gistfile1.txt

type Cache struct {
	Completions []string
	Timestamp   time.Time
}

const cacheFile = "completions_cache.gob"
const cacheExpiration = 1 * time.Hour

func addTabCompletionApp(cmd *cobra.Command, toComplete string) ([]string, cobra.ShellCompDirective) {
	cache, err := loadCache()
	if err == nil && time.Since(cache.Timestamp) < cacheExpiration {
		return filterCompletions(cache.Completions, toComplete), cobra.ShellCompDirectiveNoFileComp
	}

	latest, err := githubreleases.GetLatestReleases(true)
	if err != nil {
		cmd.PrintErrf("failed to load package manifest: %s\n", err)
		return nil, cobra.ShellCompDirectiveError
	}

	var completions []string
	for template := range latest {
		completions = append(completions, template)
	}

	saveCache(Cache{Completions: completions, Timestamp: time.Now()})
	return filterCompletions(completions, toComplete), cobra.ShellCompDirectiveNoFileComp
}

func filterCompletions(completions []string, toComplete string) []string {
	var filtered []string
	for _, c := range completions {
		if strings.HasPrefix(c, toComplete) {
			filtered = append(filtered, c)
		}
	}
	return filtered
}

func loadCache() (Cache, error) {
	file, err := os.Open(getCachePath())
	if err != nil {
		return Cache{}, err
	}
	defer file.Close()

	var cache Cache
	if err := gob.NewDecoder(file).Decode(&cache); err != nil {
		return Cache{}, err
	}
	return cache, nil
}

func saveCache(cache Cache) {
	file, err := os.Create(getCachePath())
	if err != nil {
		return
	}
	defer file.Close()

	gob.NewEncoder(file).Encode(cache)
}

func getCachePath() string {
	dir, err := os.UserCacheDir()
	if err != nil {
		return cacheFile
	}
	return filepath.Join(dir, cacheFile)
}