04/06 adding some additional functions

app/models.py

@@ -359,4 +359,63 @@ class SystemSetting(db.Model):
         return row
 
     def __repr__(self):
-        return f'<SystemSetting {self.key}={self.value}>'
+        return f'<SystemSetting {self.key}={self.value}>'
+
+class TicketLink(db.Model):
+    """Bidirectional link between two related tickets.
+
+    A single row represents a symmetric relationship — if TKT-A is linked to
+    TKT-B, the link is stored once with ticket_id < linked_ticket_id (enforced
+    at the application layer).  Queries must search both columns to find all
+    links for a given ticket.
+
+    Use cases: duplicate tickets, related outages, follow-up work items.
+    """
+    __tablename__ = 'ticket_links'
+
+    id               = db.Column(db.Integer, primary_key=True)
+    ticket_id        = db.Column(db.Integer, db.ForeignKey('tickets.id'), nullable=False)
+    linked_ticket_id = db.Column(db.Integer, db.ForeignKey('tickets.id'), nullable=False)
+    link_type        = db.Column(db.String(20), default='related', nullable=False)
+    # link_type values: 'related' | 'duplicate' | 'follow_up'
+    created_by       = db.Column(db.Integer, db.ForeignKey('users.id'), nullable=False)
+    created_at       = db.Column(db.DateTime, default=datetime.utcnow)
+
+    ticket        = db.relationship('Ticket', foreign_keys=[ticket_id],
+                                    backref=db.backref('links_as_source', lazy='dynamic',
+                                                       cascade='all, delete-orphan'))
+    linked_ticket = db.relationship('Ticket', foreign_keys=[linked_ticket_id],
+                                    backref=db.backref('links_as_target', lazy='dynamic',
+                                                       cascade='all, delete-orphan'))
+    creator       = db.relationship('User', foreign_keys=[created_by])
+
+    __table_args__ = (
+        db.UniqueConstraint('ticket_id', 'linked_ticket_id', name='uq_ticket_link'),
+    )
+
+    def __repr__(self):
+        return f'<TicketLink {self.ticket_id} ↔ {self.linked_ticket_id} ({self.link_type})>'
+
+
+class CannedResponse(db.Model):
+    """Pre-written IT reply templates for common ticket scenarios.
+
+    IT staff can insert these into comment boxes with one click, saving
+    typing time for repetitive responses like 'please restart and confirm',
+    'escalating to vendor', or 'issue resolved after patch applied'.
+    """
+    __tablename__ = 'canned_responses'
+
+    id         = db.Column(db.Integer, primary_key=True)
+    title      = db.Column(db.String(120), nullable=False)
+    body       = db.Column(db.Text, nullable=False)
+    category   = db.Column(db.String(50))   # optional grouping label
+    created_by = db.Column(db.Integer, db.ForeignKey('users.id'), nullable=False)
+    created_at = db.Column(db.DateTime, default=datetime.utcnow)
+    updated_at = db.Column(db.DateTime, default=datetime.utcnow, onupdate=datetime.utcnow)
+    is_active  = db.Column(db.Boolean, default=True, nullable=False)
+
+    creator    = db.relationship('User', foreign_keys=[created_by])
+
+    def __repr__(self):
+        return f'<CannedResponse {self.title}>'