from model.score_model import ScoreRecord


# ========== 工具函数：算等级 ==========
def calc_level(score):
    if score is None: return None
    if score >= 95: return 'A+'
    if score >= 90: return 'A'
    if score >= 80: return 'B'
    if score >= 70: return 'C'
    if score >= 60: return 'D'
    return 'E'


# ========== 工具函数：算及格 ==========
def calc_pass(score):
    if score is None: return None
    return 1 if score >= 60 else 0


# ========== 1. 添加成绩 ==========
def add_score_dao(o, db):
    try:
        # 【业务校验】该学生该课程该序次是否已存在
        existing = db.query(ScoreRecord).filter(
            ScoreRecord.student_id == o['student_id'],
            ScoreRecord.course_id == o['course_id'],
            ScoreRecord.exam_order == o['exam_order'],
            ScoreRecord.is_deleted == 0
        ).all()

        if existing:
            raise ValueError('该学生该课程该序次成绩已存在')

        o1 = ScoreRecord(**o)
        db.add(o1)
    except:
        db.rollback()
        return False
    else:
        db.commit()
        return True


# ========== 2. 修改成绩 ==========
def update_score_dao(score_id, update_data, db):
    try:
        rows = db.query(ScoreRecord).filter(
            ScoreRecord.score_id == score_id,
            ScoreRecord.is_deleted == 0
        ).update(update_data)
    except:
        db.rollback()
        return False
    else:
        db.commit()
        return rows


# ========== 3. 查询成绩（动态条件 + 分页） ==========
def get_scores_dao(score_id, student_id, course_id, teacher_id,
                   exam_order, page, page_size, db):
    q = db.query(ScoreRecord).filter(ScoreRecord.is_deleted == 0)

    if score_id:
        q = q.filter(ScoreRecord.score_id == score_id)
    if student_id:
        q = q.filter(ScoreRecord.student_id == student_id)
    if course_id:
        q = q.filter(ScoreRecord.course_id == course_id)
    if teacher_id:
        q = q.filter(ScoreRecord.teacher_id == teacher_id)
    if exam_order:
        q = q.filter(ScoreRecord.exam_order == exam_order)

    r = q.order_by(ScoreRecord.exam_order.asc()) \
         .offset((page - 1) * page_size) \
         .limit(page_size).all()

    if r:
        return [item.to_dict() for item in r]
    return []


# ========== 4. 删除成绩 ==========
def delete_score_dao(score_id, db):
    try:
        rows = db.query(ScoreRecord).filter(
            ScoreRecord.score_id == score_id,
            ScoreRecord.is_deleted == 0
        ).update({'is_deleted': 1})
    except:
        db.rollback()
        rows = 0
    else:
        db.commit()
    finally:
        return rows