from sqlalchemy import func, select
from sqlalchemy.orm import Session

from app.models.system import System


class SystemsRepository:
    def __init__(self, db: Session) -> None:
        self.db = db

    def get_by_key(self, system_key: str) -> System | None:
        stmt = select(System).where(System.system_key == system_key)
        return self.db.scalar(stmt)

    def get_by_id(self, system_id: str) -> System | None:
        stmt = select(System).where(System.id == system_id)
        return self.db.scalar(stmt)

    def list(self, status: str | None = None, limit: int = 100, offset: int = 0) -> tuple[list[System], int]:
        stmt = select(System)
        count_stmt = select(func.count()).select_from(System)
        if status:
            stmt = stmt.where(System.status == status)
            count_stmt = count_stmt.where(System.status == status)
        stmt = stmt.order_by(System.created_at.desc()).limit(limit).offset(offset)
        return list(self.db.scalars(stmt).all()), int(self.db.scalar(count_stmt) or 0)

    def create(self, system_key: str, name: str, status: str = "active") -> System:
        item = System(system_key=system_key, name=name, status=status)
        self.db.add(item)
        self.db.commit()
        self.db.refresh(item)
        return item