import fs from "node:fs";
import path from "node:path";

const rootDir = process.cwd();
const srcPagesDir = path.join(rootDir, "src", "pages");
const srcPartialsDir = path.join(rootDir, "src", "partials");
const srcI18nDir = path.join(rootDir, "src", "i18n");
const outDir = path.join(rootDir, "public");

// Локали: дефолтная (ru) собирается в корень public/, остальные — в public/<lang>/.
const LOCALES = ["ru", "en"];
const DEFAULT_LOCALE = "ru";

// Liquid Glass: инлайн SVG displacement-фильтр, инъецируется во все страницы.
// PNG-карта — мелкий равномерный шум (см. статью Хабра), даёт «живое» стекло в Chromium.
// В Safari/Firefox url()-фильтр в backdrop-filter не рендерится — там остаётся чистый blur.
const LIQUID_GLASS_FILTER = `<svg class="liquid-glass-defs" aria-hidden="true" width="0" height="0" focusable="false" style="position:absolute;width:0;height:0;overflow:hidden;pointer-events:none">
  <filter id="liquid-glass-displacement" x="-20%" y="-20%" width="140%" height="140%" color-interpolation-filters="sRGB">
    <feImage href="{{LG_ASSET_PREFIX}}assets/liquid-glass/displacement.png" xlink:href="{{LG_ASSET_PREFIX}}assets/liquid-glass/displacement.png" preserveAspectRatio="none" result="lgMap"/>
    <feDisplacementMap in="SourceGraphic" in2="lgMap" scale="14" xChannelSelector="R" yChannelSelector="G"/>
  </filter>
  <filter id="liquid-glass-displacement-btn" x="-20%" y="-20%" width="140%" height="140%" color-interpolation-filters="sRGB">
    <feImage href="{{LG_ASSET_PREFIX}}assets/liquid-glass/displacement.png" xlink:href="{{LG_ASSET_PREFIX}}assets/liquid-glass/displacement.png" preserveAspectRatio="none" result="lgMapBtn"/>
    <feDisplacementMap in="SourceGraphic" in2="lgMapBtn" scale="6" xChannelSelector="R" yChannelSelector="G"/>
  </filter>
</svg>`;

// --- SEO ---
const SITE_ORIGIN = "https://mamadaevv.site";
const OG_IMAGE_DEFAULT = `${SITE_ORIGIN}/assets/og/og-default.png`;
const AUTHOR_NAME_RU = "Николай Мамадаев";
const AUTHOR_NAME_EN = "Nikolai Mamadaev";
const SITE_NAME_RU = "Николай Мамадаев — продуктовый дизайнер";
const SITE_NAME_EN = "Nikolai Mamadaev — Product Designer";
// Служебные страницы-каталоги: закрыты от индексации.
const NOINDEX_PAGES = new Set([
  "cases/design-system",
  "cases/template-elements-demo",
  "cases/mini-projects-showcase",
]);

const titleRe = /<title>([\s\S]*?)<\/title>/i;
const descRe = /<meta\s+name="description"\s+content="([\s\S]*?)"\s*\/?>/i;

function decodeEntities(str) {
  return String(str)
    .replace(/&nbsp;/g, " ")
    .replace(/&amp;/g, "&")
    .replace(/&quot;/g, '"')
    .replace(/&#39;/g, "'")
    .replace(/&lt;/g, "<")
    .replace(/&gt;/g, ">");
}

function extractMeta(html) {
  const t = html.match(titleRe);
  const d = html.match(descRe);
  return {
    title: t ? decodeEntities(t[1]).trim() : "",
    description: d ? decodeEntities(d[1]).trim() : "",
  };
}

/** Путь страницы на сайте (без ведущего слэша, с закрывающим). */
function sitePath(relNorm, loc) {
  const base = relNorm
    .replace(/\.html$/, "")
    .replace(/(^|\/)index$/, "/");
  const norm = relNorm.startsWith("cases/")
    ? `cases/${path.basename(relNorm, ".html")}/`
    : base === "resume" ? "resume/"
    : base === "cookie-policy" ? "cookie-policy/"
    : base === "" || base === "/" ? ""
    : `${base.replace(/\/$/, "")}/`;
  return loc === DEFAULT_LOCALE ? norm : `${loc}/${norm}`;
}

/** Канонический URL страницы. */
function canonicalFor(relNorm, loc) {
  const p = sitePath(relNorm, loc);
  return `${SITE_ORIGIN}/${p}`;
}

/** Дата изменения страницы (mtime исходника) в формате YYYY-MM-DD. */
function lastModFor(relNorm) {
  const src = path.join(srcPagesDir, relNorm);
  const enSrc = src.replace(/\.html$/, ".en.html");
  let mtime = 0;
  if (fs.existsSync(src)) mtime = fs.statSync(src).mtimeMs;
  if (fs.existsSync(enSrc)) mtime = Math.max(mtime, fs.statSync(enSrc).mtimeMs);
  return new Date(mtime || Date.now()).toISOString().slice(0, 10);
}

/** JSON-LD для страницы: Person+WebSite на главной, CreativeWork на кейсах, BreadcrumbList везде. */
function buildJsonLd(relNorm, loc, meta, canonical) {
  const isRu = loc === DEFAULT_LOCALE;
  const authorName = isRu ? AUTHOR_NAME_RU : AUTHOR_NAME_EN;
  const siteName = isRu ? SITE_NAME_RU : SITE_NAME_EN;
  const graph = [];
  const personId = `${SITE_ORIGIN}/#person`;
  const websiteId = `${SITE_ORIGIN}/#website`;

  const person = {
    "@type": "Person",
    "@id": personId,
    name: authorName,
    url: SITE_ORIGIN,
    jobTitle: isRu ? "Продуктовый дизайнер" : "Product Designer",
    description: isRu
      ? "Продуктовый дизайнер с опытом более 10 лет. Проектирую цифровые продукты, интерфейсы и дизайн-системы."
      : "Product designer with 10+ years of experience. Designing digital products, interfaces and design systems.",
    knowsAbout: isRu
      ? ["UX/UI-дизайн", "продуктовый дизайн", "дизайн-системы", "прототипирование", "Figma", "no-code"]
      : ["UX/UI design", "product design", "design systems", "prototyping", "Figma", "no-code"],
    sameAs: ["https://t.me/mamadaevv", "https://vk.com/mamadaevv", "https://github.com/mamadaevv"],
  };
  graph.push(person);

  graph.push({
    "@type": "WebSite",
    "@id": websiteId,
    url: `${SITE_ORIGIN}/`,
    name: siteName,
    inLanguage: loc,
    author: { "@id": personId },
    publisher: { "@id": personId },
  });

  const isCase = relNorm.startsWith("cases/");
  const pageNode = {
    "@type": isCase ? "CreativeWork" : "WebPage",
    "@id": `${canonical}#page`,
    url: canonical,
    name: meta.title,
    description: meta.description,
    isPartOf: { "@id": websiteId },
    author: { "@id": personId },
    inLanguage: loc,
  };
  if (isCase && !NOINDEX_PAGES.has(relNorm.replace(/\.html$/, ""))) {
    pageNode.creator = { "@id": personId };
    pageNode.datePublished = lastModFor(relNorm);
    pageNode.about = isRu
      ? "UX/UI-дизайн и проектирование интерфейсов"
      : "UX/UI design and interface design";
  }
  graph.push(pageNode);

  // Хлебные крошки для вложенных страниц.
  const parts = sitePath(relNorm, loc).split("/").filter(Boolean);
  if (parts.length > 0) {
    const crumbs = [{ "@type": "ListItem", position: 1, name: siteName, item: `${SITE_ORIGIN}/` }];
    let acc = SITE_ORIGIN;
    let pos = 2;
    for (const part of parts) {
      if (part === loc) continue;
      acc += `/${part}`;
      crumbs.push({
        "@type": "ListItem",
        position: pos++,
        name: part === "cases" ? (isRu ? "Кейсы" : "Cases") : meta.title || part,
        item: `${acc}/`,
      });
    }
    if (crumbs.length > 1) {
      graph.push({
        "@type": "BreadcrumbList",
        "@id": `${canonical}#breadcrumbs`,
        itemListElement: crumbs,
      });
    }
  }

  return {
    "@context": "https://schema.org",
    "@graph": graph,
  };
}

/** Генерация sitemap.xml с hreflang-альтернатами. */
function buildSitemap(pageFiles) {
  const urls = [];
  const localeSuffixRe = new RegExp(`\\.(${LOCALES.join("|")})\\.html$`, "i");
  for (const pagePath of pageFiles) {
    const relNorm = path.relative(srcPagesDir, pagePath).split(path.sep).join("/");
    const noSlug = relNorm.replace(/\.html$/, "");
    if (NOINDEX_PAGES.has(noSlug)) continue;
    const lastmod = lastModFor(relNorm);
    const locUrl = canonicalFor(relNorm, DEFAULT_LOCALE);
    const alternates = LOCALES.map(
      (loc) =>
        `    <xhtml:link rel="alternate" hreflang="${loc}" href="${canonicalFor(relNorm, loc)}" />`
    );
    urls.push(
      `  <url>\n    <loc>${locUrl}</loc>\n    <lastmod>${lastmod}</lastmod>\n` +
        `    <xhtml:link rel="alternate" hreflang="x-default" href="${locUrl}" />\n` +
        alternates.join("\n") +
        `\n  </url>`
    );
  }
  return (
    `<?xml version="1.0" encoding="UTF-8"?>\n` +
    `<urlset xmlns="http://www.sitemaps.org/schemas/sitemap/0.9"\n` +
    `        xmlns:xhtml="http://www.w3.org/1999/xhtml">\n` +
    urls.join("\n") +
    `\n</urlset>\n`
  );
}

const includeRe = /\{\{\>\s*([a-z0-9-]+)\s*\}\}/gi;
const varRe = /\{\{\s*([a-zA-Z0-9_]+)\s*\}\}/g;
const i18nRe = /\{\{\s*i18n:([\w.-]+)\s*\}\}/g;

function readUtf8(filePath) {
  return fs.readFileSync(filePath, "utf8");
}

function walkHtmlFiles(dir, acc = []) {
  const entries = fs.readdirSync(dir, { withFileTypes: true });
  for (const entry of entries) {
    const abs = path.join(dir, entry.name);
    if (entry.isDirectory()) {
      walkHtmlFiles(abs, acc);
      continue;
    }
    if (entry.isFile() && entry.name.endsWith(".html")) {
      acc.push(abs);
    }
  }
  return acc;
}

function loadPartials() {
  const partialMap = new Map();
  for (const filePath of walkHtmlFiles(srcPartialsDir)) {
    const name = path.basename(filePath, ".html");
    partialMap.set(name, readUtf8(filePath));
  }
  return partialMap;
}

function loadI18n() {
  const map = {};
  for (const loc of LOCALES) {
    const file = path.join(srcI18nDir, `${loc}.json`);
    map[loc] = fs.existsSync(file) ? JSON.parse(readUtf8(file)) : {};
  }
  return map;
}

function resolveI18n(key, dict, fallback) {
  if (dict && Object.prototype.hasOwnProperty.call(dict, key)) return String(dict[key]);
  if (fallback && Object.prototype.hasOwnProperty.call(fallback, key)) return String(fallback[key]);
  return `{{i18n:${key}}}`;
}

function renderTemplate(input, partials, vars, dict, fallback, loc, stack = []) {
  const withIncludes = input.replace(includeRe, (_, name) => {
    const key = String(name).trim();
    const partialKey = loc && loc !== DEFAULT_LOCALE && partials.has(`${key}.${loc}`) ? `${key}.${loc}` : key;
    if (!partials.has(partialKey)) {
      throw new Error(`Partial "${key}" not found`);
    }
    if (stack.includes(partialKey)) {
      throw new Error(`Circular partial include: ${[...stack, partialKey].join(" -> ")}`);
    }
    const partialContent = partials.get(partialKey);
    return renderTemplate(partialContent, partials, vars, dict, fallback, loc, [...stack, partialKey]);
  });

  const withI18n = withIncludes.replace(i18nRe, (_, key) => resolveI18n(String(key).trim(), dict, fallback));

  return withI18n.replace(varRe, (_, name) => {
    const key = String(name).trim();
    if (Object.prototype.hasOwnProperty.call(vars, key)) {
      return String(vars[key]);
    }
    return `{{${key}}}`;
  });
}

function ensureDir(dirPath) {
  fs.mkdirSync(dirPath, { recursive: true });
}

/** На странице кейса убираем из HTML карусели карточку со ссылкой на текущий файл (href уже с подставленным casesPrefix). */
function stripCurrentCasePortfolioCarouselItem(html, omitHrefBasename) {
  if (!omitHrefBasename) return html;
  const slug = omitHrefBasename.replace(/\.html$/, "");
  const hrefDouble = `href="${slug}/"`;
  const hrefSingle = `href='${slug}/'`;
  const itemClass = "projects-carousel__item";
  let search = 0;
  while (true) {
    const i = html.indexOf("<article", search);
    if (i === -1) return html;
    const tagEnd = html.indexOf(">", i);
    if (tagEnd === -1) return html;
    const openTag = html.slice(i, tagEnd + 1);
    if (!openTag.includes(itemClass)) {
      search = i + 9;
      continue;
    }
    const contentStart = tagEnd + 1;
    const closeIdx = html.indexOf("</article>", contentStart);
    if (closeIdx === -1) return html;
    const afterArticle = closeIdx + "</article>".length;
    const block = html.slice(i, afterArticle);
    if (block.includes(hrefDouble) || block.includes(hrefSingle)) {
      return html.slice(0, i) + html.slice(afterArticle);
    }
    search = contentStart;
  }
}

/** Базовые переменны для страницы в дефолтной локали (как было до i18n). */
function baseVars(relNorm, depth) {
  if (relNorm.startsWith("cases/")) {
    return { assetPrefix: "../../", casesPrefix: "../" };
  }
  if (relNorm === "resume.html") {
    return { assetPrefix: "../", casesPrefix: "" };
  }
  if (relNorm === "cookie-policy.html") {
    return { assetPrefix: "../", casesPrefix: "" };
  }
  return {
    assetPrefix: depth === 0 ? "" : "../".repeat(depth),
    casesPrefix: depth === 0 ? "cases/" : "",
  };
}

function build() {
  const partials = loadPartials();
  const i18n = loadI18n();
  const defaultDict = i18n[DEFAULT_LOCALE] || {};
  const localeSuffixRe = new RegExp(`\\.(${LOCALES.join("|")})\\.html$`, "i");
  const pageFiles = walkHtmlFiles(srcPagesDir).filter((p) => !localeSuffixRe.test(p));

  for (const pagePath of pageFiles) {
    const rel = path.relative(srcPagesDir, pagePath);
    const relNorm = rel.split(path.sep).join("/");
    const pageDirRel = path.dirname(rel);
    const depth = pageDirRel === "." ? 0 : pageDirRel.split(path.sep).length;
    const isCase = relNorm.startsWith("cases/");
    const isResume = relNorm === "resume.html";
    const isCookiePolicy = relNorm === "cookie-policy.html";
    const omitFile = isCase ? path.basename(pagePath) : null;

    for (const loc of LOCALES) {
      const dict = i18n[loc] || {};
      const isDefault = loc === DEFAULT_LOCALE;
      const langPrefix = isDefault ? "" : `${loc}/`;

      // Переведённый исходник страницы для локали, если есть.
      let sourcePath = pagePath;
      if (!isDefault) {
        const override = pagePath.replace(/\.html$/, `.${loc}.html`);
        if (fs.existsSync(override)) sourcePath = override;
      }
      const source = readUtf8(sourcePath);

      // --- SEO-переменные для head-seo / json-ld ---
      const noSlug = relNorm.replace(/\.html$/, "");
      const isNoindex = NOINDEX_PAGES.has(noSlug);
      const canonicalUrl = canonicalFor(relNorm, loc);
      const metaSource = extractMeta(source);
      const pageTitle = metaSource.title || (isDefault ? SITE_NAME_RU : SITE_NAME_EN);
      const pageDesc = metaSource.description || pageTitle;
      const isCasePage = relNorm.startsWith("cases/");

      const vars = baseVars(relNorm, depth);
      vars.canonicalUrl = canonicalUrl;
      vars.canonicalRu = canonicalFor(relNorm, "ru");
      vars.canonicalEn = canonicalFor(relNorm, "en");
      vars.authorName = isDefault ? AUTHOR_NAME_RU : AUTHOR_NAME_EN;
      vars.siteName = isDefault ? SITE_NAME_RU : SITE_NAME_EN;
      vars.metaRobots = isNoindex ? "noindex, nofollow" : "index, follow";
      vars.themeColor = "#0f1115";
      vars.ogType = isCasePage ? "article" : "website";
      vars.ogLocale = isDefault ? "ru_RU" : "en_US";
      vars.ogLocaleAlt = isDefault ? "en_US" : "ru_RU";
      vars.ogTitle = pageTitle;
      vars.ogDescription = pageDesc;
      vars.ogImage = OG_IMAGE_DEFAULT;
      vars.ogImageAlt = pageTitle;
      vars.jsonLd = JSON.stringify(buildJsonLd(relNorm, loc, { title: pageTitle, description: pageDesc }, canonicalUrl), null, 2);

      // Префикс до КОРНЯ ЛОКАЛИ (без en-сдвига) — для навигационных ссылок,
      // чтобы они вели в ту же локаль (/en/), а не в корень сайта (/).
      vars.pagePrefix = vars.assetPrefix;
      // Для не-дефолтной локали всё содержимое уходит на уровень глубже (public/<lang>/),
      // поэтому к assetPrefix добавляем один ../, а пустой casesPrefix — в ../cases/.
      if (!isDefault) {
        vars.assetPrefix = vars.assetPrefix === "" ? "../" : vars.assetPrefix + "../";
        if (vars.casesPrefix === "") vars.casesPrefix = "../cases/";
      }
      vars.lang = loc;

      let outPath;
      if (isCase) {
        const slug = path.basename(pagePath, ".html");
        outPath = path.join(outDir, langPrefix, "cases", slug, "index.html");
      } else if (isResume) {
        outPath = path.join(outDir, langPrefix, "resume", "index.html");
      } else if (isCookiePolicy) {
        outPath = path.join(outDir, langPrefix, "cookie-policy", "index.html");
      } else {
        outPath = path.join(outDir, langPrefix, rel);
      }

      let rendered = renderTemplate(source, partials, vars, dict, defaultDict, loc);
      // Подменяем язык в <html lang="..."> под текущую локаль.
      rendered = rendered.replace(/<html\s+lang="ru"/, `<html lang="${loc}"`);
      if (isCase) {
        rendered = stripCurrentCasePortfolioCarouselItem(rendered, omitFile);
      }
      // Liquid Glass: инъецируем инлайн SVG displacement-фильтр сразу после <body>.
      const lgSvg = LIQUID_GLASS_FILTER.replace(/{{LG_ASSET_PREFIX}}/g, vars.assetPrefix);
      rendered = rendered.replace(/(<body[^>]*>)/, `$1\n  ${lgSvg}\n`);
      ensureDir(path.dirname(outPath));
      fs.writeFileSync(outPath, rendered, "utf8");
    }
  }

  const sitemapXml = buildSitemap(pageFiles);
  fs.writeFileSync(path.join(outDir, "sitemap.xml"), sitemapXml, "utf8");

  console.log(`Built ${pageFiles.length} pages × ${LOCALES.length} locales into public/`);
  console.log(`Generated sitemap.xml (${sitemapXml.split("<url>").length - 1} urls)`);
}

build();