const he = require('he');
const mercury_parser = require('@postlight/mercury-parser');
const cheerio = require('cheerio');
const got = require('@/utils/got');

module.exports = async (ctx, next) => {
    await next();

    if (!ctx.state.data && !ctx._matchedRoute) {
        throw Error('wrong path');
    }

    if (ctx.state.data) {
        if ((!ctx.state.data.item || ctx.state.data.item.length === 0) && !ctx.state.data.allowEmpty) {
            throw Error('this route is empty, please check the original site or create an issue on https://github.com/DIYgod/RSSHub/issues/new/choose');
        }

        if (ctx.query && ctx.query.mode && ctx.query.mode.toLowerCase() === 'fulltext') {
            const tasks = ctx.state.data.item.map(async (item) => {
                const { link, author, description } = item;
                const parsed_result = await ctx.cache.tryGet(`mercury-cache-${link}`, async () => {
                    const res = await got(link);
                    const $ = cheerio.load(res.data);
                    const result = await mercury_parser.parse(link, {
                        html: $.html(),
                    });
                    return result;
                });

                item.author = author || parsed_result.author;
                item.description = parsed_result.content || description;
            });
            await Promise.all(tasks);
        }

        // handle description
        if (ctx.state.data.item && ctx.state.data.item.length) {
            ctx.state.data.item.forEach((item) => {
                if (item.description) {
                    const $ = cheerio.load(item.description);
                    let baseUrl = item.link || ctx.state.data.link;

                    if (baseUrl && !baseUrl.match(/^https?:\/\//)) {
                        if (baseUrl.match(/^\/\//)) {
                            baseUrl = 'http:' + baseUrl;
                        } else {
                            baseUrl = 'http://' + baseUrl;
                        }
                    }

                    $('script').remove();

                    $('a').each((_, ele) => {
                        const $ele = $(ele);

                        // absolute link
                        if (baseUrl) {
                            try {
                                $ele.attr('href', new URL($ele.attr('href'), baseUrl).href);
                            } catch (e) {
                                // no-empty
                            }
                        }
                    });

                    $('img').each((_, ele) => {
                        const $ele = $(ele);

                        // fix lazyload
                        if (!$ele.attr('src')) {
                            for (const key in ele.attribs) {
                                const value = ele.attribs[key].trim();
                                if (['.gif', '.png', '.jpg', '.webp'].some((suffix) => value.includes(suffix))) {
                                    $ele.attr('src', value);
                                    break;
                                }
                            }
                        }

                        // absolute link
                        if (baseUrl) {
                            try {
                                $ele.attr('src', new URL($ele.attr('src'), baseUrl).href);
                            } catch (e) {
                                // no-empty
                            }
                        }

                        // referrerpolicy
                        $ele.attr('referrerpolicy', 'no-referrer');

                        // redundant attributes
                        ['onclick', 'onerror', 'onload'].forEach((e) => {
                            $ele.removeAttr(e);
                        });
                    });
                    item.description = $('body').html();
                }
            });
        }

        // decode HTML entities
        ctx.state.data.title && (ctx.state.data.title = he.decode(ctx.state.data.title + ''));
        ctx.state.data.description && (ctx.state.data.description = he.decode(ctx.state.data.description + ''));
        ctx.state.data.item &&
            ctx.state.data.item.forEach((item) => {
                item.title && (item.title = he.decode(item.title + ''));
                item.description && (item.description = he.decode(item.description + ''));
            });

        // filter
        if (ctx.query && (ctx.query.filter || ctx.query.filter_title || ctx.query.filter_description || ctx.query.filter_author)) {
            ctx.state.data.item = ctx.state.data.item.filter((item) => {
                const title = item.title || '';
                const description = item.description || title;
                const author = item.author || '';
                return !(
                    (ctx.query.filter && !title.match(ctx.query.filter) && !description.match(ctx.query.filter)) ||
                    (ctx.query.filter_title && !title.match(ctx.query.filter_title)) ||
                    (ctx.query.filter_description && !description.match(ctx.query.filter_description)) ||
                    (ctx.query.filter_author && !author.match(ctx.query.filter_author))
                );
            });
        }
        if (ctx.query && (ctx.query.filterout || ctx.query.filterout_title || ctx.query.filterout_description || ctx.query.filterout_author)) {
            ctx.state.data.item = ctx.state.data.item.filter((item) => {
                const title = item.title;
                const description = item.description || title;
                const author = item.author || '';
                return (
                    (ctx.query.filterout && !title.match(ctx.query.filterout) && !description.match(ctx.query.filterout)) ||
                    (ctx.query.filterout_title && !title.match(ctx.query.filterout_title)) ||
                    (ctx.query.filterout_description && !description.match(ctx.query.filterout_description)) ||
                    (ctx.query.filterout_author && !author.match(ctx.query.filterout_author))
                );
            });
        }
        if (ctx.query && ctx.query.filter_time) {
            const now = Date.now();
            ctx.state.data.item = ctx.state.data.item.filter(({ pubDate }) => {
                if (!pubDate) {
                    return true;
                }

                try {
                    return now - new Date(pubDate).getTime() <= parseInt(ctx.query.filter_time) * 1000;
                } catch (err) {
                    return true;
                }
            });
        }

        // limit
        if (ctx.query && ctx.query.limit) {
            ctx.state.data.item = ctx.state.data.item.slice(0, parseInt(ctx.query.limit));
        }

        // telegram instant view
        if (ctx.query && ctx.query.tgiv) {
            ctx.state.data.item.map((item) => {
                const encodedlink = encodeURIComponent(item.link);
                item.link = `https://t.me/iv?url=${encodedlink}&rhash=${ctx.query.tgiv}`;
                return item;
            });
        }
    }
};