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

from schemas.pagination import PageResult


def paginate_query(db: Session, query, current_page: int = 1, page_size: int = 10) -> PageResult:
    """通用分页查询函数"""
    # 计算总记录数
    total = db.execute(select(func.count()).select_from(query.subquery())).scalar_one_or_none() or 0

    # 计算总页数
    total_pages = (total + page_size - 1) // page_size if page_size != 0 else 0

    # 执行分页查询
    results = db.execute(query.offset((current_page - 1) * page_size).limit(page_size)).all()

    # 转换为字典列表
    records = [row._asdict() if hasattr(row, "_asdict") else dict(row) for row in results]

    return PageResult(
        current=current_page,
        size=page_size,
        total=total,
        pages=total_pages,
        records=records
    )