'use strict';

// Public modules from npm
const isUrl = require("is-url-superb");
const ky = require("ky-universal").create({
    throwHttpErrors: false
});

// Modules from file
const {
    F95_BASE_URL
} = require('./constants/urls.js');

/**
 * @protected
 * Check if the url belongs to the domain of the F95 platform.
 * @param {String} url URL to check
 * @returns {Boolean} true if the url belongs to the domain, false otherwise
 */
module.exports.isF95URL = function(url) {
    if (url.toString().startsWith(F95_BASE_URL)) return true;
    else return false;
}

/**
 * @protected
 * Checks if the string passed by parameter has a properly formatted and valid path to a URL.
 * @param {String} url String to check for correctness
 * @returns {Boolean} true if the string is a valid URL, false otherwise
 */
module.exports.isStringAValidURL = function(url) {
    try {
        new URL(url);
        return true;
    } catch (err) {
        return false;
    }
}

/**
 * @public
 * Check if a particular URL is valid and reachable on the web.
 * @param {String} url URL to check
 * @param {Boolean} checkRedirect If true, the function will consider redirects a violation and return false
 * @returns {Promise<Boolean>} true if the URL exists, false otherwise
 */
module.exports.urlExists = async function(url, checkRedirect) {
    if (!isUrl(url)) {
        return false
    }

    const response = await ky.head(url);
    let valid = response !== undefined && !/4\d\d/.test(response.status);

    if(!valid) return false;

    if(checkRedirect) {
        if (response.url === url) valid = true;
        else valid = false;
    }
    
    return valid;
}