package main

import (
	"sync"
	"time"
)

type CachedArticle struct {
	Article   *Article
	CacheTime time.Time
}

type IndexCache struct {
	sync.RWMutex
	Cache map[string]*CachedArticle
}

func NewIndexCache() *IndexCache {
	return &IndexCache{Cache: make(map[string]*CachedArticle)}
}

func (ic IndexCache) Add(title string, a *Article) {
	now := time.Now()
	ic.Lock()
	defer ic.Unlock()
	c, ok := ic.Cache[title]
	if ok && now.After(c.CacheTime) {
		c.Article = a
		c.CacheTime = now
		ic.Cache[title] = c
		return
	}
	ic.Cache[title] = &CachedArticle{a, now}
}

func (ic IndexCache) Get(title string) *Article {
	ic.RLock()
	defer ic.RUnlock()
	if a, ok := ic.Cache[title]; ok {
		return a.Article
	}
	return nil
}

func (ic *IndexCache) Delete(title string) {
	ic.Lock()
	delete(ic.Cache, title)
	ic.Unlock()
}