photo

type Creator struct {
	Name string `yaml:"name"`
	Link string `yaml:"link"`
}

type Info struct {
	// Key is a special value that is usually set.
	Key string

	// Meta is the photo metadata.
	*Meta

	// File, if not nil, holds a reference to a file handle open for reading the
	// image.
	*os.File
}

type Meta struct {
	Link  string `yaml:"link"`
	Type  string `yaml:"type"`
	Title string `yaml:"title,omitempty"`
	Color string `yaml:"color,omitempty"`
	Creator
}

type Option func(*options)

type Service struct {
	Source
	Client *http.Client
}

type Source interface {
	// CacheKey returns the cache key for a given URL. If the source does not
	// have a value for the URL, it returns false.
	CacheKey(url string) (string, bool)

	// Meta returns the photo info for a given URL.
	Photo(ctx context.Context, url string) (info *Info, err error)

	// Download downloads the photo and attaches it to the given Info.
	Download(ctx context.Context, info *Info) error
}