const fs = require('fs');
const path = require('path');
const cheerio = require('cheerio');

const langs = ['ko', 'en', 'ja', 'zh'];
const defaultLang = 'ko';
const siteUrl = 'https://minglestudio.co.kr';

const rootDir = __dirname;
const i18nDir = path.join(rootDir, 'i18n');
const componentsDir = path.join(rootDir, 'components');

// Read all html files
const htmlFiles = fs.readdirSync(rootDir).filter(f => f.endsWith('.html') && f !== 'naver-site-verification.html');

// Load translations
const translations = {};
langs.forEach(lang => {
    try {
        translations[lang] = JSON.parse(fs.readFileSync(path.join(i18nDir, `${lang}.json`), 'utf-8'));
    } catch (e) {
        console.error(`Failed to load ${lang}.json`, e);
    }
});

// Load components
const headerHtml = fs.readFileSync(path.join(componentsDir, 'header.html'), 'utf-8');
const footerHtml = fs.readFileSync(path.join(componentsDir, 'footer.html'), 'utf-8');

function t(lang, key, fallback = '') {
    if (lang === defaultLang) return fallback || key;
    const keys = key.split('.');
    let val = translations[lang];
    if (!val) return fallback || key;
    for (const k of keys) {
        if (val && typeof val === 'object' && k in val) {
            val = val[k];
        } else {
            return fallback || key;
        }
    }
    return typeof val === 'string' ? val : (fallback || key);
}

console.log('Starting i18n SSG Build...');

langs.forEach(lang => {
    const isDefault = lang === defaultLang;
    const outDir = isDefault ? rootDir : path.join(rootDir, lang);
    if (!fs.existsSync(outDir)) {
        fs.mkdirSync(outDir, { recursive: true });
    }

    htmlFiles.forEach(file => {
        const pageName = file.replace('.html', '') || 'index';
        const content = fs.readFileSync(path.join(rootDir, file), 'utf-8');
        const $ = cheerio.load(content, { decodeEntities: false });

        // Change lang attribute
        $('html').attr('lang', lang);

        // Remove existing hreflang tags if any to prevent duplicates
        $('link[rel="alternate"][hreflang]').remove();

        // Add hreflang tags
        const head = $('head');
        langs.forEach(l => {
            const href = l === defaultLang
                ? `${siteUrl}${file === 'index.html' ? '/' : '/' + file}`
                : `${siteUrl}/${l}${file === 'index.html' ? '/' : '/' + file}`;
            head.append(`\n    <link rel="alternate" hreflang="${l}" href="${href}" />`);
        });
        head.append(`\n    <link rel="alternate" hreflang="x-default" href="${siteUrl}${file === 'index.html' ? '/' : '/' + file}" />\n`);

        // Change canonical
        const canonicalHref = isDefault
            ? `${siteUrl}${file === 'index.html' ? '/' : '/' + file}`
            : `${siteUrl}/${lang}${file === 'index.html' ? '/' : '/' + file}`;
        $('link[rel="canonical"]').attr('href', canonicalHref);

        // Inject components 
        if ($('#header-placeholder').html()?.trim() === '') {
            $('#header-placeholder').html('\n' + headerHtml + '\n');
        }
        if ($('#footer-placeholder').html()?.trim() === '') {
            $('#footer-placeholder').html('\n' + footerHtml + '\n');
        }

        // Translate nodes (only if not default language)
        if (!isDefault) {
            $('[data-i18n]').each((i, el) => {
                const key = $(el).attr('data-i18n');
                const trans = t(lang, key, $(el).text());
                if (trans.includes('<')) $(el).html(trans);
                else $(el).text(trans);
            });

            $('[data-i18n-html]').each((i, el) => {
                const key = $(el).attr('data-i18n-html');
                const trans = t(lang, key, $(el).html());
                $(el).html(trans);
            });

            $('[data-i18n-placeholder]').each((i, el) => {
                const key = $(el).attr('data-i18n-placeholder');
                $(el).attr('placeholder', t(lang, key, $(el).attr('placeholder')));
            });

            $('[data-i18n-aria]').each((i, el) => {
                const key = $(el).attr('data-i18n-aria');
                $(el).attr('aria-label', t(lang, key, $(el).attr('aria-label') || ''));
            });

            $('[data-i18n-title]').each((i, el) => {
                const key = $(el).attr('data-i18n-title');
                $(el).attr('title', t(lang, key, $(el).attr('title') || ''));
            });

            // Meta tags
            const titleKey = `${pageName}.meta.title`;
            const tTitle = t(lang, titleKey, null);
            if (tTitle) $('title').text(tTitle);

            const descKey = `${pageName}.meta.description`;
            const tDesc = t(lang, descKey, null);
            if (tDesc) $('meta[name="description"]').attr('content', tDesc);

            const ogTitleKey = `${pageName}.meta.ogTitle`;
            const tOgTitle = t(lang, ogTitleKey, null);
            if (tOgTitle) $('meta[property="og:title"]').attr('content', tOgTitle);

            const ogDescKey = `${pageName}.meta.ogDescription`;
            const tOgDesc = t(lang, ogDescKey, null);
            if (tOgDesc) $('meta[property="og:description"]').attr('content', tOgDesc);
        }

        if (!isDefault) {
            // Rewrite asset paths
            $('link[href^="css/"]').attr('href', (i, val) => '/' + val);
            $('link[href^="components/"]').attr('href', (i, val) => '/' + val);
            $('script[src^="js/"]').attr('src', (i, val) => '/' + val);
            $('img[src^="images/"]').attr('src', (i, val) => '/' + val);

            // Re-map internal links to proper language folder
            $('a[href^="/"], a.nav-link').each((i, el) => {
                const href = $(el).attr('href');
                if (!href) return;

                // If it's a root-relative link (e.g., /about, /contact)
                if (href.startsWith('/') && href.length > 1 && !href.startsWith('/images') && !href.startsWith('/css') && !href.startsWith('/js') && !href.startsWith('/i18n')) {
                    const newHref = `/${lang}${href}`;
                    $(el).attr('href', newHref);
                } else if (href === '/') {
                    $(el).attr('href', `/${lang}/`);
                } else if (!href.startsWith('http') && !href.startsWith('#') && !href.startsWith('/') && !href.startsWith('tel:') && !href.startsWith('mailto:')) {
                    // For links like href="about.html" or href="contact.html", we need to change it
                    if (href.endsWith('.html')) {
                        const newHref = `/${lang}/${href.replace('.html', '')}`;
                        $(el).attr('href', newHref);
                    }
                }
            });
        }

        fs.writeFileSync(path.join(outDir, file), $.html());
        console.log(`[${lang}] Processed ${file}`);
    });
});

console.log('Generating sitemap.xml...');
let sitemapUrls = '';
langs.forEach(lang => {
    htmlFiles.forEach(file => {
        const isDefault = lang === defaultLang;
        const pageRoute = file === 'index.html' ? '' : file.replace('.html', '');
        const loc = isDefault
            ? `${siteUrl}/${pageRoute}`
            : `${siteUrl}/${lang}/${pageRoute}`;

        // Remove trailing slash if it's just root, but wait siteUrl + '/' for root
        const cleanLoc = loc.endsWith('/') ? loc : (pageRoute === '' && loc === siteUrl ? `${siteUrl}/` : loc);

        sitemapUrls += `
  <url>
    <loc>${cleanLoc}</loc>
    <lastmod>${new Date().toISOString().split('T')[0]}</lastmod>
    <changefreq>weekly</changefreq>
    <priority>${file === 'index.html' ? '1.0' : '0.8'}</priority>
  </url>`;
    });
});

const sitemapContent = `<?xml version="1.0" encoding="UTF-8"?>
<urlset xmlns="http://www.sitemaps.org/schemas/sitemap/0.9"
        xmlns:xhtml="http://www.w3.org/1999/xhtml">
${sitemapUrls}
</urlset>
`;
fs.writeFileSync(path.join(rootDir, 'sitemap.xml'), sitemapContent);
console.log('Sitemap generated!');

console.log('Build completed! Language HTML files have been generated.');