"""Delete the seeded demo data (generated-dot 'dogs' from scripts.make_sample_images) and everything
attached to it, leaving the real loaded datasets untouched.

Demo records are the ones created directly by scripts/seed.py (NOT via the batch loader), so they
have ``dataset_id IS NULL``. We remove:
  * every known/unknown dog with ``dataset_id IS NULL`` (Rex, Maple, the demo found dogs) +
    their pictures, embeddings, breed predictions, cases, matches, notifications, and media files;
  * the demo OWNER users of those dogs — but ONLY non-admin users who own no *dataset* dogs, so the
    admin account and the (dataset_id-NULL but real) detached dataset owners are preserved.

Idempotent. Dry-run by default.

Usage (from backend/):  python -m scripts.purge_seed_data --delete
"""
from __future__ import annotations

import argparse

from sqlalchemy import and_, delete, func, or_, select

from app.db import SessionLocal
from app.models import (
    BreedPrediction, Case, Embedding, KnownDog, Match, Notification, Picture, UnknownDog, User,
)
from app.models.base import SubjectType, UserRole
from app.storage import get_storage


def run(do_delete: bool) -> None:
    db = SessionLocal()
    try:
        known_ids = [i for (i,) in db.execute(select(KnownDog.id).where(KnownDog.dataset_id.is_(None)))]
        unknown_ids = [i for (i,) in db.execute(select(UnknownDog.id).where(UnknownDog.dataset_id.is_(None)))]

        # Demo owners: owners of these known dogs that are NOT admin and own no dataset dog.
        owner_ids = {
            o for (o,) in db.execute(
                select(KnownDog.owner_id).where(KnownDog.dataset_id.is_(None)).distinct()
            )
        }
        demo_user_ids = []
        for uid in owner_ids:
            u = db.get(User, uid)
            if u is None or u.role == UserRole.admin:
                continue
            keeps = db.execute(
                select(func.count()).select_from(KnownDog).where(
                    KnownDog.owner_id == uid, KnownDog.dataset_id.isnot(None)
                )
            ).scalar_one()
            if keeps == 0:
                demo_user_ids.append(uid)

        # Cases / pictures / matches tied to the demo dogs or demo owners.
        case_conds = []
        if known_ids:
            case_conds.append(Case.known_dog_id.in_(known_ids))
        if unknown_ids:
            case_conds.append(Case.unknown_dog_id.in_(unknown_ids))
        if demo_user_ids:
            case_conds.append(Case.person_id.in_(demo_user_ids))
        case_ids = (
            [i for (i,) in db.execute(select(Case.id).where(or_(*case_conds)))] if case_conds else []
        )

        pic_conds = []
        if known_ids:
            pic_conds.append(and_(Picture.subject_type == SubjectType.known, Picture.subject_id.in_(known_ids)))
        if unknown_ids:
            pic_conds.append(and_(Picture.subject_type == SubjectType.unknown, Picture.subject_id.in_(unknown_ids)))
        pic_rows = (
            db.execute(select(Picture.id, Picture.file_path, Picture.thumb_path).where(or_(*pic_conds))).all()
            if pic_conds else []
        )
        pic_ids = [r[0] for r in pic_rows]
        media_keys = [k for r in pic_rows for k in (r[1], r[2]) if k]

        match_conds = []
        if case_ids:
            match_conds.append(Match.case_id.in_(case_ids))
            match_conds.append(Match.candidate_case_id.in_(case_ids))
        if known_ids:
            match_conds.append(and_(Match.candidate_type == SubjectType.known, Match.candidate_id.in_(known_ids)))
        if unknown_ids:
            match_conds.append(and_(Match.candidate_type == SubjectType.unknown, Match.candidate_id.in_(unknown_ids)))
        match_ids = (
            [i for (i,) in db.execute(select(Match.id).where(or_(*match_conds)))] if match_conds else []
        )

        print("Seed data to remove:")
        print(f"  known dogs:   {len(known_ids)}  {known_ids}")
        print(f"  unknown dogs: {len(unknown_ids)}  {unknown_ids}")
        print(f"  demo owners:  {len(demo_user_ids)}  "
              f"{[db.get(User, u).email for u in demo_user_ids]}")
        print(f"  cases: {len(case_ids)}  matches: {len(match_ids)}  pictures: {len(pic_ids)}  "
              f"media files: {len(set(media_keys))}")

        if not do_delete:
            print("\nDRY RUN — nothing deleted. Re-run with --delete.")
            return

        def _del(stmt):
            return db.execute(stmt).rowcount or 0

        # Children first (FK order), mirroring services.datasets.purge_dataset.
        if demo_user_ids or case_ids or match_ids:
            nconds = []
            if demo_user_ids:
                nconds.append(Notification.user_id.in_(demo_user_ids))
            if case_ids:
                nconds.append(Notification.case_id.in_(case_ids))
            if match_ids:
                nconds.append(Notification.match_id.in_(match_ids))
            if nconds:
                _del(delete(Notification).where(or_(*nconds)))
        if pic_ids:
            _del(delete(BreedPrediction).where(BreedPrediction.picture_id.in_(pic_ids)))
            _del(delete(Embedding).where(Embedding.picture_id.in_(pic_ids)))
        if match_ids:
            _del(delete(Match).where(Match.id.in_(match_ids)))
        if demo_user_ids:
            db.execute(Match.__table__.update().where(Match.reviewed_by.in_(demo_user_ids)).values(reviewed_by=None))
        if pic_ids:
            _del(delete(Picture).where(Picture.id.in_(pic_ids)))
        if case_ids:
            _del(delete(Case).where(Case.id.in_(case_ids)))
        if unknown_ids:
            _del(delete(UnknownDog).where(UnknownDog.id.in_(unknown_ids)))
        if known_ids:
            _del(delete(KnownDog).where(KnownDog.id.in_(known_ids)))
        if demo_user_ids:
            _del(delete(User).where(User.id.in_(demo_user_ids)))
        db.commit()

        # Files after commit (best-effort; leftovers are recoverable via scripts.prune_media).
        storage = get_storage()
        removed = 0
        for key in dict.fromkeys(media_keys):
            try:
                storage.delete(key)
                removed += 1
            except Exception:  # noqa: BLE001
                pass
        print(f"\nDeleted seed data. Media files removed: {removed}. Admin + dataset dogs untouched.")
    finally:
        db.close()


def main() -> None:
    ap = argparse.ArgumentParser(description="Purge seeded demo (generated-dot) data.")
    ap.add_argument("--delete", action="store_true", help="Actually delete (default: dry run)")
    args = ap.parse_args()
    run(args.delete)


if __name__ == "__main__":
    main()