import path from "path";
import fs from "fs";
import os from "os";
import { execFileSync } from "child_process";

const SRC_DIR = "./docs";
const PUBLIC_DIR = "./public";
const DOCS_PUBLIC_DIR = path.join(SRC_DIR, "public");
const DOC_ROUTE_PREFIX = "/docs";
const PUBLIC_ARCHITECTURE_FILE = "ARCHITECTURE.md";
const PUBLIC_ARCHITECTURE_NOTICE = `> Локальная копия канонической спецификации SLM Design.
> Источник: https://slm-design.gromlab.ru/ARCHITECTURE.md
> Не редактировать вручную в этом проекте.`;

interface SidebarItem {
  text: string;
  link: string;
}

interface SidebarGroup {
  text: string;
  items: SidebarItem[];
}

function parseSidebar(): SidebarGroup[] {
  const configPath = path.join(".vitepress", "config.ts");
  const raw = fs.readFileSync(configPath, "utf8");
  const start = raw.indexOf("const sidebar = [");
  const end = raw.indexOf("];", start) + 2;
  const section = raw.substring(start, end);

  const groups: SidebarGroup[] = [];
  const groupParts = section.split(/\n\s*\}\s*,?\s*\n/).filter(Boolean);

  for (const part of groupParts) {
    const textMatch = part.match(/text:\s*'([^']*)'/);
    if (!textMatch) continue;
    const items: SidebarItem[] = [];
    const itemRe = /\{\s*text:\s*'([^']*)'\s*,\s*link:\s*'([^']*)'\s*\}/g;
    let im: RegExpExecArray | null;
    while ((im = itemRe.exec(part)) !== null) {
      items.push({ text: im[1], link: im[2] });
    }
    if (items.length > 0) groups.push({ text: textMatch[1], items });
  }
  return groups;
}

const SIDEBAR = parseSidebar();

function linkToFileRel(link: string): string {
  const rel = link.replace(/^\//, "");
  if (rel === "" || rel.endsWith("/")) return `${rel}index.md`;
  return `${rel}.md`;
}

function fileRelToRoute(file: string): string {
  const route = file.endsWith("/index.md")
    ? file.replace(/index\.md$/, "")
    : file.replace(/\.md$/, "");
  return `${DOC_ROUTE_PREFIX}/${route}`;
}

function fileRelToMdUrl(file: string): string {
  return `${DOC_ROUTE_PREFIX}/${file}`;
}

const ARCHITECTURE_LINK_RE = /\]\((\/architecture(?:\/[^)\s#]*)?)(#[^)\s]*)?\)/g;

function architectureRouteToFileRel(route: string): string {
  if (route.replace(/\/$/, "") === "/architecture") return "architecture/index.md";
  return linkToFileRel(route);
}

function transformArchitectureLinks(
  content: string,
  toHref: (route: string, hash: string) => string,
): string {
  return content.replace(ARCHITECTURE_LINK_RE, (_match, route: string, hash = "") => {
    return `](${toHref(route, hash)})`;
  });
}

function transformArchiveLinks(content: string): string {
  return transformArchitectureLinks(content, (route, hash) => {
    const fileName = path.basename(architectureRouteToFileRel(route));
    return `./${fileName}${hash}`;
  });
}

function transformSiteMarkdownLinks(content: string): string {
  return transformArchitectureLinks(content, (route, hash) => {
    return `${fileRelToMdUrl(architectureRouteToFileRel(route))}${hash}`;
  });
}

function getAllFiles(): string[] {
  return SIDEBAR.flatMap((g) => g.items.map((item) => linkToFileRel(item.link)));
}

const stripFrontmatter = (content: string) =>
  content.replace(/^---[\s\S]*?---\n*/m, "");

const stripRulesLink = (content: string) =>
  content.replace(/<!-- rules-link -->[\s\S]*?<!-- \/rules-link -->\n*/g, "");

function slugifyHeading(heading: string): string {
  return heading
    .trim()
    .replace(/[`*_~[\]()]/g, "")
    .toLowerCase()
    .replace(/[^\p{L}\p{N}\s-]/gu, "")
    .trim()
    .replace(/\s+/g, "-");
}

function fileRelToSingleFileAnchor(file: string): string {
  const filePath = path.join(SRC_DIR, file);
  if (!fs.existsSync(filePath)) return slugifyHeading(path.basename(file, ".md"));

  const raw = stripFrontmatter(fs.readFileSync(filePath, "utf8"));
  const title = raw.match(/^#\s+(.+)$/m)?.[1];
  return slugifyHeading(title ?? path.basename(file, ".md"));
}

function transformSingleFileLinks(content: string): string {
  return transformArchitectureLinks(content, (route, hash) => {
    if (hash) return hash;
    return `#${fileRelToSingleFileAnchor(architectureRouteToFileRel(route))}`;
  });
}

function transformReadmeLinks(content: string): string {
  return transformArchitectureLinks(content, (route, hash) => {
    return `docs/${architectureRouteToFileRel(route)}${hash}`;
  });
}

const shiftHeadings = (content: string) => {
  const lines = content.split("\n");
  let inCodeBlock = false;
  return lines
    .map((line) => {
      if (line.startsWith("```")) inCodeBlock = !inCodeBlock;
      if (inCodeBlock) return line;
      if (/^#{1,5}\s/.test(line)) return "#" + line;
      return line;
    })
    .join("\n");
};

const buildArchitectureMarkdown = (routePrefix: string) => {
  const files = getAllFiles();
  const parts: string[] = [];

  for (const file of files) {
    const filePath = path.join(SRC_DIR, file);
    if (!fs.existsSync(filePath)) continue;
    const raw = fs.readFileSync(filePath, "utf8");
    const content = stripRulesLink(stripFrontmatter(raw)).trim();
    if (!content) continue;

    const route = routePrefix + fileRelToRoute(file).replace(DOC_ROUTE_PREFIX, "");
    const shifted = file.endsWith("index.md") ? content : shiftHeadings(content);
    const processed = transformSingleFileLinks(shifted);
    parts.push(`<!-- ${route} -->\n${processed}`);
  }

  return parts.join("\n\n");
};

function buildLlms() {
  const parts: string[] = [`# SLM Design\n`];
  parts.push(`> Scoped Layered Module Design — модульная архитектура фронтенд-приложений\n`);

  for (const group of SIDEBAR) {
    parts.push(`## ${group.text}`);
    for (const item of group.items) {
      const fileRel = linkToFileRel(item.link);
      const filePath = path.join(SRC_DIR, fileRel);
      let desc = "";
      if (fs.existsSync(filePath)) {
        const raw = fs.readFileSync(filePath, "utf8");
        const fm = raw.match(/^---[\s\S]*?---\n*/m);
        desc = fm ? fm[0].match(/description:\s*(.+)/)?.[1] || "" : "";
      }
      const route = fileRelToMdUrl(fileRel);
      const line = desc
        ? `- [${item.text}](${route}): ${desc}`
        : `- [${item.text}](${route})`;
      parts.push(line);
    }
    parts.push("");
  }

  const outPath = path.join(PUBLIC_DIR, "llms.txt");
  fs.mkdirSync(PUBLIC_DIR, { recursive: true });
  fs.writeFileSync(outPath, parts.join("\n"), "utf8");
  console.log(`llms.txt создан: ${outPath}`);
}

function buildLlmsFull() {
  const outPath = path.join(PUBLIC_DIR, "llms-full.txt");
  fs.writeFileSync(outPath, buildArchitectureMarkdown("/docs"), "utf8");
  console.log(`llms-full.txt создан: ${outPath}`);
}

function copyMarkdownFiles() {
  fs.rmSync(DOCS_PUBLIC_DIR, { recursive: true, force: true });

  let copied = 0;
  for (const file of getAllFiles()) {
    const src = path.join(SRC_DIR, file);
    if (!fs.existsSync(src)) continue;

    const content = transformSiteMarkdownLinks(fs.readFileSync(src, "utf8"));
    const dest = path.join(DOCS_PUBLIC_DIR, file);
    fs.mkdirSync(path.dirname(dest), { recursive: true });
    fs.writeFileSync(dest, content, "utf8");
    copied++;
  }

  console.log(`скопировано ${copied} .md-файлов в ${DOCS_PUBLIC_DIR}`);
}

function buildPublicArchitecture() {
  const outPath = path.join(PUBLIC_DIR, PUBLIC_ARCHITECTURE_FILE);
  const content = `${PUBLIC_ARCHITECTURE_NOTICE}\n\n${buildArchitectureMarkdown("/docs")}`;
  fs.mkdirSync(PUBLIC_DIR, { recursive: true });
  fs.writeFileSync(outPath, content, "utf8");
  console.log(`${PUBLIC_ARCHITECTURE_FILE} создан: ${outPath}`);
}

function buildZip() {
  const tmpRoot = fs.mkdtempSync(path.join(os.tmpdir(), "slm-"));
  const tmpDir = path.join(tmpRoot, "slm-design");
  fs.mkdirSync(tmpDir, { recursive: true });

  const files = getAllFiles();
  for (const file of files) {
    const src = path.join(SRC_DIR, file);
    if (!fs.existsSync(src)) continue;
    let content = fs.readFileSync(src, "utf8");
    content = stripRulesLink(stripFrontmatter(content)).trim();
    content = transformArchiveLinks(content);
    const destName = path.basename(file);
    fs.writeFileSync(path.join(tmpDir, destName), content, "utf8");
  }

  const pkg = JSON.parse(fs.readFileSync("./package.json", "utf8"));
  const version = `v${pkg.version}`;
  fs.writeFileSync(path.join(tmpDir, "VERSION"), `${version}\n${new Date().toISOString()}\n`, "utf8");

  const outPath = path.resolve(PUBLIC_DIR, "slm-design.zip");
  fs.mkdirSync(PUBLIC_DIR, { recursive: true });
  if (fs.existsSync(outPath)) fs.unlinkSync(outPath);

  execFileSync("zip", ["-rq", outPath, "slm-design"], { cwd: tmpRoot });
  fs.rmSync(tmpRoot, { recursive: true });
  console.log(`slm-design.zip создан: ${outPath}`);
}

function buildReadme() {
  const indexPath = path.join(SRC_DIR, "architecture/index.md");
  if (!fs.existsSync(indexPath)) {
    console.log("Пропуск README: index.md не найден");
    return;
  }

  let content = stripFrontmatter(fs.readFileSync(indexPath, "utf8"));
  content = content.replace(/<!-- rules-link -->[\s\S]*?<!-- \/rules-link -->\n*/g, "");
  content = transformReadmeLinks(content);
  fs.writeFileSync("./README.md", content, "utf8");
  console.log("README.md создан");
}

buildLlms();
buildLlmsFull();
copyMarkdownFiles();
buildPublicArchitecture();
buildZip();
buildReadme();