"use strict";

module.exports = function(msg, rules) {
    if (!rules || !Array.isArray(rules)) {
        return null;
    }

    for (let rule of rules) {
        if (!rule.pattern || !rule.value) return null;

        const re = new RegExp(rule.pattern, rule.flags);
        if (msg.search(re) >= 0) {
            return rule.value;
        }
    }

    return null;
}