From 06265292283185527bb5401f42ad099afd2b13bc Mon Sep 17 00:00:00 2001
From: Roberto Rosario <roberto.rosario.gonzalez@gmail.com>
Date: Fri, 3 Aug 2018 18:52:13 -0400
Subject: [PATCH] Add natural key support to Document pages.

Signed-off-by: Roberto Rosario <roberto.rosario.gonzalez@gmail.com>
---
 mayan/apps/documents/managers.py | 40 +++++++++++++++++++++++++++++---
 mayan/apps/documents/models.py   | 16 +++++++++----
 2 files changed, 48 insertions(+), 8 deletions(-)

diff --git a/mayan/apps/documents/managers.py b/mayan/apps/documents/managers.py
index 5efb8d9f80..5a835ec83c 100644
--- a/mayan/apps/documents/managers.py
+++ b/mayan/apps/documents/managers.py
@@ -4,6 +4,7 @@ from datetime import timedelta
 import logging
 
 from django.apps import apps
+from django.contrib.auth import get_user_model
 from django.db import models
 from django.db.models import F, Max
 from django.utils.encoding import force_text
@@ -33,17 +34,30 @@ class DocumentManager(models.Manager):
             document.invalidate_cache()
 
 
+class DocumentPageManager(models.Manager):
+    def get_by_natural_key(self, page_number, document_version_natural_key):
+        DocumentVersion = apps.get_model(
+            app_label='documents', model_name='DocumentVersion'
+        )
+        try:
+            document_version = DocumentVersion.objects.get_by_natural_key(*document_version_natural_key)
+        except DocumentVersion.DoesNotExist:
+            raise self.model.DoesNotExist
+
+        return self.get(document_version__pk=document_version.pk, page_number=page_number)
+
+
 class DocumentVersionManager(models.Manager):
-    def get_by_natural_key(self, document_natural_key, checksum):
+    def get_by_natural_key(self, checksum, document_natural_key):
         Document = apps.get_model(
             app_label='documents', model_name='Document'
         )
         try:
-            document = Document.objects.get_by_natural_key(document_natural_key)
+            document = Document.objects.get_by_natural_key(*document_natural_key)
         except Document.DoesNotExist:
             raise self.model.DoesNotExist
 
-        return document.versions.get(checksum=checksum)
+        return self.get(document__pk=document.pk, checksum=checksum)
 
 
 class DocumentTypeManager(models.Manager):
@@ -189,6 +203,26 @@ class RecentDocumentManager(models.Manager):
             self.filter(pk__in=list(recent_to_delete)).delete()
         return new_recent
 
+    def get_by_natural_key(self, datetime_accessed, document_natural_key, user_natural_key):
+        Document = apps.get_model(
+            app_label='documents', model_name='Document'
+        )
+        User = get_user_model()
+        try:
+            document = Document.objects.get_by_natural_key(*document_natural_key)
+        except Document.DoesNotExist:
+            raise self.model.DoesNotExist
+        else:
+            try:
+                user = User.objects.get_by_natural_key(*user_natural_key)
+            except User.DoesNotExist:
+                raise self.model.DoesNotExist
+
+        return self.get(
+            document__pk=document.pk, user__pk=user.pk,
+            datetime_accessed=datetime_accessed
+        )
+
     def get_for_user(self, user):
         document_model = apps.get_model('documents', 'document')
 
diff --git a/mayan/apps/documents/models.py b/mayan/apps/documents/models.py
index 370cbd0ada..aeb8791e9a 100644
--- a/mayan/apps/documents/models.py
+++ b/mayan/apps/documents/models.py
@@ -33,9 +33,9 @@ from .events import (
 )
 from .literals import DEFAULT_DELETE_PERIOD, DEFAULT_DELETE_TIME_UNIT
 from .managers import (
-    DocumentManager, DocumentVersionManager, DocumentTypeManager,
-    DuplicatedDocumentManager, PassthroughManager, RecentDocumentManager,
-    TrashCanManager
+    DocumentManager, DocumentPageManager, DocumentVersionManager,
+    DocumentTypeManager, DuplicatedDocumentManager, PassthroughManager,
+    RecentDocumentManager, TrashCanManager
 )
 from .permissions import permission_document_view
 from .settings import (
@@ -509,7 +509,7 @@ class DocumentVersion(models.Model):
         )
 
     def natural_key(self):
-        return self.document.natural_key() + (self.checksum,)
+        return (self.checksum, self.document.natural_key())
     natural_key.dependencies = ['documents.Document']
 
     def invalidate_cache(self):
@@ -735,6 +735,8 @@ class DocumentPage(models.Model):
         verbose_name=_('Page number')
     )
 
+    objects = DocumentPageManager()
+
     class Meta:
         ordering = ('page_number',)
         verbose_name = _('Document page')
@@ -894,6 +896,10 @@ class DocumentPage(models.Model):
         for cached_image in self.cached_images.all():
             cached_image.delete()
 
+    def natural_key(self):
+        return (self.page_number, self.document_version.natural_key())
+    natural_key.dependencies = ['documents.DocumentVersion']
+
     @property
     def siblings(self):
         return DocumentPage.objects.filter(
@@ -962,7 +968,7 @@ class RecentDocument(models.Model):
         return force_text(self.document)
 
     def natural_key(self):
-        return self.document.natural_key() + self.user.natural_key()
+        return (self.datetime_accessed, self.document.natural_key(), self.user.natural_key())
     natural_key.dependencies = ['documents.Document', settings.AUTH_USER_MODEL]