const { google } = require('googleapis');
const { OAuth2 } = google.auth;
const { art } = require('@/utils/render');
const path = require('path');
const config = require('@/config').value;

let count = 0;
const youtube = {};
if (config.youtube && config.youtube.key) {
    const keys = config.youtube.key.split(',');

    keys.forEach((key, index) => {
        if (key) {
            youtube[index] = google.youtube({
                version: 'v3',
                auth: key,
            });
            count = index + 1;
        }
    });
}

let index = -1;
const exec = async (func) => {
    let result;
    for (let i = 0; i < count; i++) {
        index++;
        try {
            // eslint-disable-next-line no-await-in-loop
            result = await func(youtube[index % count]);
            break;
        } catch (error) {
            // console.error(error);
        }
    }
    return result;
};

let youtubeOAuth2Client;
if (config.youtube && config.youtube.clientId && config.youtube.clientSecret && config.youtube.refreshToken) {
    youtubeOAuth2Client = new OAuth2(config.youtube.clientId, config.youtube.clientSecret, 'https://developers.google.com/oauthplayground');
    youtubeOAuth2Client.setCredentials({ refresh_token: config.youtube.refreshToken });
}

const youtubeUtils = {
    getPlaylistItems: (id, part, cache) =>
        cache.tryGet(
            `youtube:getPlaylistItems:${id}`,
            async () => {
                const res = await exec((youtube) =>
                    youtube.playlistItems.list({
                        part,
                        playlistId: id,
                        maxResults: 50, // youtube api param value default is 5
                    })
                );
                return res;
            },
            config.cache.routeExpire,
            false
        ),
    getPlaylist: (id, part, cache) =>
        cache.tryGet(`youtube:getPlaylist:${id}`, async () => {
            const res = await exec((youtube) =>
                youtube.playlists.list({
                    part,
                    id,
                })
            );
            return res;
        }),
    getChannelWithId: (id, part, cache) =>
        cache.tryGet(`youtube:getChannelWithId:${id}`, async () => {
            const res = await exec((youtube) =>
                youtube.channels.list({
                    part,
                    id,
                })
            );
            return res;
        }),
    getChannelWithUsername: (username, part, cache) =>
        cache.tryGet(`youtube:getChannelWithUsername:${username}`, async () => {
            const res = await exec((youtube) =>
                youtube.channels.list({
                    part,
                    forUsername: username,
                })
            );
            return res;
        }),
    // not in use
    // getVideoAuthor: async (id, part) => {
    //     const res = await exec((youtube) =>
    //         youtube.videos.list({
    //             part,
    //             id,
    //         })
    //     );
    //     return res;
    // },
    getThumbnail: (thumbnails) => thumbnails.maxres || thumbnails.standard || thumbnails.high || thumbnails.medium || thumbnails.default,
    formatDescription: (description) => description.replace(/(?:\r\n|\r|\n)/g, '<br>'),
    renderDescription: (embed, videoId, img, description) =>
        art(path.join(__dirname, 'templates/description.art'), {
            embed,
            videoId,
            img,
            description,
        }),

    getSubscriptions: async (part, cache) => {
        // access tokens expire after one hour
        let accessToken = await cache.get('youtube:accessToken', false);
        if (!accessToken) {
            const data = await youtubeOAuth2Client.getAccessToken();
            accessToken = data.token;
            await cache.set('youtube:accessToken', accessToken, 3600); // ~3600s
        }
        youtubeOAuth2Client.setCredentials({ access_token: accessToken, refresh_token: config.youtube.refreshToken });

        return cache.tryGet('youtube:getSubscriptions', () => youtubeUtils.getSubscriptionsRecusive(part), config.cache.routeExpire, false);
    },
    getSubscriptionsRecusive: async (part, nextPageToken = undefined) => {
        const res = await google.youtube('v3').subscriptions.list({
            auth: youtubeOAuth2Client,
            part,
            mine: true,
            maxResults: 50,
            pageToken: nextPageToken ? nextPageToken : undefined,
        });
        // recursively get next page
        if (res.data.nextPageToken) {
            const next = await youtubeUtils.getSubscriptionsRecusive(part, res.data.nextPageToken);
            res.data.items = [...res.data.items, ...next.data.items];
        }
        return res;
    },
    // taken from https://webapps.stackexchange.com/a/101153
    isYouTubeChannelId: (id) => /^UC[\w-]{21}[AQgw]$/.test(id),
    getLive: (id, cache) =>
        cache.tryGet(`youtube:getLive:${id}`, async () => {
            const res = await exec((youtube) =>
                youtube.search.list({
                    part: 'snippet',
                    channelId: id,
                    eventType: 'live',
                    type: 'video',
                })
            );
            return res;
        }),
};

module.exports = youtubeUtils;