/**
 * @module adaptive-expressions
 */
/**
 * Copyright (c) Microsoft Corporation. All rights reserved.
 * Licensed under the MIT License.
 */

import { EvaluateExpressionDelegate, ExpressionEvaluator } from '../expressionEvaluator';
import { ExpressionType } from '../expressionType';
import { FunctionUtils } from '../functionUtils';
import { ReturnType } from '../returnType';
import atob from 'atob-lite';

/**
 * Return the string version of a data uniform resource identifier (URI).
 */
export class DataUriToString extends ExpressionEvaluator {
    /**
     * Initializes a new instance of the [DataUriToString](xref:adaptive-expressions.DataUriToString) class.
     */
    constructor() {
        super(
            ExpressionType.DataUriToString,
            DataUriToString.evaluator(),
            ReturnType.String,
            FunctionUtils.validateUnary
        );
    }

    /**
     * @private
     */
    private static evaluator(): EvaluateExpressionDelegate {
        return FunctionUtils.apply(
            (args: any[]): string => atob(args[0].slice(args[0].indexOf(',') + 1)),
            FunctionUtils.verifyString
        );
    }
}