/* =============================================================
   dashboard.js  —  Home page dashboard behaviour
   Runs after DOM is ready. All IDs are db-* scoped.
   ============================================================= */

(function () {
  "use strict";

  /* ── Greeting ──────────────────────────────────────────────── */

  function updateGreeting() {
    const el = document.getElementById("db-greeting");
    if (!el) return;
    const h = new Date().getHours();
    if (h < 5)       el.textContent = "Burning the midnight oil";
    else if (h < 12) el.textContent = "Good morning";
    else if (h < 17) el.textContent = "Good afternoon";
    else if (h < 21) el.textContent = "Good evening";
    else             el.textContent = "Good night";
  }

  /* ── Live clock ────────────────────────────────────────────── */

  function updateClock() {
    const el = document.getElementById("db-clock");
    if (!el) return;
    const now = new Date();
    const pad = (n) => String(n).padStart(2, "0");
    el.textContent = `${pad(now.getHours())}:${pad(now.getMinutes())}:${pad(now.getSeconds())}`;
  }

  /* ── Date stats ────────────────────────────────────────────── */

  function updateStats() {
    const now = new Date();
    const year = now.getFullYear();

    // Day of year
    const start = new Date(year, 0, 0);
    const diff = now - start;
    const oneDay = 1000 * 60 * 60 * 24;
    const dayOfYear = Math.floor(diff / oneDay);

    // ISO week number
    const d = new Date(Date.UTC(now.getFullYear(), now.getMonth(), now.getDate()));
    const dayNum = d.getUTCDay() || 7;
    d.setUTCDate(d.getUTCDate() + 4 - dayNum);
    const yearStart = new Date(Date.UTC(d.getUTCFullYear(), 0, 1));
    const weekNum = Math.ceil((((d - yearStart) / 86400000) + 1) / 7);

    // Days left
    const isLeap = (year % 4 === 0 && year % 100 !== 0) || year % 400 === 0;
    const daysInYear = isLeap ? 366 : 365;
    const daysLeft = daysInYear - dayOfYear;

    // Month name
    const months = [
      "Jan", "Feb", "Mar", "Apr", "May", "Jun",
      "Jul", "Aug", "Sep", "Oct", "Nov", "Dec",
    ];

    // Write out
    const set = (id, val) => {
      const el = document.getElementById(id);
      if (el) el.textContent = val;
    };

    set("db-stat-day",   dayOfYear);
    set("db-stat-week",  "W" + weekNum);
    set("db-stat-month", months[now.getMonth()]);
    set("db-stat-left",  daysLeft);

    // Year progress bar
    const pct = ((dayOfYear / daysInYear) * 100).toFixed(1);
    const fill = document.getElementById("db-year-fill");
    const label = document.getElementById("db-year-pct");
    if (fill)  fill.style.width = pct + "%";
    if (label) label.textContent = pct + "%";
  }

  /* ── Feed builder ──────────────────────────────────────────── */

  /**
   * Parse a simple HTML sitemap/list page and extract links.
   * Looks for <li> elements containing <a> tags.
   * @param {Document} doc     - parsed document
   * @param {number}   max     - max items to return
   * @param {string}   prefix  - path prefix to prepend to relative hrefs (e.g. "/blogs")
   * @returns {{ href: string, title: string, date: string|null }[]}
   */
  function extractLinks(doc, max, prefix) {
    const base = (prefix || "").replace(/\/$/, ""); // strip trailing slash
    const items = [];
    // org-publish sitemaps use <li> inside #content
    const lis = doc.querySelectorAll("#content li, .org-ul li, ul li");
    for (const li of lis) {
      const a = li.querySelector("a[href]");
      if (!a) continue;
      let href = a.getAttribute("href");
      if (!href || href.startsWith("http")) continue; // skip external
      // Prepend the section prefix when the href doesn't already start with it
      if (base && !href.startsWith(base)) {
        // href may start with "/" or be relative like "2026/03-march/foo.html"
        href = href.startsWith("/")
          ? base + href
          : base + "/" + href;
      }
      const title = a.textContent.trim();
      if (!title) continue;
      // Grab any date text that follows the link
      const dateMatch = li.textContent.replace(title, "").match(/\d{4}-\d{2}-\d{2}/);
      items.push({ href, title, date: dateMatch ? dateMatch[0] : null });
      if (items.length >= max) break;
    }
    return items;
  }

  /**
   * Render items into a db-feed <ul>.
   */
  function renderFeed(ulId, items, fallbackHref) {
    const ul = document.getElementById(ulId);
    if (!ul) return;

    if (!items || items.length === 0) {
      // keep the fallback link already in the HTML
      return;
    }

    ul.innerHTML = items
      .map(
        ({ href, title, date }) => `
      <li class="db-feed__item">
        <span class="db-feed__dot"></span>
        <a href="${escHtml(href)}">${escHtml(title)}</a>
        ${date ? `<span class="db-feed__meta">${escHtml(date)}</span>` : ""}
      </li>`
      )
      .join("");
  }

  function escHtml(str) {
    return str
      .replace(/&/g, "&amp;")
      .replace(/</g, "&lt;")
      .replace(/>/g, "&gt;")
      .replace(/"/g, "&quot;");
  }

  /**
   * Fetch a sitemap page and populate a feed.
   * Fails silently — the fallback link is already in the DOM.
   * @param {string} listUrl  - absolute path to the sitemap page to fetch
   * @param {string} ulId     - id of the <ul> to populate
   * @param {number} max      - max entries to show
   * @param {string} prefix   - path prefix to prepend to extracted hrefs
   */
  async function loadFeed(listUrl, ulId, max, prefix) {
    try {
      const resp = await fetch(listUrl, { credentials: "same-origin" });
      if (!resp.ok) return;
      const html = await resp.text();
      const parser = new DOMParser();
      const doc = parser.parseFromString(html, "text/html");
      const items = extractLinks(doc, max, prefix);
      renderFeed(ulId, items);
    } catch (_) {
      // Network error or cross-origin — silently ignore
    }
  }

  /* ── Init ──────────────────────────────────────────────────── */

  function init() {
    updateGreeting();
    updateStats();
    updateClock();
    setInterval(updateClock, 1000);

    // Populate feeds — pass the section prefix so relative hrefs are correct
    loadFeed("/blogs/blogs-list.html",    "db-feed-blogs",  6, "/blogs");
    loadFeed("/posts/posts-list.html",    "db-feed-posts",  6, "/posts");
    loadFeed("/recently-updated.html",    "db-feed-recent", 6, "");
  }

  if (document.readyState === "loading") {
    document.addEventListener("DOMContentLoaded", init);
  } else {
    init();
  }
})();