package learning

import (
	"context"

	"github.com/flipped-aurora/gin-vue-admin/server/global"
	"github.com/flipped-aurora/gin-vue-admin/server/model/learning"
	learningReq "github.com/flipped-aurora/gin-vue-admin/server/model/learning/request"
)

type CourseService struct{}

// CreateCourse 创建课程
func (courseService *CourseService) CreateCourse(ctx context.Context, course *learning.Course) (err error) {
	err = global.GVA_DB.WithContext(ctx).Create(course).Error
	return err
}

// DeleteCourse 删除课程
func (courseService *CourseService) DeleteCourse(ctx context.Context, ID string) (err error) {
	err = global.GVA_DB.WithContext(ctx).Delete(&learning.Course{}, ID).Error
	return err
}

// DeleteCourseByIds 批量删除课程
func (courseService *CourseService) DeleteCourseByIds(ctx context.Context, IDs []string) (err error) {
	err = global.GVA_DB.WithContext(ctx).Delete(&[]learning.Course{}, "id in ?", IDs).Error
	return err
}

// UpdateCourse 更新课程
func (courseService *CourseService) UpdateCourse(ctx context.Context, course learning.Course) (err error) {
	err = global.GVA_DB.WithContext(ctx).Model(&learning.Course{}).Where("id = ?", course.ID).Updates(&course).Error
	return err
}

// GetCourse 根据ID获取课程
func (courseService *CourseService) GetCourse(ctx context.Context, ID string) (course learning.Course, err error) {
	err = global.GVA_DB.WithContext(ctx).Where("id = ?", ID).First(&course).Error
	return
}

// GetCourseInfoList 分页获取课程列表
func (courseService *CourseService) GetCourseInfoList(ctx context.Context, info learningReq.CourseSearch) (list []learning.Course, total int64, err error) {
	limit := info.PageSize
	offset := info.PageSize * (info.Page - 1)
	// 创建db
	db := global.GVA_DB.WithContext(ctx).Model(&learning.Course{})
	var courses []learning.Course
	// 如果有条件搜索 下方会自动创建搜索语句
	if info.StartCreatedAt != nil && info.EndCreatedAt != nil {
		db = db.Where("created_at BETWEEN ? AND ?", info.StartCreatedAt, info.EndCreatedAt)
	}
	if info.Title != "" {
		db = db.Where("title LIKE ?", "%"+info.Title+"%")
	}
	if info.Status != "" {
		db = db.Where("status = ?", info.Status)
	}
	if info.Difficulty != "" {
		db = db.Where("difficulty = ?", info.Difficulty)
	}
	err = db.Count(&total).Error
	if err != nil {
		return
	}

	if limit != 0 {
		db = db.Limit(limit).Offset(offset)
	}

	err = db.Order("sort desc, created_at desc").Find(&courses).Error
	return courses, total, err
}

// GetPublishedCourses 获取已发布的课程列表（供学员选择）
func (courseService *CourseService) GetPublishedCourses(ctx context.Context) (list []learning.Course, err error) {
	err = global.GVA_DB.WithContext(ctx).Where("status = ?", "published").Order("sort desc, created_at desc").Find(&list).Error
	return
}

// UpdateCourseStatus 更新课程状态
func (courseService *CourseService) UpdateCourseStatus(ctx context.Context, ID string, status string) (err error) {
	err = global.GVA_DB.WithContext(ctx).Model(&learning.Course{}).Where("id = ?", ID).Update("status", status).Error
	return err
}