// Feed / reader mode. Presents the stories currently on the page one at a
// time in a focused overlay, marking each read as it's shown. Left/right arrow
// keys (or the on-screen buttons) page through them; the full article text is
// whatever Pete captured at ingest (content:encoded or the scraped body),
// fetched on demand from /api/article and cached for the session.
//
// Read state lives in localStorage under pete.read.v1. It's deliberately
// device-local — unlike the small prefs blob, the read set grows unbounded, so
// it isn't mirrored through PetePrefs to the account.
(function () {
  var overlay = document.getElementById("pete-reader");
  if (!overlay) return;

  var READ_KEY = "pete.read.v1";
  var articleEl = overlay.querySelector("[data-reader-article]");
  var scrollEl = overlay.querySelector("[data-reader-scroll]");
  var progressEl = overlay.querySelector("[data-reader-progress]");
  var linkEl = overlay.querySelector("[data-reader-link]");
  var prevBtn = overlay.querySelector("[data-reader-prev]");
  var nextBtn = overlay.querySelector("[data-reader-next]");
  var closeBtn = overlay.querySelector("[data-reader-close]");
  var backdrop = overlay.querySelector("[data-reader-backdrop]");

  var items = []; // {id, url, headline, lede, image, time, source, chTitle, chEmoji, chTheme, posted, paywalled}
  var index = 0;
  var open = false;
  var contentCache = {}; // id -> {content, lede}
  var inflight = null;

  // ---- read-state store -----------------------------------------------------
  function loadRead() {
    try {
      var raw = localStorage.getItem(READ_KEY);
      var obj = raw ? JSON.parse(raw) : {};
      return obj && typeof obj === "object" ? obj : {};
    } catch (e) { return {}; }
  }
  function saveRead(set) {
    try { localStorage.setItem(READ_KEY, JSON.stringify(set)); } catch (e) {}
  }
  var readSet = loadRead();

  function isRead(id) { return !!readSet[id]; }
  function setRead(id, on) {
    if (on) readSet[id] = 1; else delete readSet[id];
    saveRead(readSet);
    paintCard(id, on);
  }
  // Reflect read state onto every matching card on the page (a story can appear
  // in more than one section on the home page).
  function paintCard(id, on) {
    document.querySelectorAll('[data-story-card][data-id="' + cssEsc(id) + '"]').forEach(function (c) {
      if (on) c.setAttribute("data-read", "1");
      else c.removeAttribute("data-read");
    });
  }
  function cssEsc(s) {
    return String(s).replace(/["\\]/g, "\\$&");
  }

  // ---- collecting the page's stories ----------------------------------------
  function isVisible(el) {
    return window.getComputedStyle(el).display !== "none";
  }
  function collect() {
    var seen = Object.create(null);
    var out = [];
    document.querySelectorAll("[data-story-card]").forEach(function (c) {
      var id = c.getAttribute("data-id");
      if (!id || seen[id] || !isVisible(c)) return;
      var url = c.getAttribute("data-url") || c.getAttribute("href") || "";
      if (!/^https?:\/\//i.test(url)) url = "";
      seen[id] = true;
      out.push({
        id: id,
        url: url,
        headline: c.getAttribute("data-headline") || "",
        lede: c.getAttribute("data-lede") || "",
        image: c.getAttribute("data-image") || "",
        time: c.getAttribute("data-time") || "",
        source: c.getAttribute("data-source") || "",
        chTitle: c.getAttribute("data-ch-title") || "",
        chEmoji: c.getAttribute("data-ch-emoji") || "",
        chTheme: c.getAttribute("data-ch-theme") || "",
        paywalled: c.getAttribute("data-paywalled") === "1"
      });
    });
    return out;
  }

  // ---- rendering ------------------------------------------------------------
  function escapeHTML(s) {
    return String(s == null ? "" : s)
      .replace(/&/g, "&amp;").replace(/</g, "&lt;").replace(/>/g, "&gt;")
      .replace(/"/g, "&quot;").replace(/'/g, "&#39;");
  }
  function safeURL(s) {
    var raw = String(s == null ? "" : s).trim();
    return /^https?:\/\//i.test(raw) ? raw : "";
  }
  // Turn stored plain text (paragraphs separated by blank lines) into escaped
  // <p> blocks. Single newlines inside a paragraph become spaces.
  function paragraphs(text) {
    var blocks = String(text || "").split(/\n{2,}/);
    var html = "";
    for (var i = 0; i < blocks.length; i++) {
      var t = blocks[i].replace(/\s*\n\s*/g, " ").trim();
      if (t) html += "<p>" + escapeHTML(t) + "</p>";
    }
    return html;
  }

  function eyebrow(it) {
    var chip = it.chTheme
      ? '<span class="pete-reader-chip bg-theme-' + escapeHTML(it.chTheme) + '">' +
        (it.chEmoji ? '<span aria-hidden="true">' + escapeHTML(it.chEmoji) + "</span>" : "") +
        escapeHTML(it.chTitle) + "</span>"
      : "";
    var src = it.source ? '<span class="pete-reader-source">' + escapeHTML(it.source) + "</span>" : "";
    var time = it.time ? '<span class="pete-reader-time">' + escapeHTML(it.time) + "</span>" : "";
    return '<div class="pete-reader-eyebrow">' + chip + src + time + "</div>";
  }

  function renderBody(it, bodyHTML) {
    var hero = it.image
      ? '<img class="pete-reader-hero" src="' + escapeHTML(it.image) + '" alt="" loading="lazy" decoding="async">'
      : "";
    var href = safeURL(it.url);
    var note = '<p class="pete-reader-note">' +
      (it.paywalled ? "This source is paywalled — the text above may be partial. " : "") +
      (href ? 'Read it at the source: <a href="' + escapeHTML(href) + '" target="_blank" rel="noopener noreferrer">' +
              escapeHTML(it.source || "original article") + " ↗</a>." : "") +
      "</p>";
    articleEl.innerHTML =
      eyebrow(it) +
      '<h1 class="pete-reader-title">' + escapeHTML(it.headline) + "</h1>" +
      hero +
      '<div class="pete-reader-body">' + bodyHTML + "</div>" +
      note;
  }

  function loadingBody(it) {
    renderBody(it, '<p style="opacity:.55">Loading the full story…</p>');
  }

  function fillContent(it, data) {
    var text = (data && data.content) ? data.content : ((data && data.lede) || it.lede);
    var html = paragraphs(text);
    if (!html) {
      html = '<p style="opacity:.7">No article text was captured for this story. Open the original to read it.</p>';
    }
    renderBody(it, html);
  }

  function fetchContent(it) {
    if (contentCache[it.id]) { fillContent(it, contentCache[it.id]); return; }
    loadingBody(it);
    if (inflight) inflight.abort();
    var ctrl = new AbortController();
    inflight = ctrl;
    var reqId = it.id;
    fetch("/api/article?id=" + encodeURIComponent(it.id), { signal: ctrl.signal, credentials: "same-origin" })
      .then(function (r) { if (!r.ok) throw new Error("status " + r.status); return r.json(); })
      .then(function (data) {
        contentCache[reqId] = data;
        if (ctrl !== inflight) return;      // superseded by a newer navigation
        if (items[index] && items[index].id === reqId) fillContent(it, data);
      })
      .catch(function (err) {
        if (err.name === "AbortError") return;
        if (items[index] && items[index].id === reqId) fillContent(it, null); // fall back to lede
      })
      .finally(function () { if (ctrl === inflight) inflight = null; });
  }

  // ---- navigation -----------------------------------------------------------
  function show(i) {
    index = i;
    if (index >= items.length) { renderDone(); return; }
    var it = items[index];
    progressEl.textContent = (index + 1) + " / " + items.length;
    var href = safeURL(it.url);
    if (href) { linkEl.href = href; linkEl.style.display = ""; }
    else linkEl.style.display = "none";
    prevBtn.disabled = index === 0;
    nextBtn.disabled = false;
    nextBtn.textContent = index === items.length - 1 ? "done ✓" : "→";
    if (scrollEl) scrollEl.scrollTop = 0;
    fetchContent(it);
    setRead(it.id, true); // presenting a story marks it read
  }

  function renderDone() {
    progressEl.textContent = items.length + " / " + items.length;
    linkEl.style.display = "none";
    prevBtn.disabled = items.length === 0;
    nextBtn.disabled = true;
    nextBtn.textContent = "→";
    if (scrollEl) scrollEl.scrollTop = 0;
    articleEl.innerHTML =
      '<div class="pete-reader-empty">' +
      '<span class="pete-reader-empty-emoji" aria-hidden="true">🎉</span>' +
      '<h1 class="pete-reader-title" style="margin:0">You\'re all caught up</h1>' +
      '<p style="opacity:.7;max-width:28rem">That\'s every story on this page. ' +
      "Head back to browse more, or press ← to revisit the last one.</p>" +
      "</div>";
  }

  function next() { if (index < items.length) show(index + 1); }
  function prev() { if (index > 0) show(index - 1); }

  function firstUnread() {
    for (var i = 0; i < items.length; i++) if (!isRead(items[i].id)) return i;
    return 0;
  }

  // ---- open / close ---------------------------------------------------------
  function openReader() {
    items = collect();
    if (items.length === 0) return;
    open = true;
    overlay.classList.remove("hidden");
    document.body.classList.add("overflow-hidden");
    show(firstUnread());
  }
  function closeReader() {
    open = false;
    if (inflight) { inflight.abort(); inflight = null; }
    overlay.classList.add("hidden");
    document.body.classList.remove("overflow-hidden");
  }

  // ---- wiring ---------------------------------------------------------------
  document.addEventListener("DOMContentLoaded", function () {
    // Dim stories already read on this device.
    document.querySelectorAll("[data-story-card]").forEach(function (c) {
      var id = c.getAttribute("data-id");
      if (id && isRead(id)) c.setAttribute("data-read", "1");
    });

    document.querySelectorAll("[data-reader-open]").forEach(function (b) {
      b.addEventListener("click", function (e) { e.preventDefault(); openReader(); });
    });
    if (prevBtn) prevBtn.addEventListener("click", prev);
    if (nextBtn) nextBtn.addEventListener("click", next);
    if (closeBtn) closeBtn.addEventListener("click", closeReader);
    if (backdrop) backdrop.addEventListener("click", closeReader);
  });

  document.addEventListener("keydown", function (e) {
    // Enter feed mode with `f` when nothing is focused and no other overlay is up.
    if (!open && (e.key === "f" || e.key === "F") && !e.metaKey && !e.ctrlKey && !e.altKey) {
      var tag = (document.activeElement && document.activeElement.tagName) || "";
      if (tag === "INPUT" || tag === "TEXTAREA") return;
      var searchOpen = document.getElementById("pete-search");
      if (searchOpen && !searchOpen.classList.contains("hidden")) return;
      e.preventDefault();
      openReader();
      return;
    }
    if (!open) return;
    switch (e.key) {
      case "ArrowRight": case "l": case " ": e.preventDefault(); next(); break;
      case "ArrowLeft": case "h": e.preventDefault(); prev(); break;
      case "Escape": e.preventDefault(); closeReader(); break;
      case "o": case "Enter": {
        var it = items[index];
        var href = it && safeURL(it.url);
        if (href) { e.preventDefault(); window.open(href, "_blank", "noopener"); }
        break;
      }
      case "u": {
        var cur = items[index];
        if (cur) setRead(cur.id, false); // let the user undo an accidental read
        break;
      }
    }
  });
})();