from django.core.management.base import BaseCommand
from core.models import Entry

class Command(BaseCommand):
    help = "Normalize subjects (split by commas, unify delimiters like ; and -)"

    def add_arguments(self, parser):
        parser.add_argument(
            "--dry-run",
            action="store_true",
            help="Preview changes without saving"
        )

    def handle(self, *args, **options):
        dry_run = options["dry_run"]
        changes = 0

        for entry in Entry.objects.all():
            subj = entry.subject or ""
            normalized = self.normalize_subjects(subj)

            if subj != normalized:
                changes += 1
                self.stdout.write(
                    f"Would change: {subj} → {normalized}"
                )
                if not dry_run:
                    entry.subject = normalized
                    entry.save(update_fields=["subject"])

        if dry_run:
            self.stdout.write(self.style.WARNING(f"[DRY RUN] {changes} subjects would be changed."))
        else:
            self.stdout.write(self.style.SUCCESS(f"Updated {changes} subjects."))

    def normalize_subjects(self, text: str) -> str:
        if not text:
            return ""

        # Unify delimiters into commas
        cleaned = text.replace(";", ",").replace("|", ",").replace("/", ",").replace(" - ", ",").replace("-", ",")

        # Split, strip spaces, remove empties
        parts = [p.strip() for p in cleaned.split(",") if p.strip()]

        # Rejoin with a standard ", " separator
        return ", ".join(parts)