must be >=2 and <=20"
+                raise ValidationError(err)
+
+
+@deconstructible
+class PromocodeUniqueValidator(BaseValidator):
+    def __init__(self) -> None:
+        pass
+
+    def __call__(self, promocodes: list) -> None:
+        if not isinstance(promocodes, list):
+            err = "unque promocodes must be a list"
+            raise ValidationError(err)
+
+        if not (
+            MIN_UNIQUE_PROMOCODES_LIST_LEN
+            <= len(promocodes)
+            <= MAX_UNIQUE_PROMOCODES_LIST_LEN
+        ):
+            err = "unique promocodes length must be >=1 and <=5000"
+            raise ValidationError(err)
+
+        for promocode in promocodes:
+            if not (
+                MIN_UNIQUE_PROMOCODE_LEN
+                <= len(promocode)
+                <= MAX_UNIQUE_PROMOCODE_LEN
+            ):
+                err = "unique promocode length must be >=3 and <=30"
+                raise ValidationError(err)