/**
 * @license
 * SPDX-License-Identifier: Apache-2.0
 */
import '../environment/dev';
import { ensureTokenIsValid, secretToken } from './secrets';
/**
 * Sequence of CSS declarations safe to use in style contexts in an HTML
 * document or in DOM APIs.
 */
export class SafeStyle {
    // @ts-ignore: error TS6133: 'brand' is declared but its value is never read.
    brand; // To prevent structural typing.
}
/** Implementation for `SafeStyle` */
class StyleImpl extends SafeStyle {
    privateDoNotAccessOrElseWrappedStyle;
    constructor(style, token) {
        super();
        if (process.env.NODE_ENV !== 'production') {
            ensureTokenIsValid(token);
        }
        this.privateDoNotAccessOrElseWrappedStyle = style;
    }
    toString() {
        return this.privateDoNotAccessOrElseWrappedStyle;
    }
}
/**
 * Builds a new `SafeStyle` from the given string, without enforcing
 * safety guarantees. This shouldn't be exposed to application developers, and
 * must only be used as a step towards safe builders or safe constants.
 */
export function createStyle(style) {
    return new StyleImpl(style, secretToken);
}
/**
 * Checks if the given value is a `SafeStyle` instance.
 */
export function isStyle(value) {
    return value instanceof StyleImpl;
}
/**
 * Returns the string value of the passed `SafeStyle` object while ensuring it
 * has the correct type.
 */
export function unwrapStyle(value) {
    if (value instanceof StyleImpl) {
        return value.privateDoNotAccessOrElseWrappedStyle;
    }
    else {
        let message = '';
        if (process.env.NODE_ENV !== 'production') {
            message = 'Unexpected type when unwrapping SafeStyle';
        }
        throw new Error(message);
    }
}