add bookmarks page

judge/models/bookmark.py

@@ -1,8 +1,12 @@
 from django.db import models
 from django.db.models import CASCADE
 from django.utils.translation import gettext_lazy as _
+from django.core.exceptions import ObjectDoesNotExist
 
 from judge.models import Profile
+from judge.models.contest import Contest
+from judge.models.interface import BlogPost
+from judge.models.problem import Problem, Solution
 
 __all__ = ["BookMark"]
 
@@ -21,12 +25,28 @@ class BookMark(models.Model):
         else:
             return False
 
+    def page_object(self):
+        try:
+            page = self.page
+            if page.startswith("p:"):
+                return Problem.objects.get(code=page[2:])
+            elif page.startswith("c:"):
+                return Contest.objects.get(key=page[2:])
+            elif page.startswith("b:"):
+                return BlogPost.objects.get(id=page[2:])
+            elif page.startswith("s:"):
+                return Solution.objects.get(problem__code=page[2:])
+            return None
+        except ObjectDoesNotExist:
+            return None
+
+
     class Meta:
         verbose_name = _("bookmark")
         verbose_name_plural = _("bookmarks")
 
     def __str__(self):
-        return f"bookmark for {self.page}"
+        return self.page
 
 class MakeBookMark(models.Model):
     bookmark = models.ForeignKey(BookMark, related_name="bookmark", on_delete=CASCADE)