import uuid

from fastapi import APIRouter, Depends
from pydantic import BaseModel
from sqlalchemy import select
from sqlalchemy.ext.asyncio import AsyncSession

from ...auth import verify_token
from ...outbound.postgres.database import get_db
from ...outbound.postgres.entities.vocab_entities import UserLanguagePairEntity
from ...outbound.postgres.repositories.pack_repository import PostgresPackRepository

router = APIRouter(prefix="/packs", tags=["bff-packs"])


class PackSelectionItem(BaseModel):
    id: str
    name: str
    name_target: str
    description: str
    description_target: str
    source_lang: str
    target_lang: str
    proficiencies: list[str]
    entry_count: int
    already_added: bool


@router.get("", response_model=list[PackSelectionItem])
async def list_packs_for_selection(
    source_lang: str,
    target_lang: str,
    db: AsyncSession = Depends(get_db),
    token_data: dict = Depends(verify_token),
) -> list[PackSelectionItem]:
    user_id = uuid.UUID(token_data["sub"])

    pack_repo = PostgresPackRepository(db)

    packs = await pack_repo.list_packs(
        source_lang=source_lang,
        target_lang=target_lang,
        published_only=True,
    )

    # The UserLanguagePair may not exist yet for brand-new users
    result = await db.execute(
        select(UserLanguagePairEntity).where(
            UserLanguagePairEntity.user_id == user_id,
            UserLanguagePairEntity.source_lang == source_lang,
            UserLanguagePairEntity.target_lang == target_lang,
        )
    )
    pair_entity = result.scalar_one_or_none()
    already_added_ids: set[str] = set()
    if pair_entity is not None:
        already_added_ids = await pack_repo.get_pack_ids_added_by_user(
            user_id, pair_entity.id
        )

    items = []
    for pack in packs:
        count = await pack_repo.count_entries_for_pack(uuid.UUID(pack.id))
        items.append(
            PackSelectionItem(
                id=pack.id,
                name=pack.name,
                name_target=pack.name_target,
                description=pack.description,
                description_target=pack.description_target,
                source_lang=pack.source_lang,
                target_lang=pack.target_lang,
                proficiencies=pack.proficiencies,
                entry_count=count,
                already_added=pack.id in already_added_ids,
            )
        )
    return items