import {db} from '../databases/databases';
import {config} from '../config';
import {Request, Response} from 'express';
import fetch from 'node-fetch';
import {Logger} from '../utils/logger';

// A cache of the number of chrome web store users
let chromeUsersCache = 0;
let firefoxUsersCache = 0;

// By the privacy friendly user counter
let apiUsersCache = 0;

let lastUserCountCheck = 0;

export async function getTotalStats(req: Request, res: Response) {
    let row = await db.prepare('get', `SELECT COUNT(DISTINCT "userID") as "userCount", COUNT(*) as "totalSubmissions",
        SUM("views") as "viewCount", SUM(("endTime" - "startTime") / 60 * "views") as "minutesSaved" FROM "sponsorTimes" WHERE "shadowHidden" != 1 AND "votes" >= 0`, []);

    if (row !== undefined) {
        let extensionUsers = chromeUsersCache + firefoxUsersCache;

        //send this result
        res.send({
            userCount: row.userCount,
            activeUsers: extensionUsers,
            apiUsers: Math.max(apiUsersCache, extensionUsers),
            viewCount: row.viewCount,
            totalSubmissions: row.totalSubmissions,
            minutesSaved: row.minutesSaved,
        });

        // Check if the cache should be updated (every ~14 hours)
        let now = Date.now();
        if (now - lastUserCountCheck > 5000000) {
            lastUserCountCheck = now;

            updateExtensionUsers();
        }
    }
}

function updateExtensionUsers() {
    if (config.userCounterURL) {
        fetch(config.userCounterURL + "/api/v1/userCount")
        .then(res => res.json())
        .then(data => {
            apiUsersCache = Math.max(apiUsersCache, data.userCount);
        })
        .catch(() => Logger.debug("Failing to connect to user counter at: " + config.userCounterURL));
    }
    
    const mozillaAddonsUrl = "https://addons.mozilla.org/api/v3/addons/addon/sponsorblock/";
    const chromeExtensionUrl = "https://chrome.google.com/webstore/detail/sponsorblock-for-youtube/mnjggcdmjocbbbhaepdhchncahnbgone";
    
    fetch(mozillaAddonsUrl)
    .then(res => res.json())
    .then(data => {
        firefoxUsersCache = data.average_daily_users;
        
        fetch(chromeExtensionUrl)
        .then(res => res.text())
        .then(body => {
            // 2021-01-05
            // [...]<span><meta itemprop="interactionCount" content="UserDownloads:100.000+"/><meta itemprop="opera[...]
            const matchingString = '"UserDownloads:';
            const matchingStringLen = matchingString.length;
            const userDownloadsStartIndex = body.indexOf(matchingString);
            if (userDownloadsStartIndex >= 0) {
                const closingQuoteIndex = body.indexOf('"', userDownloadsStartIndex + matchingStringLen);
                const userDownloadsStr = body.substr(userDownloadsStartIndex + matchingStringLen, closingQuoteIndex - userDownloadsStartIndex).replace(',','').replace('.','');
                chromeUsersCache = parseInt(userDownloadsStr);
            }
            else {
                lastUserCountCheck = 0;
            }
        })
        .catch(() => Logger.debug("Failing to connect to " + chromeExtensionUrl));
    })
    .catch(err => {
        Logger.debug("Failing to connect to " + mozillaAddonsUrl);
    });
}