"use strict";
Object.defineProperty(exports, "__esModule", { value: true });
const DEFAULT_MAX_AGE = 180 * 24 * 60 * 60;
function parseMaxAge(value) {
    if (value === undefined) {
        return DEFAULT_MAX_AGE;
    }
    else if (typeof value === "number" &&
        value >= 0 &&
        Number.isFinite(value)) {
        return Math.floor(value);
    }
    else {
        throw new Error(`Strict-Transport-Security: ${JSON.stringify(value)} is not a valid value for maxAge. Please choose a positive integer.`);
    }
}
function getHeaderValueFromOptions(options) {
    if ("maxage" in options) {
        throw new Error("Strict-Transport-Security received an unsupported property, `maxage`. Did you mean to pass `maxAge`?");
    }
    if ("includeSubdomains" in options) {
        console.warn('Strict-Transport-Security middleware should use `includeSubDomains` instead of `includeSubdomains`. (The correct one has an uppercase "D".)');
    }
    if ("setIf" in options) {
        console.warn("Strict-Transport-Security middleware no longer supports the `setIf` parameter. See the documentation and <https://github.com/helmetjs/helmet/wiki/Conditionally-using-middleware> if you need help replicating this behavior.");
    }
    const directives = [`max-age=${parseMaxAge(options.maxAge)}`];
    if (options.includeSubDomains === undefined || options.includeSubDomains) {
        directives.push("includeSubDomains");
    }
    if (options.preload) {
        directives.push("preload");
    }
    return directives.join("; ");
}
function strictTransportSecurity(options = {}) {
    const headerValue = getHeaderValueFromOptions(options);
    return function strictTransportSecurityMiddleware(_req, res, next) {
        res.setHeader("Strict-Transport-Security", headerValue);
        next();
    };
}
module.exports = strictTransportSecurity;
exports.default = strictTransportSecurity;