/**
 * @fileoverview Interpolate keys from an object into a string with {{ }} markers.
 * @author Jed Fox
 */

"use strict";

//------------------------------------------------------------------------------
// Public Interface
//------------------------------------------------------------------------------

/**
 * Returns a global expression matching placeholders in messages.
 * @returns {RegExp} Global regular expression matching placeholders
 */
function getPlaceholderMatcher() {
    return /\{\{([^{}]+?)\}\}/gu;
}

/**
 * Replaces {{ placeholders }} in the message with the provided data.
 * Does not replace placeholders not available in the data.
 * @param {string} text Original message with potential placeholders
 * @param {Record<string, string>} data Map of placeholder name to its value
 * @returns {string} Message with replaced placeholders
 */
function interpolate(text, data) {
    if (!data) {
        return text;
    }

    const matcher = getPlaceholderMatcher();

    // Substitution content for any {{ }} markers.
    return text.replace(matcher, (fullMatch, termWithWhitespace) => {
        const term = termWithWhitespace.trim();

        if (term in data) {
            return data[term];
        }

        // Preserve old behavior: If parameter name not provided, don't replace it.
        return fullMatch;
    });
}

module.exports = {
    getPlaceholderMatcher,
    interpolate
};