from __future__ import annotations

from dataclasses import dataclass
from uuid import uuid4

from app.application.users.dto import UserDTO
from app.application.users.ports.unit_of_work import UnitOfWork
from app.domain.users.entities import User
from app.domain.users.services import ensure_unique_email
from app.domain.users.value_objects import Email


@dataclass(frozen=True)
class CreateUserCommand:
    email: str
    full_name: str


class CreateUserUseCase:
    """
    Inbound port (use case).
    Outbound ports: UnitOfWork -> UserRepository, and email integration.
    """

    def __init__(self, uow: UnitOfWork, welcome_email_sender) -> None:
        self._uow = uow
        self._welcome_email_sender = welcome_email_sender

    async def execute(self, cmd: CreateUserCommand) -> UserDTO:
        email_vo = Email(cmd.email)
        async with self._uow:
            existing = await self._uow.users.get_by_email(str(email_vo))
            ensure_unique_email(existing_user=existing)

            user = User.register(
                user_id=uuid4(), email=email_vo, full_name=cmd.full_name
            )
            await self._uow.users.add(user)
            await self._uow.commit()

        for ev in user.pull_events():
            from app.domain.users.events import UserRegistered

            if isinstance(ev, UserRegistered):
                await self._welcome_email_sender.send_welcome(
                    to_email=ev.email, full_name=cmd.full_name
                )

        return UserDTO(
            id=user.id,
            email=str(user.email),
            full_name=user.full_name,
            is_active=user.is_active,
            created_at=user.created_at,
        )