package questionnaire_template

import (
	"fmt"
	"surveyService/model"
	"surveyService/response"
	"surveyService/service/questionnaire_subject"
	"surveyService/validators"

	"github.com/samber/lo"
	"gorm.io/gorm"
)

// 获取问题模板下的问题库列表
func ListSubjects(templateId int64) []*model.QuestionnaireTemplateSubject {
	var subjects []*model.QuestionnaireTemplateSubject

	// 获取问题模板下的问题库列表
	model.DB.Where("template_id = ?", templateId).Preload("Subject").Order("sort asc").Order("id asc").Find(&subjects)

	return subjects
}

// 删除问题模板下的问题库
func DeleteSubject(templateId int64, subjectIds []int64) *response.ErrCode {
	model.DB.Where("template_id = ?", templateId).Where("id in (?)", subjectIds).Delete(&model.QuestionnaireTemplateSubject{})

	return nil
}

// 添加问题模板下的问题库
func AddSubject(templateId int64, subjectIds []int64) *response.ErrCode {
	// 检查模板是否存在
	_, findErr := Find(templateId)
	if findErr != nil {
		return findErr
	}

	if len(subjectIds) > 0 {
		// 检查问题是否都存在
		existsSubjects := questionnaire_subject.ListByIds(subjectIds)
		if len(existsSubjects) < len(subjectIds) {
			return &response.ErrCode{
				Code: response.ERROR,
				Msg:  fmt.Sprintf("有%d个问题无效或不存在", len(subjectIds)-len(existsSubjects)),
			}
		}

		// 将已经存在的问题模板下的问题过滤掉
		var existsSubjectIds []int64
		model.DB.Model(&model.QuestionnaireTemplateSubject{}).Where("template_id = ?", templateId).Where("subject_id in (?)", subjectIds).Pluck("subject_id", &existsSubjectIds)

		// 取差集
		diffSubjectIds, _ := lo.Difference(subjectIds, existsSubjectIds)

		if len(diffSubjectIds) > 0 {
			var templateSubjects []*model.QuestionnaireTemplateSubject
			for _, subjectId := range diffSubjectIds {
				templateSubjects = append(templateSubjects, &model.QuestionnaireTemplateSubject{
					TemplateID: templateId,
					SubjectID:  subjectId,
					Sort:       999,
				})
			}

			// 批量插入
			model.DB.CreateInBatches(&templateSubjects, 100)
		}
	}
	return nil
}

// 批量修改排序
func UpdateSort(templateId int64, templateSubjectIds []int64) *response.ErrCode {
	// 检查模板是否存在
	_, findErr := Find(templateId)
	if findErr != nil {
		return findErr
	}

	if len(templateSubjectIds) > 0 {
		sqlExpr := "case id"
		for templateSubjectIndex, templateSubjectId := range templateSubjectIds {
			sqlExpr += " when " + fmt.Sprint(templateSubjectId) + " then " + fmt.Sprint(templateSubjectIndex+1)
		}
		sqlExpr += " else sort end"
		model.DB.Model(&model.QuestionnaireTemplateSubject{}).Where("template_id = ?", templateId).Update("sort", gorm.Expr(sqlExpr))
	}

	return nil
}

// 格式化
func FormatTemplateSubject(templateSubject *model.QuestionnaireTemplateSubject) *validators.QuestionnaireTemplateSubject {
	return &validators.QuestionnaireTemplateSubject{
		ID:                   templateSubject.ID,
		Sort:                 templateSubject.Sort,
		QuestionnaireSubject: questionnaire_subject.Format(&templateSubject.Subject),
	}
}