Add system announcement feature.

models.py

@@ -527,4 +527,89 @@ class SubTask(db.Model):
     
     def can_user_access(self, user):
         """Check if a user can access this subtask"""
-        return self.parent_task.can_user_access(user)
+        return self.parent_task.can_user_access(user)
+
+# Announcement model for system-wide announcements
+class Announcement(db.Model):
+    id = db.Column(db.Integer, primary_key=True)
+    title = db.Column(db.String(200), nullable=False)
+    content = db.Column(db.Text, nullable=False)
+    
+    # Announcement properties
+    is_active = db.Column(db.Boolean, default=True)
+    is_urgent = db.Column(db.Boolean, default=False)  # For urgent announcements with different styling
+    announcement_type = db.Column(db.String(20), default='info')  # info, warning, success, danger
+    
+    # Scheduling
+    start_date = db.Column(db.DateTime, nullable=True)  # When to start showing
+    end_date = db.Column(db.DateTime, nullable=True)    # When to stop showing
+    
+    # Targeting
+    target_all_users = db.Column(db.Boolean, default=True)
+    target_roles = db.Column(db.Text, nullable=True)  # JSON string of roles if not all users
+    target_companies = db.Column(db.Text, nullable=True)  # JSON string of company IDs if not all companies
+    
+    # Metadata
+    created_at = db.Column(db.DateTime, default=datetime.now)
+    updated_at = db.Column(db.DateTime, default=datetime.now, onupdate=datetime.now)
+    created_by_id = db.Column(db.Integer, db.ForeignKey('user.id'), nullable=False)
+    
+    # Relationships
+    created_by = db.relationship('User', foreign_keys=[created_by_id])
+    
+    def __repr__(self):
+        return f'<Announcement {self.title}>'
+    
+    def is_visible_now(self):
+        """Check if announcement should be visible at current time"""
+        if not self.is_active:
+            return False
+        
+        now = datetime.now()
+        
+        # Check start date
+        if self.start_date and now < self.start_date:
+            return False
+        
+        # Check end date
+        if self.end_date and now > self.end_date:
+            return False
+        
+        return True
+    
+    def is_visible_to_user(self, user):
+        """Check if announcement should be visible to specific user"""
+        if not self.is_visible_now():
+            return False
+        
+        # If targeting all users, show to everyone
+        if self.target_all_users:
+            return True
+        
+        # Check role targeting
+        if self.target_roles:
+            import json
+            try:
+                target_roles = json.loads(self.target_roles)
+                if user.role.value not in target_roles:
+                    return False
+            except (json.JSONDecodeError, AttributeError):
+                pass
+        
+        # Check company targeting
+        if self.target_companies:
+            import json
+            try:
+                target_companies = json.loads(self.target_companies)
+                if user.company_id not in target_companies:
+                    return False
+            except (json.JSONDecodeError, AttributeError):
+                pass
+        
+        return True
+    
+    @staticmethod
+    def get_active_announcements_for_user(user):
+        """Get all active announcements visible to a specific user"""
+        announcements = Announcement.query.filter_by(is_active=True).all()
+        return [ann for ann in announcements if ann.is_visible_to_user(user)]