import * as cheerio from 'cheerio';
import { IncomingMessage } from 'http';
import http from 'https';

//making long regex rather than splitting the string at ":" because regex would be easier to debug than logic in the case the website changes
//while names cant have spaces, the name slot in ogtitle could be shown as "No Player Name" which has spaces
const uniteApiRegex = {
    //$1 = name, $2 = id
    ogtitle: /Unite API - ([\w\d ]+) \((.*)\)/,
    //$1 = level, $2 = rank, $3 = elo, $4 = battles, $5 = wins, $6 = win rate
    ogdescription: /Pokémon Unite : Lv.(\d+) (\w+) \((\d+)\)\n    Battles : (\d+)\n    Wins : (\d+)\n    Win Rate : (\d+)%/,
}

type uniteApiData = {
    name: string,
    id: string,

    level: string,
    rank: string,
    elo: string,
    battles: string,
    wins: string,
    winrate: string
}
/*
og:title
Unite API - IanWhysp (X188GF7)

og:description
Pokémon Unite : Lv.40 Master (1741)
    Battles : 1089
    Wins : 576
    Win Rate : 52%
*/

/**
 * gets the html of the uniteApi page for the player
 * @param name name of player
 * @returns the html of the page through a promise (rejects if the page status is not 200)
 */
function getHTML(name: string): Promise<string> {

    name = name.replace(/[^\w\d]/g, '');

    return new Promise((resolve, reject) => {
        
        const init = {
            host: 'uniteapi.dev',
            path: `/p/${encodeURIComponent(name)}`,
            method: 'GET',
        };

        const callback = (response: IncomingMessage) => {
            
            if (response.statusCode !== 200) {
                reject(`HTTP ERROR ${response.statusCode}: ${response.statusMessage}`);
                return;
            }

            let result = Buffer.alloc(0);
            response.on('data', function(chunk) {
                result = Buffer.concat([result, chunk]);
            });
            
            response.on('end', function() {
                // result has response body buffer
                resolve(result.toString());
            });
        };

        const req = http.request(init, callback);
        req.end();

    });

}

/**
 * interprets the html from getHTML()
 * @param name name of player
 * @returns player data from site
 */
function readHTML(html: string): uniteApiData {
    let metaElems = cheerio.load(html)('meta').toArray(),
        foundData: uniteApiData = {
            name: "",
            id: "",

            level: "",
            rank: "",
            elo: "",
            battles: "",
            wins: "",
            winrate: ""
        };
    
    //filter down to just ones named "og:..."
    metaElems = metaElems.filter(el => el.attribs.property?.startsWith('og:'));

    metaElems.forEach(el => {
        let attr = el.attribs;

        if (attr.property === 'og:title') {
            let data = uniteApiRegex.ogtitle.exec(attr.content);
            if (data !== null && data.length >= 3) {
                foundData.name = data[1];
                foundData.id = data[2];
            }
        } else if (attr.property === 'og:description') {
            let data = uniteApiRegex.ogdescription.exec(attr.content);
            if (data !== null && data.length >= 7) {
                foundData.level = data[1];
                foundData.rank = data[2];
                foundData.elo = data[3];
                foundData.battles = data[4];
                foundData.wins = data[5];
                foundData.winrate = data[6];
            }
        }

    })

    return foundData;

}

/**
 * verifies the data
 * @param data uniteApi data
 * @returns boolean, valid or invalid
 */
function verifyData(data: uniteApiData): boolean {
    if (data.id.length)
        return true;
    return false;
}

/**
 * gets player data from uniteApi
 * @param name name of player
 * @returns player data
 */
export async function getPlayer(name: string): Promise<uniteApiData|null> {
    let html = await getHTML(name);
    let data = readHTML(html);
    if (verifyData(data))
        return data;
    return null;
}

//await getPlayer('IanWhysp')