import test from "node:test";
import assert from "node:assert/strict";
import fs from "node:fs";
import path from "node:path";
import { execSync } from "node:child_process";

const siteDir = path.resolve("_site");

function getAllHtmlFiles(dir) {
  let results = [];
  const list = fs.readdirSync(dir);
  for (const file of list) {
    const filePath = path.join(dir, file);
    const stat = fs.statSync(filePath);
    if (stat && stat.isDirectory()) {
      results = results.concat(getAllHtmlFiles(filePath));
    } else if (file.endsWith(".html")) {
      results.push(filePath);
    }
  }
  return results;
}

test("Build & Link Integrity: Output inspection and link verification", () => {
  // Ensure fresh build exists
  if (!fs.existsSync(siteDir)) {
    execSync("npm run build", { stdio: "pipe" });
  }

  // 1. Core Pages Exist
  assert.ok(fs.existsSync(path.join(siteDir, "index.html")), "Root _site/index.html must exist");
  assert.ok(fs.existsSync(path.join(siteDir, "dispatches/index.html")), "_site/dispatches/index.html must exist");
  assert.ok(fs.existsSync(path.join(siteDir, "assets/css/main.css")), "_site/assets/css/main.css must exist");

  const htmlFiles = getAllHtmlFiles(siteDir);
  assert.ok(htmlFiles.length >= 4, "Must compile all core pages and articles");

  for (const htmlFile of htmlFiles) {
    const relHtml = path.relative(siteDir, htmlFile);
    const content = fs.readFileSync(htmlFile, "utf-8");

    // 2. HTML Boilerplate Invariants
    assert.match(content, /<!DOCTYPE html>/i, `${relHtml} must contain <!DOCTYPE html>`);
    assert.match(content, /<meta\s+name="viewport"/i, `${relHtml} must have viewport meta tag`);
    assert.match(content, /<link\s+rel="stylesheet"\s+href="\/assets\/css\/main\.css">/i, `${relHtml} must link to main.css`);

    // 3. Internal Link Integrity (No 404s!)
    const internalLinks = [...content.matchAll(/href="(\/[^"#?]*)"/g)].map((m) => m[1]);
    for (const link of internalLinks) {
      if (link.startsWith("/feed.xml")) continue; // dynamic RSS route
      // Normalize link to file on disk: /dispatches/ -> _site/dispatches/index.html or _site/dispatches.html
      let targetPath;
      if (link.endsWith("/")) {
        targetPath = path.join(siteDir, link, "index.html");
      } else if (path.extname(link)) {
        targetPath = path.join(siteDir, link);
      } else {
        targetPath = path.join(siteDir, `${link}.html`);
        if (!fs.existsSync(targetPath)) {
          targetPath = path.join(siteDir, link, "index.html");
        }
      }

      assert.ok(
        fs.existsSync(targetPath),
        `Broken internal link in ${relHtml}: href="${link}" resolves to missing file: ${targetPath}`
      );
    }

    // 4. Anchor Link Integrity (TOC anchor links match actual heading IDs)
    const anchorLinks = [...content.matchAll(/href="#([^"]+)"/g)].map((m) => m[1]);
    for (const anchor of anchorLinks) {
      // Ignore skip-to-content or standard body anchors
      if (anchor === "main-content") continue;
      const expectedIdRegex = new RegExp(`id="${anchor}"`, "i");
      assert.match(
        content,
        expectedIdRegex,
        `Broken TOC anchor link in ${relHtml}: href="#${anchor}" has no corresponding id="${anchor}"`
      );
    }
  }
});