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 ChapterService struct{}

// CreateChapter 创建章节
func (chapterService *ChapterService) CreateChapter(ctx context.Context, chapter *learning.Chapter) (err error) {
	err = global.GVA_DB.WithContext(ctx).Create(chapter).Error
	return err
}

// DeleteChapter 删除章节
func (chapterService *ChapterService) DeleteChapter(ctx context.Context, ID string) (err error) {
	err = global.GVA_DB.WithContext(ctx).Delete(&learning.Chapter{}, ID).Error
	return err
}

// DeleteChapterByIds 批量删除章节
func (chapterService *ChapterService) DeleteChapterByIds(ctx context.Context, IDs []string) (err error) {
	err = global.GVA_DB.WithContext(ctx).Delete(&[]learning.Chapter{}, "id in ?", IDs).Error
	return err
}

// UpdateChapter 更新章节
func (chapterService *ChapterService) UpdateChapter(ctx context.Context, chapter learning.Chapter) (err error) {
	err = global.GVA_DB.WithContext(ctx).Model(&learning.Chapter{}).Where("id = ?", chapter.ID).Updates(&chapter).Error
	return err
}

// GetChapter 根据ID获取章节
func (chapterService *ChapterService) GetChapter(ctx context.Context, ID string) (chapter learning.Chapter, err error) {
	err = global.GVA_DB.WithContext(ctx).Where("id = ?", ID).First(&chapter).Error
	if err != nil {
		return
	}
	// 手动查询关联的课程信息
	if chapter.CourseId != 0 {
		var course learning.Course
		courseErr := global.GVA_DB.WithContext(ctx).Where("id = ?", chapter.CourseId).First(&course).Error
		if courseErr == nil {
			chapter.Course = course
		}
	}
	return
}

// GetChapterInfoList 分页获取章节列表
func (chapterService *ChapterService) GetChapterInfoList(ctx context.Context, info learningReq.ChapterSearch) (list []learning.Chapter, total int64, err error) {
	limit := info.PageSize
	offset := info.PageSize * (info.Page - 1)
	// 创建db
	db := global.GVA_DB.WithContext(ctx).Model(&learning.Chapter{})
	var chapters []learning.Chapter
	// 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.CourseId != 0 {
		db = db.Where("course_id = ?", info.CourseId)
	}
	err = db.Count(&total).Error
	if err != nil {
		return
	}

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

	err = db.Order("sort asc, created_at desc").Find(&chapters).Error
	if err != nil {
		return chapters, total, err
	}

	// 手动查询关联的课程信息
	courseIds := make([]uint, 0)
	courseMap := make(map[uint]learning.Course)

	for _, chapter := range chapters {
		if chapter.CourseId != 0 {
			courseIds = append(courseIds, chapter.CourseId)
		}
	}

	if len(courseIds) > 0 {
		var courses []learning.Course
		global.GVA_DB.WithContext(ctx).Where("id in ?", courseIds).Find(&courses)
		for _, course := range courses {
			courseMap[course.ID] = course
		}

		// 为每个章节设置课程信息
		for i := range chapters {
			if course, exists := courseMap[chapters[i].CourseId]; exists {
				chapters[i].Course = course
			}
		}
	}

	return chapters, total, err
}

// GetChaptersByCourse 根据课程ID获取章节列表
func (chapterService *ChapterService) GetChaptersByCourse(ctx context.Context, courseId uint) (list []learning.Chapter, err error) {
	err = global.GVA_DB.WithContext(ctx).Where("course_id = ? AND status = ?", courseId, "published").Order("sort asc, created_at asc").Find(&list).Error
	return
}

// UpdateChapterStatus 更新章节状态
func (chapterService *ChapterService) UpdateChapterStatus(ctx context.Context, ID string, status string) (err error) {
	err = global.GVA_DB.WithContext(ctx).Model(&learning.Chapter{}).Where("id = ?", ID).Update("status", status).Error
	return err
}