From 8b40ebe282f4e24db725a7d63af28314adf3c29a Mon Sep 17 00:00:00 2001
From: Tomasz Zielinski <tomasz.zielinski@pyconsultant.eu>
Date: Fri, 9 Dec 2011 15:34:53 +0100
Subject: Tickets 104, 107: Added the unmanaged Post model along with the
 underlying VIEW SQL

---
 askbot/models/__init__.py   |   3 +-
 askbot/models/post.py       |  33 +++++++++++++-
 askbot/models/post_view.sql | 107 ++++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 140 insertions(+), 3 deletions(-)
 create mode 100644 askbot/models/post_view.sql

diff --git a/askbot/models/__init__.py b/askbot/models/__init__.py
index 3ba9825e..f4bf165c 100644
--- a/askbot/models/__init__.py
+++ b/askbot/models/__init__.py
@@ -29,7 +29,7 @@ from askbot.models.answer import Answer, AnonymousAnswer
 from askbot.models.tag import Tag, MarkedTag
 from askbot.models.meta import Vote, Comment
 from askbot.models.user import EmailFeedSetting, ActivityAuditStatus, Activity
-from askbot.models.post import PostRevision
+from askbot.models.post import Post, PostRevision
 from askbot.models import signals
 from askbot.models.badges import award_badges_signal, get_badge, init_badges
 #from user import AuthKeyUserAssociation
@@ -2717,6 +2717,7 @@ __all__ = [
         'Answer',
         'AnonymousAnswer',
 
+        'Post',
         'PostRevision',
 
         'Tag',
diff --git a/askbot/models/post.py b/askbot/models/post.py
index fd8fc292..eaa2cb8d 100644
--- a/askbot/models/post.py
+++ b/askbot/models/post.py
@@ -3,9 +3,38 @@ from django.core.exceptions import ValidationError
 
 from askbot.utils import markup
 from askbot.utils.html import sanitize_html
+from askbot.models import content
+
+
+class Post(content.Content):
+    post_type = models.CharField(max_length=255)
+    parent = models.ForeignKey('Post', blank=True, null=True)
+    self_answer = models.ForeignKey('Answer', blank=True, null=True)
+    self_question = models.ForeignKey('Question', blank=True, null=True)
+    thread = models.ForeignKey('Thread')
+
+    class Meta:
+        app_label = 'askbot'
+        db_table = 'askbot_post'
+        managed = False
+
+    def delete(self, *args, **kwargs):
+        # Redirect the deletion to the relevant Question or Answer instance
+        # WARNING: This is not called for batch deletions so watch out!
+        if self.self_answer:
+            return self.self_answer.delete(*args, **kwargs)
+        elif self.self_question:
+            return self.self_question.delete(*args, **kwargs)
+        raise NotImplementedError
+
+for field in Post._meta.fields:
+    if isinstance(field, models.ForeignKey):
+        # HACK: Patch all foreign keys to not cascade when deleted
+        # This is required because foreign keys on Post create normal backreferences
+        # in the destination models, so e.g. deleting User instance would trigger Post instance deletion,
+        # which is not what should happen.
+        field.rel.on_delete = models.DO_NOTHING
 
-#class Post(models.Model):
-#    pass
 
 class PostRevisionManager(models.Manager):
     def create(self, *kargs, **kwargs):
diff --git a/askbot/models/post_view.sql b/askbot/models/post_view.sql
new file mode 100644
index 00000000..a3487265
--- /dev/null
+++ b/askbot/models/post_view.sql
@@ -0,0 +1,107 @@
+/*
+
+SQL for creating a database VIEW for the unmanaged `Post` model
+
+Tested with: SQLite3
+
+*/
+
+CREATE VIEW askbot_post AS
+
+SELECT
+    answer.id + 1000000 AS id,   -- fake unique ID
+
+    /* Some required pseudo-fields */
+    "answer" AS post_type,
+
+    joined_question.id AS parent_id,
+    joined_question.thread_id AS thread_id,
+
+    answer.id AS self_answer_id,
+    NULL AS self_question_id,
+
+    /* Shared fields from content.Content */
+    answer.author_id,
+    answer.added_at,
+
+    answer.deleted,
+    answer.deleted_at,
+    answer.deleted_by_id,
+
+    answer.wiki,
+    answer.wikified_at,
+
+    answer.locked,
+    answer.locked_by_id,
+    answer.locked_at,
+
+    answer.score,
+    answer.vote_up_count,
+    answer.vote_down_count,
+
+    answer.comment_count,
+    answer.offensive_flag_count,
+
+    answer.last_edited_at,
+    answer.last_edited_by_id,
+
+    answer.html,
+    answer.text,
+
+    answer.summary,
+
+    answer.is_anonymous
+
+FROM answer
+
+INNER JOIN question as joined_question
+ON joined_question.id=answer.question_id
+
+UNION
+
+SELECT
+    question.id AS id,   -- fake unique ID
+
+    /* Some required pseudo-fields */
+    "question" AS post_type,
+
+    NULL AS parent_id,
+    thread_id,
+
+    NULL AS self_answer_id,
+    id AS self_question_id,
+
+    /* Shared fields from content.Content */
+    author_id,
+    added_at,
+
+    deleted,
+    deleted_at,
+    deleted_by_id,
+
+    wiki,
+    wikified_at,
+
+    locked,
+    locked_by_id,
+    locked_at,
+
+    score,
+    vote_up_count,
+    vote_down_count,
+
+    comment_count,
+    offensive_flag_count,
+
+    last_edited_at,
+    last_edited_by_id,
+
+    html,
+    text,
+
+    summary,
+
+    is_anonymous
+
+
+FROM question;
\ No newline at end of file
-- 
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