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

// ------------------------------------------------------------
// 1. Fetch the list of blog post files
// ------------------------------------------------------------
async function getPostFiles() {
  // Try manifest first
  try {
    const r = await fetch(MANIFEST, { cache: 'no-cache' });
    if (r.ok) {
      const data = await r.json();
      return data.filter(f => f.endsWith('.txt'));
    }
  } catch (_) { /* ignore */ }

  // Fallback: parse directory listing (requires autoindex)
  try {
    const r = await fetch(BLOG_DIR, { cache: 'no-cache' });
    if (r.ok) {
      const text = await r.text();
      const hrefs = [];
      const re = /href="([^"]+)"/g;
      let m;
      while ((m = re.exec(text)) !== null) {
        const name = m[1];
        if (name.endsWith('.txt')) hrefs.push(name);
      }
      return hrefs;
    }
  } catch (e) {
    console.warn('Could not read blog directory listing', e);
  }
  return [];
}

// ------------------------------------------------------------
// 2. Parse a single blog post file
// ------------------------------------------------------------
async function fetchPost(filename) {
  const url = BLOG_DIR + filename;
  const resp = await fetch(url);
  if (!resp.ok) throw new Error(`Failed to fetch ${filename}`);
  const text = await resp.text();
  const lines = text.split('\n');
  // First line: date/time, second: title, rest: content
  const dateTime = lines[0]?.trim() || 'Unknown date';
  const title = lines[1]?.trim() || 'Untitled';
  const content = lines.slice(2).join('\n').trim();
  return { filename, dateTime, title, content };
}

// ------------------------------------------------------------
// 3. Generate a preview for long posts
// ------------------------------------------------------------
function createPreview(content, maxLen = 300) {
  // Return { preview: string, truncated: boolean }
  if (content.length <= maxLen) {
    return { preview: content, truncated: false };
  }

  // Try to get at least 3 sentences
  const sentences = content.match(/[^.!?]*[.!?](\s+|$)/g) || [];
  if (sentences.length >= 3) {
    let preview = sentences.slice(0, 3).join('');
    // If preview is still > maxLen, trim to nearest space
    if (preview.length > maxLen) {
      const trimmed = preview.slice(0, maxLen);
      const lastSpace = trimmed.lastIndexOf(' ');
      if (lastSpace > 0) preview = trimmed.slice(0, lastSpace) + '…';
      else preview = trimmed + '…';
    } else {
      preview = preview.trim() + '…';
    }
    return { preview, truncated: true };
  }

  // Fallback: at least 3 lines (by newline)
  const lines = content.split('\n').filter(l => l.trim() !== '');
  if (lines.length >= 3) {
    let preview = lines.slice(0, 3).join('\n');
    if (preview.length > maxLen) {
      const trimmed = preview.slice(0, maxLen);
      const lastSpace = trimmed.lastIndexOf(' ');
      if (lastSpace > 0) preview = trimmed.slice(0, lastSpace) + '…';
      else preview = trimmed + '…';
    } else {
      preview = preview.trim() + '…';
    }
    return { preview, truncated: true };
  }

  // Last resort: take first maxLen chars, break at word boundary
  if (content.length > maxLen) {
    const trimmed = content.slice(0, maxLen);
    const lastSpace = trimmed.lastIndexOf(' ');
    const preview = (lastSpace > 0 ? trimmed.slice(0, lastSpace) : trimmed) + '…';
    return { preview, truncated: true };
  }

  return { preview: content, truncated: false };
}

// ------------------------------------------------------------
// 4. Render a single blog post
// ------------------------------------------------------------
function renderPost(post) {
  const { dateTime, title, content } = post;

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

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

  // Meta (date)
  const meta = document.createElement('div');
  meta.className = 'blog-meta';
  meta.textContent = dateTime;
  article.appendChild(meta);

  // Body content: split paragraphs by double newline, wrap in <p>
  const bodyDiv = document.createElement('div');
  bodyDiv.className = 'blog-body';
  const paragraphs = content.split(/\n\s*\n/);
  paragraphs.forEach(para => {
    const p = document.createElement('p');
    p.textContent = para.trim();
    bodyDiv.appendChild(p);
  });

  // Decide if we need collapse
  const { preview, truncated } = createPreview(content);

  if (!truncated) {
    // Short post – show full content directly
    article.appendChild(bodyDiv);
  } else {
    // Long post – wrap in <details>
    const details = document.createElement('details');
    details.className = 'blog-collapse';

    const summary = document.createElement('summary');
    // Preview text
    const previewDiv = document.createElement('div');
    previewDiv.className = 'blog-preview';
    // Split preview by newline and create lines, but we can just set innerHTML with <br>
    previewDiv.innerHTML = preview.replace(/\n/g, '<br>');
    summary.appendChild(previewDiv);

    // "Read more" text
    const moreSpan = document.createElement('span');
    moreSpan.className = 'read-more-text';
    moreSpan.textContent = 'Read more';
    summary.appendChild(moreSpan);

    details.appendChild(summary);
    // Full content inside the details
    details.appendChild(bodyDiv);
    article.appendChild(details);
  }

  return article;
}

// ------------------------------------------------------------
// 5. Main: load posts and render
// ------------------------------------------------------------
async function initBlog() {
  const feed = document.querySelector('.blog-feed');
  if (!feed) return;

  feed.innerHTML = 'Loading blog posts…';

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

    // Fetch and parse all posts
    const posts = await Promise.all(files.map(f => fetchPost(f)));

    // Sort by date descending (assuming ISO-like date in first line)
    posts.sort((a, b) => {
      const dA = new Date(a.dateTime);
      const dB = new Date(b.dateTime);
      return dB - dA;
    });

    // Render each post
    feed.innerHTML = '';
    posts.forEach(post => {
      const el = renderPost(post);
      feed.appendChild(el);
    });
  } catch (err) {
    console.error(err);
    feed.innerHTML = 'Error loading blog posts.';
  }
}

document.addEventListener('DOMContentLoaded', initBlog);