from typing import List, Optional

from sqlalchemy import text
from sqlalchemy.orm import Session

from . import dto, models

DRIVER_ID_SEQ = "a76.driver_driver_id_seq"


def allocate_driver_id(db: Session) -> int:
    """Next surrogate driver_id (sequence from migration ca7d3c4e8b2a)."""
    return db.execute(text(f"SELECT nextval('{DRIVER_ID_SEQ}')")).scalar()


class DriverService:
    @staticmethod
    def list_drivers(
        db: Session, company_id: str, tenant_id: Optional[str] = None
    ) -> List[models.Driver]:
        query = db.query(models.Driver).filter(models.Driver.company_id == company_id)
        if tenant_id:
            query = query.filter(models.Driver.tenant_id == tenant_id)
        return query.all()

    @staticmethod
    def get_driver_by_key_and_line(
        db: Session,
        transporter_key: str,
        line: int,
        company_id: str,
        tenant_id: Optional[str] = None,
    ) -> Optional[models.Driver]:
        query = db.query(models.Driver).filter(
            models.Driver.transporter_key == transporter_key,
            models.Driver.line == line,
            models.Driver.company_id == company_id,
        )
        if tenant_id:
            query = query.filter(models.Driver.tenant_id == tenant_id)
        return query.first()

    @staticmethod
    def create_driver(db: Session, driver_data: dto.DriverCreateDTO):
        data = driver_data.model_dump()
        if data.get("driver_id") is None:
            data["driver_id"] = allocate_driver_id(db)
        new_driver = models.Driver(**data)
        db.add(new_driver)
        db.commit()
        db.refresh(new_driver)
        return new_driver

    @staticmethod
    def update_driver(
        db: Session,
        transporter_key: str,
        line: int,
        company_id: str,
        tenant_id: Optional[str],
        data: dto.DriverUpdateDTO,
    ) -> Optional[models.Driver]:
        driver = DriverService.get_driver_by_key_and_line(
            db, transporter_key, line, company_id, tenant_id
        )
        if not driver:
            return None
        update_data = data.model_dump(exclude_unset=True)
        for key, value in update_data.items():
            setattr(driver, key, value)
        db.commit()
        db.refresh(driver)
        return driver

    @staticmethod
    def delete_driver(
        db: Session,
        transporter_key: str,
        line: int,
        company_id: str,
        tenant_id: Optional[str] = None,
    ) -> Optional[models.Driver]:
        driver = DriverService.get_driver_by_key_and_line(
            db, transporter_key, line, company_id, tenant_id
        )
        if driver:
            db.delete(driver)
            db.commit()
        return driver