"""Admin для приложения backups."""

from apps.backups.models import BackupExportJob
from apps.backups.serializers import BackupExportRequestSerializer
from apps.backups.services import BackupExportError, BackupExportJobService
from django.contrib import admin
from django.contrib import messages
from django.http import HttpResponse
from django.shortcuts import redirect
from django.urls import path, reverse
from django.utils import timezone


@admin.register(BackupExportJob)
class BackupExportJobAdmin(admin.ModelAdmin):
    """Admin для задач backup-экспорта."""

    list_display = [
        "id",
        "actual_date",
        "status",
        "task_id",
        "requested_by",
        "organizations_count",
        "archive_size",
        "started_at",
        "completed_at",
    ]
    list_filter = ["status", "actual_date", "created_at", "completed_at"]
    search_fields = ["task_id", "checksum_sha256", "archive_filename"]
    readonly_fields = [
        "task_id",
        "archive_path",
        "archive_filename",
        "checksum_filename",
        "checksum_sha256",
        "archive_size",
        "organizations_count",
        "error",
        "started_at",
        "completed_at",
        "created_at",
        "updated_at",
    ]
    ordering = ["-actual_date", "-created_at"]
    change_list_template = "admin/backups/backupexportjob/change_list.html"

    def get_urls(self):
        urls = super().get_urls()
        custom_urls = [
            path(
                "export/",
                self.admin_site.admin_view(self.export_view),
                name="backups_backupexportjob_export",
            ),
        ]
        return custom_urls + urls

    def changelist_view(self, request, extra_context=None):
        extra_context = extra_context or {}
        extra_context["backup_export_url"] = reverse(
            "admin:backups_backupexportjob_export"
        )
        extra_context["backup_export_default_date"] = timezone.localdate().isoformat()
        return super().changelist_view(request, extra_context=extra_context)

    def export_view(self, request):
        changelist_url = reverse("admin:backups_backupexportjob_changelist")

        if request.method != "POST":
            self.message_user(
                request,
                "Выгрузка backup доступна только через POST.",
                level=messages.WARNING,
            )
            return redirect(changelist_url)

        serializer = BackupExportRequestSerializer(
            data={"actual_date": request.POST.get("actual_date")}
        )
        if not serializer.is_valid():
            self.message_user(
                request,
                f"Некорректная дата: {serializer.errors}",
                level=messages.ERROR,
            )
            return redirect(changelist_url)

        actual_date = serializer.validated_data.get("actual_date") or timezone.localdate()
        try:
            result = BackupExportJobService.check_or_start_job(
                actual_date=actual_date,
                requested_by_id=request.user.id if request.user.is_authenticated else None,
            )
        except BackupExportError as exc:
            self.message_user(request, f"Ошибка запуска резервного экспорта: {exc}", level=messages.ERROR)
            return redirect(changelist_url)

        if result.action in {"started", "wait"}:
            self.message_user(
                request,
                result.message,
                level=messages.INFO
                if result.action == "started"
                else messages.WARNING,
            )
            return redirect(changelist_url)

        if result.action == "download":
            try:
                artifact = BackupExportJobService.consume_ready_archive(
                    actual_date=result.actual_date
                )
            except BackupExportError as exc:
                self.message_user(request, f"Ошибка загрузки backup: {exc}", level=messages.ERROR)
                return redirect(changelist_url)

            response = HttpResponse(artifact.archive_bytes, content_type="application/zip")
            response.status_code = 200
            response[
                "Content-Disposition"
            ] = f'attachment; filename="{artifact.archive_filename}"'
            response["X-Backup-SHA256"] = artifact.checksum_sha256
            response["X-Backup-Checksum-File"] = artifact.checksum_filename
            response["X-Backup-Organizations"] = str(artifact.organizations_count)
            response["X-Backup-Actual-Date"] = artifact.actual_date.isoformat()
            return response

        self.message_user(
            request,
            f"Неожиданный статус задачи: {result.action}",
            level=messages.ERROR,
        )
        return redirect(changelist_url)