// ===========================================
// 多班级版班级管理系统 - Go 后端
//
// 开发者: Canglan
// 联系方式: admin@sea-studio.top
// 版权归属: Sea Network Technology Studio
// 许可证: Apache License 2.0
//
// 版权所有 © Sea Network Technology Studio
// ===========================================

package service

import (
	"fmt"
	"strconv"
	"time"

	"gorm.io/gorm"

	"hz-gitea.sea-studio.top/canglan/SharedClassManager/internal/model"
	"hz-gitea.sea-studio.top/canglan/SharedClassManager/internal/repository"
	"hz-gitea.sea-studio.top/canglan/SharedClassManager/pkg/logger"
)

// AttendanceService 考勤服务
type AttendanceService struct {
	attendanceRepo *repository.AttendanceRepo
	studentRepo    *repository.StudentRepo
	userRepo       *repository.UserRepo
	conductRepo    *repository.ConductRepo
	semesterRepo   *repository.SemesterRepo
	settingRepo    *repository.SystemSettingRepo
	classRepo      *repository.ClassRepo
}

// NewAttendanceService 创建考勤服务
func NewAttendanceService(
	attendanceRepo *repository.AttendanceRepo,
	studentRepo *repository.StudentRepo,
	userRepo *repository.UserRepo,
	conductRepo *repository.ConductRepo,
	semesterRepo *repository.SemesterRepo,
	settingRepo *repository.SystemSettingRepo,
	classRepo *repository.ClassRepo,
) *AttendanceService {
	return &AttendanceService{
		attendanceRepo: attendanceRepo,
		studentRepo:    studentRepo,
		userRepo:       userRepo,
		conductRepo:    conductRepo,
		semesterRepo:   semesterRepo,
		settingRepo:    settingRepo,
		classRepo:      classRepo,
	}
}

// CreateRecord 创建考勤记录
func (s *AttendanceService) CreateRecord(studentID int, dateStr, slot, status string, reason *string,
	applyDeduction bool, customDeduction *int, recorderID int, classID int) (map[string]interface{}, error) {

	// 校验学生是否属于当前班级（#7）
	student, err := s.studentRepo.GetByID(studentID)
	if err != nil || student == nil || student.ClassID != classID {
		return map[string]interface{}{"success": false, "message": "学生不属于当前班级"}, nil
	}

	// 解析日期
	parsedDate, err := time.Parse("2006-01-02", dateStr)
	if err != nil {
		return map[string]interface{}{"success": false, "message": "日期格式错误"}, nil
	}

	// 获取活跃学期
	var semesterID *int
	activeSemester, _ := s.semesterRepo.GetActive()
	if activeSemester != nil {
		semesterID = &activeSemester.SemesterID
	}

	record := &model.AttendanceRecord{
		StudentID:  studentID,
		Date:       parsedDate,
		Slot:       slot,
		Status:     status,
		Reason:     reason,
		RecorderID: recorderID,
		SemesterID: semesterID,
	}

	createResult, err := s.attendanceRepo.CreateRecord(record)
	if err != nil {
		return map[string]interface{}{"success": false, "message": "添加考勤记录失败"}, nil
	}
	attendanceID := createResult.AttendanceID

	// 更新已有记录时，先撤销旧扣分再应用新扣分
	if createResult.IsUpdate && createResult.OldDeductionApplied == 1 && createResult.OldDeductionRecordID != nil {
		if err := s.conductRepo.RevokeRecord(*createResult.OldDeductionRecordID, recorderID); err != nil {
			logger.Sugared.Errorf("撤销旧考勤扣分失败: attendance_id=%d, old_record_id=%d, err=%v",
				attendanceID, *createResult.OldDeductionRecordID, err)
			return nil, fmt.Errorf("撤销旧扣分失败，操作已中止以避免双重扣分: %w", err)
		}
	}

	// 应用扣分（事务保护，避免数据不一致）
	if applyDeduction && (status == "absent" || status == "late" || status == "leave") {
		// 校验自定义扣分值必须为非负数
		if customDeduction != nil && *customDeduction < 0 {
			return map[string]interface{}{"success": false, "message": "自定义扣分值不能为负数"}, nil
		}

		var pointsChange int
		if customDeduction != nil {
			pointsChange = -*customDeduction
		} else {
			pointsChange = s.getDeductionPoints(classID, status)
		}

		if pointsChange == 0 {
			return map[string]interface{}{"success": true, "message": "考勤记录添加成功（不扣分）"}, nil
		}

		// 获取操作人姓名
		recorderName := "班主任"
		user, err := s.userRepo.GetByUserID(recorderID)
		if err == nil && user != nil {
			recorderName = user.RealName
		}

		statusText := map[string]string{
			"absent": "缺勤", "late": "迟到", "leave": "请假",
		}[status]

		// 使用事务确保操行分记录创建、总分更新、考勤标记的原子性
		db := s.semesterRepo.GetDB()
		txErr := db.Transaction(func(tx *gorm.DB) error {
			conductRecord := &model.ConductRecord{
				StudentID:    studentID,
				PointsChange: pointsChange,
				Reason:       fmt.Sprintf("考勤：%s", statusText),
				RecorderID:   recorderID,
				RecorderName: &recorderName,
				RelatedType:  "attendance",
				RelatedID:    &attendanceID,
				SemesterID:   semesterID,
			}
			if err := tx.Create(conductRecord).Error; err != nil {
				return err
			}
			if err := tx.Model(&model.Student{}).
				Where("student_id = ?", studentID).
				Update("total_points", gorm.Expr("GREATEST(total_points + ?, 0)", pointsChange)).Error; err != nil {
				return err
			}
			if err := tx.Model(&model.AttendanceRecord{}).
				Where("attendance_id = ?", attendanceID).
				Updates(map[string]interface{}{
					"deduction_applied":     1,
					"deduction_record_id":   conductRecord.RecordID,
				}).Error; err != nil {
				return err
			}
			return nil
		})
		if txErr != nil {
			logger.Sugared.Errorf("考勤扣分事务失败: attendance_id=%d, student_id=%d, err=%v", attendanceID, studentID, txErr)
			return map[string]interface{}{
				"success":          false,
				"message":          "考勤记录添加成功，但扣分失败，请手动处理",
				"attendance_id":    attendanceID,
				"deduction_failed": true,
			}, nil
		}

		logger.Sugared.Infof("用户[%d] 添加考勤记录[%d] -> %s (扣%d分)", recorderID, attendanceID, status, -pointsChange)
	}

	return map[string]interface{}{"success": true, "message": "考勤记录添加成功"}, nil
}

// GetRecords 获取考勤记录
func (s *AttendanceService) GetRecords(classID int, date string, studentID *int, slot string) (map[string]interface{}, error) {
	records, err := s.attendanceRepo.GetClassRecords(classID, date, derefInt(studentID), slot)
	if err != nil {
		return nil, err
	}
	return map[string]interface{}{"records": records}, nil
}

// getClassSettingValue 从 class_settings 读取设置值，若无则返回默认值
func (s *AttendanceService) getClassSettingValue(classID int, key, defaultVal string) string {
	if classID > 0 && s.classRepo != nil {
		setting, err := s.classRepo.GetSetting(classID, key)
		if err == nil && setting != nil && setting.SettingValue != "" {
			return setting.SettingValue
		}
	}
	return defaultVal
}

// getDeductionPoints 获取考勤扣分数值（优先从 class_settings 读取班级级配置）
func (s *AttendanceService) getDeductionPoints(classID int, status string) int {
	switch status {
	case "absent":
		val := s.getClassSettingValue(classID, "deduction_attendance_absent", "3")
		if v, err := strconv.Atoi(val); err == nil {
			return -v
		}
		return -3
	case "late":
		val := s.getClassSettingValue(classID, "deduction_attendance_late", "1")
		if v, err := strconv.Atoi(val); err == nil {
			return -v
		}
		return -1
	case "leave":
		val := s.getClassSettingValue(classID, "deduction_attendance_leave", "0")
		if v, err := strconv.Atoi(val); err == nil {
			return -v
		}
		return 0
	default:
		return 0
	}
}