from typing import List
from sqlalchemy.orm.query import Query as SAQuery
from sqlalchemy import asc, desc, nullslast, and_
from sqlalchemy.sql import func

from db import db
from models import Project, Campaign

from models.campaign_ad import CampaignAd
from campaign_ads.schemas import CampaignAdsQueryParams


class CampaignAdsRepository:
    __sort_map = {
        "id": (CampaignAd.id,),
        "name": (CampaignAd.name, CampaignAd.id),
        "spend": (CampaignAd.budget_spend, CampaignAd.id),
        "startDate": (CampaignAd.start_date, CampaignAd.id),
        "endDate": (func.coalesce(CampaignAd.end_date, Project.end_date), CampaignAd.id),
        "remainingDays": ((CampaignAd.end_date - CampaignAd.start_date), CampaignAd.id),
    }

    def __filtered_campaign_ads_query(self, query: SAQuery, campaign_uuid: str, params: CampaignAdsQueryParams):
        query = query.filter(and_(Campaign.uuid == campaign_uuid, CampaignAd.campaign_id == Campaign.id))
        filter_items = []
        if params.freeText:
            found_ids = CampaignAd.search(expression=params.freeText)
            filter_items.append(CampaignAd.id.in_(found_ids))

        for f in filter_items:
            query = query.filter(f)
        return query

    def get_filtered_campaign_ads_count(self, campaign_uuid: str, params: CampaignAdsQueryParams) -> int:
        count_query = db.session.query(func.count(CampaignAd.id))
        query = self.__filtered_campaign_ads_query(count_query, campaign_uuid, params)
        return query.scalar()

    def get_filtered_campaign_ads(self, campaign_uuid: str, params: CampaignAdsQueryParams) -> List[CampaignAd]:
        campaign_ads_query = db.session.query(CampaignAd).join(Campaign).outerjoin(Project)
        query = self.__filtered_campaign_ads_query(campaign_ads_query, campaign_uuid, params)
        sort_dir = asc
        sort = params.sort
        if sort.startswith("-"):
            sort = sort[1:]
            sort_dir = desc

        order_expression = map(lambda x: nullslast(sort_dir(x)), self.__sort_map[sort])

        return query.order_by(*order_expression).limit(params.limit).offset(params.offset).all()