(() => {
  "use strict";

  const reduceMotion = window.matchMedia("(prefers-reduced-motion: reduce)").matches;

  /* ---------------- nav ---------------- */
  const nav = document.querySelector(".nav");
  if (nav) {
    window.addEventListener("scroll", () => {
      nav.classList.toggle("scrolled", window.scrollY > 8);
    }, { passive: true });
  }

  const navToggle = document.querySelector(".nav-toggle");
  const navLinks = document.querySelector(".nav-links");
  if (navToggle) {
    navToggle.addEventListener("click", () => {
      const open = navLinks.style.display === "flex";
      navLinks.style.display = open ? "none" : "flex";
      navLinks.style.cssText += open ? "" : "position:fixed;top:62px;left:0;right:0;background:#0b0d12;flex-direction:column;padding:18px 28px;border-bottom:1px solid var(--border);gap:16px;";
    });
  }

  /* ---------------- scroll reveal ---------------- */
  const revealEls = document.querySelectorAll("[data-reveal]");
  if (reduceMotion) {
    revealEls.forEach(el => el.classList.add("in-view"));
  } else {
    const io = new IntersectionObserver((entries) => {
      entries.forEach(e => {
        if (e.isIntersecting) {
          e.target.classList.add("in-view");
          io.unobserve(e.target);
        }
      });
    }, { threshold: 0.15 });
    revealEls.forEach(el => io.observe(el));
  }

  /* ---------------- pipeline sequential activation ---------------- */
  const pipeStages = document.querySelectorAll(".pipe-stage");
  if (pipeStages.length) {
    const pipeIO = new IntersectionObserver((entries) => {
      entries.forEach(e => {
        if (e.isIntersecting) {
          pipeStages.forEach((stage, i) => {
            setTimeout(() => stage.classList.add("active"), reduceMotion ? 0 : i * 260);
          });
          pipeIO.disconnect();
        }
      });
    }, { threshold: 0.4 });
    pipeIO.observe(document.querySelector(".pipeline"));
  }

  /* ---------------- diff console (signature element) ---------------- */
  function buildConsoleLines(diff) {
    const lines = [];
    diff.added_entities.forEach(e => lines.push({ type: "add", tag: "+", body: `entity     ${e}` }));
    diff.removed_entities.forEach(e => lines.push({ type: "rem", tag: "-", body: `entity     ${e}` }));
    diff.added_relations.forEach(([s, p, o]) => lines.push({ type: "add", tag: "+", body: `relation   ${s} --${p}--> ${o}` }));
    diff.removed_relations.forEach(([s, p, o]) => lines.push({ type: "rem", tag: "-", body: `relation   ${s} --${p}--> ${o}` }));
    lines.push({
      type: "info", tag: "\u2713",
      body: `diff complete \u2014 ${diff.added_entities.length + diff.added_relations.length} added \u00b7 ${diff.removed_entities.length + diff.removed_relations.length} removed \u00b7 ${diff.unchanged_entities.length + diff.unchanged_relations.length} unchanged`
    });
    return lines;
  }

  function playConsole(el, lines, { loop = false, lineDelay = 110, restartDelay = 4200 } = {}) {
    let timers = [];
    function clearTimers() { timers.forEach(t => clearTimeout(t)); timers = []; }
    function run() {
      clearTimers();
      el.innerHTML = "";
      lines.forEach((ln, i) => {
        const t = setTimeout(() => {
          const row = document.createElement("div");
          row.className = `console-line ${ln.type}`;
          row.innerHTML = `<span class="tag">${ln.tag}</span><span class="body"></span>`;
          row.querySelector(".body").textContent = ln.body;
          el.appendChild(row);
        }, reduceMotion ? 0 : i * lineDelay);
        timers.push(t);
      });
      const cursor = document.createElement("span");
      cursor.className = "cursor";
      const t2 = setTimeout(() => el.appendChild(cursor), reduceMotion ? 0 : lines.length * lineDelay + 100);
      timers.push(t2);
      if (loop && !reduceMotion) {
        const t3 = setTimeout(run, lines.length * lineDelay + restartDelay);
        timers.push(t3);
      }
    }
    run();
    return clearTimers;
  }

  const heroConsole = document.getElementById("hero-console");
  if (heroConsole) {
    playConsole(heroConsole, buildConsoleLines(DEMO_FIXTURE.diff), { loop: true, lineDelay: 95, restartDelay: 3600 });
  }

  /* ---------------- D3 force graph ---------------- */
  function colorForNode(id, diff) {
    if (diff.added_entities.includes(id)) return "var(--add)";
    if (diff.removed_entities.includes(id)) return "var(--rem)";
    return "var(--neu)";
  }
  function tripleKey(s, p, o) { return `${s}\u0001${p}\u0001${o}`; }
  function colorForEdge(link, diff) {
    const k = tripleKey(link.source.id || link.source, link.label, link.target.id || link.target);
    const addedSet = new Set(diff.added_relations.map(([s, p, o]) => tripleKey(s, p, o)));
    const removedSet = new Set(diff.removed_relations.map(([s, p, o]) => tripleKey(s, p, o)));
    if (addedSet.has(k)) return "var(--add)";
    if (removedSet.has(k)) return "var(--rem)";
    return "var(--edge)";
  }

  function renderGraph(svgEl, graph, diff) {
    const svg = d3.select(svgEl);
    svg.selectAll("*").remove();
    const bbox = svgEl.getBoundingClientRect();
    const width = bbox.width || 460;
    const height = bbox.height || 300;
    svg.attr("viewBox", `0 0 ${width} ${height}`);

    if (!graph.nodes.length) {
      svg.append("text")
        .attr("x", width / 2).attr("y", height / 2)
        .attr("text-anchor", "middle")
        .attr("fill", "var(--text-faint)")
        .attr("font-family", "var(--mono)")
        .attr("font-size", 12)
        .text("no entities extracted");
      return;
    }

    const nodes = graph.nodes.map(d => ({ ...d }));
    const links = graph.links.map(d => ({ ...d }));

    const defs = svg.append("defs");
    ["add", "rem", "edge"].forEach(kind => {
      defs.append("marker")
        .attr("id", `arrow-${kind}-${svgEl.id}`)
        .attr("viewBox", "0 -5 10 10")
        .attr("refX", 19).attr("refY", 0)
        .attr("markerWidth", 6).attr("markerHeight", 6)
        .attr("orient", "auto")
        .append("path")
        .attr("d", "M0,-5L10,0L0,5")
        .attr("fill", `var(--${kind === "edge" ? "edge" : kind})`);
    });

    const sim = d3.forceSimulation(nodes)
      .force("link", d3.forceLink(links).id(d => d.id).distance(78).strength(0.7))
      .force("charge", d3.forceManyBody().strength(-220))
      .force("center", d3.forceCenter(width / 2, height / 2))
      .force("collide", d3.forceCollide(26));

    const link = svg.append("g").selectAll("line")
      .data(links).join("line")
      .attr("stroke", d => colorForEdge(d, diff))
      .attr("stroke-width", d => {
        const k = tripleKey(d.source.id || d.source, d.label, d.target.id || d.target);
        const changed = diff.added_relations.some(([s, p, o]) => tripleKey(s, p, o) === k) ||
                         diff.removed_relations.some(([s, p, o]) => tripleKey(s, p, o) === k);
        return changed ? 2.2 : 1.1;
      })
      .attr("marker-end", d => {
        const k = tripleKey(d.source.id || d.source, d.label, d.target.id || d.target);
        if (diff.added_relations.some(([s, p, o]) => tripleKey(s, p, o) === k)) return `url(#arrow-add-${svgEl.id})`;
        if (diff.removed_relations.some(([s, p, o]) => tripleKey(s, p, o) === k)) return `url(#arrow-rem-${svgEl.id})`;
        return `url(#arrow-edge-${svgEl.id})`;
      })
      .attr("opacity", 0.85);

    link.append("title").text(d => d.label);

    const node = svg.append("g").selectAll("circle")
      .data(nodes).join("circle")
      .attr("r", d => (diff.added_entities.includes(d.id) || diff.removed_entities.includes(d.id)) ? 9 : 7)
      .attr("fill", d => colorForNode(d.id, diff))
      .attr("stroke", "var(--bg-card)")
      .attr("stroke-width", 2)
      .style("cursor", "grab")
      .call(d3.drag()
        .on("start", (event, d) => { if (!event.active) sim.alphaTarget(0.25).restart(); d.fx = d.x; d.fy = d.y; })
        .on("drag", (event, d) => { d.fx = event.x; d.fy = event.y; })
        .on("end", (event, d) => { if (!event.active) sim.alphaTarget(0); d.fx = null; d.fy = null; }));

    node.append("title").text(d => d.id);

    const label = svg.append("g").selectAll("text")
      .data(nodes).join("text")
      .attr("class", "graph-node-label")
      .attr("text-anchor", "middle")
      .attr("dy", -12)
      .text(d => d.id.length > 16 ? d.id.slice(0, 15) + "\u2026" : d.id);

    sim.on("tick", () => {
      link
        .attr("x1", d => d.source.x).attr("y1", d => d.source.y)
        .attr("x2", d => d.target.x).attr("y2", d => d.target.y);
      node.attr("cx", d => d.x).attr("cy", d => d.y);
      label.attr("x", d => d.x).attr("y", d => d.y);
    });

    if (reduceMotion) { for (let i = 0; i < 200; i++) sim.tick(); sim.stop(); }
  }

  /* ---------------- stat count-up ---------------- */
  function countUp(el, target, duration = 700) {
    if (reduceMotion) { el.textContent = target; return; }
    const start = performance.now();
    function frame(now) {
      const p = Math.min(1, (now - start) / duration);
      const eased = 1 - Math.pow(1 - p, 3);
      el.textContent = Math.round(eased * target);
      if (p < 1) requestAnimationFrame(frame);
    }
    requestAnimationFrame(frame);
  }

  /* ---------------- summary typewriter ---------------- */
  function typewrite(el, text, speed = 14) {
    el.textContent = "";
    const cursor = document.createElement("span");
    cursor.className = "typecursor";
    if (reduceMotion) { el.textContent = text; return; }
    let i = 0;
    el.appendChild(cursor);
    function step() {
      if (i <= text.length) {
        el.textContent = text.slice(0, i);
        el.appendChild(cursor);
        i += 2;
        requestAnimationFrame(() => setTimeout(step, speed));
      } else {
        cursor.remove();
      }
    }
    step();
  }

  /* ---------------- JSON pretty print with diff highlighting ---------------- */
  function renderJson(diff) {
    const pretty = JSON.stringify(diff, null, 2);
    return pretty
      .replace(/"(added_\w+|removed_\w+|unchanged_\w+)":/g, '<span class="k">"$1"</span>:');
  }

  /* ---------------- demo orchestration ---------------- */
  const els = {
    v1: document.getElementById("input-v1"),
    v2: document.getElementById("input-v2"),
    apiKey: document.getElementById("input-apikey"),
    advToggle: document.getElementById("adv-toggle"),
    advPanel: document.getElementById("adv-panel"),
    runBtn: document.getElementById("run-diff-btn"),
    resetBtn: document.getElementById("reset-sample-btn"),
    status: document.getElementById("demo-status"),
    results: document.getElementById("demo-results"),
    console: document.getElementById("demo-console"),
    g1: document.getElementById("graph-v1"),
    g2: document.getElementById("graph-v2"),
    statAdd: document.getElementById("stat-add"),
    statRem: document.getElementById("stat-rem"),
    statAddRel: document.getElementById("stat-add-rel"),
    statRemRel: document.getElementById("stat-rem-rel"),
    summary: document.getElementById("summary-text"),
    json: document.getElementById("json-output"),
  };

  if (els.v1) {
    els.v1.value = DEMO_FIXTURE.doc_v1;
    els.v2.value = DEMO_FIXTURE.doc_v2;
  }

  // Never let the browser silently restore a previously typed API key on
  // reload or back/forward navigation — it's never stored, but make that
  // visibly true too.
  if (els.apiKey) {
    els.apiKey.value = "";
    window.addEventListener("pageshow", () => { els.apiKey.value = ""; });
  }

  if (els.advToggle) {
    els.advToggle.addEventListener("click", () => {
      els.advPanel.classList.toggle("open");
      els.advToggle.textContent = els.advPanel.classList.contains("open")
        ? "\u2212 use your own Groq API key"
        : "+ use your own Groq API key";
    });
  }

  if (els.resetBtn) {
    els.resetBtn.addEventListener("click", () => {
      els.v1.value = DEMO_FIXTURE.doc_v1;
      els.v2.value = DEMO_FIXTURE.doc_v2;
    });
  }

  function setStatus(text, live) {
    els.status.querySelector(".status-text").textContent = text;
    els.status.querySelector(".status-dot").classList.toggle("live", !!live);
  }

  function renderResults(data) {
    els.results.classList.remove("hidden");

    playConsole(els.console, buildConsoleLines(data.diff), { loop: false, lineDelay: 70 });

    renderGraph(els.g1, data.graph_json.v1, data.diff);
    renderGraph(els.g2, data.graph_json.v2, data.diff);

    countUp(els.statAdd, data.diff.added_entities.length);
    countUp(els.statRem, data.diff.removed_entities.length);
    countUp(els.statAddRel, data.diff.added_relations.length);
    countUp(els.statRemRel, data.diff.removed_relations.length);

    typewrite(els.summary, data.summary);
    els.json.innerHTML = renderJson(data.diff);

    els.results.scrollIntoView({ behavior: reduceMotion ? "auto" : "smooth", block: "nearest" });
  }

  async function runDiff() {
    const v1 = els.v1.value.trim();
    const v2 = els.v2.value.trim();
    const key = els.apiKey ? els.apiKey.value.trim() : "";

    els.runBtn.disabled = true;
    const originalLabel = els.runBtn.textContent;
    els.runBtn.textContent = "computing diff\u2026";

    if (!key) {
      setStatus("bundled sample \u2014 add a Groq key above to run on your own text", false);
      renderResults(DEMO_FIXTURE);
      els.runBtn.disabled = false;
      els.runBtn.textContent = originalLabel;
      return;
    }

    try {
      setStatus("calling live backend\u2026", true);
      const res = await fetch("/api/diff", {
        method: "POST",
        headers: { "Content-Type": "application/json" },
        body: JSON.stringify({ v1, v2, api_key: key }),
      });
      const data = await res.json().catch(() => ({}));
      if (!res.ok || data.error) throw new Error(data.error || `backend responded ${res.status}`);
      setStatus("live result from your Flask backend + Groq", true);
      renderResults(data);
    } catch (err) {
      setStatus(`couldn't reach the live backend (${err.message}) \u2014 showing bundled sample instead`, false);
      renderResults(DEMO_FIXTURE);
    } finally {
      els.runBtn.disabled = false;
      els.runBtn.textContent = originalLabel;
    }
  }

  if (els.runBtn) els.runBtn.addEventListener("click", runDiff);

  // auto-run the bundled demo once, the first time the section scrolls into view
  const demoSection = document.getElementById("demo");
  if (demoSection) {
    const demoIO = new IntersectionObserver((entries) => {
      entries.forEach(e => {
        if (e.isIntersecting) {
          setStatus("bundled sample diff \u2014 computed from this repo's own data/doc_v1.txt & doc_v2.txt", false);
          renderResults(DEMO_FIXTURE);
          demoIO.disconnect();
        }
      });
    }, { threshold: 0.3 });
    demoIO.observe(demoSection);
  }

  // re-render graphs cleanly on resize (debounced)
  let resizeT;
  window.addEventListener("resize", () => {
    clearTimeout(resizeT);
    resizeT = setTimeout(() => {
      if (els.results && !els.results.classList.contains("hidden")) {
        renderGraph(els.g1, DEMO_FIXTURE.graph_json.v1, DEMO_FIXTURE.diff);
        renderGraph(els.g2, DEMO_FIXTURE.graph_json.v2, DEMO_FIXTURE.diff);
      }
    }, 250);
  });

})();