package com.example.classroomattendance.controller;

import com.example.classroomattendance.model.Student;
import com.example.classroomattendance.service.StudentService;
import org.apache.poi.ss.usermodel.*;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Controller;
import org.springframework.ui.Model;
import org.springframework.web.bind.annotation.*;
import org.springframework.web.multipart.MultipartFile;

import java.io.IOException;
import java.text.DecimalFormat;
import java.util.ArrayList;
import java.util.List;

@Controller
public class FileUploadController {

    @Autowired
    private StudentService studentService;

    @PostMapping("/upload")
    public String handleFileUpload(@RequestParam("file") MultipartFile file, Model model) {
        if (file.isEmpty()) {
            model.addAttribute("message", "文件为空");
            return "index";
        }

        try {
            List<Student> students = parseExcel(file);
            studentService.addStudents(students);
            model.addAttribute("message", "文件接收成功");
            model.addAttribute("students", students);
            model.addAttribute("uploadSuccess", true); // 添加标志以显示下一步按钮
            return "index"; // 返回 index 视图
        } catch (IOException ex) {
            ex.printStackTrace();
            model.addAttribute("message", "文件处理失败: " + ex.getMessage());
            return "index";
        } catch (Exception ex) {
            ex.printStackTrace();
            model.addAttribute("message", "未知错误: " + ex.getMessage());
            return "index";
        }
    }

    private List<Student> parseExcel(MultipartFile file) throws IOException {
        List<Student> students = new ArrayList<>();
        Workbook workbook = WorkbookFactory.create(file.getInputStream());
        Sheet sheet = workbook.getSheetAt(0);

        for (Row row : sheet) {
            if (row.getRowNum() == 0) {
                continue; // 跳过标题行
            }

            Cell nameCell = row.getCell(0);
            Cell studentIdCell = row.getCell(1);
            Cell pointsCell = row.getCell(2);

            if (nameCell == null || studentIdCell == null) {
                continue; // 跳过不完整的记录
            }

            Student student = new Student();
            student.setId((long) row.getRowNum()); // 使用行号作为 ID 示例

            student.setName(getCellStringValue(nameCell));
            student.setStudentId(getCellStringValue(studentIdCell));
            student.setPoints(getCellDoubleValue(pointsCell));

            students.add(student);
        }

        workbook.close();
        return students;
    }

    private String getCellStringValue(Cell cell) {
        if (cell == null) {
            return "";
        }
        switch (cell.getCellType()) {
            case STRING:
                return cell.getStringCellValue();
            case NUMERIC:
                // 对于学号这种需要转换为字符串的情况，使用 DecimalFormat 保证不使用科学计数法
                DecimalFormat df = new DecimalFormat("0");
                return df.format(cell.getNumericCellValue());
            default:
                return cell.toString();
        }
    }

    private double getCellDoubleValue(Cell cell) {
        if (cell == null) {
            return 0.0;
        }
        switch (cell.getCellType()) {
            case NUMERIC:
                return cell.getNumericCellValue();
            case STRING:
                try {
                    return Double.parseDouble(cell.getStringCellValue());
                } catch (NumberFormatException e) {
                    return 0.0;
                }
            default:
                return 0.0;
        }
    }
}