package internal

import (
	"sync"
	"time"
)

type CacheItem[T any] struct {
	item       T
	imutex     sync.Mutex
	expiry     time.Time
	TTLSeconds uint
	FetchFunc  func() (T, error)
}

func (c *CacheItem[T]) Get() (T, error) {
	c.imutex.Lock()
	defer c.imutex.Unlock()

	if !c.expiry.After(time.Now()) {
		c.expiry = time.Now().Add(time.Duration(c.TTLSeconds) * time.Second)

		item, err := c.FetchFunc()
		if err != nil {
			return item, err
		}

		c.item = item
	}

	return c.item, nil
}

func (c *CacheItem[T]) Invalidate() {
	c.imutex.Lock()
	defer c.imutex.Unlock()
	c.expiry = time.Now()
}

func NewCache[T any](fetchfunc func() (T, error), ttl uint) CacheItem[T] {
	return CacheItem[T]{
		TTLSeconds: ttl,
		FetchFunc:  fetchfunc,
	}
}