package service

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

type RegistrationService struct{}

func (s *RegistrationService) CreateRegistration(userID, examID uint64, remark string) error {
	// 检查考试是否存在
	var exam model.Exam
	if err := dao.DB.First(&exam, examID).Error; err != nil {
		return errors.New("考试不存在")
	}

	// 检查报名时间
	now := time.Now()
	if now.Before(exam.RegistrationStart) {
		return errors.New("尚未开始报名")
	}
	if now.After(exam.RegistrationEnd) {
		return errors.New("报名已截止")
	}

	// 检查是否已报名
	var existingReg model.ExamRegistration
	if err := dao.DB.Where("user_id = ? AND exam_id = ?", userID, examID).First(&existingReg).Error; err == nil {
		return errors.New("您已经报过名了")
	}

	// 检查考试容量
	if exam.MaxCandidates > 0 {
		var count int64
		dao.DB.Model(&model.ExamRegistration{}).Where("exam_id = ? AND status IN (?)", []int{0, 1}).Count(&count)
		if count >= int64(exam.MaxCandidates) {
			return errors.New("报名人数已满")
		}
	}

	registration := model.ExamRegistration{
		UserID:        userID,
		ExamID:        examID,
		Status:        0, // 待审核
		PaymentStatus: 0, // 未支付
		Remark:        remark,
	}

	return dao.DB.Create(&registration).Error
}

func (s *RegistrationService) GetRegistrationList(userID, examID, page, pageSize int) ([]model.ExamRegistration, int64, error) {
	var registrations []model.ExamRegistration
	var total int64

	offset := (page - 1) * pageSize
	query := dao.DB.Model(&model.ExamRegistration{}).Preload("User").Preload("Exam")

	if userID > 0 {
		query = query.Where("user_id = ?", userID)
	}
	if examID > 0 {
		query = query.Where("exam_id = ?", examID)
	}

	if err := query.Count(&total).Error; err != nil {
		return nil, 0, err
	}

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

func (s *RegistrationService) AuditRegistration(regID uint64, status int, comment string) error {
	now := time.Now()
	updates := map[string]interface{}{
		"status":       status,
		"audit_time":   now,
		"audit_comment": comment,
	}

	if status == 1 { // 审核通过，生成准考证号
		ticketNumber := fmt.Sprintf("TKT%d%d", regID, now.Unix())
		updates["ticket_number"] = ticketNumber
		// TODO: 编排考场座位
	}

	return dao.DB.Model(&model.ExamRegistration{}).Where("id = ?", regID).Updates(updates).Error
}

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

func (s *RegistrationService) DeleteRegistration(regID uint64) error {
	return dao.DB.Delete(&model.ExamRegistration{}, regID).Error
}