from dataclasses import dataclass

from campaigns.auth.dtos import User
from campaigns.connectors.db import Database, session_context
from campaigns.core.handler import Handler
from campaigns.meta.dtos import CampaignPost
from campaigns.meta.exceptions import CampaignPostDoesNotExist
from campaigns.meta.services import CampaignPostService, CampaignService


@dataclass(frozen=True)
class GetCampaignPostRequest:
    user: User
    campaign_id: str


@dataclass
class GetCampaignPostHandler(
    Handler[GetCampaignPostRequest, CampaignPost | None],
):
    db: Database
    campaign_service: CampaignService
    campaign_post_service: CampaignPostService

    @session_context(in_transaction=False)
    async def handle(self, request: GetCampaignPostRequest) -> CampaignPost | None:
        campaign = await self.campaign_service.get_user_campaign(
            user=request.user, campaign_id=request.campaign_id
        )
        try:
            return await self.campaign_post_service.get_campaign_post(campaign)
        except CampaignPostDoesNotExist:
            pass
        return None