const got = require('@/utils/got');
const utils = require('./utils');
const md5 = require('@/utils/md5');
const g_encrypt = require('./execlib/x-zse-96_v3');
const { parseDate } = require('@/utils/parse-date');

module.exports = async (ctx) => {
    const {
        questionId,
        sortBy = 'default', // default,created,updated
    } = ctx.params;
    // Because the API of zhihu.com has changed, we must use the value of `d_c0` (extracted from cookies) to calculate
    // `x-zse-96`. So first get `d_c0`, then get the actual data of a ZhiHu question. In this way, we don't need to
    // require users to set the cookie in environmental variables anymore.

    // fisrt: get cookie(dc_0) from zhihu.com
    const cookie_mes = await ctx.cache.tryGet('zhihu:cookies:d_c0', async () => {
        const response = await got({
            method: 'get',
            url: `https://www.zhihu.com/question/${questionId}`,
            headers: {
                ...utils.header,
            },
        });

        const cookie_org = response.headers['set-cookie'];
        const cookie = cookie_org.toString();
        const match = cookie.match(/d_c0=(\S+?)(?:;|$)/);
        const cookie_mes = match && match[1];
        if (!cookie_mes) {
            throw Error('Failed to extract `d_c0` from cookies');
        }
        return cookie_mes;
    });
    const cookie = `d_c0=${cookie_mes}`;

    // second: get real data from zhihu
    const limit = 20;
    const include =
        'data%5B*%5D.is_normal%2Cadmin_closed_comment%2Creward_info%2Cis_collapsed%2Cannotation_action%2Cannotation_detail%2Ccollapse_reason%2Cis_sticky%2Ccollapsed_by%2Csuggest_edit%2Ccomment_count%2Ccan_comment%2Ccontent%2Ceditable_content%2Cattachment%2Cvoteup_count%2Creshipment_settings%2Ccomment_permission%2Ccreated_time%2Cupdated_time%2Creview_info%2Crelevant_info%2Cquestion%2Cexcerpt%2Cis_labeled%2Cpaid_info%2Cpaid_info_content%2Crelationship.is_authorized%2Cis_author%2Cvoting%2Cis_thanked%2Cis_nothelp%2Cis_recognized%3Bdata%5B*%5D.mark_infos%5B*%5D.url%3Bdata%5B*%5D.author.follower_count%2Cbadge%5B*%5D.topics%3Bdata%5B*%5D.settings.table_of_content.enabled&offset=0';
    const rootUrl = 'https://www.zhihu.com';
    const apiPath = `/api/v4/questions/${questionId}/answers?include=${include}&limit=${limit}&sort_by=${sortBy}&platform=desktop`;
    const url = rootUrl + apiPath;

    // calculate x-zse-96, refer to https://github.com/srx-2000/spider_collection/issues/18
    const f = `101_3_3.0+${apiPath}+${cookie_mes}`;
    const xzse96 = '2.0_' + g_encrypt(md5(f));
    const _header = { cookie, 'x-zse-96': xzse96, 'x-app-za': 'OS=Web', 'x-zse-93': '101_3_3.0' };

    const response = await got({
        method: 'get',
        url,
        headers: {
            ...utils.header,
            ..._header,
            Referer: `https://www.zhihu.com/question/${questionId}`,
            // Authorization: 'oauth c3cef7c66a1843f8b3a9e6a1e3160e20', // previously hard-coded in js, outdated
        },
    });

    const listRes = response.data.data;

    ctx.state.data = {
        title: `知乎-${listRes[0].question.title}`,
        link: `https://www.zhihu.com/question/${questionId}`,
        item: listRes.map((item) => {
            const title = `${item.author.name}的回答：${item.excerpt}`;
            const description = `${item.author.name}的回答<br/><br/>${utils.ProcessImage(item.content)}`;

            return {
                title,
                description,
                author: item.author.name,
                pubDate: parseDate(item.updated_time * 1000),
                guid: item.id.toString(),
                link: `https://www.zhihu.com/question/${questionId}/answer/${item.id}`,
            };
        }),
    };
};