"""Business logic för tenant-hantering."""
from typing import Optional
from uuid import UUID

from sqlalchemy.ext.asyncio import AsyncSession
from sqlalchemy import select, func
from fastapi import HTTPException, status

from app.models import Tenant
from app.schemas import TenantCreate, TenantUpdate


class TenantService:
    def __init__(self, db: AsyncSession):
        self.db = db

    async def get_by_id(self, tenant_id: UUID) -> Optional[Tenant]:
        result = await self.db.execute(select(Tenant).where(Tenant.id == tenant_id))
        return result.scalar_one_or_none()

    async def get_by_slug(self, slug: str) -> Optional[Tenant]:
        result = await self.db.execute(select(Tenant).where(Tenant.slug == slug.lower().strip()))
        return result.scalar_one_or_none()

    async def list_tenants(self, skip: int = 0, limit: int = 100) -> tuple[list[Tenant], int]:
        total_result = await self.db.execute(select(func.count()).select_from(Tenant))
        total = total_result.scalar_one()
        result = await self.db.execute(
            select(Tenant).offset(skip).limit(limit).order_by(Tenant.created_at.desc())
        )
        return result.scalars().all(), total

    async def create_tenant(self, data: TenantCreate) -> Tenant:
        existing = await self.get_by_slug(data.slug)
        if existing:
            raise HTTPException(
                status_code=status.HTTP_409_CONFLICT,
                detail="Tenant with this slug already exists",
            )

        tenant = Tenant(
            name=data.name.strip(),
            slug=data.slug.lower().strip(),
            description=data.description.strip() if data.description else None,
        )
        self.db.add(tenant)
        await self.db.commit()
        await self.db.refresh(tenant)
        return tenant

    async def update_tenant(self, tenant_id: UUID, data: TenantUpdate) -> Tenant:
        tenant = await self.get_by_id(tenant_id)
        if tenant is None:
            raise HTTPException(status_code=status.HTTP_404_NOT_FOUND, detail="Tenant not found")

        if data.name is not None:
            tenant.name = data.name.strip()
        if data.description is not None:
            tenant.description = data.description.strip() if data.description else None

        await self.db.commit()
        await self.db.refresh(tenant)
        return tenant

    async def delete_tenant(self, tenant_id: UUID) -> None:
        tenant = await self.get_by_id(tenant_id)
        if tenant is None:
            raise HTTPException(status_code=status.HTTP_404_NOT_FOUND, detail="Tenant not found")

        await self.db.delete(tenant)
        await self.db.commit()