package com.wbq.service.impl;

import com.github.pagehelper.Page;
import com.github.pagehelper.PageHelper;
import com.wbq.context.BaseContext;
import com.wbq.dto.CourseDTO;
import com.wbq.dto.StudentDTO;
import com.wbq.dto.StudentLoginDTO;
import com.wbq.dto.StudentPageQueryDTO;
import com.wbq.entity.CallRecord;
import com.wbq.entity.Course;
import com.wbq.entity.Student;
import com.wbq.mapper.*;
import com.wbq.result.PageResult;
import com.wbq.service.StudentService;
import com.wbq.vo.CourseCallVO;
import com.wbq.vo.CourseVO;
import com.wbq.vo.StudentCourseInfoVO;
import org.apache.poi.ss.usermodel.*;
import org.springframework.beans.BeanUtils;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.security.crypto.bcrypt.BCrypt;
import org.springframework.stereotype.Service;
import org.springframework.web.multipart.MultipartFile;

import javax.print.attribute.IntegerSyntax;
import java.io.InputStream;
import java.time.LocalDateTime;
import java.util.ArrayList;
import java.util.Iterator;
import java.util.List;
import java.util.Random;

@Service
public class StudentServiceImpl implements StudentService {
    @Autowired
    private StudentMapper studentMapper;
    @Autowired
    private StudentCourseMapper studentCourseMapper;
    @Autowired
    private CourseMapper courseMapper;
    @Autowired
    private CallRecordMapper callRecordMapper;
    @Autowired
    private AdminMapper adminMapper;

    @Override
    public Student getById(int id) {
        return studentMapper.getById(id);
    }

    /**
     * 更新学生信息
     * @param studentDTO
     */
    @Override
    public void update(StudentDTO studentDTO) {
        studentMapper.update(studentDTO);
    }

    /**
     * 分页查询学生（按课程积分排名）
     * @param studentPageQueryDTO
     * @param courseId
     * @return
     */
    @Override
    public PageResult pageQuery(StudentPageQueryDTO studentPageQueryDTO, int courseId) {
        PageHelper.startPage(studentPageQueryDTO.getPage(), studentPageQueryDTO.getPageSize());
        Page<StudentCourseInfoVO> page = studentCourseMapper.pageQuery4CourseInfo(courseId);
        return new PageResult(page.getTotal(), page.getResult());
    }

    /**
     * 随机点名核心代码
     * @param courseId
     * @param studentIds
     * @return
     */
    @Override
    public Student coreCall(int courseId, List<Integer> studentIds) {
        // 生成权重
        double totalWeight = 0;
        for (int studentId : studentIds) {
            StudentCourseInfoVO studentCourseInfoVO = studentCourseMapper.getCourseInfo(studentId, courseId);
            double studentScore = studentCourseInfoVO.getScore();
            totalWeight += 1.0/(studentScore + 1);
        }

        double cumulativeWeight = 0;
        Random random = new Random();
        double rand = random.nextDouble();
        int selectedStudentId = 0;

        // 轮盘赌算法
        for (int studentId : studentIds) {
            StudentCourseInfoVO studentCourseInfoVO = studentCourseMapper.getCourseInfo(studentId, courseId);
            double studentScore = studentCourseInfoVO.getScore();

            cumulativeWeight += 1.0/(studentScore + 1);
            if (cumulativeWeight >= rand*totalWeight) {
                selectedStudentId = studentId;
                break;
            }
        }

        // 增加被叫次数
        int oldCallCount = studentCourseMapper.getCourseInfo(selectedStudentId, courseId).getCallCount();
        int newCallCount = oldCallCount + 1;
        studentCourseMapper.updateCallCountByStudentIdAndCourseId(newCallCount, selectedStudentId, courseId);

        Student selectedStudent = studentMapper.getByStudentId(selectedStudentId);
        // 生成点名记录
        CallRecord callRecord = CallRecord.builder()
                .callTime(LocalDateTime.now())
                .courseDescription(courseMapper.getByCourseId(courseId).getDescription())
                .adminName(adminMapper.getById(BaseContext.getCurrentId()).getName())
                .studentId(selectedStudentId)
                .build();
        callRecordMapper.insert(callRecord);
        return selectedStudent;
    }

    /**
     * 随机点名
     * @param courseId
     * @return
     */
    @Override
    public StudentCourseInfoVO callStudent(int courseId) {
        List<Integer> studentIds = studentCourseMapper.getByCourseId(courseId);

        Student selectedStudent = coreCall(courseId, studentIds);

        StudentCourseInfoVO studentCourseInfoVO = studentCourseMapper.getCourseInfo(selectedStudent.getStudentId(), courseId);

        return studentCourseInfoVO;
    }


    /**
     * 根据姓氏点名，积分越高，概率越低
     * @param courseId
     * @param firstname
     * @return
     */
    @Override
    public StudentCourseInfoVO callStudentByFirstname(int courseId, String firstname) {
        List<Integer> studentIds = studentCourseMapper.getByCourseId(courseId);

        // 筛选方式
        Iterator<Integer> iterator = studentIds.iterator();
        while (iterator.hasNext()) {
            Integer studentId = iterator.next();
            Student student = studentMapper.getByStudentId(studentId);
            String studentName = student.getName();
            if (!firstname.equals(Character.toString(studentName.charAt(0)))) {
                iterator.remove();  // 使用 iterator.remove() 安全地移除元素
            }
        }

        Student selectedStudent = coreCall(courseId, studentIds);

        StudentCourseInfoVO studentCourseInfoVO = studentCourseMapper.getCourseInfo(selectedStudent.getStudentId(), courseId);

        return studentCourseInfoVO;
    }

    /**
     * 根据学号尾数点名
     * @param courseId
     * @param lastNum
     * @return
     */
    @Override
    public StudentCourseInfoVO callStudentByLastNum(int courseId, int lastNum) {
        List<Integer> studentIds = studentCourseMapper.getByCourseId(courseId);

        // 筛选方式
        Iterator<Integer> iterator = studentIds.iterator();
        while (iterator.hasNext()) {
            Integer studentId = iterator.next();
            if (studentId % 10 != lastNum) {
                iterator.remove();  // 使用 iterator.remove() 安全地移除元素
            }
        }

        Student selectedStudent = coreCall(courseId, studentIds);

        StudentCourseInfoVO studentCourseInfoVO = studentCourseMapper.getCourseInfo(selectedStudent.getStudentId(), courseId);

        return studentCourseInfoVO;
    }

    /**
     * 手动加分
     * @param courseDTO
     * @param studentDTO
     * @param score
     * @return
     */
    @Override
    public StudentCourseInfoVO addScore(CourseDTO courseDTO, StudentDTO studentDTO, double score) {
        double oldScore = studentCourseMapper.getCourseInfo(studentDTO.getStudentId(), courseDTO.getCourseId()).getScore();

        studentCourseMapper.updateScoreByStudentIdAndCourseId(oldScore + score,
                studentDTO.getStudentId(),
                courseDTO.getCourseId());

        // 返回更新值
        StudentCourseInfoVO studentCourseInfoVO = studentCourseMapper.getCourseInfo(studentDTO.getStudentId(), courseDTO.getCourseId());

        // 更新记录
        List<CallRecord> callRecordList = callRecordMapper.getByStudentId(studentDTO.getStudentId());
        CallRecord newCallRecord = callRecordList.getFirst();
        newCallRecord.setScore(score);
        callRecordMapper.update(newCallRecord);

        return studentCourseInfoVO;
    }

    /**
     * 学生登录
     * @param studentLoginDTO
     * @return
     */
    @Override
    public Student login(StudentLoginDTO studentLoginDTO) {
        Student student = null;
        String hashedPassword =  studentMapper.getPasswordByStudentId(studentLoginDTO.getStudentId());
        // 使用BCrypt的checkpw方法来验证密码
        boolean isPasswordCorrect = BCrypt.checkpw(studentLoginDTO.getPassword(), hashedPassword);

        // 验证成功
        if (isPasswordCorrect)
            student = studentMapper.getByStudentId(studentLoginDTO.getStudentId());
        return student;
    }

    /**
     * 加入课程
     * @param courseDTO
     */
    @Override
    public void joinCourse(StudentDTO studentDTO, CourseDTO courseDTO) {
        studentCourseMapper.insert(studentDTO.getStudentId(), courseDTO.getCourseId());
    }

    /**
     * 退出班级
     * @param courseDTO
     * @param studentDTO
     */
    @Override
    public void dropCourse(CourseDTO courseDTO, StudentDTO studentDTO) {
        studentCourseMapper.delete(studentDTO.getStudentId(), courseDTO.getCourseId());
    }

    /**
     * 查询自己加入的班级
     * @return
     */
    @Override
    public List<CourseVO> courseList() {
        int studentId = studentMapper.getById(BaseContext.getCurrentId()).getStudentId();
        List<CourseVO> courseVOList = new ArrayList<>();
        List<Integer> courseIdList = studentCourseMapper.getByStudentId(studentId);
        List<Course> courseList = courseMapper.getByCourseIdList(courseIdList);

        for (Course course : courseList) {
            CourseVO courseVO = new CourseVO();
            BeanUtils.copyProperties(course, courseVO);
            courseVOList.add(courseVO);
        }

        return courseVOList;
    }

    /**
     * 查询自己的某门课程信息
     * @param studentId
     * @param courseId
     * @return
     */
    @Override
    public StudentCourseInfoVO getStudentCourseInfo(int studentId, int courseId) {
        return studentCourseMapper.getCourseInfo(studentId, courseId);
    }

    /**
     * 批量增加点名系统的学生
     * @param courseId
     * @param studentDTOs
     */
    @Override
    public void batchAddStudents(List<StudentDTO> studentDTOs, int courseId) {
        if (studentDTOs != null && !studentDTOs.isEmpty()) {
            for (StudentDTO studentDTO : studentDTOs) {
                String initPassword = "1234";
                String hashedPassword = BCrypt.hashpw(initPassword, BCrypt.gensalt());
                studentDTO.setPassword(hashedPassword);
            }
            studentCourseMapper.batchInsert(studentDTOs, courseId);
        }
    }

    /**
     * 解析Excel
     * @param file
     * @return
     * @throws Exception
     */
    @Override
    public List<StudentDTO> parseExcel(MultipartFile file) throws Exception {
        List<StudentDTO> studentDTOs = new ArrayList<>();

        // 获取 Excel 文件的输入流
        InputStream inputStream = file.getInputStream();
        Workbook workbook = WorkbookFactory.create(inputStream);
        // 学生信息在第一张表
        Sheet sheet = workbook.getSheetAt(0);

        for (Row row : sheet) {
            // 跳过表头
            /*if (row.getRowNum() == 0) {
                continue;
            }*/

            StudentDTO studentDTO = new StudentDTO();

            if(row.getRowNum() == 103) break;

            //debug
            System.out.println("第" + row.getRowNum() + "行");
            System.out.println(row.getCell(0).getCellType() + " " +
                    row.getCell(1).getCellType() + " " +
                    row.getCell(2).getCellType());


            if(row.getCell(0).getCellType() == CellType.STRING)
                studentDTO.setStudentId(Integer.parseInt(row.getCell(0).getStringCellValue()));
            else
                studentDTO.setStudentId((int)row.getCell(0).getNumericCellValue());  // 学号

            studentDTO.setName(row.getCell(1).getStringCellValue());              // 姓名
            studentDTO.setPassword(row.getCell(2).getStringCellValue());          // 密码
            studentDTOs.add(studentDTO);
        }

        workbook.close();
        return studentDTOs;
    }

    /**
     * 查询自己某门课程的历次点名记录
     * @param  courseId
     * @param studentPageQueryDTO
     * @return
     */
    @Override
    public PageResult getCallRecord(StudentPageQueryDTO studentPageQueryDTO, int courseId) {
        int studentId = studentMapper.getById(BaseContext.getCurrentId()).getStudentId();
        String courseDescription = courseMapper.getByCourseId(courseId).getDescription();

        PageHelper.startPage(studentPageQueryDTO.getPage(), studentPageQueryDTO.getPageSize());

        Page<CallRecord> page = callRecordMapper.pageQuery(studentPageQueryDTO, studentId, courseDescription);
        List<CallRecord> callRecordList = page.getResult();

        List<CourseCallVO> courseCallVOList = new ArrayList<>();

        for (CallRecord callRecord : callRecordList) {
            CourseCallVO courseCallVO = new CourseCallVO();
            BeanUtils.copyProperties(callRecord, courseCallVO);

            courseCallVOList.add(courseCallVO);
        }

        return new PageResult(page.getTotal(), courseCallVOList);
    }

    /**
     * 修改密码
     * @param studentDTO
     */
    @Override
    public void changePassword(StudentDTO studentDTO) {
        String password = studentDTO.getPassword();
        String hashPassword = BCrypt.hashpw(password, BCrypt.gensalt());
        studentDTO.setPassword(hashPassword);
        studentMapper.update(studentDTO);
    }
}