package com.njuzr.eaibackend.mapper;

import com.baomidou.mybatisplus.core.mapper.BaseMapper;
import com.njuzr.eaibackend.po.ClassStudent;
import com.njuzr.eaibackend.vo.StudentInfoVO;
import org.apache.ibatis.annotations.*;

import java.util.List;

@Mapper
public interface ClassStudentMapper extends BaseMapper<ClassStudent> {
    int batchInsert(@Param("list") List<ClassStudent> students);

    /**
     * 根据班级ID和学号列表批量删除学生
     * @param classId 班级ID
     * @param officialNumbers 学号列表
     * @return 删除的行数
     */
    int batchDeleteByClassIdAndNumbers(
            @Param("classId") Long classId,
            @Param("officialNumbers") List<String> officialNumbers);

    @Select("SELECT u.id as student_id, cs.official_number, cs.stu_name, cs.state FROM class_student cs JOIN users u ON cs.official_number = u.official_number WHERE cs.class_id = #{classId}")
    @Results({
            @Result(property = "studentId", column = "student_id"),
            @Result(property = "officialNumber", column = "official_number"),
            @Result(property = "stuName", column = "stu_name")
    })
    List<StudentInfoVO> selectStudentsByClassId(@Param("classId") Long classId);

    /**
     * 根据学生ID和课程ID查找班级学生记录
     */
    @Select("SELECT cs.* FROM class_student cs " +
            "JOIN class c ON cs.class_id = c.class_id " +
            "JOIN users u ON cs.official_number = u.official_number " +
            "WHERE u.id = #{studentId} AND c.course_id = #{courseId}")
    ClassStudent findClassStudentByStudentAndCourse(@Param("studentId") Long studentId,
                                                    @Param("courseId") Long courseId);

    /**
     * 更新学生加入状态
     */
    @Update("UPDATE class_student SET state = #{state} WHERE id = #{id}")
    int updateStateById(@Param("id") Long id, @Param("state") int state);
}