// Import modules
var URLManage = require(`./database/URLs`).URLManage;
var Messaging = require(`./utilities/messaging`).Messaging;
const bodyParser = require('body-parser');

class ShortenAPI {
    /*
        Paths used by this API. 
    */
    #paths = {
        "create": ["/api/shorturl"],
        "access": ["/:ID", "/api/shorturl/:ID"]
    }
    
    /*
        Create the URL shortener parser API. 

		@param {Express} INSTANCE - The Express instance
    */
    constructor (INSTANCE) {
        this[`instance`] = INSTANCE;
        this[`instance`].use(bodyParser.json());
        this[`instance`].use(bodyParser.urlencoded({extended: true}));

        this[`management`] = new URLManage;

        this.prepareRedirect();
        this.startCreation();
    }

    /*
        Redirect from the short link. 
    */
    prepareRedirect() {
        const findRedirect = (REQUEST, RESPONSE) => {
            const redirectBrowser = (URL) => {
                return((URL) ? RESPONSE.redirect(URL) : null);
            }

            try {
                ((Object.keys(REQUEST.params).length)
                    ? REQUEST.params.ID 
                    : false) ? 
                    this[`management`].open(REQUEST.params.ID, redirectBrowser)
                    : false;
            } catch(ERR) {
                Messaging.exception(RESPONSE, ERR);
            }
        };

        
        this.#paths[`access`].forEach((PATH) => {
            this[`instance`].get(PATH, findRedirect)
            console.log(`Redirection ready on ${PATH}.`);
        });
    }

    /*
        Enable receiving requests. 
    */
    startCreation() {
        const redirect = (REQUEST, RESPONSE) => {
            try {
                let QUERY = {};
                if ((REQUEST.body) ? Object.keys(REQUEST.body).length : false) {
                    QUERY = REQUEST.body;
                } else if ((REQUEST.query) ? Object.keys(REQUEST.query).length : false) {
                    QUERY = REQUEST.query;
                }

                let RESULT = {};
                RESULT[`original_url`] = QUERY[`url`];
    

                const sendRedirect = (HASH) => {
                    RESULT[`short_url`] = HASH;
                    RESPONSE.json(RESULT);
                }

                this[`management`].create(RESULT[`original_url`], sendRedirect);
            } catch(ERR) {
                Messaging.exception(RESPONSE, ERR);
            };
        };
        
        [`get`, `post`].forEach((METHOD) => {
            this.#paths[`create`].forEach((PATH) => {
                this[`instance`][METHOD](PATH, redirect);
                console.log(`Creation ready on ${PATH} for method ${METHOD}.`)
            });
        })
    }
}

module.exports = {ShortenAPI};