import * as cheerio from 'cheerio';
import { CommandInteraction, MessageEmbed } from 'discord.js';
import { IncomingMessage } from 'http';
import http from 'https';
import { emsg } from './util';

const uniteApiRegex = {
    //$1 = name, $2 = id
    ogtitle: /unite api - (.+) \((.*)\)/i,
    //$1 = level, $2 = rank, $3 = elo/class (rest is found by splitting each line)
    ogdescription: [ //just the first line
        /lv\.(\d+) (\w+) \((\d+)\)/i,   //master
        /lv\.(\d+) (\w+): class (\d+)/i //other
    ]
}

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

    level: string,
    rank: string,
    class: string|null,
    elo: string|null,
    battles: string,
    wins: string,
    winrate: string
}

/**
 * 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', chunk => {
                result = Buffer.concat([result, chunk]);
            });
            
            response.on('end', () => {
                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
 * @throws errorMessage class if the request fails
 */
function readHTML(html: string): uniteApiData {
    let $ = cheerio.load(html)
    let metaElems = $('meta').toArray(),
        foundData: uniteApiData = {
            name: "",
            id: "",
            avatar: "",

            level: "",
            rank: "",
            elo: null,
            class: null,
            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') {

            //all lines
            let lines = attr.content.split('\n').map(l => l.trim()),
                extraLines: string[] = [];

            //ensure first line is correct
            while (lines.length && !/pok.mon unite/i.test(lines[0])) {
                let line = lines.shift();
                if (line)
                    extraLines.push(line);
            }

            if (!lines.length)
                throw emsg('Unable to read data, please try again');
            
            //bring the first lines removed back into the data
            lines = [
                ...lines,
                ...extraLines.filter(d => d)
            ];
            
            //first line
            {
                //will be only text after "pokemon unite:"
                let line = lines[0].split(':').slice(1).join(':').trim();
                
                let regex = uniteApiRegex.ogdescription;

                if (regex[0].test(line)) { //is master/has elo

                    let regexData = line.match(regex[0]);

                    if (!regexData || regexData.length < 4)
                        throw emsg('Unable to read data, please try again');

                    foundData.level = regexData[1];
                    foundData.rank = regexData[2];
                    foundData.elo = regexData[3];

                } else { //is not master/has a class

                    let regexData = line.match(regex[1]);

                    if (!regexData || regexData.length < 4)
                        throw emsg('Unable to read data, please try again');

                    foundData.level = regexData[1];
                    foundData.rank = regexData[2];
                    foundData.class = regexData[3];

                }

            }

            lines.shift();
            
            //rest of lines
            lines.forEach(line => {

                let split = line.split(':').map(l => l.trim()),
                    key = split[0].toLowerCase().replace(/[^\w]/g, ''),
                    value = split[1];

                switch(key) {
                    case 'battles':
                        foundData.battles = value;
                        break;
                    case 'wins':
                        foundData.wins = value;
                        break;
                    case 'winrate':
                        foundData.winrate = value;
                        break;
                }

            });

        }

    });

    foundData.avatar = $('.player-card-image img').attr('src') || "";
    foundData.avatar = foundData.avatar.replace('../', 'https://uniteapi.dev/');

    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;
}

async function sendPlayerEmbed(interaction: CommandInteraction, data: uniteApiData) {

    let embed = new MessageEmbed()
        .setTitle(`${data.name} (${data.id})`)
        .setURL(`https://uniteapi.dev/p/${encodeURIComponent(data.name)}`)
        .setTimestamp()
        .setThumbnail(data.avatar)
        .setDescription(`Level ${data.level}
${data.rank} ${data.elo ? `(${data.elo})` : `Class ${data.class}`}

**Battles** ${data.battles}
**Wins** ${data.wins}
**Win Rate** ${data.winrate}`);

    await interaction.editReply({embeds: [embed]});
}

/**
 * calls getPlayer() with the name from the interaction
 * @param interaction discord interaction
 * @throws errorMessage class if the user cannot be found
 */
export async function getPlayerInteraction(interaction: CommandInteraction) {
    let username = interaction.options.getString('username', true);
    await interaction.deferReply();
    
    let data = await getPlayer(username);
    if (data === null)
        throw emsg('api.noUser');
    else
        sendPlayerEmbed(interaction, data);
}