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.utils import timezone

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.resolve()
        now = timezone.now()
        jobs = files = 0

        for job in FormulaExport.objects.filter(status="succeeded", expires_at__lte=now).iterator():
            path = Path(job.path) if job.path else None
            resolved = path.resolve() if path and path.is_absolute() and not path.is_symlink() else None
            in_root = bool(resolved and resolved.is_relative_to(root))
            try:
                with transaction.atomic():
                    if in_root and resolved.is_file():
                        resolved.unlink()
                        files += 1
                    job.status, job.path = "expired", ""
                    job.save(update_fields=["status", "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