Add comment and reply functionality with preview and notification templates

history_tracking/models.py

@@ -1,6 +1,6 @@
 from django.db import models
 from django.contrib.contenttypes.models import ContentType
-from django.contrib.contenttypes.fields import GenericForeignKey
+from django.contrib.contenttypes.fields import GenericForeignKey, GenericRelation
 from django.contrib.auth import get_user_model
 from simple_history.models import HistoricalRecords
 from .mixins import HistoricalChangeMixin
@@ -60,6 +60,14 @@ class VersionBranch(models.Model):
     created_by = models.ForeignKey(User, on_delete=models.SET_NULL, null=True)
     metadata = models.JSONField(default=dict, blank=True)
     is_active = models.BooleanField(default=True)
+    lock_status = models.JSONField(
+        default=dict,
+        help_text="Current lock status: {user: ID, expires: datetime, reason: str}"
+    )
+    lock_history = models.JSONField(
+        default=list,
+        help_text="History of lock operations: [{user: ID, action: lock/unlock, timestamp: datetime, reason: str}]"
+    )
 
     class Meta:
         ordering = ['-created_at']
@@ -91,6 +99,10 @@ class VersionTag(models.Model):
     created_at = models.DateTimeField(auto_now_add=True)
     created_by = models.ForeignKey(User, on_delete=models.SET_NULL, null=True)
     metadata = models.JSONField(default=dict, blank=True)
+    comparison_metadata = models.JSONField(
+        default=dict,
+        help_text="Stores diff statistics and comparison results"
+    )
 
     class Meta:
         ordering = ['-created_at']
@@ -104,6 +116,74 @@ class VersionTag(models.Model):
     def __str__(self) -> str:
         return f"{self.name} ({self.branch.name})"
 
+class CommentThread(models.Model):
+    """Represents a thread of comments on a historical record"""
+    content_type = models.ForeignKey(ContentType, on_delete=models.CASCADE)
+    object_id = models.PositiveIntegerField()
+    content_object = GenericForeignKey('content_type', 'object_id')
+    created_at = models.DateTimeField(auto_now_add=True)
+    created_by = models.ForeignKey(User, on_delete=models.SET_NULL, null=True, related_name='created_threads')
+    anchor = models.JSONField(
+        default=dict,
+        help_text="Anchoring information: {line_start: int, line_end: int, file_path: str}"
+    )
+    is_resolved = models.BooleanField(default=False)
+    resolved_by = models.ForeignKey(
+        User,
+        on_delete=models.SET_NULL,
+        null=True,
+        related_name='resolved_threads'
+    )
+    resolved_at = models.DateTimeField(null=True, blank=True)
+
+    class Meta:
+        ordering = ['-created_at']
+        indexes = [
+            models.Index(fields=['content_type', 'object_id']),
+            models.Index(fields=['created_at']),
+            models.Index(fields=['is_resolved']),
+        ]
+
+    def __str__(self) -> str:
+        return f"Comment Thread {self.pk} on {self.content_type}"
+
+class Comment(models.Model):
+    """Individual comment within a thread"""
+    thread = models.ForeignKey(CommentThread, on_delete=models.CASCADE, related_name='comments')
+    author = models.ForeignKey(User, on_delete=models.SET_NULL, null=True)
+    content = models.TextField()
+    created_at = models.DateTimeField(auto_now_add=True)
+    updated_at = models.DateTimeField(auto_now=True)
+    mentioned_users = models.ManyToManyField(
+        User,
+        related_name='mentioned_in_comments',
+        blank=True
+    )
+    parent_comment = models.ForeignKey(
+        'self',
+        on_delete=models.CASCADE,
+        null=True,
+        blank=True,
+        related_name='replies'
+    )
+
+    class Meta:
+        ordering = ['created_at']
+
+    def __str__(self) -> str:
+        return f"Comment {self.pk} by {self.author}"
+
+    def extract_mentions(self) -> None:
+        """Extract @mentions from comment content and update mentioned_users"""
+        # Simple @username extraction - could be enhanced with regex
+        mentioned = [
+            word[1:] for word in self.content.split()
+            if word.startswith('@') and len(word) > 1
+        ]
+        if mentioned:
+            users = User.objects.filter(username__in=mentioned)
+            self.mentioned_users.set(users)
+
 class ChangeSet(models.Model):
     """Groups related changes together for atomic version control operations"""
     branch = models.ForeignKey(VersionBranch, on_delete=models.CASCADE, related_name='changesets')
@@ -115,12 +195,41 @@ class ChangeSet(models.Model):
     status = models.CharField(
         max_length=20,
         choices=[
-            ('pending', 'Pending'),
+            ('draft', 'Draft'),
+            ('pending_approval', 'Pending Approval'),
+            ('approved', 'Approved'),
+            ('rejected', 'Rejected'),
             ('applied', 'Applied'),
             ('failed', 'Failed'),
             ('reverted', 'Reverted')
         ],
-        default='pending'
+        default='draft'
+    )
+    approval_state = models.JSONField(
+        default=list,
+        help_text="List of approval stages and their status"
+    )
+    approval_history = models.JSONField(
+        default=list,
+        help_text="History of approval actions and decisions"
+    )
+    required_approvers = models.ManyToManyField(
+        User,
+        related_name='pending_approvals',
+        blank=True
+    )
+    approval_policy = models.CharField(
+        max_length=20,
+        choices=[
+            ('sequential', 'Sequential'),
+            ('parallel', 'Parallel')
+        ],
+        default='sequential'
+    )
+    approval_deadline = models.DateTimeField(
+        null=True,
+        blank=True,
+        help_text="Optional deadline for approvals"
     )
 
     # Instead of directly relating to HistoricalRecord, use GenericForeignKey