export default class OnThisDay {
  data() {
    return {
      layout: 'layouts/base',
      permalink: '/blog/on-this-day/',
      title: 'On this day'
    };
  }

  async render(data) {
    const today = new Date(new Date().toLocaleString('en-US', { timeZone: 'America/Toronto' }));
    const options = { month: 'long', day: 'numeric' };
    const date = today.toLocaleDateString('en-US', options);
    const currentMonthDay = today.toISOString().substring(5, 10);
    let list = data.collections._posts
        .filter(post => {
          const postDateTime = new Date(post.date).toLocaleString('en-US', { timeZone: 'America/Toronto' });
          const postMonthDay = (new Date(postDateTime)).toISOString().substring(5, 10);
          return postMonthDay === currentMonthDay;
        })
        .sort((a, b) => {
          if (a.date < b.date) return 1;
          if (a.date > b.date) return -1;
          return 0;
        })
        .map(post => {
          const postDateTime = new Date(post.date).toLocaleString('en-US', { timeZone: 'America/Toronto' });
          const postDate = new Date(postDateTime);
          const postYear = postDate.getFullYear();
          return `<li>${postYear}: <a href="${post.url}">${post.data.title}</a></li>`;
        })
        .join('\n');
    list = list.length > 0
      ? `<ul>${list}</ul>`
      : `<p>No posts were written on ${date} in previous years.</p>`;

    return `<section><h2>On this day</h2>
<p>This page lists posts written on this day throughout the years. If you've enabled Javascript, it will show the current day. If you don't, it'll show the posts from the day I last updated this blog. You might also like to explore <a href="/blog/all">all posts</a>, <a href="/topic">a topic-based outline</a> or <a href="/blog/category">categories</a>.</p>
<h3 class="date">${date}</h3>
<div id="posts-container">${list}</div>

<script>
  $(document).ready(function() { onThisDay(); });
</script>
</section>`;
  }
};

function onThisDay() {
  const tz = 'America/Toronto';
  function getEffectiveDate() {
    const urlParams = new URLSearchParams(window.location.search);
    const dateParam = urlParams.get('date');
    if (dateParam && /^\d{2}-\d{2}$/.test(dateParam)) {
      const currentYear = new Date().getFullYear();
      const dateObj = new Date(`${currentYear}-${dateParam}T12:00:00Z`);
      if (dateObj.getTime()) {
        return {
          monthDay: dateParam,
          formatted: dateObj.toLocaleDateString('en-US', { month: 'long', day: 'numeric' })
        };
      }
    }
    const today = new Date(new Date().toLocaleString('en-US', { timeZone: tz }));
    return {
      monthDay: today.toISOString().substring(5, 10), // MM-DD
      formatted: today.toLocaleDateString('en-US', { month: 'long', day: 'numeric' })
    };
  }
  // Fetch and process the posts
  fetch('/blog/all/index.json')
    .then(response => response.json())
    .then(posts => {
      const dateInfo = getEffectiveDate();
      const dateElement = document.querySelector('h3.date');
      if (dateElement) {
        dateElement.textContent = dateInfo.formatted;
      }
      const matchingPosts = posts.filter(post => {
        const postDate = new Date(post.date).toLocaleString('en-US', { timeZone: tz });
        const postMonthDay = (new Date(postDate)).toISOString().substring(5, 10);
        return postMonthDay === dateInfo.monthDay;
      });

      matchingPosts.sort((a, b) => {
        const dateA = new Date(a.date);
        const dateB = new Date(b.date);
        return dateB - dateA;
      });

      const elem = document.getElementById('posts-container');
      if (matchingPosts.length > 0) {
        const postsHTML = matchingPosts.map(post => {
          const postDate = new Date(post.date).toLocaleString('en-US', { timeZone: tz });
          const postYear = new Date(postDate).getFullYear();
          return `<li>${postYear}: <a href="${post.permalink}">${post.title}</a></li>`;
        }).join('\n');
        elem.innerHTML = `<ul>${postsHTML}</ul>`;
      } else {
        elem.innerHTML = `<p>No posts were written on ${dateInfo.formatted}.</p>`;
      }
    })
    .catch(error => {
      console.error('Error fetching posts:', error);
    });
}

(defun my-assign-custom-ids ()
  (interactive)
  (let ((custom-ids
         (org-map-entries (lambda () (org-entry-get (point) "CUSTOM_ID")) "CUSTOM_ID={.}")))
    (org-map-entries
     (lambda ()
       (let ((slug
              (replace-regexp-in-string
               "^-\\|-$" ""
               (replace-regexp-in-string "[^A-Za-z0-9]+" "-"
                                         (downcase (string-join (org-get-outline-path t) " "))))))
         (while (member slug custom-ids)
           (setq slug (read-string "Manually set custom ID: ")))
         (org-entry-put (point) "CUSTOM_ID" slug)))
     "-CUSTOM_ID={.}")))