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, TicketEvent

router = Router(tags=["solutions"])


@router.post("", response=SolutionOut)
def create_solution(request, payload: SolutionIn):
    require_permission(request, "solution.manage")
    solution = Solution.objects.create(
        title=payload.title,
        problem_signature=payload.problem_signature,
        related_system=payload.related_system,
        environment_scope=payload.environment_scope,
        root_cause=payload.root_cause,
        solution=payload.solution,
        risk_note=payload.risk_note,
        status=payload.status,
        created_by=request.user if request.user.is_authenticated else None,
    )
    if solution.status == "published":
        from apps.knowledge.services import index_published_solution

        index_published_solution(solution)
    return solution


@router.get("", response=list[SolutionOut])
def list_solutions(request, status: str | None = None):
    require_permission(request, "solution.view")
    queryset = Solution.objects.all()
    if status:
        queryset = queryset.filter(status=status)
    return queryset[:100]


@router.get("/tickets/{ticket_id}", response=list[TicketSolutionOut])
def list_ticket_solutions(request, ticket_id: int):
    require_permission(request, "solution.view")
    queryset = TicketSolutionLink.objects.select_related("solution", "ticket").filter(
        ticket_id=ticket_id
    )
    return [
        {
            "id": link.id,
            "ticket_id": link.ticket_id,
            "solution_id": link.solution_id,
            "link_type": link.link_type,
            "solution": link.solution,
            "created_at": link.created_at,
        }
        for link in queryset
    ]


@router.get("/{solution_id}", response=SolutionOut)
def get_solution(request, solution_id: int):
    require_permission(request, "solution.view")
    return Solution.objects.get(id=solution_id)


@router.post("/{solution_id}/link-ticket", response=TicketSolutionLinkOut)
def link_solution_to_ticket(request, solution_id: int, payload: TicketSolutionLinkIn):
    require_permission(request, "solution.manage")
    solution = Solution.objects.get(id=solution_id)
    ticket = Ticket.objects.get(id=payload.ticket_id)
    link, _ = TicketSolutionLink.objects.get_or_create(
        ticket=ticket,
        solution=solution,
        link_type=payload.link_type,
        defaults={
            "agent_run_id": payload.agent_run_id,
            "created_by": request.user if request.user.is_authenticated else None,
        },
    )
    if payload.link_type == "adopted":
        solution.usage_count = solution.ticket_links.filter(link_type="adopted").count()
        solution.save(update_fields=["usage_count", "updated_at"])
    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,
    }


@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,
    }