import { fetchJson } from './fetchJson.ts';
import type { Translator } from './translator.ts';

let census_groups: Record<string, string> = {};
let census_comparisons: Record<string, string> = {};

const replaceQuoteEntity = (string: string): string => string.replace(/&quot;/g, '"');

const mainPlusDetails = (dict: Record<string, string>, wide: boolean) => (_: string, keys: string, content: string) => {
    let selectedDict: Record<string, string> = {};
    if (keys === undefined) {
        selectedDict = dict;
    } else {
        for (const key of keys.substring(1).split(',')) {
            selectedDict[key] = dict[key];
        }
    }

    return `
        <div class="${wide ? 'wide-escape' : ''}">
            ${content.replace(/%group%/g, 'general').replace(/<iframe class="graph" /g, '<iframe class="graph border" ')}${
                Object.keys(selectedDict).map((group) => `
                <details class="border mb-3">
                    <summary class="bg-light px-2 py-1" onclick="this.parentElement.querySelector('iframe.graph').contentDocument.location.reload()">${selectedDict[group]}</summary>
                    <div class="border-top p-md-3 bg-white">${content.replace(/%group%/g, group)}</div>
                </details>`)
                    .join('\n')
            }</div>`;
};

async function replaceAsync(str: string, regex: RegExp, asyncFn: (...args: string[]) => Promise<string>): Promise<string> {
    const promises = [...str.matchAll(regex)].map((match) => asyncFn(...match));
    const data = await Promise.all(promises);
    return str.replace(regex, () => data.shift()!);
}

const generateToC = (content: string, translator: Translator) => (_: string) => {
    const tags = [];
    let curentLevel = 2;
    let needsClosing = false;
    for (const [, levelString, id, title] of content.matchAll(/<h([2-6]) id="([^"]+)">([^<]+)<\/h\1>/g)) {
        const level = parseInt(levelString);
        while (level < curentLevel) {
            tags.push('</li>');
            tags.push('</ul>');
            curentLevel--;
        }
        while (level > curentLevel) {
            tags.push('<ul>');
            curentLevel++;
            needsClosing = false;
        }
        if (needsClosing) {
            tags.push('</li>');
        }
        tags.push('<li>');
        tags.push(`<a href="#${id}">`);
        tags.push(title);
        tags.push('</a>');
        needsClosing = true;
    }
    while (curentLevel < 2) {
        tags.push('</li>');
        tags.push('</ul>');
        curentLevel--;
        needsClosing = false;
    }
    if (needsClosing) {
        tags.push('</li>');
    }

    return `
        <div class="alert alert-light border">
            <h2 class="h4"><span class="fal fa-list"></span> ${translator.translate('links.blogTOC')}</h2>
            <ul class="mb-0">${tags.join('')}</ul>
        </div>
    `;
};

const generateGallery = (_: string, itemsString: string) => {
    const items: Record<string, string> = JSON.parse(`{${replaceQuoteEntity(itemsString).replace(/,\s*$/, '')}}`);

    const label = (alt: string): string => {
        if (!alt.startsWith('! ')) {
            return '';
        }

        return `<p class="small mt-2">${alt.substring(2)}</p>`;
    };

    const cells = Object.entries(items).map(([src, alt]) => `
        <div class="col-6 col-lg-4 columnist-column mb-3">
            <a href="${src}" target="_blank" rel="noopener">
                <img src="${src}" alt="${alt.startsWith('! ') ? alt.substring(2) : alt}">
            </a>
            ${label(alt)}
        </div>
    `);

    return `<div class="row columnist-wall--disabled">${cells.join('')}</div>`;
};

export interface MarkdownInfo {
    title: string | null;
    img: string | null;
    intro: string | null;
    content: string | null;
}

export default async function parseMarkdown(markdown: string, translator: Translator): Promise<MarkdownInfo> {
    let content = `<div>${
        markdown
            .replace(/<table>(.+?)<\/table>/gs, '<div class="table-responsive"><table class="table table-striped small">$1</table></div>')
            .replace(/align="([^"]+)"/g, 'style="text-align:$1"')
            .replace(/<a (href="http[^>]+)>/g, (_match, attributes) => {
                return `<a ${attributes.includes('target=') ? '' : 'target="_blank" '}${attributes.includes('rel=') ? '' : 'rel="noopener" '}${attributes}>`;
            })
            .replace(/<p>{details=(.+?)}<\/p>(.+?)<p>{\/details}<\/p>/gms, '<details class="border mb-3"><summary class="bg-light p-3">$1</summary><div class="border-top p-3 bg-white">$2</div></details>')
            .replace(/<p><img (.*?)><\/p>/g, (_, attrs) => {
                let classNames = 'border';
                const m = attrs.match(/alt="\{(.*)\}/);
                if (m) {
                    classNames = m[1];
                    attrs = attrs.replace(/alt="{(.*)}/, 'alt="');
                }
                return `<div class="mb-3 text-center"><img ${attrs} class="${classNames}" loading="lazy"></div>`;
            })
            .replace(/{favicon=(.+?)}/g, '<img src="https://$1" alt="Favicon" style="width: 1em; height: 1em;">')
            .replace(/<p>{embed=\/\/(.+?)=(.+?)}<\/p>/g, '<div style="position: relative;height: 0;padding-bottom: 56.25%;"><iframe src="https://$1" title="$2" allowfullscreen sandbox="allow-same-origin allow-scripts allow-popups" style="position: absolute;top: 0; left: 0;width: 100%;height: 100%;border:0;"></iframe></div>')
            .replace(/<p>{graph=([^}]+)}<\/p>/g, '<iframe class="graph" src="$1.html" loading="lazy"></iframe>')

            .replace(/<p>{set_census_groups=(.+?)}<\/p>/gms, (_, value) => {
                census_groups = JSON.parse(replaceQuoteEntity(value));
                return '';
            })
            .replace(/<p>{set_census_comparisons=(.+?)}<\/p>/gms, (_, value) => {
                census_comparisons = JSON.parse(replaceQuoteEntity(value));
                return '';
            })
            .replace(/<p>{census_groups(:.+?)?}<\/p>(.+?)<p>{\/census_groups}<\/p>/gms, mainPlusDetails(census_groups, false))
            .replace(/<p>{census_comparisons(:.+?)?}<\/p>(.+?)<p>{\/census_comparisons}<\/p>/gms, mainPlusDetails(census_comparisons, true))
            .replace(/<h1 id="🏳️🌈-/g, '<h1 id="') // license header
            .replace(/ id=""/g, '')
            .replace(/<p>{wide_table}<\/p>/g, '<div class="table-wide table-responsive my-5 headers-nowrap">')
            .replace(/<p>{\/wide_table}<\/p>/g, '</div>')
            .replace(/<p>{gallery={(.*?)}}<\/p>/gms, generateGallery)
            .replace(/(?<![\w!])!!([^<>]*?)!!(?![\w!])/g, (_: string, spoilerString: string): string => {
                return `<span class="spoiler">${spoilerString}</span>`;
            })
    }</div>`;

    content = await replaceAsync(content, /{json=([^=}]+)=([^=}]+)}/g, async (_, filename, key) => {
        try {
            return await fetchJson(translator.config.locale, filename, key);
        } catch (error) {
            return `<span class="badge bg-danger text-white">${error}</span>`;
        }
    });

    content = content.replace(/<p>{table_of_contents}<\/p>/g, generateToC(content, translator));

    content = content.replace(/{optional}(.+?){\/optional}/gms, (_, content) => {
        if (content.includes('badge bg-danger')) {
            return '';
        }
        return content;
    });

    const titleMatch = content.match('<h1[^>]*>(.+?)</h1>');
    const title = titleMatch ? replaceQuoteEntity(titleMatch[1]) : null;
    const imgMatch = content.match('<img src="([^"]+)"[^>]*>');
    const img = imgMatch ? imgMatch[1] : null;
    let intro: string[] = [];

    for (const introMatch of content.matchAll(/<p[^>]*>(.+?)<\/p>/gms)) {
        const p = introMatch[1].replace(/(<([^>]+)>)/ig, '').replace(/\s+/g, ' ');
        intro = [...intro, ...p.split(' ')];
    }

    return {
        title,
        img,
        intro: intro.length ? intro.slice(0, 24).join(' ') : null,
        content,
    };
}