cpolis/cmd/data/articles.go

package data

import (
	"sync"
	"time"

	"github.com/google/uuid"
)

type Article struct {
	Title   string
	Created time.Time
	Desc    string
	Content string
	Tags    []string
	UUID    uuid.UUID
}

type ArticleList struct {
	addCh chan *Article
	delCh chan uuid.UUID
	retCh chan *Article
	getCh chan []Article
	list  []*Article
	wg    sync.WaitGroup
}

func minArticleList() *ArticleList {
	return &ArticleList{
		addCh: make(chan *Article),
		delCh: make(chan uuid.UUID),
		retCh: make(chan *Article),
		getCh: make(chan []Article),
	}
}

func (l *ArticleList) start() {
	l.wg.Done()
	for {
		select {
		case article := <-l.addCh:
			l.list = append(l.list, article)
		case uuid := <-l.delCh:
			for i, article := range l.list {
				if article.UUID == uuid {
					l.list = append(l.list[:i], l.list[i+1:]...)
					l.retCh <- article
				}
			}
		case l.getCh <- func() []Article {
			var list []Article
			for _, article := range l.list {
				list = append(list, *article)
			}
			return list
		}():
		}
	}
}

func NewArticleList() *ArticleList {
	list := minArticleList()
	list.list = []*Article{}

	list.wg.Add(1)
	go list.start()
	list.wg.Wait()

	return list
}

func (l *ArticleList) Add(a *Article) {
	l.addCh <- a
}

func (l *ArticleList) Release(uuid uuid.UUID) (*Article, bool) {
	l.delCh <- uuid
	article := <-l.retCh
	if article == nil {
		return nil, false
	}
	return article, true
}

func (l *ArticleList) Get() []Article {
	return <-l.getCh
}