import time
from datetime import timedelta
from pathlib import Path

from django.conf import settings
from django.core.management.base import BaseCommand
from django.db import transaction
from django.db.models import Q
from django.utils import timezone

from finance.exporting import _safe_unlink_export
from finance.models import FormulaExport


class Command(BaseCommand):
    help = "Remove expired formula workbooks and stale temporary files"

    def add_arguments(self, parser):
        parser.add_argument("--loop", action="store_true")
        parser.add_argument("--interval", type=int, default=3600)

    def handle(self, *args, **options):
        while True:
            jobs, files = self.clean_expired()
            self.stdout.write(f"Expired {jobs} jobs; removed {files} files")
            if not options["loop"]:
                return
            time.sleep(max(60, options["interval"]))

    def clean_expired(self):
        export_root = Path(settings.MEDIA_ROOT) / "formula-exports"
        if export_root.is_symlink():
            raise ValueError("公式导出目录不能是符号链接")
        root = export_root.absolute()
        now = timezone.now()
        jobs = files = 0

        jobs_qs = FormulaExport.objects.filter(
            Q(status="succeeded", expires_at__lte=now) | Q(status="failed", path__gt="")
        ).iterator()
        for job in jobs_qs:
            path = Path(job.path) if job.path else None
            try:
                with transaction.atomic():
                    deleted = bool(path and _safe_unlink_export(path, root))
                    if job.status == "succeeded":
                        if deleted or not path or not path.is_absolute() or not path.is_relative_to(root):
                            if deleted:
                                files += 1
                            job.status, job.path = "expired", ""
                            job.save(update_fields=["status", "path"])
                            jobs += 1
                    elif deleted:
                        files += 1
                        job.path = ""
                        job.save(update_fields=["path"])
                        jobs += 1
            except OSError as exc:
                self.stderr.write(f"Could not remove expired export {job.pk}: {exc}")

        cutoff = (now - timedelta(hours=24)).timestamp()
        if root.is_dir() and not root.is_symlink():
            for user_dir in root.iterdir():
                if user_dir.is_symlink() or not user_dir.is_dir():
                    continue
                for path in user_dir.glob("*.tmp"):
                    try:
                        if path.is_symlink() or not path.is_file() or path.stat().st_mtime > cutoff:
                            continue
                        path.unlink()
                        files += 1
                    except OSError as exc:
                        self.stderr.write(f"Could not remove stale temporary export {path.name}: {exc}")

        return jobs, files