/* Demo player. Renders image or dom steps with hotspot overlay; emits privacy-first beacons. */
(function () {
  "use strict";
  var token = location.pathname.split("/").pop();
  var params = new URLSearchParams(location.search);
  var viewerToken = params.get("v") || null; // R7: identity only via explicit link token

  var state = { demo: null, i: 0 };
  var snap = document.getElementById("snap");
  var dots = document.getElementById("dots");
  var titleEl = document.getElementById("title");

  function beacon(event, stepId) {
    if (!state.demo) return;
    var payload = JSON.stringify({
      demo_id: state.demo.demo_id,
      step_id: stepId || null,
      viewer_token: viewerToken,
      event: event,
    });
    if (navigator.sendBeacon) {
      navigator.sendBeacon("/api/public/analytics", new Blob([payload], { type: "application/json" }));
    } else {
      fetch("/api/public/analytics", { method: "POST", headers: { "Content-Type": "application/json" }, body: payload });
    }
  }

  function render() {
    var step = state.demo.steps[state.i];
    snap.innerHTML = "";

    var container;
    if (step.snapshot_type === "image") {
      container = document.createElement("img");
      container.src = "/assets/" + step.asset_id;
      container.draggable = false;
    } else {
      container = document.createElement("iframe");
      container.setAttribute("sandbox", ""); // R1/R2: fully inert document, no scripts
      container.srcdoc = step.dom_html || "";
    }
    snap.appendChild(container);

    if (step.hotspot) {
      var h = document.createElement("div");
      h.className = "hotspot";
      h.style.left = step.hotspot.x + "%";
      h.style.top = step.hotspot.y + "%";
      h.style.width = step.hotspot.w + "%";
      h.style.height = step.hotspot.h + "%";
      h.addEventListener("click", next);
      snap.appendChild(h);

      if (step.annotation) {
        var t = document.createElement("div");
        t.className = "tooltip";
        var below = step.hotspot.y < 70;
        t.style.left = Math.min(step.hotspot.x, 70) + "%";
        t.style.top = below ? (step.hotspot.y + step.hotspot.h + 2) + "%" : "auto";
        if (!below) t.style.bottom = (100 - step.hotspot.y + 2) + "%";
        t.innerHTML =
          (step.annotation.title ? "<h3></h3>" : "") + (step.annotation.body ? "<p></p>" : "");
        if (step.annotation.title) t.querySelector("h3").textContent = step.annotation.title;
        if (step.annotation.body) t.querySelector("p").textContent = step.annotation.body;
        snap.appendChild(t);
      }
    }

    dots.innerHTML = "";
    state.demo.steps.forEach(function (_, j) {
      var d = document.createElement("div");
      d.className = "dot" + (j === state.i ? " active" : "");
      dots.appendChild(d);
    });
  }

  function next() {
    var cur = state.demo.steps[state.i];
    if (state.i >= state.demo.steps.length - 1) {
      beacon("complete", cur.id);
      return;
    }
    state.i++;
    beacon("advance", state.demo.steps[state.i].id);
    render();
  }
  function prev() {
    if (state.i === 0) return;
    state.i--;
    beacon("back", state.demo.steps[state.i].id);
    render();
  }

  document.getElementById("next").addEventListener("click", next);
  document.getElementById("prev").addEventListener("click", prev);
  document.addEventListener("keydown", function (e) {
    if (e.key === "ArrowRight") next();
    if (e.key === "ArrowLeft") prev();
  });

  fetch("/api/public/demo/" + token)
    .then(function (r) { if (!r.ok) throw new Error("not found"); return r.json(); })
    .then(function (demo) {
      state.demo = demo;
      titleEl.textContent = demo.name;
      document.title = demo.name;
      beacon("view", demo.steps.length ? demo.steps[0].id : null);
      render();
    })
    .catch(function () {
      snap.innerHTML = "<div style='padding:40px;color:#64748b'>This demo is not available.</div>";
    });
})();