(function () {
  "use strict";

  /*
   * Hidden site details
   * -------------------
   * This file adds small hidden interactions across the site: footer notes,
   * click targets, search/keyboard secrets, rare messages, and page-specific
   * behavior for the hidden /play pages.
   *
   * How to add your own things:
   * - Add new text to EDITABLE CONTENT arrays such as `details`, `poems`,
   *   `greetings`, or `lore`.
   * - Add search-triggered toast messages to `SEARCH_TOASTS`.
   * - Add search-triggered page redirects to `SEARCH_ROUTES`.
   * - Add typed keyboard phrases to `KEYBOARD_SECRETS` or `LONG_KEYBOARD_SECRETS`.
   * - Add a new feature by writing an `addYourFeature(memory)` function and
   *   adding it to the `FEATURES` list at the bottom of the file.
   */

  // Storage keys. v1 is read once so old visitors keep their hidden progress.
  const STORAGE_KEY = "zxh_hidden_details_v2";
  const OLD_STORAGE_KEY = "zxh_hidden_details_v1";

  // Shared page context. These are captured once so daily random picks stay stable.
  const now = new Date();
  const hour = now.getHours();
  const path = window.location.pathname;
  const state = readState();
  // -----------------------------
  // EDITABLE CONTENT
  // -----------------------------
  // Generated by the hidden narrative authoring page.
  // Friendly source of truth: assets/content/hidden-details.json

  const familyLayers = [];

  const details = [];

  const poems = [];

  const greetings = [];

  const nightMessages = [];

  const lore = {
    "quotes": [],
    "conversations": [],
    "journals": [
        "10/07/26 - surviving a heatwave whilst working :-)"
    ],
    "warnings": [],
    "dreams": [],
    "cassettes": [],
    "fakeUsers": [],
    "seasonal": {},
    "homepageTakeovers": [],
    "roomLinks": []
};

  // Exact search text -> toast message.
  const SEARCH_TOASTS = {};

  // Exact search text -> hidden page route.
  const SEARCH_ROUTES = {};

  // Short typed phrases. Stored in sessionStorage as a rolling key chain.
  const KEYBOARD_SECRETS = [];

  // Longer typed phrases and character names.
  const LONG_KEYBOARD_SECRETS = [];


  // -----------------------------
  // STATE HELPERS
  // -----------------------------

  function readState() {
    let current = {};
    try {
      current = JSON.parse(localStorage.getItem(STORAGE_KEY) || "{}");
    } catch (_) {}
    if (!current.visits) {
      try {
        const oldState = JSON.parse(localStorage.getItem(OLD_STORAGE_KEY) || "{}");
        current = { ...oldState, migratedFromV1: true };
        localStorage.setItem(STORAGE_KEY, JSON.stringify(current));
      } catch (_) {}
    }
    return current;
  }

  function writeState(next) {
    try {
      localStorage.setItem(STORAGE_KEY, JSON.stringify(next));
    } catch (_) {}
  }

  function pick(list, salt) {
    const seed = hash(`${path}|${now.toDateString()}|${salt || ""}`);
    return list[seed % list.length];
  }

  function hash(value) {
    let h = 2166136261;
    for (let i = 0; i < value.length; i += 1) {
      h ^= value.charCodeAt(i);
      h = Math.imul(h, 16777619);
    }
    return Math.abs(h >>> 0);
  }

  // -----------------------------
  // UI HELPERS
  // -----------------------------

  function hiddenMessageMarkup(message) {
    return `<span class="hidden-message-text">${escapeHtml(message)}</span>`;
  }

  function setHiddenMessage(el, message) {
    delete el.dataset.hiddenCharacter;
    el.innerHTML = hiddenMessageMarkup(message);
  }

  function toast(message, duration) {
    let el = document.querySelector(".hidden-toast");
    if (!el) {
      el = document.createElement("div");
      el.className = "hidden-toast";
      el.setAttribute("role", "status");
      document.body.appendChild(el);
    }
    setHiddenMessage(el, message);
    el.classList.add("is-visible");
    window.clearTimeout(el._timer);
    el._timer = window.setTimeout(() => el.classList.remove("is-visible"), duration || 5600);
  }

  function redirectTo(route) {
    window.location.href = route;
  }

  function runSecretAction(secret) {
    if (secret.route) redirectTo(secret.route);
    if (secret.message) toast(secret.message);
    if (secret.song) playTinySong();
  }

  function layerForSearch(value) {
    if (value.includes("future")) return 4;
    if (value.includes("sensei") || value.includes("aphy")) return 3;
    return 2;
  }

  function rememberVisit() {
    const visits = (state.visits || 0) + 1;
    const seen = Array.isArray(state.seen) ? state.seen : [];
    const pathCounts = { ...(state.pathCounts || {}) };
    pathCounts[path] = (pathCounts[path] || 0) + 1;
    const layerVisits = { ...(state.layerVisits || {}) };
    const next = {
      ...state,
      visits,
      lastPath: path,
      pathCounts,
      layerVisits,
      seen: Array.from(new Set([...seen, path])).slice(-100),
      firstSeen: state.firstSeen || new Date().toISOString(),
      lastSeen: new Date().toISOString()
    };
    writeState(next);
    return next;
  }

  function awardLayer(layer, reason) {
    const next = readState();
    next.layerVisits = { ...(next.layerVisits || {}) };
    next.layerVisits[layer] = (next.layerVisits[layer] || 0) + 1;
    next.lastLayerReason = reason;
    writeState(next);
  }

  // -----------------------------
  // GLOBAL FEATURES
  // -----------------------------

  function addFooterNote(memory) {
    const footer = document.querySelector("footer");
    if (!footer || !details.length) return;
    const note = document.createElement("p");
    note.className = "hidden-footer-note";
    const base = pick(details, "footer");
    setHiddenMessage(note, memory.visits > 4 ? `${base} You have passed through ${memory.visits} times.` : base);
    footer.appendChild(note);
  }

  function addHomepageGreeting(memory) {
    const target = document.querySelector("#db-greeting");
    if (!target || !greetings.length) return;
    setHiddenMessage(target, pick(greetings, `greeting-${memory.visits}`));
    const extra = document.createElement("p");
    extra.className = "hidden-greeting";
    setHiddenMessage(extra, "");
    target.closest("div")?.appendChild(extra);
  }

  function addWhispers() {
    // Event: click one of the tiny "?" marks appended to long paragraphs.
    const paragraphs = Array.from(document.querySelectorAll("main p, #content p, article p")).filter((p) => p.textContent.trim().length > 80);
    paragraphs.slice(0, 5).forEach((p, index) => {
      if ((hash(path + index) + index) % 3 !== 0) return;
      const mark = document.createElement("span");
      mark.className = "hidden-whisper";
      mark.tabIndex = 0;
      mark.textContent = " ?";
      const source = index % 2 ? poems : details;
      if (!source.length) return;
      mark.title = pick(source, `whisper-${index}`);
      mark.addEventListener("click", () => {
        awardLayer(index % 2 ? 2 : 1, "paragraph whisper");
        toast(mark.title);
      });
      p.appendChild(mark);
    });
  }

  function addCornerObject() {
    // Event: click the small fixed button in the bottom-left corner.
    const object = document.createElement("button");
    object.className = "hidden-corner-object";
    object.type = "button";
    object.title = "hidden interaction";
    object.textContent = state.visits % 2 ? "*" : "~";
    document.body.appendChild(object);
    let clicks = 0;
    object.addEventListener("click", () => {
      clicks += 1;
      awardLayer(clicks > 3 ? 3 : 1, "corner object");
      toast("Hidden interaction recorded.");
      if (clicks === 7) window.location.href = "/play/left-behind.html";
    });
  }

  function addLogoSearchAndKeyboardSecrets(memory) {
    // Events:
    // - Click `.site-brand` repeatedly on the homepage.
    // - Type exact words into `#search-input`.
    // - Type phrases anywhere on the page.
    const nav = document.querySelector(".site-brand");
    if (nav) {
      let taps = Number(sessionStorage.getItem("zxh_logo_taps") || 0);
      nav.addEventListener("click", (event) => {
        if (path === "/" || path === "/index.html") {
          event.preventDefault();
          taps += 1;
          sessionStorage.setItem("zxh_logo_taps", String(taps));
          awardLayer(taps >= 5 ? 3 : 1, "logo taps");
          toast(taps >= 5 ? "Hidden route available: /play/dream-corridor.html" : "Hidden interaction recorded.");
          if (taps >= 8) window.location.href = "/play/dream-corridor.html";
        }
      });
    }

    const search = document.querySelector("#search-input");
    if (search) {
      search.addEventListener("input", () => {
        const value = search.value.trim().toLowerCase();
        if (SEARCH_TOASTS[value]) toast(SEARCH_TOASTS[value]);
        if (SEARCH_ROUTES[value]) {
          awardLayer(layerForSearch(value), `search ${value}`);
          redirectTo(SEARCH_ROUTES[value]);
        }
      });
    }

    document.addEventListener("keydown", (event) => {
      const key = event.key.toLowerCase();
      const chain = `${sessionStorage.getItem("zxh_key_chain") || ""}${key}`.slice(-18);
      sessionStorage.setItem("zxh_key_chain", chain);
      KEYBOARD_SECRETS
        .filter((secret) => chain.endsWith(secret.phrase))
        .forEach(runSecretAction);
    });

    if (memory.seen?.length >= 6 && !state.travellerNoteShown) {
      window.setTimeout(() => {
        toast("Hidden path recorded.");
        writeState({ ...readState(), travellerNoteShown: true });
      }, 1600);
    }
  }

  function addRareEvents() {
    if (hour >= 22 || hour < 5) {
      document.body.classList.add("hidden-late-night");
      if (nightMessages.length) window.setTimeout(() => toast(pick(nightMessages, "night"), 2200), 900);
    }
    const roll = Math.random();
    if (roll < 0.003) {
      window.setTimeout(() => showDriftNote("", ""), 1800);
      awardLayer(3, "rare sensei appearance");
    } else if (roll < 0.008) {
      window.setTimeout(() => toast("Hidden warning."), 2400);
      awardLayer(4, "future warning");
    }
  }

  function showDriftNote(text, art) {
    const panel = document.createElement("aside");
    panel.className = "hidden-drift-note";
    panel.innerHTML = `<div class="hidden-drift-message">${hiddenMessageMarkup(text)}</div><pre>${escapeHtml(art)}</pre><button type="button">Close</button>`;
    panel.querySelector("button").addEventListener("click", () => panel.remove());
    document.body.appendChild(panel);
  }

  function addSecretLinks() {
    [
      ["/play/left-behind.html", "left behind"],
      ["/play/dream-corridor.html", "dream corridor"],
      ["/play/kitchen-light.html", "kitchen light"],
      ...lore.roomLinks
    ].forEach(([href, label], index) => {
      const link = document.createElement("a");
      link.className = "hidden-secret-link";
      link.href = href;
      link.textContent = label;
      link.style.left = `${index + 1}px`;
      document.body.appendChild(link);
    });
  }

  function enhanceErrors() {
    if (document.title.match(/404|not found/i) || document.body.textContent.match(/404|not found/i)) {
      toast("Page not found.");
    }
  }

  function addContinuity(memory) {
    const milestones = {
      64: "Hidden layer unlocked."
    };
    if (milestones[memory.visits] && !state[`milestone_${memory.visits}`]) {
      const layer = memory.visits >= 31 ? 4 : memory.visits >= 9 ? 3 : 2;
      awardLayer(layer, `visit milestone ${memory.visits}`);
      window.setTimeout(() => toast(milestones[memory.visits], 7000), 1200);
      writeState({ ...readState(), [`milestone_${memory.visits}`]: true });
    }

    const count = memory.pathCounts?.[path] || 0;
    if ([3, 7, 12].includes(count)) {
      window.setTimeout(() => toast("Page revisit recorded.", 6400), 1700);
    }
  }

  function addSeasonAndDates(memory) {
    const month = now.getMonth();
    const day = now.getDate();
    const season = month < 2 || month === 11 ? "winter" : month < 5 ? "spring" : month < 8 ? "summer" : "autumn";
    if (Math.random() < 0.18 && lore.seasonal[season]) window.setTimeout(() => toast(lore.seasonal[season], 5600), 2600);
    const first = memory.firstSeen ? new Date(memory.firstSeen) : null;
    if (first && memory.visits > 1 && first.getMonth() === month && first.getDate() === day) {
      window.setTimeout(() => toast("Visitor anniversary recorded.", 7000), 1400);
    }
  }

  function addObjectConstellation() {
    // Event: click the small keepsake buttons along the bottom rail.
    const rail = document.createElement("div");
    rail.className = "hidden-object-rail";
    rail.setAttribute("aria-label", "Hidden objects");
    const objects = [
      ["ring", "Hidden object recorded."],
      ["bot", "Hidden object recorded."],
      ["tea", "Hidden object recorded."],
      ["crayon", "Hidden object recorded."],
      ["clock", "Hidden object recorded."]
    ];
    objects.forEach(([name, message]) => {
      const button = document.createElement("button");
      button.type = "button";
      button.className = `hidden-keepsake hidden-keepsake--${name}`;
      button.title = name;
      button.textContent = { ring: "o", bot: "#", tea: "u", crayon: "/", clock: ":" }[name];
      button.addEventListener("click", () => {
        const next = readState();
        next.keepsakes = Array.from(new Set([...(next.keepsakes || []), name]));
        writeState(next);
        awardLayer(next.keepsakes.length >= 3 ? 3 : 2, `keepsake ${name}`);
        toast(message);
        if (next.keepsakes.length >= objects.length) {
          window.setTimeout(() => toast("Hidden object set completed."), 1100);
        }
      });
      rail.appendChild(button);
    });
    document.body.appendChild(rail);
  }

  function addWeatherWindow(memory) {
    // Event: click the small "window" button. This asks for browser geolocation.
    if (memory.visits < 3 || !("geolocation" in navigator)) return;
    const button = document.createElement("button");
    button.className = "hidden-weather-window";
    button.type = "button";
    button.title = "Check outside weather";
    button.textContent = "window";
    button.addEventListener("click", () => {
      toast("Checking outside weather.");
      navigator.geolocation.getCurrentPosition((pos) => {
        const { latitude, longitude } = pos.coords;
        fetch(`https://api.open-meteo.com/v1/forecast?latitude=${latitude.toFixed(3)}&longitude=${longitude.toFixed(3)}&current=temperature_2m,precipitation&timezone=auto`)
          .then((res) => res.json())
          .then((data) => {
            const current = data.current || {};
            const rain = Number(current.precipitation || 0) > 0;
            const temp = Math.round(Number(current.temperature_2m));
            toast(rain ? `Outside: rain, ${temp}C.` : `Outside: ${temp}C.`);
          })
          .catch(() => toast("Weather check failed."));
      }, () => toast("No outside weather today."));
    });
    document.body.appendChild(button);
  }

  function addOldWebLayer(memory) {
    if (Math.random() < 0.08 || memory.visits > 10) {
      const stamp = document.createElement("div");
      stamp.className = "hidden-oldweb-stamp";
      if (!lore.fakeUsers.length) return;
      stamp.title = pick(lore.fakeUsers, "fake-user");
      stamp.textContent = "best viewed with patience";
      stamp.addEventListener("click", () => {
        awardLayer(1, "old web stamp");
        toast(stamp.title);
      });
      document.body.appendChild(stamp);
    }
    const comments = document.querySelector("#comments");
    if (comments && lore.fakeUsers.length && !comments.querySelector(".hidden-guestbook-line")) {
      const line = document.createElement("p");
      line.className = "hidden-guestbook-line";
      setHiddenMessage(line, pick(lore.fakeUsers, "comment-lore"));
      comments.appendChild(line);
    }
  }

  function addSourceRelics() {
    const marker = document.createComment("hidden-details");
    document.documentElement.appendChild(marker);
    document.querySelectorAll("img[alt=''], img:not([alt])").forEach((img, index) => {
      if (index > 2) return;
      img.alt = "Decorative image.";
    });
  }

  function addLongKeyboardSecrets() {
    // Event: type longer hidden phrases anywhere on the page.
    document.addEventListener("keydown", (event) => {
      const chain = `${sessionStorage.getItem("zxh_second_chain") || ""}${event.key.toLowerCase()}`.slice(-24);
      sessionStorage.setItem("zxh_second_chain", chain);
      LONG_KEYBOARD_SECRETS
        .filter((secret) => chain.endsWith(secret.phrase))
        .forEach(runSecretAction);
    });
  }

  function addPatienceRewards(memory) {
    // Event: no movement, key presses, scrolling, or clicking for 90 seconds.
    if (memory.visits < 2) return;
    let idleTimer = null;
    const startIdle = () => {
      window.clearTimeout(idleTimer);
      idleTimer = window.setTimeout(() => {
        awardLayer(5, "patience");
        toast("Idle moment recorded.", 7600);
        const next = readState();
        next.patientMoments = (next.patientMoments || 0) + 1;
        writeState(next);
      }, 90000);
    };
    ["mousemove", "keydown", "scroll", "click"].forEach((name) => document.addEventListener(name, startIdle, { passive: true }));
    startIdle();
  }

  function addRareSecondLayer() {
    const roll = Math.random();
    if ((path === "/" || path === "/index.html") && roll < 0.006) {
      document.body.classList.add("hidden-home-takeover");
      if (lore.homepageTakeovers.length) window.setTimeout(() => showDriftNote(pick(lore.homepageTakeovers, "takeover"), ""), 600);
    } else if (roll < 0.002) {
      window.setTimeout(() => showDriftNote("", ""), 1500);
    } else if (roll < 0.006) {
      if (lore.dreams.length) window.setTimeout(() => toast(pick(lore.dreams, "rare-dream"), 7600), 2000);
    } else if (roll < 0.014) {
      if (lore.warnings.length) window.setTimeout(() => toast(pick(lore.warnings, "rare-warning"), 6800), 2300);
    }
  }

  function addFamilyLayerIndex(memory) {
    if (!path.includes("/play/family-layer-index")) return;
    const target = document.querySelector("[data-family-layer-index]");
    if (!target) return;
    const visits = readState().layerVisits || {};
    target.innerHTML = familyLayers.map((line, layer) => {
      const count = visits[layer] || 0;
      return `<li class="hidden-layer-message"><strong>${hiddenMessageMarkup(line)}</strong><br><span>local encounters: ${count}</span></li>`;
    }).join("");
  }

  function addPageSpecificSecrets() {
    // Events only used by specific `/play/...` pages.
    if (path.includes("/play/cassette-log")) {
      document.querySelectorAll("[data-cassette]").forEach((button, index) => {
        button.addEventListener("click", () => {
          awardLayer(index >= 2 ? 4 : 2, "voice note");
          if (lore.cassettes.length) toast(lore.cassettes[index % lore.cassettes.length], 7600);
          playTinySong();
        });
      });
    }
    if (path.includes("/play/patience-game")) {
      const target = document.querySelector("[data-patience-target]");
      const count = document.querySelector("[data-patience-count]");
      if (target && count) {
        let seconds = 0;
        setInterval(() => {
          seconds += 1;
          count.textContent = String(seconds);
          if ([30, 90, 180].includes(seconds)) {
            setHiddenMessage(target, "Patience milestone recorded.");
          }
        }, 1000);
      }
    }
    if (path.includes("/play/terminal-cupboard")) {
      const input = document.querySelector("[data-cupboard-input]");
      const log = document.querySelector("[data-cupboard-log]");
      const commands = {
        help: "commands: layer, exit",
        layer: familyLayers.join("\n"),
        exit: "Closed."
      };
      input?.addEventListener("keydown", (event) => {
        if (event.key !== "Enter") return;
        const value = input.value.trim().toLowerCase();
        const line = document.createElement("p");
        setHiddenMessage(line, `> ${value}\n${commands[value] || "Unknown command."}`);
        log.appendChild(line);
        input.value = "";
      });
    }
  }

  function addInvisibleHoverSecrets() {
    document.querySelectorAll("h1, h2").forEach((heading, index) => {
      if (index > 5) return;
      heading.classList.add("hidden-hover-memory");
      const source = [...lore.quotes, ...lore.journals, ...poems];
      if (!source.length) return;
      heading.dataset.hiddenMemory = pick(source, `heading-${index}`);
    });
  }

  function playTinySong() {
    try {
      const AudioContext = window.AudioContext || window.webkitAudioContext;
      if (!AudioContext) return;
      const ctx = new AudioContext();
      const notes = [392, 494, 440, 330, 392];
      notes.forEach((freq, index) => {
        const osc = ctx.createOscillator();
        const gain = ctx.createGain();
        osc.frequency.value = freq;
        osc.type = "sine";
        gain.gain.setValueAtTime(0.0001, ctx.currentTime + index * 0.18);
        gain.gain.exponentialRampToValueAtTime(0.05, ctx.currentTime + index * 0.18 + 0.03);
        gain.gain.exponentialRampToValueAtTime(0.0001, ctx.currentTime + index * 0.18 + 0.16);
        osc.connect(gain);
        gain.connect(ctx.destination);
        osc.start(ctx.currentTime + index * 0.18);
        osc.stop(ctx.currentTime + index * 0.18 + 0.18);
      });
    } catch (_) {}
  }

  function escapeHtml(value) {
    return String(value).replace(/[&<>"']/g, (char) => ({
      "&": "&amp;",
      "<": "&lt;",
      ">": "&gt;",
      '"': "&quot;",
      "'": "&#039;"
    }[char]));
  }

  // Features run in this order on every page after the DOM is ready.
  // Each function receives the current `memory` object.
  const FEATURES = [
    addFooterNote,
    addHomepageGreeting,
    addWhispers,
    addCornerObject,
    addLogoSearchAndKeyboardSecrets,
    addRareEvents,
    addSecretLinks,
    enhanceErrors,
    addContinuity,
    addSeasonAndDates,
    addObjectConstellation,
    addWeatherWindow,
    addOldWebLayer,
    addSourceRelics,
    addLongKeyboardSecrets,
    addPatienceRewards,
    addRareSecondLayer,
    addFamilyLayerIndex,
    addPageSpecificSecrets,
    addInvisibleHoverSecrets
  ];

  document.addEventListener("DOMContentLoaded", () => {
    const memory = rememberVisit();
    FEATURES.forEach((addFeature) => addFeature(memory));
  });
}());