const got = require('@/utils/got');
const cheerio = require('cheerio');

const fetchPageHtml = async (linkPath, cacheKey, cache) => {
    const url = `https://mbasic.facebook.com${linkPath}`;

    return cache.tryGet(cacheKey, async () => {
        const { data: html } = await got.get(url);
        return html;
    });
};

const parseStoryPage = async (linkPath, cache) => {
    const { searchParams: q } = new URL('https://mbasic.facebook.com' + linkPath);
    const storyFbId = q.get('story_fbid');
    const storyId = q.get('id');
    const cacheKey = `story/${storyFbId}/${storyId}`;

    const html = await fetchPageHtml(linkPath, cacheKey, cache);
    const $ = cheerio.load(html);

    const url = `https://www.facebook.com/story.php?story_fbid=${storyFbId}&id=${storyId}`;
    const $story = $('#m_story_permalink_view').first();
    const $box = $story.find('div > div > div > div').eq(0);
    const $header = $box.find('header').eq(0);
    const $content = $box.find('div > div').eq(0);
    const $attach = $box.find('div > div').eq(1);

    const attachLinkList = $attach
        .find('a')
        .toArray()
        .map((a) => $(a).attr('href'));
    const isAttachAreImageSet = attachLinkList.filter((link) => new RegExp('/photos/').test(link)).length === attachLinkList.length;
    const title = $header.find('h3').text();

    let content = '';
    if ($content.find('p').length === 0) {
        $content.find('br').replaceWith('\n');
        content = $content.text();
    } else {
        const $ps = $content.find('p');
        $ps.find('br').replaceWith('\n');
        content = $ps
            .toArray()
            .map((p) => $(p).text())
            .join('\n');
    }

    let images = [];
    if (isAttachAreImageSet) {
        images = await Promise.all(attachLinkList.map((link) => parsePhotoPage(link, cache)));
    }

    return {
        url,
        title,
        content,
        images,
    };
};

const parsePhotoPage = async (linkPath, cache) => {
    const { pathname } = new URL('https://mbasic.facebook.com' + linkPath);
    const cacheKey = `photos${pathname}`;

    const html = await fetchPageHtml(linkPath, cacheKey, cache);
    const $ = cheerio.load(html);

    const title = $('#MPhotoContent div.msg > a > strong').first().text();
    const url = `https://www.facebook.com${pathname}`;
    const $content = $('#MPhotoContent div.msg > div');
    $content.find('br').replaceWith('\n');
    const content = $content.text();
    const image = $('#MPhotoContent div.desc.attachment > span > div > span > a[target=_blank].sec').attr('href');

    return {
        title,
        url,
        content,
        image,
    };
};

module.exports = async (ctx) => {
    const { id } = ctx.params;
    const pageId = encodeURIComponent(id);
    const linkPath = `/${pageId}`;

    const html = await fetchPageHtml(linkPath, pageId, ctx.cache);
    const $ = cheerio.load(html);

    const itemLinks = $('footer > div:nth-child(2) > a:nth-child(1)')
        .toArray()
        .map((a) => $(a).attr('href'));

    const items = await Promise.all(
        itemLinks.map(async (itemLink) => {
            if (new RegExp(`^/.+/photos/`).test(itemLink)) {
                const data = await parsePhotoPage(itemLink, ctx.cache);
                return {
                    title: data.title,
                    link: data.url,
                    description: `<img src="${data.image}"><br>${data.content.replace(/\n/g, '<br>')}`,
                };
            }
            if (new RegExp(`^/story.php`).test(itemLink)) {
                const data = await parseStoryPage(itemLink, ctx.cache);
                const isSingleImageStory = data.images.length === 1;
                const isEmptyImageList = data.images.length === 0;

                let desc = '';
                desc += data.images.map((image) => `<img src="${image.image}"><br>${image.content.replace(/\n/g, '<br>')}`).join('<br>');
                if (!isSingleImageStory) {
                    !isEmptyImageList && (desc += '<br>');
                    desc += data.content.replace(/\n/g, '<br>');
                }

                return {
                    title: data.title,
                    link: data.url,
                    description: desc,
                };
            }
        })
    );

    ctx.state.data = {
        title: $('#m-timeline-cover-section h1 span').text(),
        link: `https://www.facebook.com/${pageId}`,
        description: $('#sub_profile_pic_content>div>div:nth-child(3) div>span').find('br').replaceWith('\n').text(),
        item: items.filter((item) => !!item),
    };
};