from sqlalchemy.orm import Session
from fastapi import HTTPException, status
from app.repositories.alumni import alumni_repository
from app.schemas.alumni import AlumniCreate, AlumniUpdate
from app.models.alumni import Alumni
from typing import List, Optional, Tuple

class AlumniService:
    """
    Service containing business logic for Alumni tracking features.
    """
    @staticmethod
    def get_by_id(db: Session, alumni_id: int) -> Alumni:
        """Fetch alumni by ID or raise HTTP 404 if not found."""
        alumni = alumni_repository.get(db, alumni_id)
        if not alumni:
            raise HTTPException(
                status_code=status.HTTP_404_NOT_FOUND,
                detail=f"Data alumni dengan ID {alumni_id} tidak ditemukan"
            )
        return alumni

    @staticmethod
    def get_by_id_detailed(db: Session, alumni_id: int) -> Alumni:
        """Fetch alumni by ID with all relations (pekerjaan, kompetensi, tracer_responses, clustering)."""
        alumni = alumni_repository.get_with_relations(db, alumni_id)
        if not alumni:
            raise HTTPException(
                status_code=status.HTTP_404_NOT_FOUND,
                detail=f"Data alumni dengan ID {alumni_id} tidak ditemukan"
            )
        return alumni

    @staticmethod
    def get_all(db: Session, skip: int = 0, limit: int = 100) -> List[Alumni]:
        """Fetch all alumni with pagination limits."""
        return alumni_repository.get_all(db, skip=skip, limit=limit)

    @staticmethod
    def get_filtered(
        db: Session,
        skip: int = 0,
        limit: int = 10,
        search: Optional[str] = None,
        kode_prodi: Optional[str] = None,
        tahun_lulus: Optional[int] = None,
        status_kerja: Optional[str] = None,
    ) -> Tuple[List[Alumni], int]:
        """Fetch alumni with multi-criteria filtering and count."""
        return alumni_repository.get_filtered(
            db=db,
            skip=skip,
            limit=limit,
            search=search,
            kode_prodi=kode_prodi,
            tahun_lulus=tahun_lulus,
            status_kerja=status_kerja,
        )

    @staticmethod
    def create(db: Session, alumni_in: AlumniCreate) -> Alumni:
        """Create a new alumni record after verifying NIM uniqueness."""
        existing_nim = alumni_repository.get_by_nim(db, alumni_in.nim)
        if existing_nim:
            raise HTTPException(
                status_code=status.HTTP_400_BAD_REQUEST,
                detail=f"Alumni dengan NIM {alumni_in.nim} sudah terdaftar"
            )
        return alumni_repository.create(db, alumni_in)

    @staticmethod
    def update(db: Session, alumni_id: int, alumni_in: AlumniUpdate) -> Alumni:
        """Update an existing alumni record or raise HTTP 404 if not found."""
        alumni = AlumniService.get_by_id(db, alumni_id)
        return alumni_repository.update(db, alumni, alumni_in)

    @staticmethod
    def delete(db: Session, alumni_id: int) -> Alumni:
        """Delete an alumni record by ID or raise HTTP 404 if not found."""
        alumni = AlumniService.get_by_id(db, alumni_id)
        deleted = alumni_repository.delete(db, alumni_id)
        return deleted if deleted is not None else alumni