from dataclasses import dataclass
from datetime import timedelta
from uuid import UUID, uuid4

from domain.sandbox import SandboxSession
from usecase.interface import (
    Clock,
    Logger,
    SandboxLifecycleLocker,
    SandboxRuntime,
    SandboxSessionRepository,
)


@dataclass(frozen=True, slots=True)
class CreateSandboxCommand:
    chat_id: UUID


class CreateSandbox:
    def __init__(
        self,
        repository: SandboxSessionRepository,
        locker: SandboxLifecycleLocker,
        runtime: SandboxRuntime,
        clock: Clock,
        logger: Logger,
        ttl: timedelta,
    ) -> None:
        self._repository = repository
        self._locker = locker
        self._runtime = runtime
        self._clock = clock
        self._logger = logger
        self._ttl = ttl

    def execute(self, command: CreateSandboxCommand) -> SandboxSession:
        chat_id = command.chat_id

        with self._locker.lock(chat_id):
            session = self._repository.get_active_by_chat_id(chat_id)
            now = self._clock.now()

            if session is not None and session.expires_at > now:
                self._logger.info(
                    'sandbox_reused',
                    attrs=_sandbox_attrs(session),
                )
                return session

            if session is not None:
                self._logger.info(
                    'sandbox_replaced',
                    attrs=_sandbox_attrs(session),
                )
                self._runtime.stop(session.container_id)
                self._repository.delete(session.session_id)

            created_at = self._clock.now()
            expires_at = created_at + self._ttl
            new_session = self._runtime.create(
                session_id=_new_session_id(),
                chat_id=chat_id,
                created_at=created_at,
                expires_at=expires_at,
            )
            self._repository.save(new_session)
            self._logger.info(
                'sandbox_created',
                attrs=_sandbox_attrs(new_session),
            )
            return new_session


class CleanupExpiredSandboxes:
    def __init__(
        self,
        repository: SandboxSessionRepository,
        locker: SandboxLifecycleLocker,
        runtime: SandboxRuntime,
        clock: Clock,
        logger: Logger,
    ) -> None:
        self._repository = repository
        self._locker = locker
        self._runtime = runtime
        self._clock = clock
        self._logger = logger

    def execute(self) -> list[SandboxSession]:
        expired_sessions = self._repository.list_expired(self._clock.now())
        cleaned_sessions: list[SandboxSession] = []

        for session in expired_sessions:
            try:
                cleaned_session = self._cleanup_session(session)
            except Exception as exc:
                attrs = _sandbox_attrs(session)
                attrs['error'] = type(exc).__name__
                self._logger.error(
                    'sandbox_clean_failed',
                    attrs=attrs,
                )
                continue

            if cleaned_session is None:
                continue

            cleaned_sessions.append(cleaned_session)
            self._logger.info(
                'sandbox_cleaned',
                attrs=_sandbox_attrs(cleaned_session),
            )

        return cleaned_sessions

    def _cleanup_session(self, session: SandboxSession) -> SandboxSession | None:
        with self._locker.lock(session.chat_id):
            current_session = self._repository.get_active_by_chat_id(session.chat_id)
            now = self._clock.now()
            if current_session is None:
                return None

            if current_session.session_id != session.session_id:
                return None

            if current_session.expires_at > now:
                return None

            self._runtime.stop(current_session.container_id)
            self._repository.delete(current_session.session_id)
            return current_session


def _new_session_id() -> UUID:
    return uuid4()


def _sandbox_attrs(session: SandboxSession) -> dict[str, str]:
    return {
        'chat_id': str(session.chat_id),
        'session_id': str(session.session_id),
        'container_id': session.container_id,
    }