// blog.js – Loads and renders blog posts with automatic collapse for long entries

const BLOG_DIR = 'blog/';
const MANIFEST = BLOG_DIR + 'manifest.json';

// ---------- helpers ----------

// crude HTML parser for directory listings (when manifest is missing)
function parseIndexHtmlList(html) {
  const hrefs = [];
  const re = /href="([^"]+)"/g;
  let m;
  while ((m = re.exec(html)) !== null) {
    const name = m[1];
    // accept typical text file extensions (and no extension)
    if (name.match(/\.(txt|md|text)$/i) || !name.includes('.')) {
      // avoid directory links (ending with /)
      if (!name.endsWith('/')) hrefs.push(name);
    }
  }
  return hrefs;
}

// fetch list of blog post filenames (manifest first, fallback to directory listing)
async function loadPostList() {
  try {
    const r = await fetch(MANIFEST, { cache: 'no-cache' });
    if (r.ok) return await r.json();
  } catch (_) { /* ignore */ }

  try {
    const r = await fetch(BLOG_DIR, { cache: 'no-cache' });
    if (r.ok) {
      const html = await r.text();
      return parseIndexHtmlList(html);
    }
  } catch (e) {
    console.warn('Could not read blog directory listing', e);
  }
  return [];
}

// fetch a single post file
async function fetchPost(filename) {
  const res = await fetch(BLOG_DIR + filename, { cache: 'no-cache' });
  if (!res.ok) throw new Error(`Failed to fetch ${filename}`);
  return await res.text();
}

// generate preview: up to 3 sentences, but not exceeding ~300 chars
function getPreview(text, maxLen = 300) {
  if (text.length <= maxLen) return text;

  // try to split on sentence boundaries (. ! ?) followed by space or newline
  const sentences = text.match(/[^.!?]+[.!?]+/g) || [];
  let preview = '';
  let count = 0;
  for (const s of sentences) {
    if (preview.length + s.length <= maxLen) {
      preview += s;
      count++;
      if (count >= 3) break;
    } else {
      // if we haven't reached 3 sentences, break and use what we have
      break;
    }
  }

  // If we have at least one sentence, use that; otherwise fallback to word‑break
  if (preview.trim().length > 0) {
    return preview.trim();
  }

  // fallback: take first maxLen chars and cut at last space
  let truncated = text.slice(0, maxLen);
  const lastSpace = truncated.lastIndexOf(' ');
  if (lastSpace > 0) truncated = truncated.slice(0, lastSpace);
  return truncated + '…';
}

// ---------- rendering ----------

function renderPost(filename, content) {
  const lines = content.split('\n');
  if (lines.length < 3) {
    // malformed: skip or treat as title‑only
    return null;
  }
  const dateTime = lines[0].trim();
  const title = lines[1].trim();
  const bodyLines = lines.slice(2);
  const body = bodyLines.join('\n').trim();

  const postDiv = document.createElement('div');
  postDiv.className = 'blog-post';

  // title
  const titleEl = document.createElement('h3');
  titleEl.className = 'blog-title';
  titleEl.textContent = title;
  postDiv.appendChild(titleEl);

  // meta
  const metaEl = document.createElement('p');
  metaEl.className = 'blog-meta';
  metaEl.textContent = dateTime;
  postDiv.appendChild(metaEl);

  const isLong = body.length > 300;

  if (!isLong) {
    // short post – display full body directly
    const bodyDiv = document.createElement('div');
    bodyDiv.className = 'blog-body';
    bodyDiv.style.whiteSpace = 'pre-line';
    bodyDiv.textContent = body;
    postDiv.appendChild(bodyDiv);
  } else {
    // long post – show preview with toggle
    const container = document.createElement('div');
    container.className = 'blog-collapsible';

    // preview
    const previewDiv = document.createElement('div');
    previewDiv.className = 'blog-preview';
    previewDiv.style.whiteSpace = 'pre-line';
    let previewText = getPreview(body);
    // ensure ellipsis if preview is truncated
    if (previewText.length < body.length && !previewText.endsWith('…')) {
      previewText += '…';
    }
    previewDiv.textContent = previewText;
    container.appendChild(previewDiv);

    // Read more button
    const readMoreBtn = document.createElement('button');
    readMoreBtn.className = 'blog-toggle read-more';
    readMoreBtn.textContent = 'Read more';
    container.appendChild(readMoreBtn);

    // Full content (hidden initially)
    const fullDiv = document.createElement('div');
    fullDiv.className = 'blog-full';
    fullDiv.style.whiteSpace = 'pre-line';
    fullDiv.textContent = body;
    fullDiv.style.display = 'none';
    container.appendChild(fullDiv);

    // Show less button (hidden initially) – appears at the bottom
    const showLessBtn = document.createElement('button');
    showLessBtn.className = 'blog-toggle show-less';
    showLessBtn.textContent = '✕ Show less';
    showLessBtn.style.display = 'none';
    container.appendChild(showLessBtn);

    // Toggle logic
    function expand() {
      fullDiv.style.display = 'block';
      readMoreBtn.style.display = 'none';
      showLessBtn.style.display = 'inline-block';
    }
    function collapse() {
      fullDiv.style.display = 'none';
      readMoreBtn.style.display = 'inline-block';
      showLessBtn.style.display = 'none';
    }
    readMoreBtn.addEventListener('click', expand);
    showLessBtn.addEventListener('click', collapse);

    postDiv.appendChild(container);
  }

  return postDiv;
}

// ---------- main ----------

async function initBlog() {
  const feed = document.querySelector('.blog-feed');
  if (!feed) return;

  feed.textContent = 'Loading blog posts…';

  try {
    const files = await loadPostList();
    if (!files.length) {
      feed.textContent = 'No blog posts found.';
      return;
    }

    // sort files by name (oldest first? we'll sort by date if embedded, but we'll just alphabetical)
    // Typically filenames like 2025-01-01.txt, so alphabetical = chronological
    files.sort();

    // clear feed
    feed.innerHTML = '';

    for (const file of files) {
      try {
        const content = await fetchPost(file);
        const el = renderPost(file, content);
        if (el) feed.appendChild(el);
      } catch (err) {
        console.warn(`Failed to load ${file}:`, err);
        // optionally show error placeholder
        const errDiv = document.createElement('div');
        errDiv.className = 'blog-post';
        errDiv.style.color = '#b91c1c';
        errDiv.textContent = `⚠️ Could not load post: ${file}`;
        feed.appendChild(errDiv);
      }
    }

    // if nothing was added, show message
    if (feed.children.length === 0) {
      feed.textContent = 'No valid blog posts found.';
    }
  } catch (err) {
    console.error('Blog init error:', err);
    feed.textContent = 'Error loading blog posts.';
  }
}

document.addEventListener('DOMContentLoaded', initBlog);