from __future__ import annotations

from dataclasses import dataclass
from typing import TYPE_CHECKING
from typing import Any
from uuid import UUID

from django.db.models import Count
from django.db.models import Prefetch
from django.http import JsonResponse
from django.shortcuts import get_object_or_404
from django.views.generic import TemplateView
from django.views.generic import View

from control_plane.local_test_runtime import build_test_django_local_url
from control_plane.models import Deployment
from control_plane.models import DeploymentStatus
from control_plane.models import RuntimeService
from control_plane.observability import JsonValue
from control_plane.observability import load_test_deployment_diagnostics
from control_plane.observability import probe_test_deployment_health

if TYPE_CHECKING:
    from django.db.models import QuerySet
    from django.http import HttpRequest


type RouteKwarg = str | UUID
type DashboardContextValue = int | tuple[DeploymentCard, ...] | tuple[DeploymentStatusSummary, ...]
type DetailContextValue = (
    DashboardContextValue | Deployment | tuple[RuntimeService, ...] | str | dict[str, JsonValue] | None
)


@dataclass(frozen=True, slots=True)
class DeploymentStatusSummary:
    """Aggregate deployments by lifecycle state for dashboard cards."""

    status: str
    label: str
    total: int


@dataclass(frozen=True, slots=True)
class DeploymentCard:
    """Small view model used by the dashboard templates."""

    deployment: Deployment
    sentinel_url: str
    runtime_services: tuple[RuntimeService, ...]

    @property
    def runtime_ready_total(self) -> int:
        """Return total runtime services currently marked ready."""
        return sum(runtime_service.status == "ready" for runtime_service in self.runtime_services)

    @property
    def runtime_failed_total(self) -> int:
        """Return total runtime services currently marked failed."""
        return sum(runtime_service.status == "failed" for runtime_service in self.runtime_services)


def _deployment_queryset() -> QuerySet[Deployment]:
    runtime_services = RuntimeService.objects.order_by("kind")
    return Deployment.objects.select_related("hosted_site__tenant").prefetch_related(
        Prefetch("runtime_services", queryset=runtime_services),
    )


class DeploymentDashboardView(TemplateView):
    """Render recent test deployments with links to diagnostics and sentinel probes."""

    template_name = "control_plane/deployment_dashboard.html"

    def get_context_data(self, **kwargs: RouteKwarg) -> dict[str, DashboardContextValue]:
        """Build recent deployment cards plus aggregate status counts for the dashboard.

        Returns:
            Template context containing deployment cards and summary counters.
        """
        context = super().get_context_data(**kwargs)
        deployments = tuple(_deployment_queryset().order_by("-created_at")[:24])
        context.update(
            {
                "deployment_cards": tuple(_build_deployment_card(deployment) for deployment in deployments),
                "status_summaries": _build_status_summaries(),
                "running_total": sum(deployment.status == DeploymentStatus.RUNNING.value for deployment in deployments),
                "deployment_total": len(deployments),
            },
        )
        return context


class DeploymentDetailView(TemplateView):
    """Render one deployment with persisted diagnostics, logs, and live health state."""

    template_name = "control_plane/deployment_detail.html"

    def get_context_data(self, **kwargs: RouteKwarg) -> dict[str, DetailContextValue]:
        """Build one deployment view with persisted diagnostics and an initial health probe.

        Returns:
            Template context containing deployment metadata, diagnostics, and health state.
        """
        context: dict[str, Any] = super().get_context_data(**kwargs)
        deployment: Deployment = get_object_or_404(_deployment_queryset(), pk=self.kwargs["deployment_id"])
        runtime_services = tuple(deployment.runtime_services.all())
        context.update(
            {
                "deployment": deployment,
                "runtime_services": runtime_services,
                "sentinel_url": build_test_django_local_url(deployment),
                "diagnostics": load_test_deployment_diagnostics(deployment),
                "health_probe": probe_test_deployment_health(deployment),
            },
        )
        return context


class DeploymentHealthView(View):
    """Return live sentinel health JSON for one deployment."""

    def get(self, request: HttpRequest, deployment_id: str) -> JsonResponse:
        """Return JSON probe state for one deployment sentinel endpoint."""
        del request
        deployment = get_object_or_404(_deployment_queryset(), pk=deployment_id)
        return JsonResponse(probe_test_deployment_health(deployment))


class DeploymentDashboardHomeView(DeploymentDashboardView):
    """Alias the dashboard at the site root for local testing convenience."""

    template_name = "control_plane/deployment_dashboard.html"


def _build_deployment_card(deployment: Deployment) -> DeploymentCard:
    return DeploymentCard(
        deployment=deployment,
        sentinel_url=build_test_django_local_url(deployment),
        runtime_services=tuple(deployment.runtime_services.all()),
    )


def _build_status_summaries() -> tuple[DeploymentStatusSummary, ...]:
    summary_rows = tuple(
        Deployment.objects.values("status").annotate(total=Count("id")).order_by("status"),
    )
    return tuple(
        DeploymentStatusSummary(
            status=status,
            label=_resolve_status_label(status),
            total=int(total),
        )
        for status, total in ((row["status"], row["total"]) for row in summary_rows)
    )


def _resolve_status_label(status: str) -> str:
    for choice in DeploymentStatus:
        if choice.value == status:
            return choice.label

    return status.replace("-", " ").title()