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 outDir = path.join(rootDir, "public");

const includeRe = /\{\{\>\s*([a-z0-9-]+)\s*\}\}/gi;
const varRe = /\{\{\s*([a-zA-Z0-9_]+)\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 renderTemplate(input, partials, vars, stack = []) {
  const withIncludes = input.replace(includeRe, (_, name) => {
    const key = String(name).trim();
    if (!partials.has(key)) {
      throw new Error(`Partial "${key}" not found`);
    }
    if (stack.includes(key)) {
      throw new Error(`Circular partial include: ${[...stack, key].join(" -> ")}`);
    }
    const partialContent = partials.get(key);
    return renderTemplate(partialContent, partials, vars, [...stack, key]);
  });

  return withIncludes.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;
  }
}

function build() {
  const partials = loadPartials();
  const pageFiles = walkHtmlFiles(srcPagesDir);

  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";

    let outPath;
    let vars;

    if (isCase) {
      const slug = path.basename(pagePath, ".html");
      outPath = path.join(outDir, "cases", slug, "index.html");
      vars = {
        assetPrefix: "../../",
        casesPrefix: "../",
      };
    } else if (isResume) {
      outPath = path.join(outDir, "resume", "index.html");
      vars = {
        assetPrefix: "../",
        casesPrefix: "",
      };
    } else if (isCookiePolicy) {
      outPath = path.join(outDir, "cookie-policy", "index.html");
      vars = {
        assetPrefix: "../",
        casesPrefix: "",
      };
    } else {
      outPath = path.join(outDir, rel);
      vars = {
        assetPrefix: depth === 0 ? "" : "../".repeat(depth),
        casesPrefix: depth === 0 ? "cases/" : "",
      };
    }

    const source = readUtf8(pagePath);
    let rendered = renderTemplate(source, partials, vars);
    if (isCase) {
      const omitFile = path.basename(pagePath);
      rendered = stripCurrentCasePortfolioCarouselItem(rendered, omitFile);
    }
    ensureDir(path.dirname(outPath));
    fs.writeFileSync(outPath, rendered, "utf8");
  }

  console.log(`Built ${pageFiles.length} pages into public/`);
}

build();