// GODSEED — Genesis Log. Pure client-side replay: build the world at
// features[0..K), then perform wish K's recorded thoughts + deltas again.
// Live: /api/wishes + /api/wishes/{id} + /api/state. Dev: ?mock=1.
// Deep link: book.html#w_000005
import { createPlanetApp } from "./planet/scene.js";
import { buildWishScript, ScriptRunner } from "./planet/replay.js";
import { latLonToDir, PLANET_R } from "./planet/util.js";

// Re-anchor + frame the town heart from the current world.
function syncTown() {
  app.rig.setTownCenter(app.world.features);
}

const params = new URLSearchParams(location.search);
const MOCK = params.has("mock");
const qs = MOCK ? "?mock=1" : "";

const els = {
  ledger: document.getElementById("ledger"),
  voiceDot: document.getElementById("voiceDot"),
  voiceWish: document.getElementById("voiceWish"),
  stream: document.getElementById("voiceStream"),
  epitaph: document.getElementById("epitaph"),
  epitaphText: document.getElementById("epitaphText"),
  status: document.getElementById("status"),
  hint: document.getElementById("replayHint"),
};

const caret = document.createElement("span");
caret.className = "voice__caret";
function tickerPush(text, tone = "thought") {
  caret.remove();
  let inner = els.stream.querySelector(".voice__innertext");
  if (!inner) {
    inner = document.createElement("span");
    inner.className = "voice__innertext";
    els.stream.appendChild(inner);
  }
  const span = document.createElement("span");
  span.className = `tone-${tone}`;
  span.textContent = text;
  inner.appendChild(span);
  inner.appendChild(caret);
  while (inner.children.length > 420) inner.firstChild.remove();
}

let app;
try {
  app = createPlanetApp(document.getElementById("scene"), { interactive: true });
} catch (err) {
  els.status.textContent = "this vessel cannot hold the world (WebGL unavailable)";
  throw err;
}
app.start();

// left-side dark scrim so the log column reads over the bright planet rim +
// gold trail (sits behind the canvas overlays, above the scene).
if (!document.querySelector(".ledger-scrim")) {
  const scrim = document.createElement("div");
  scrim.className = "ledger-scrim";
  scrim.setAttribute("aria-hidden", "true");
  document.body.insertBefore(scrim, document.querySelector(".vignette") || els.ledger);
}

// ---------------------------------------------------------------- data
async function loadIndex() {
  if (MOCK) {
    const traces = await fetch("./mock/traces.json").then((r) => r.json());
    const { FEED_WISH } = await import("./mock/feed.js");
    const list = Object.values(traces).map((t, i) => ({
      wish_id: t.wish_id, text: t.text, epitaph: t.epitaph, ts: t.submitted_at,
      epoch: i + 1, // grant order mirrors the API's enumerate(start=1)
    }));
    list.push({
      wish_id: FEED_WISH.trace.wish_id, text: FEED_WISH.trace.text,
      epitaph: FEED_WISH.trace.epitaph, ts: 1718201100, epoch: list.length + 1,
    });
    return { list, traces: { ...traces, [FEED_WISH.trace.wish_id]: FEED_WISH.trace }, feed: FEED_WISH };
  }
  const list = await fetch("/api/wishes").then((r) => {
    if (!r.ok) throw new Error(`wishes ${r.status}`);
    return r.json();
  });
  return { list, traces: null, feed: null };
}

async function loadState() {
  if (MOCK) {
    const state = await fetch("./mock/world.json").then((r) => r.json());
    const { FEED_WISH } = await import("./mock/feed.js");
    return {
      features: [...state.world.features, ...FEED_WISH.features],
      epoch: state.world.epoch + 1,
    };
  }
  const state = await fetch("/api/state").then((r) => r.json());
  return { features: state.world?.features ?? [], epoch: state.world?.epoch ?? 0 };
}

async function loadTrace(ctx, wishId) {
  if (ctx.traces) return ctx.traces[wishId];
  const r = await fetch(`/api/wishes/${encodeURIComponent(wishId)}`);
  if (!r.ok) throw new Error(`trace ${r.status}`);
  return r.json();
}

// ---------------------------------------------------------------- replay
const runner = new ScriptRunner({});
let phase = "reading";
let lastDescentDir = null;

// The direction a feature landed at (descent target). Sky/weather have none.
function featureDir(feature) {
  const a = feature?.args || {};
  if (feature?.tool === "set_sky" || feature?.tool === "set_weather") return null;
  if (a.path && a.path.length) return latLonToDir(a.path[0][0], a.path[0][1]);
  if (a.lat != null && a.lon != null) return latLonToDir(a.lat, a.lon);
  return null;
}

function replayWish(trace, allFeatures) {
  runner.cancel();
  els.stream.innerHTML = "";
  els.epitaph.classList.remove("is-shown");
  els.voiceWish.textContent = `“${trace.text}”`;
  els.voiceDot.classList.add("is-live");
  phase = "reading";
  lastDescentDir = null;

  // world at features[0..K)
  const mine = allFeatures.filter((f) => f.wish_id === trace.wish_id);
  const firstIdx = allFeatures.findIndex((f) => f.wish_id === trace.wish_id);
  const base = firstIdx === -1 ? allFeatures : allFeatures.slice(0, firstIdx);
  const features = mine.length ? mine : (trace.features ?? []);
  app.world.reset(base, app.simTime);
  app.rig.setMode("town"); // replays begin in the close town view
  syncTown();

  runner.handlers = {
    started: () => {},
    phase: () => {},
    token: (e) => {
      const tone = e.text.startsWith("\n›") ? "obs" : phase === "reading" ? "reading" : "thought";
      tickerPush(e.text, tone);
    },
    call: (e) => {
      phase = "turn";
      const a = e.call.args || {};
      tickerPush(`\n⟡ ${e.call.tool}\n`, "call");
      let target = null;
      if (a.path?.length) target = latLonToDir(a.path[0][0], a.path[0][1]).multiplyScalar(PLANET_R);
      else if (a.lat != null) target = latLonToDir(a.lat, a.lon).multiplyScalar(PLANET_R);
      app.rig.gaze(target, { hold: 4.5 });
    },
    delta: (e) => {
      const cue = app.world.applyFeature(e.feature, { animate: true, t: app.simTime });
      if (e.feature.tool === "place_structure" || e.feature.tool === "build_district") {
        syncTown(); // the town heart follows each new building during the replay
      }
      if (cue.target) app.rig.gaze(cue.target.clone().multiplyScalar(PLANET_R), { hold: 4 });
      else if (cue.wide) app.rig.gaze(null, { hold: 3.5 });
      const dir = cue.target || featureDir(e.feature);
      if (dir) lastDescentDir = dir.clone().normalize();
    },
    granted: (e) => {
      els.epitaphText.textContent = e.epitaph;
      els.epitaph.classList.add("is-shown");
      els.voiceDot.classList.remove("is-live");
      app.world.sky.flash(0.3);
      // visit it: after the final delta, swoop down over the wish site, then rise
      if (lastDescentDir) {
        app.rig.setTerrain?.(app.world.terrain);
        app.rig.descend(lastDescentDir.clone().multiplyScalar(PLANET_R));
      } else {
        app.rig.release();
      }
      setTimeout(() => els.epitaph.classList.remove("is-shown"), 8500);
    },
  };
  runner.start(buildWishScript(trace, features), app.simTime);
}

app.onTick((t) => runner.update(t));

// ---------------------------------------------------------------- boot
(async () => {
  try {
    const [ctx, state] = await Promise.all([loadIndex(), loadState()]);
    // newest first — a just-granted wish must appear at the TOP of the log.
    // epoch is the server's monotonic grant count (start=1); ts can be 0, so
    // epoch is the primary key, ts the tiebreak.
    const ord = (w, i) => (w.epoch ?? w.ts ?? i) * 1e6 + (w.ts ?? 0);
    const list = ctx.list
      .map((w, i) => ({ ...w, _ord: ord(w, i) }))
      .sort((a, b) => b._ord - a._ord);

    // world as it stands now (zero GPU, gorgeous by default). Count source is
    // unified with the landing page: epoch === number of granted wishes.
    app.world.reset(state.features, app.simTime);
    syncTown(); // open the log over the close town view (matches the landing page)
    const granted = state.epoch ?? list.length;
    els.status.textContent = `epoch ${granted} · ${granted} ${granted === 1 ? "wish" : "wishes"} granted`;

    if (!list.length) {
      const div = document.createElement("div");
      div.className = "ledger__empty";
      div.textContent = "No wishes yet. The god waits for the first voice.";
      els.ledger.appendChild(div);
      return;
    }

    const buttons = new Map();
    list.forEach((w) => {
      const btn = document.createElement("button");
      btn.className = "ledger__entry";
      btn.innerHTML = `
        <div class="ledger__epoch">epoch ${w.epoch ?? "—"}</div>
        <div class="ledger__wish"></div>
        <div class="ledger__epitaph"></div>`;
      btn.querySelector(".ledger__wish").textContent = `“${w.text}”`;
      btn.querySelector(".ledger__epitaph").textContent = w.epitaph ?? "";
      btn.addEventListener("click", async () => {
        location.hash = w.wish_id;
        buttons.forEach((b) => b.classList.remove("is-active"));
        btn.classList.add("is-active");
        els.hint.textContent = "replaying — the same words make the same world";
        try {
          const trace = await loadTrace(ctx, w.wish_id);
          if (trace) replayWish(trace, state.features);
        } catch (err) {
          els.status.textContent = "that page of the log would not open";
          console.error(err);
        }
      });
      els.ledger.appendChild(btn);
      buttons.set(w.wish_id, btn);
    });

    // deep link #w_000005
    const target = location.hash.replace("#", "");
    if (target && buttons.has(target)) buttons.get(target).click();

    window.__godseed = {
      ready: true, app,
      tick: (s) => app.tick(s),
      seek: (t) => app.seek(t),
      pause: (v) => app.pause(v),
      stats: () => app.stats(),
      replay: (id) => buttons.get(id)?.click(),
      descend: (lat, lon, duration = 13) => {
        app.rig.setTerrain?.(app.world.terrain);
        app.rig.descend(latLonToDir(lat, lon).multiplyScalar(PLANET_R), { duration });
      },
      setCamera: (theta, phi, dist) => {
        Object.assign(app.rig, {
          theta, thetaT: theta, phi, phiT: phi,
          dist: dist ?? app.rig.dist, distT: dist ?? app.rig.distT,
        });
      },
    };
  } catch (err) {
    els.status.textContent = "the log could not be opened";
    console.error(err);
  }
})();