"""Пользователи: создание из внешней личности, ник, активная группа."""
from __future__ import annotations

import re

from sqlmodel import Session, select

from app.auth.provider import ExternalIdentity
from app.core.errors import NicknameTakenError, NotFoundError, ValidationError
from app.models import AuthIdentity, GroupMember, User

_NICK_RE = re.compile(r"^[\w .\-]{2,64}$", re.UNICODE)


def get_user(session: Session, user_id: int) -> User:
    user = session.get(User, user_id)
    if user is None:
        raise NotFoundError("Пользователь не найден.")
    return user


def nickname_available(session: Session, nickname: str, exclude_user_id: int | None = None) -> bool:
    stmt = select(User).where(User.nickname == nickname)
    existing = session.exec(stmt).first()
    return existing is None or existing.id == exclude_user_id


def _unique_nickname(session: Session, base: str) -> str:
    base = (base or "Игрок").strip()[:60] or "Игрок"
    candidate = base
    suffix = 1
    while session.exec(select(User).where(User.nickname == candidate)).first() is not None:
        suffix += 1
        candidate = f"{base} {suffix}"
    return candidate


def get_or_create_from_identity(session: Session, identity: ExternalIdentity) -> User:
    link = session.exec(
        select(AuthIdentity).where(
            AuthIdentity.provider == identity.provider,
            AuthIdentity.external_id == identity.external_id,
        )
    ).first()
    if link is not None:
        return get_user(session, link.user_id)

    user = User(
        nickname=_unique_nickname(session, identity.suggested_nickname or identity.external_id),
        role="player",
        auth_provider=identity.provider,
        telegram_id=identity.telegram_id,
    )
    session.add(user)
    session.flush()
    session.add(
        AuthIdentity(
            user_id=user.id,  # type: ignore[arg-type]
            provider=identity.provider,
            external_id=identity.external_id,
        )
    )
    session.commit()
    session.refresh(user)
    return user


def update_nickname(session: Session, user: User, new_nickname: str) -> User:
    new_nickname = (new_nickname or "").strip()
    if not _NICK_RE.match(new_nickname):
        raise ValidationError("Ник: 2–64 символа, буквы/цифры/пробел/.-_")
    if not nickname_available(session, new_nickname, exclude_user_id=user.id):
        raise NicknameTakenError()
    user.nickname = new_nickname
    session.add(user)
    session.commit()
    session.refresh(user)
    return user


def set_active_group(session: Session, user: User, group_id: int | None) -> User:
    if group_id is not None:
        member = session.exec(
            select(GroupMember).where(
                GroupMember.group_id == group_id, GroupMember.user_id == user.id
            )
        ).first()
        if member is None:
            raise ValidationError("Нельзя сделать активной группу, в которой вы не состоите.")
    user.active_group_id = group_id
    session.add(user)
    session.commit()
    session.refresh(user)
    return user