feat: adopt solution and close ticket

backend/apps/solutions/api.py

@@ -1,15 +1,18 @@
+from django.db import transaction
+from django.utils import timezone
 from ninja import Router
 
 from apps.accounts.api import require_permission
 from apps.solutions.models import Solution, TicketSolutionLink
 from apps.solutions.schemas import (
+    AdoptSolutionIn,
     SolutionIn,
     SolutionOut,
     TicketSolutionLinkIn,
     TicketSolutionLinkOut,
     TicketSolutionOut,
 )
-from apps.tickets.models import Ticket
+from apps.tickets.models import Ticket, TicketEvent
 
 router = Router(tags=["solutions"])
 
@@ -89,3 +92,62 @@ def link_solution_to_ticket(request, solution_id: int, payload: TicketSolutionLi
         "solution_usage_count": solution.usage_count,
         "created_at": link.created_at,
     }
+
+
+@router.post("/{solution_id}/adopt-ticket", response=TicketSolutionLinkOut)
+def adopt_solution_and_close_ticket(request, solution_id: int, payload: AdoptSolutionIn):
+    require_permission(request, "solution.manage")
+    operator = request.user if request.user.is_authenticated else None
+    with transaction.atomic():
+        solution = Solution.objects.select_for_update().get(id=solution_id)
+        ticket = Ticket.objects.select_for_update().get(id=payload.ticket_id)
+        link, _ = TicketSolutionLink.objects.get_or_create(
+            ticket=ticket,
+            solution=solution,
+            link_type="adopted",
+            defaults={"created_by": operator},
+        )
+        now = timezone.now()
+        from_status = ticket.status
+        ticket.status = "closed"
+        ticket.resolution_summary = solution.solution
+        ticket.is_resolved = True
+        ticket.replied_to_customer = payload.replied_to_customer
+        ticket.resolved_at = ticket.resolved_at or now
+        ticket.closed_at = now
+        ticket.save(
+            update_fields=[
+                "status",
+                "resolution_summary",
+                "is_resolved",
+                "replied_to_customer",
+                "resolved_at",
+                "closed_at",
+                "updated_at",
+            ]
+        )
+        solution.usage_count = solution.ticket_links.filter(link_type="adopted").count()
+        solution.save(update_fields=["usage_count", "updated_at"])
+        TicketEvent.objects.create(
+            ticket=ticket,
+            event_type="solution_adopted",
+            from_value={"status": from_status},
+            to_value={
+                "status": ticket.status,
+                "solution_id": solution.id,
+                "solution_title": solution.title,
+                "resolution": ticket.resolution_summary,
+                "is_resolved": ticket.is_resolved,
+                "replied_to_customer": ticket.replied_to_customer,
+            },
+            operator=operator,
+            remark=payload.remark,
+        )
+    return {
+        "id": link.id,
+        "ticket_id": ticket.id,
+        "solution_id": solution.id,
+        "link_type": link.link_type,
+        "solution_usage_count": solution.usage_count,
+        "created_at": link.created_at,
+    }