package service

import (
	"exam_registration/internal/dao"
	"exam_registration/internal/model"
	"errors"
	"fmt"
	"time"
)

type ExamService struct{}

func (s *ExamService) CreateExam(exam *model.Exam) error {
	// 验证时间逻辑
	if exam.StartTime.Before(time.Now()) {
		return errors.New("考试开始时间不能早于当前时间")
	}
	if exam.EndTime.Before(exam.StartTime) {
		return errors.New("考试结束时间不能早于开始时间")
	}
	if exam.RegistrationEnd.Before(exam.RegistrationStart) {
		return errors.New("报名截止时间不能早于开始时间")
	}

	return dao.DB.Create(exam).Error
}

func (s *ExamService) GetExamByID(id uint64) (*model.Exam, error) {
	var exam model.Exam
	if err := dao.DB.First(&exam, id).Error; err != nil {
		return nil, errors.New("考试不存在")
	}
	return &exam, nil
}

func (s *ExamService) GetExamList(page, pageSize int) ([]model.Exam, int64, error) {
	var exams []model.Exam
	var total int64

	offset := (page - 1) * pageSize
	
	if err := dao.DB.Model(&model.Exam{}).Count(&total).Error; err != nil {
		return nil, 0, err
	}

	err := dao.DB.Offset(offset).Limit(pageSize).Order("id DESC").Find(&exams).Error
	return exams, total, err
}

func (s *ExamService) UpdateExam(id uint64, updates map[string]interface{}) error {
	return dao.DB.Model(&model.Exam{}).Where("id = ?", id).Updates(updates).Error
}

func (s *ExamService) DeleteExam(id uint64) error {
	return dao.DB.Delete(&model.Exam{}, id).Error
}

func (s *ExamService) UpdateExamStatus(id uint64, status int) error {
	// 更新考试状态并同步更新相关报名记录的状态
	return dao.DB.Transaction(func(tx *dao.DB) error {
		if err := tx.Model(&model.Exam{}).Where("id = ?", id).Update("status", status).Error; err != nil {
			return err
		}
		return nil
	})
}