#!/usr/bin/env python3
"""
Sauvegarde en JSON les glossaires dupliqués (même user_id + même nom) créés
avant la mise en place de la garde anti-doublon dans le backend.

⚠️  Ce script ne supprime RIEN — il produit uniquement un fichier de backup
contenant l'intégralité des doublons (métadonnées + termes) en vue d'une
analyse ou d'une suppression manuelle ultérieure.

Pour chaque couple (user_id, name) avec > 1 glossaire, le plus ancien
(premier créé) est marqué "keeper" et les copies sont listées dans "duplicates"
avec tous leurs termes.

Les glossaires multilingues (« Français → Multilingue ») ont un nom distinct
de leurs homologues « Français → Anglais » : ils ne sont jamais fusionnés.

Usage:
    # Cible la base de prod PostgreSQL (lu via DATABASE_URL) :
    DATABASE_URL=postgresql://user:pass@host:5432/db python scripts/backup_duplicate_glossaries.py

    # Ou préciser une base SQLite spécifique :
    SQLITE_PATH=/path/to/translate.db python scripts/backup_duplicate_glossaries.py

    # Limiter à un seul utilisateur :
    DATABASE_URL=... python scripts/backup_duplicate_glossaries.py --user <user_id>

    # Choisir le fichier de sortie :
    DATABASE_URL=... python scripts/backup_duplicate_glossaries.py --output backups/dupes.json
"""

import argparse
import json
import logging
import sys
from collections import defaultdict
from datetime import datetime, timezone
from pathlib import Path

ROOT = Path(__file__).resolve().parent.parent
sys.path.insert(0, str(ROOT))

from sqlalchemy import text

from database.connection import get_sync_session

logging.basicConfig(
    level=logging.INFO,
    format="%(asctime)s [%(levelname)s] %(message)s",
)
logger = logging.getLogger("backup_dup_glossaries")


def find_duplicates(
    session, user_id: str | None = None,
) -> dict[tuple[str, str], list[dict]]:
    """Group glossaries by (user_id, name). Returns lightweight dicts (not ORM).

    Utilise du SQL brut pour rester robuste si la colonne `template_id` est
    absente du schéma (ex. ancienne DB de dev). En cas d'absence, retombe
    automatiquement sur une requête sans `template_id`.
    """
    base_cols = "id, user_id, name, source_language, target_language, created_at, updated_at"
    try:
        sql = f"SELECT {base_cols}, template_id FROM glossaries"
        params: dict = {}
        if user_id:
            sql += " WHERE user_id = :user_id"
            params["user_id"] = user_id
        sql += " ORDER BY user_id, name, created_at"
        rows = session.execute(text(sql), params).fetchall()
        has_template_id = True
    except Exception as e:
        if "no such column" not in str(e).lower() and "undefined column" not in str(e).lower():
            raise
        logger.warning("⚠️  Colonne `template_id` absente du schéma — fallback sans template_id.")
        sql = f"SELECT {base_cols} FROM glossaries"
        params = {}
        if user_id:
            sql += " WHERE user_id = :user_id"
            params["user_id"] = user_id
        sql += " ORDER BY user_id, name, created_at"
        rows = session.execute(text(sql), params).fetchall()
        has_template_id = False

    groups: dict[tuple[str, str], list[dict]] = defaultdict(list)
    for r in rows:
        groups[(r.user_id, r.name)].append({
            "id": r.id,
            "user_id": r.user_id,
            "name": r.name,
            "source_language": r.source_language,
            "target_language": r.target_language,
            "template_id": r.template_id if has_template_id else None,
            "created_at": r.created_at,
            "updated_at": r.updated_at,
        })
    return {k: v for k, v in groups.items() if len(v) > 1}


def _stable_sort(glossaries: list[dict]) -> tuple[list[dict], int]:
    """Sort glossaries by (created_at ASC, id ASC) for deterministic ordering.

    Returns the sorted list and the number of entries with None created_at.
    """
    none_count = sum(1 for g in glossaries if g["created_at"] is None)
    if none_count:
        logger.warning(
            "⚠️  %d glossaire(s) ont un created_at NULL — tri secondaire par id.",
            none_count,
        )
    return sorted(
        glossaries,
        key=lambda g: (g["created_at"] or datetime.min.replace(tzinfo=timezone.utc), g["id"]),
    ), none_count


def serialize_group(user_id: str, name: str, glossaries: list[dict]) -> dict:
    """Convert a duplicate group to a JSON-serializable dict."""
    sorted_glossaries, _ = _stable_sort(glossaries)
    keeper = sorted_glossaries[0]
    duplicates = sorted_glossaries[1:]

    def to_iso(value) -> str | None:
        if value is None:
            return None
        if isinstance(value, datetime):
            return value.isoformat()
        if isinstance(value, str):
            try:
                return datetime.fromisoformat(value).isoformat()
            except ValueError:
                return value
        return str(value)

    def count_terms(session, glossary_id: str) -> int:
        return session.execute(
            text("SELECT COUNT(*) FROM glossary_terms WHERE glossary_id = :id"),
            {"id": glossary_id},
        ).scalar() or 0

    with get_sync_session() as session:
        keeper_terms = count_terms(session, keeper["id"])
        duplicate_payload = []
        for d in duplicates:
            tcount = count_terms(session, d["id"])
            duplicate_payload.append({
                **d,
                "created_at": to_iso(d["created_at"]),
                "updated_at": to_iso(d["updated_at"]),
                "terms": _fetch_terms(session, d["id"]),
                "terms_count": tcount,
            })

    return {
        "user_id": user_id,
        "name": name,
        "keep": {
            "id": keeper["id"],
            "name": keeper["name"],
            "source_language": keeper["source_language"],
            "target_language": keeper["target_language"],
            "template_id": keeper["template_id"],
            "created_at": to_iso(keeper["created_at"]),
            "updated_at": to_iso(keeper["updated_at"]),
            "terms_count": keeper_terms,
        },
        "duplicates_count": len(duplicates),
        "duplicates": duplicate_payload,
    }


def _fetch_terms(session, glossary_id: str) -> list[dict]:
    """Fetch all terms for a glossary (used to back up duplicates before deletion)."""
    rows = session.execute(
        text(
            "SELECT id, source, target, translations "
            "FROM glossary_terms WHERE glossary_id = :id ORDER BY id"
        ),
        {"id": glossary_id},
    ).fetchall()
    return [
        {
            "id": r.id,
            "source": r.source,
            "target": r.target,
            "translations": r.translations or {},
        }
        for r in rows
    ]


def write_backup(groups: dict[tuple[str, str], list[dict]], output_path: Path) -> dict:
    """Write the full backup to `output_path` and return a stats dict."""
    output_path.parent.mkdir(parents=True, exist_ok=True)

    payload = {
        "generated_at": datetime.now(timezone.utc).isoformat(),
        "schema_version": 2,
        "note": "Aucun glossaire n'a été supprimé. Ce fichier documente les doublons. "
                "Les glossaires multilingues (« → Multilingue ») ont un nom distinct "
                "et ne sont jamais fusionnés avec leurs homologues « → Anglais ».",
        "total_groups": len(groups),
        "total_duplicates": sum(len(v) - 1 for v in groups.values()),
        "groups": [
            serialize_group(uid, name, gs)
            for (uid, name), gs in sorted(groups.items(), key=lambda x: (x[0][1], x[0][0]))
        ],
    }

    with open(output_path, "w", encoding="utf-8") as f:
        json.dump(payload, f, ensure_ascii=False, indent=2)

    return payload


def print_report(payload: dict) -> None:
    """Print a human-readable summary on stdout."""
    logger.info("=" * 78)
    logger.info("Récapitulatif du backup")
    logger.info("=" * 78)
    logger.info("Généré le        : %s", payload["generated_at"])
    logger.info("Groupes concernés: %d", payload["total_groups"])
    logger.info("Doublons totaux  : %d", payload["total_duplicates"])
    logger.info("")
    logger.info("Détail par nom :")
    for g in payload["groups"]:
        logger.info("  '%s'  →  %d doublon(s) à supprimer", g["name"], g["duplicates_count"])
    logger.info("=" * 78)


def main() -> int:
    parser = argparse.ArgumentParser(
        description="Sauvegarde (sans suppression) les glossaires dupliqués en JSON."
    )
    parser.add_argument(
        "--user",
        metavar="USER_ID",
        help="Limite le backup à un seul utilisateur.",
    )
    parser.add_argument(
        "--output",
        metavar="PATH",
        help="Chemin du fichier JSON de sortie (défaut : backups/glossary_duplicates_<timestamp>.json).",
    )
    args = parser.parse_args()

    logger.info(
        "🔍 Recherche de doublons (user_id, name)%s…",
        f" pour user_id={args.user}" if args.user else "",
    )

    with get_sync_session() as session:
        groups = find_duplicates(session, user_id=args.user)

    if not groups:
        if args.user:
            logger.info("✅ Aucun doublon trouvé pour user_id=%s.", args.user)
        else:
            logger.info("✅ Aucun doublon trouvé.")
        return 0

    if args.output:
        output_path = Path(args.output)
    else:
        ts = datetime.now(timezone.utc).strftime("%Y%m%dT%H%M%SZ")
        output_path = ROOT / "backups" / f"glossary_duplicates_{ts}.json"

    logger.info("💾 Écriture du backup vers %s …", output_path)
    payload = write_backup(groups, output_path)

    print_report(payload)
    logger.info("✅ Backup écrit : %s (%d octets)", output_path, output_path.stat().st_size)
    logger.info("ℹ️  Aucune suppression effectuée. Relire le JSON pour décider de l'action manuelle.")

    return 0


if __name__ == "__main__":
    sys.exit(main())