import json
from datetime import datetime, timezone
from typing import Any

from sqlalchemy import select
from sqlalchemy.orm import Session

from app.character.card import DEFAULT_CARD, build_system_prompt, normalize_card
from app.db.models import CharacterCard


class CharacterService:
    def __init__(self, db: Session, user_id: int):
        self.db = db
        self.user_id = user_id

    def get_card(self) -> dict[str, Any]:
        row = self.db.scalar(
            select(CharacterCard).where(CharacterCard.user_id == self.user_id).limit(1)
        )
        if not row:
            return normalize_card(DEFAULT_CARD)
        try:
            return normalize_card(json.loads(row.card_json or "{}"))
        except json.JSONDecodeError:
            return normalize_card(DEFAULT_CARD)

    def save_card(self, raw: dict[str, Any]) -> dict[str, Any]:
        card = normalize_card(raw)
        row = self.db.scalar(
            select(CharacterCard).where(CharacterCard.user_id == self.user_id).limit(1)
        )
        if not row:
            row = CharacterCard(user_id=self.user_id, card_json="{}")
            self.db.add(row)
            self.db.flush()
        row.card_json = json.dumps(card, ensure_ascii=False)
        row.updated_at = datetime.now(timezone.utc)
        self.db.commit()
        return card

    def get_system_prompt(self) -> str:
        return build_system_prompt(self.get_card())