/*
 * pw-crtc-collapse.js — progressive-enhancement reading aid for the long
 * Canada CRTC carrier page (public/services/telecom/canada-crtc/index.html).
 *
 * Why a runtime script instead of editing the HTML: that page is a single
 * 183 KB minified file with auto-generated markup whose section headings sit
 * at inconsistent DOM depths. Rewriting it by hand risks corrupting the markup
 * and is hard to maintain. This script enhances it non-destructively:
 *
 *   1. Injects a "5-minute read" TL;DR + jump menu at the top of the article.
 *   2. Collapses a curated set of deep-detail H2 sections into <details>-style
 *      accordions (collapsed by default) so the page reads short, while every
 *      word remains present for SEO and for anyone who expands it.
 *
 * It is idempotent (guards against double-run) and degrades gracefully: with
 * JS off, the full page renders exactly as before.
 */
(function () {
  "use strict";
  if (window.__pwCrtcCollapse) return;
  window.__pwCrtcCollapse = true;

  // H2 headings (matched by normalized text prefix) to collapse by default.
  // Order here is also the order used in the TL;DR jump menu.
  var COLLAPSE = [
    { key: "why canada", label: "Why Canada: FCC vs CRTC" },
    { key: "corporate tax comparison", label: "Corporate tax comparison (BC vs US)" },
    { key: "canada telecom m&a", label: "Canada telecom M&A climate" },
    { key: "step 6: canadian business banking", label: "Canadian business banking" },
    { key: "included: canadian wholesale", label: "Wholesale vendor directory" },
    { key: "frequently asked questions", label: "FAQ", open: false },
    { key: "us wholesale voice market", label: "US wholesale / DID restrictions" },
    { key: "the growing burden", label: "The growing burden of a US carrier" },
    { key: "what you'll need", label: "What you'll need to get started" }
  ];

  function norm(s) {
    return (s || "").replace(/\s+/g, " ").trim().toLowerCase();
  }

  function ready(fn) {
    if (document.readyState !== "loading") fn();
    else document.addEventListener("DOMContentLoaded", fn);
  }

  ready(function () {
    var h2s = Array.prototype.slice.call(document.querySelectorAll("h2"));
    if (!h2s.length) return;

    var made = [];

    COLLAPSE.forEach(function (cfg) {
      var h2 = h2s.find(function (h) {
        return norm(h.textContent).indexOf(cfg.key) === 0 ||
               norm(h.textContent).indexOf(cfg.key) !== -1;
      });
      if (!h2 || h2.dataset.pwCollapsed) return;

      var parent = h2.parentNode;
      // Collect this H2 plus its following siblings up to the next H2 sibling.
      var nodes = [h2];
      var n = h2.nextSibling;
      while (n) {
        if (n.nodeType === 1 && n.tagName === "H2") break;
        var next = n.nextSibling;
        // Skip (don't absorb) a standalone block such as the "is this real?"
        // proof expander — it must stay visible outside any collapsed body.
        // We leave it in place; surrounding siblings still get collected, so it
        // ends up rendered right after this accordion.
        if (!(n.nodeType === 1 && n.classList &&
              n.classList.contains("pw-standalone"))) {
          nodes.push(n);
        }
        n = next;
      }
      if (nodes.length < 2) {
        // Heading has no sibling body at this level (body nested elsewhere);
        // skip rather than risk an empty/incorrect accordion.
        return;
      }

      var details = document.createElement("details");
      details.className = "pw-collapse";
      if (cfg.open) details.open = true;

      var summary = document.createElement("summary");
      summary.className = "pw-collapse-summary";
      summary.textContent = h2.textContent.replace(/\s+/g, " ").trim();
      details.appendChild(summary);

      var body = document.createElement("div");
      body.className = "pw-collapse-body";

      // Move the original H2 (hidden, keeps heading in DOM for SEO) + siblings in.
      h2.style.display = "none";
      h2.dataset.pwCollapsed = "1";
      parent.insertBefore(details, nodes[0]);
      nodes.forEach(function (node) { body.appendChild(node); });
      details.appendChild(body);

      var id = "crtc-" + cfg.key.replace(/[^a-z0-9]+/g, "-").replace(/(^-|-$)/g, "");
      details.id = id;
      made.push({ id: id, label: cfg.label });
    });

    if (!made.length) return;

    // Build the TL;DR + jump menu and insert it right after the hero/pricing card.
    var anchor = document.querySelector("nav[aria-label], .max-w-4xl") || document.body;
    var tldr = document.createElement("div");
    tldr.className = "pw-tldr";
    tldr.innerHTML =
      '<div class="pw-tldr-head">' +
      '<span class="pw-tldr-badge">5-min read</span>' +
      '<strong>The short version</strong></div>' +
      '<p class="pw-tldr-lead">Become a single <strong>Canadian CRTC/BITS carrier</strong> ' +
      'and lawfully serve US &amp; international customers \u2014 without taking on the US ' +
      'FCC&nbsp;499/USF, RMD, STIR/SHAKEN and state-PUC stack a US carrier carries. ' +
      'A Canadian carrier serving US customers as one entity is a common, established ' +
      'structure (per public FCC records). Details below are optional \u2014 tap any to expand.</p>' +
      '<div class="pw-tldr-jump"><span>Jump to:</span></div>';

    var jump = tldr.querySelector(".pw-tldr-jump");
    made.forEach(function (m) {
      var a = document.createElement("a");
      a.href = "#" + m.id;
      a.className = "pw-tldr-chip";
      a.textContent = m.label;
      a.addEventListener("click", function (e) {
        var d = document.getElementById(m.id);
        if (d) {
          d.open = true;
          e.preventDefault();
          d.scrollIntoView({ behavior: "smooth", block: "start" });
        }
      });
      jump.appendChild(a);
    });

    // Insert TL;DR before the first collapsed section for a clean top-of-article placement.
    var firstDetails = document.querySelector("details.pw-collapse");
    if (firstDetails && firstDetails.parentNode) {
      firstDetails.parentNode.insertBefore(tldr, firstDetails);
    } else {
      anchor.insertBefore(tldr, anchor.firstChild);
    }
  });
})();