import {LiteralUnion} from 'type-fest';

export interface Options {
	/**
	[Size](https://en.gravatar.com/site/implement/images/#size) of the image. Values: `1..2048`.

	@default 80
	*/
	readonly size?: number;

	/**
	[Image](https://en.gravatar.com/site/implement/images/#default-image) to return if the identifier didn't match any Gravatar profile. Either a ustom URL or [`404`](https://gravatar.com/avatar/5cc22f8c06631cccead907acbb627b69?default=404), [`mm`](https://gravatar.com/avatar/5cc22f8c06631cccead907acbb627b69?default=mm), [`identicon`](https://gravatar.com/avatar/5cc22f8c06631cccead907acbb627b69?default=identicon), [`monsterid`](https://gravatar.com/avatar/5cc22f8c06631cccead907acbb627b69?default=monsterid), [`wavatar`](https://gravatar.com/avatar/5cc22f8c06631cccead907acbb627b69?default=wavatar), [`retro`](https://gravatar.com/avatar/5cc22f8c06631cccead907acbb627b69?default=retro), [`blank`](https://gravatar.com/avatar/5cc22f8c06631cccead907acbb627b69?default=blank).

	@default 'https://gravatar.com/avatar/00000000000000000000000000000000'
	*/
	readonly default?: LiteralUnion<'404' | 'mm' | 'identicon' | 'monsterid' | 'wavatar' | 'retro' | 'blank', string>;

	/**
	Allowed [rating](https://en.gravatar.com/site/implement/images/#rating) of the image.

	@default 'g'
	*/
	readonly rating?: 'g' | 'pg' | 'r' | 'x';
}

/**
Get the URL to a Gravatar image from an identifier, such as an email.

@param identifier - Identifier for which to get the Gravatar image. This will typically be an email matching a Gravatar profile, but can technically be any string. The Gravatar service only sees a hash of the identifier, so you could actually use this to get pseudo-random avatars for any entity, e.g. based on its ID. Note that if the identifier contains an `@`, it is assumed to be an email, and will therefore be lower-cased and trimmed before hashing, as per the Gravatar instructions - otherwise it will be hashed as-is.

@example
```
import gravatarUrl from 'gravatar-url';

gravatarUrl('sindresorhus@gmail.com', {size: 200});
//=> 'https://gravatar.com/avatar/d36a92237c75c5337c17b60d90686bf9?size=200'
```
*/
export default function gravatarUrl(identifier: string, options?: Options): string;