package db

import (
	"git.obamna.ru/erius/ozon-task/graph/model"
	"gorm.io/gorm"
)

type Database struct {
	db *gorm.DB
}

func (s *Database) AddPost(input *model.PostInput) (*model.AddResult, error) {
	post := model.PostFromInput(input)
	err := s.db.Create(post).Error
	return &model.AddResult{ItemID: &post.ID}, err
}

func (s *Database) AddComment(input *model.CommentInput) (*model.AddResult, error) {
	comment := model.CommentFromInput(input)
	if input.ParentPostID == nil {
		// multiple operations performed in one transaction
		err := s.db.Transaction(func(tx *gorm.DB) error {
			var parent model.Comment
			// find parent comment in db
			err := s.db.First(&parent, *input.ParentCommentID).Error
			if err != nil {
				return err
			}
			// set new comment fields to reference parent post and comment
			comment.ReplyTo = &parent
			comment.PostID = parent.PostID
			// insert comment
			err = s.db.Create(comment).Error
			if err != nil {
				return err
			}
			// add new reply to parent and save
			parent.Replies = append(parent.Replies, comment)
			err = s.db.Save(parent).Error
			if err != nil {
				return err
			}
			return nil
		})
		if err != nil {
			return nil, err
		}
	} else {
		comment.PostID = *input.ParentPostID
		err := s.db.Create(comment).Error
		if err != nil {
			return nil, err
		}
	}
	return &model.AddResult{ItemID: &comment.ID}, nil
}

func (s Database) GetPosts() ([]*model.Post, error) {
	var posts []*model.Post
	err := s.db.Find(&posts).Error
	return posts, err
}