/*
 * main.ts — boot choreography (D-08, D-09, D-10).
 * ORDER IS LOAD-BEARING: the basemap mounts and starts rendering tiles
 * FIRST; the location chain starts SECOND. The reverse order produces the
 * blank map D-09 forbids. Every boot stage renders Rams furniture over the
 * live map — validating then acquiring then live; none blank.
 *
 * Planner amendment (RESEARCH Open Question 1): when WebGL2 is absent,
 * bootMap() returns null and the shell renders over --color-surface-dim
 * with data-map="absent" — no blank screen, no crash. EVERY map-consuming
 * call site is null-guarded; the ARAHARAH-LIVE signal is emitted outside
 * the guard so the capture race still resolves on a map-less device.
 *
 * Theme flips re-slot CSS custom properties only (D-10 / PX-02); watchTheme
 * is the entire theming surface and the map style is never re-set. The Fix
 * lives in this module's closure and is passed by argument (D-07) — no
 * storage API anywhere on the path.
 */

/* Ambient harness constant `__ARAHARAH_HARNESS__` is declared in
   web/src/vite-env.d.ts (its canonical home, plan 03-04) and supplied by
   Vite's `define` (vite.config.ts): true ONLY in --mode harness builds,
   false everywhere else, so plain dev runs cannot hit a ReferenceError. */

import "./shell.css";
import { bootMap } from "./map/map.ts";
import { createPositionMarker } from "./map/marker.ts";
import { createFollowController } from "./map/follow.ts";
import { createStatusStrip } from "./ui/strip.ts";
import { buildBootCard, buildDeniedCard, buildSignalLostCard, startGantry, stopGantry } from "./ui/cards.ts";
import { telegramLocationSupported } from "./location/telegram.ts";
import { createRecenterControl } from "./ui/recenter.ts";
import { getWebApp } from "./telegram/webapp.ts";
import { watchTheme } from "./telegram/theme.ts";
import { wireBackButton } from "./telegram/backbutton.ts";
import { resolveSafeInsets, applySafeArea, watchSafeAreaChanges } from "./telegram/safe-area.ts";
import { createSession } from "./session/client.ts";
import { getSession, isSessionStale } from "./session/store.ts";
import { acquireFix, isFixStale, fixAgeSeconds } from "./location/chain.ts";
import { requestChatFallback } from "./location/chat-pin.ts";
import type { Fix, LocationState } from "./location/types.ts";
import { localeFromInitData, strings, type Locale } from "./i18n/strings.ts";
import { installMockWebApp } from "./mock/telegram-mock.ts";
import { readDestinationId, resolveDestination, setDestination } from "./search/resolve-destination.ts";
import { buildDestinationCard, buildDestinationUnavailableCard } from "./search/destination-card.ts";
import { wireHomeScreen } from "./telegram/homescreen.ts";
import {
  createFixtureRoutingSource,
  createHttpRoutingSource,
  decodePolyline6,
  deriveCumulativeDistanceM,
  type RoutingSource,
} from "@araharah/routing/src/index.ts";
import { createRouteController, type RouteState } from "./route/route.ts";
import { buildRouteCard, buildRoutePendingCard } from "./route/route-card.ts";
import { attachRouteEndpoints, removeRouteEndpoints } from "./route/route-markers.ts";
import { installRouteLayers, type MapLike } from "./route/route-layers.ts";
import { GUIDANCE_CAMERA_PADDING, GUIDANCE_CAMERA_PITCH, GUIDANCE_ZOOM, GUIDANCE_EASE_MS } from "./guidance/camera.ts";
import type { BackAction } from "./telegram/backbutton.ts";
import { createGuidanceWatch } from "./guidance/watch.ts";

declare global {
  interface Window {
    // set by plan 03-04's profile-configured runner page BEFORE this module
    // runs — read-only here, never written, never a storage surface (D-07)
    __ARAHARAH_MOCK__?: unknown;
  }
}

void boot();

async function boot(): Promise<void> {
  // 1 — safe-area vars are set before any layout reads them (PX-03 groundwork).
  applySafeArea(resolveSafeInsets(getWebApp()));
  // PX-04/D-03: the insets re-resolve at RUNTIME too — rotation and fullscreen
  // transitions re-apply through the same union authority on the client's
  // inset events. Same one-shot getWebApp() value as the apply line above;
  // internally guarded (null WebApp / missing onEvent → returns immediately).
  watchSafeAreaChanges(getWebApp());

  // 3 (declared ahead of their first use inside the closures below) — the
  //    single-shell state the BackButton resolver and the stale branch read:
  //    the route phase, the walk total function, the controller itself, and
  //    the wire's re-apply handle (assigned once the wire exists).
  let routePhase: () => RouteState = () => "idle";
  let routeController: ReturnType<typeof createRouteController> | null = null;
  let backSync: (() => void) | null = null;

  // 12 — the locale comes from the RAW initData string (the session POST
  //      returns only {token} — the claim's language_code is not reachable
  //      client-side). Derived BEFORE the Telegram-bindings block so the
  //      home-screen wire (ONBD-03) receives it; the strip consumes it below
  //      exactly where it always has.
  const wa = getWebApp();
  const locale: Locale = wa ? localeFromInitData(wa.initData) : "en";

  // 2 — Telegram bindings: theme slot switch + the BackButton's full PX-01
  //     graph. The resolver is CONTEXT-AWARE: the controller owns the walk
  //     decision (guidance → confirm; confirm → CONTINUE; ended → the
  //     search-root walk; route → the Phase 5 walk; root → close), the wire
  //     only applies it — per click AND per state change (wire.sync()).
  if (wa) {
    watchTheme(wa);
    const backResolve = (): BackAction => {
      const controller = routeController;
      if (controller !== null) return controller.backAction();
      return { kind: "hidden" }; // pre-boot — nothing pushed yet
    };
    const wire = wireBackButton(wa, () => backResolve());
    backSync = wire.sync;
  }

  // 3 — the map register mounts FIRST (D-08/D-09 anti-blank invariant).
  const appRoot = document.getElementById("app") ?? document.body;
  const mainEl = document.createElement("main");
  const mapEl = document.createElement("div");
  mapEl.id = "map";
  mainEl.appendChild(mapEl);
  appRoot.appendChild(mainEl);

  // The route consult waits on this: the harness session stubs resolve the
  // location chain faster than WebGL/style init, so consult+setData could
  // land BEFORE the map's load event — the draw would hit sources that do
  // not exist yet and the empty post-load install would silently discard it
  // (found by the 05-05 capture legs: card rendered, line never painted).
  // Resolves in map.ts's ONE load handler, right after installRouteLayers;
  // a cards-only boot (map === null) resolves immediately. The Promise
  // executor runs synchronously, so the resolver is assigned before any
  // caller below reaches it.
  let resolveMapLayersReady!: () => void;
  const mapLayersReady: Promise<void> = new Promise((res) => {
    resolveMapLayersReady = res;
  });
  const map = bootMap(document.getElementById("map")!, {
    // The route layers install at map load, inside the ONE load handler
    // (after building-3d, before the ready log — map.ts hosts the hook).
    // 05-05 capture-leg fix: without this callback the sources never exist
    // and setRouteDrawn's setData silently no-ops — cards rendered, the
    // line never painted (the fakes in the RS gates could not see it).
    onLoad: (m) => {
      try {
        installRouteLayers(m as unknown as MapLike);
      } finally {
        resolveMapLayersReady(); // the consult never wedges, even on install failure
      }
    },
  });
  if (!map) {
    document.body.dataset.map = "absent"; // WebGL2 absent — the shell still renders
    resolveMapLayersReady(); // cards-only degradation: nothing to wait for
  }

  let follow: ReturnType<typeof createFollowController> | null = null;
  const marker = createPositionMarker(); // created here, attached in the guarded block below

  // 4 — chrome registers: strip, card stack, recenter control.
  const stripHost = document.createElement("div");
  mainEl.appendChild(stripHost);
  const strip = createStatusStrip(stripHost);
  const stack = document.createElement("div");
  stack.className = "card-stack";
  mainEl.appendChild(stack);

  // Phase 5 — the route surface's OWN stack (a second register holder): the
  // Phase 3 stack logic above stays byte-identical (the "no destination →
  // Phase 3 behavior byte-identical" law), and the pending + signal-lost
  // coexistence (different registers) falls out of two independent stacks.
  const routeStack = document.createElement("div");
  routeStack.className = "route-stack";
  routeStack.style.display = "none";
  mainEl.appendChild(routeStack);

  // 06-06 — the guidance chrome's mounts: the banner band (the top register
  //  occupant) and the maneuver list's overlay layer (collapsed default).
  const bannerHost = document.createElement("div");
  mainEl.appendChild(bannerHost);
  const listHost = document.createElement("div");
  mainEl.appendChild(listHost);

  // 12 — the strip consumes the locale derived above the bindings block.
  strip.setLocale(locale);

  // 13 — the destination (ONBD-02). TWO carriers, ONE validation (mechanism
  //      corrected per RESEARCH Pitfall 1): the URL's own query string first
  //      (the inline-button path — a web_app button's WebAppInfo carries only
  //      a `url`), then initData's start_param (the documented direct-link /
  //      home-screen path). An unknown id yields the honest unavailable state
  //      and the boot continues into the normal staged boot — never a blank
  //      map. The id resolves against the webview's OWN build-time copy of
  //      the shared gazetteer, and the result is held in MEMORY ONLY
  //      (GEO-03/D-07) — seeded once here, no persistence anywhere.
  const destPayload = readDestinationId(window.location.search, wa?.initData ?? null);
  const destination = resolveDestination(destPayload.id);
  setDestination(destination);
  // 13 — the ?g= resume carrier (GUID-05/06): a killed webview re-opens
  //      straight into its live trip. The id is an opaque UUID validated
  //      BEFORE any GET (V5 posture); a failed/foreign GET is an honest
  //      destination-less boot — never a fake route.
  const resumeId = (() => {
    const raw = new URLSearchParams(window.location.search).get("g");
    return raw !== null && /^[0-9a-f]{8}-[0-9a-f]{4}-[0-9a-f]{4}-[0-9a-f]{4}-[0-9a-f]{12}$/.test(raw) ? raw : null;
  })();
  // The destination surface — the confirmation card when the id resolved, the
  // honest unavailable card when an id ARRIVED and resolved to nothing, and
  // null when no id arrived at all: the Phase 3 boot is then byte-identical
  // (D-12's startapp-less boot landing in the search-ready map is UNCHANGED).
  const destinationCard =
    destination !== null
      ? buildDestinationCard(locale, destination, { withRouteAction: true })
      : destPayload.id !== null
        ? buildDestinationUnavailableCard(locale)
        : null;

  // ONBD-03 — the home-screen affordance behind the Bot API 8.0 capability
  // guard. Wired after the strip exists (it hosts the affordance) and after
  // the locale is known. Telegram-native methods only — no browser install
  // APIs exist in the webview (T-04-38).
  if (wa) wireHomeScreen(wa, locale);

  // The destination capture signal — emitted UNCONDITIONALLY (outside any map
  // guard, the same shape as the ARAHARAH-LIVE token): a WebGL2-absent device
  // still resolves the race. A STATE TOKEN, never the id (D-15 hygiene: a
  // console line carries no place data); the capture leg pairs it with a DOM
  // check on the rendered card's text.
  console.log("ARAHARAH-DEST state=" + (destination ? "resolved" : "absent"));

  // The document title mirrors the Telegram header (device-gate feedback,
  // 2026-10-25): a resolved destination re-titles the app "arah² → Routing to
  // <name>" (en/ms via the strings module — the NAME is public data, no
  // coordinates, D-12/D-15); the root state restores the bare brand. The
  // title element always exists (index.html's <title> is the base).
  const titleEl = document.querySelector("title");
  if (titleEl !== null) {
    titleEl.textContent = destination !== null
      ? strings[locale].titleRoute.replace("{name}", destination.name)
      : "araharah";
  }

  const recenter = createRecenterControl(mainEl, locale, () => {
    if (lastFix !== null && map !== null) {
      if (routeController !== null && routeController.guidancePhase === "driving") {
        // re-lock at the GUIDANCE pose (UI-SPEC camera table) — the Phase 3
        // padding would put the puck back under the strip
        follow?.follow(lastFix, {
          padding: GUIDANCE_CAMERA_PADDING,
          pitch: GUIDANCE_CAMERA_PITCH,
          zoom: GUIDANCE_ZOOM,
          durationMs: GUIDANCE_EASE_MS,
        });
      } else {
        follow?.follow(lastFix);
      }
    }
  });

  // Cards are built once at boot (boot-time locale) and reused across re-runs.
  const bootCard1 = buildBootCard(locale, 1);
  const bootCard2 = buildBootCard(locale, 2);
  const deniedCard = buildDeniedCard(
    locale,
    // Debug round 2/3: Telegram-only deep-link via LocationManager.openSettings.
    { awaitingPin: false, withLocationSettings: telegramLocationSupported(wa) },
  );
  const awaitingCard = buildDeniedCard(
    locale,
    // Debug round 2: the Telegram-only deep-link. LocationManager presence
    // is the whole eligibility test — off-Telegram (Desktop/browser) there
    // is nothing for openSettings() to open, and navigator.geolocation
    // denial is handled by the OS settings hint copy instead.
    { awaitingPin: true, withLocationSettings: telegramLocationSupported(wa) },
  );
  const lostCard = buildSignalLostCard(locale);
  const gantryOf = (card: HTMLElement): HTMLElement => {
    const el = card.querySelector(".gantry");
    return el instanceof HTMLElement ? el : card;
  };

  let lastFix: Fix | null = null; // in-memory only (D-07)
  let staleHandled = false;
  let tickStarted = false;
  let chainInFlight = false;
  let routeConsulted = false; // the route consults AUTOMATICALLY, EXACTLY ONCE per boot (D-10: no route button)

  // D-06: BOTH denied-shaped instances get live CTAs. 'denied-then-waiting'
  // is a second buildDeniedCard instance (03-03 stub note) — wiring only the
  // first left TRY AGAIN / ASK VIA CHAT dead on the awaiting-pin card.
  const wireDeniedActions = (card: HTMLElement): void => {
    const settingsButton = card.querySelector('[data-role="open-location-settings"]');
    if (settingsButton instanceof HTMLButtonElement) {
      // Debug round 2: deep-links Telegram's pane where the user re-grants
      // location for this bot (the "no way to turn on location" report).
      settingsButton.addEventListener("click", () => {
        const lm = wa?.LocationManager;
        if (lm && typeof lm.openSettings === "function") lm.openSettings();
        void runFromSession(); // sheet open OR older client without the API — re-request either way
      });
    }
    const retryButton = card.querySelector(".card-actions .btn-secondary:not([data-role])");
    if (retryButton instanceof HTMLButtonElement) {
      retryButton.addEventListener("click", () => void runFromSession()); // re-runs from link 1
    }
    const askButton = card.querySelector(".btn-primary");
    if (askButton instanceof HTMLButtonElement) {
      askButton.addEventListener("click", () => void askViaChat()); // the Desktop Telegram path
    }
  };
  wireDeniedActions(deniedCard);
  wireDeniedActions(awaitingCard);

  // Debug round 2: after the user grants location from Telegram's sheet
  // (opened via openSettings), the client fires locationManagerUpdated —
  // re-run the chain immediately instead of waiting for a manual tap.
  // The Wire: only live Data events on the wrapper — guard chainInFlight.
  if (wa && typeof wa.onEvent === "function" && wa.LocationManager) {
    wa.onEvent("locationManagerUpdated", () => {
      if (chainInFlight) return;
      void runFromSession();
    });
  }

  function showCard(card: HTMLElement | null, register: "center" | "bottom" = "center"): void {
    if (card !== null) {
      stack.replaceChildren(card);
      stack.style.display = "";
    } else {
      stack.style.display = "none";
    }
    if (register === "bottom") {
      // signal-lost folds into the bottom register (UI-SPEC boot table);
      // space-md clearance above the recenter control's safe-bottom offset
      stack.style.top = "auto";
      stack.style.bottom = "calc(var(--safe-bottom, 0px) + var(--spacing-space-xl))";
      stack.style.transform = "none";
    } else {
      stack.style.top = "";
      stack.style.bottom = "";
      stack.style.transform = "";
    }
  }

  // The route stack's shower — mirrors showCard's shape. Showing a route or
  // pending card vacates BOTH Phase 3 registers (the map is the center
  // surface per the UI-SPEC state table); walkBack restores the destination
  // card through showCard. Different registers never collide: the pending
  // card lives here (center) while the signal-lost card uses the Phase 3
  // stack's bottom register.
  function showRouteCard(card: HTMLElement | null, register: "center" | "bottom"): void {
    if (card !== null) {
      showCard(null);
      routeStack.replaceChildren(card);
      routeStack.dataset.register = register;
      routeStack.style.display = "";
    } else {
      routeStack.style.display = "none";
    }
  }

  function renderState(state: LocationState): void {
    const ageSec = lastFix !== null ? fixAgeSeconds(lastFix, Date.now()) : null;
    const accuracyM = lastFix !== null ? lastFix.accuracyM : null;
    strip.render(state, ageSec, accuracyM);
    switch (state.kind) {
      case "validating":
        showCard(bootCard1);
        startGantry(gantryOf(bootCard1));
        break;
      case "acquiring":
        showCard(bootCard2);
        startGantry(gantryOf(bootCard2));
        break;
      case "live":
        // With a preloaded destination the destination surface IS the live
        // state's card (the visible confirmation); with an id that arrived
        // but resolved to nothing, the honest unavailable card holds the
        // register. No id → null → the stack hides exactly as Phase 3 left it.
        // Once the route surface has taken over (route or pending), the
        // destination card must NOT return — a staleness recovery re-enters
        // this branch and must never evict the route/pending card (UI-SPEC
        // state table: "staleness never evicts the route card").
        if (routePhase() === "idle") showCard(destinationCard);
        break;
      case "stale":
        // Stale during route: the route card PERSISTS in the route stack —
        // the strip lamp + dimmed marker carry the signal (UI-SPEC stale-
        // during-route row; evicting the terminal surface would break D-10).
        // Stale during pending: the pending card (route stack, center)
        // COEXISTS with the signal-lost card (Phase 3 stack, bottom) —
        // different registers. Idle: exactly the Phase 3 behavior.
        if (routePhase() !== "route") showCard(lostCard, "bottom");
        break;
      case "denied":
        showCard(deniedCard);
        break;
      case "awaiting-pin":
        showCard(awaitingCard);
        break;
      default:
        showCard(null);
    }
  }

  // 8 — every map-consuming call site is behind the null guard: with
  //     bootMap() returning null (no WebGL2), map.on/getCanvas/flyTo would
  //     throw and convert the graceful fallback into a blank screen (D-09).
  if (map !== null) {
    follow = createFollowController(map, (m) => recenter.setMode(m));
    marker.marker.addTo(map); // FIRST attachment — the map is the marker's only parent
  }

  // Phase 5 — the route surface (D-05/D-12: the fixture RoutingSource is
  // consulted in the webview only; the origin stays in memory, no route
  // persists, no /api/route exists). The null-tolerant wrappers keep the
  // controller's types total: on a WebGL2-absent device the shell degrades
  // to cards-only (the no-op MapLike + no-op endpoints; the cards still
  // render — D-09's anti-blank law).
  const routeMap: MapLike =
    map !== null
      ? (map as unknown as MapLike) // typed alias at the call site (the map.ts:32 precedent) — MapLibre's Source union is wider than the route seam needs
      : {
          addSource: () => {},
          addLayer: () => {},
          getSource: () => undefined,
          fitBounds: () => {},
          getBearing: () => 0,
        };
  // Phase 6 — the COMPOSED LADDER (D-01's law, code-constructed — no env
  // read, no registry, no config): engine-a answers when the Worker can
  // (arbitrary origins, real reroutes); the fixture corpus carries the
  // golden-demo path and every honest-null fallback. The bearer getter is
  // the memory-held session token — minted after this line is still sent.
  const fixtureSource = createFixtureRoutingSource();
  const httpSource = createHttpRoutingSource({ endpoint: "/api/route", bearer: () => getSession() });
  const routingSource: RoutingSource = {
    name: "ladder",
    route: async (req) => (await httpSource.route(req)) ?? (await fixtureSource.route(req)),
  };
  routeController = createRouteController({
    map: routeMap,
    source: routingSource,
    locale,
    buildRouteCard,
    buildPendingCard: buildRoutePendingCard,
    showRouteCard,
    showDestinationCard: () => showCard(destinationCard),
    follow: { follow: (fix, opts) => follow?.follow(fix, opts) }, // null-tolerant wrapper — the controller sees a total object
    getLatestFix: () => lastFix,
    attachEndpoints: (firstPoint, lastPoint, name) => {
      if (map !== null) attachRouteEndpoints(map, firstPoint, lastPoint, name);
    },
    removeEndpoints: () => {
      if (map !== null) removeRouteEndpoints(map);
    },
    onStateChange: (s) => {
      routePhase = () => s; // the ONE source of truth for the overlay predicate AND the stale branch
      if (backSync !== null) backSync(); // visible exactly when a pushed state exists
    },
    // — the guidance concerns (06-06) —
    wa,
    shellRoot: mainEl, // [data-guidance="active"] compacts the strip through CSS
    bannerHost,
    listHost,
    startWatch: (onFix) => createGuidanceWatch(navigator.geolocation, onFix),
    findGantry: (banner) => {
      const el = banner.querySelector(".guide-gantry");
      return el instanceof HTMLElement ? el : null;
    },
    onGuidanceChange: () => {
      if (backSync !== null) backSync(); // confirm open/close + activation/teardown re-apply the graph
    },
    // 06-08 G7c: the pump's fixes ride the chain's surfaces — the puck moves
    // (the UI-SPEC's recorded call: the puck carries progress) and the
    // chain's freshness axis stays live (a drive past 45s never flips
    // SIGNAL LOST while fixes flow). The camera is NOT touched here: the
    // guidance camera owns the viewport (the same guard handleLive keeps).
    updatePuck: (fix) => {
      lastFix = fix;
      if (map !== null) {
        marker.update(map, fix);
        marker.setStale(false);
      }
    },
    fetchImpl: fetch.bind(globalThis),
    bearer: getSession,
  });

  // 5 — mock install is a fallback, never an override: the capture runner
  //     page installs a profile-configured mock BEFORE this module runs, and
  //     an unconditional install would clobber it (Android/light fake over a
  //     configured Desktop/dark profile). In plain vite dev nothing set the
  //     global, so the default install still fires.
  if ((__ARAHARAH_HARNESS__ || import.meta.env.DEV) && !window.__ARAHARAH_MOCK__) installMockWebApp();

  // 6 — session is validated SECOND (HMAC server-side, T-03-08); a failure
  //     renders the persistent denied card (D-06) and stops — never blank.
  await runFromSession();

  // 14 — the envelope lifecycle (D-11's structural foreground gate) + the
  //      ?g= resume. Both ride Telegram's activated/deactivated events
  //      behind the capability guard (T-06-06); the minimize POST carries
  //      keepalive so a frozen webview still hands off (RESEARCH Pitfall 2).
  if (wa && typeof wa.onEvent === "function" && routeController !== null) {
    const guided = routeController;
    wa.onEvent("deactivated", () => void guided.onDeactivated());
    wa.onEvent("activated", () => guided.onActivated());
  }
  if (resumeId !== null && routeController !== null && map !== null) {
    void tryResume(resumeId, routeController);
  }

  // Device-gate fix (2026-10-24): the destination card's ROUTE button — the
  // forward action SEARCH AGAIN's destination state was missing (auto-consult
  // fires exactly once per boot; a user walking back was stranded). Re-consults
  // with the latest fix + the resolved destination; no fix yet = the honest
  // boot continues (the chain is already running or will render its own state).
  const routeButton = destinationCard?.querySelector('[data-role="route-to-destination"]');
  if (routeButton instanceof HTMLButtonElement && routeController !== null && destination !== null) {
    const controller = routeController;
    const dest = destination;
    routeButton.addEventListener("click", () => {
      const fix = lastFix;
      if (fix === null) return; // no position yet — the chain's own surfaces own this state
      void controller.consult(fix, dest);
    });
  }

  /** GET the ?g= envelope and resume: rebuild the model from the frozen
   *  snapshot (decode + cumulative + destination fields), hand the RAW
   *  anchors to the controller — it owns the projection. A failed,
   *  foreign, or malformed GET is an honest boot (Phase 4 flow) — never a
   *  fake route, never guidance chrome over nothing. */
  async function tryResume(id: string, controller: NonNullable<typeof routeController>): Promise<void> {
    const token = getSession();
    if (token === null) return; // no session yet — the honest boot continues
    try {
      const res = await fetch(`/api/guidance?id=${id}`, { headers: { authorization: `Bearer ${token}` } });
      if (!res.ok) return; // absent/foreign → byte-indistinguishable 404 → the honest boot
      const payload: unknown = await res.json();
      if (payload === null || typeof payload !== "object") return;
      const snap = (payload as { route_snapshot?: unknown }).route_snapshot;
      if (snap === null || typeof snap !== "object") return;
      const s = snap as {
        destinationId?: unknown;
        destinationName?: unknown;
        distanceM?: unknown;
        durationS?: unknown;
        geometry?: unknown;
        startedAtSec?: unknown;
      };
      if (
        typeof s.destinationId !== "string" ||
        typeof s.destinationName !== "string" ||
        typeof s.geometry !== "string" ||
        typeof s.distanceM !== "number" ||
        !Number.isFinite(s.distanceM) ||
        typeof s.durationS !== "number" ||
        !Number.isFinite(s.durationS) ||
        typeof s.startedAtSec !== "number" ||
        !Number.isSafeInteger(s.startedAtSec) ||
        s.startedAtSec <= 0
      ) {
        return; // a corrupt envelope is no envelope (the defensive-read law)
      }
      const points = decodePolyline6(s.geometry); // throws on truncation → the catch
      if (points.length < 2) return;
      await mapLayersReady; // the route sources exist before the line draws
      controller.resume({
        model: {
          points,
          cumulative: deriveCumulativeDistanceM(points),
          steps: [], // the envelope carries geometry only — the controller synthesizes the terminal marks
          destinationId: s.destinationId,
          destinationName: s.destinationName,
        },
        envelopeId: id,
        distanceM: s.distanceM,
        durationS: s.durationS,
        startedAtSec: s.startedAtSec,
      });
    } catch {
      return; // fail-honest — never a fabricated trip
    }
  }

  async function runFromSession(): Promise<void> {
    renderState({ kind: "validating" });
    const session = await createSession(wa?.initData ?? "");
    if (!session.ok) {
      staleHandled = false; // session-first failure is boot-level, not a stale-fix recovery
      renderDenied();
      return;
    }
    staleHandled = false;
    await runChain();
  }

  function renderDenied(): void {
    renderState({ kind: "denied", reason: "no-permission" });
  }

  function renderAwaitingPin(): void {
    renderState({ kind: "awaiting-pin", since: Date.now() });
  }

  // 7 — stage 2 renders BEFORE the chain runs; never an empty card swap.
  async function runChain(): Promise<void> {
    if (chainInFlight) return;
    chainInFlight = true;
    try {
      renderState({ kind: "acquiring", since: Date.now() });
      const { fix, state } = await acquireFix({ wa, getToken: getSession }, lastFix);
      if (fix !== null) {
        handleLive(fix);
      } else if (state.kind === "awaiting-pin") {
        renderAwaitingPin();
      } else {
        renderDenied();
      }
    } finally {
      chainInFlight = false;
    }
  }

  // 9 — live: guarded map path + the ALWAYS-emitted capture signal.
  function handleLive(fix: Fix): void {
    lastFix = fix;
    staleHandled = false;
    stopGantry(gantryOf(bootCard1));
    stopGantry(gantryOf(bootCard2));
    if (map !== null) {
      marker.update(map, fix);
      if (routeController !== null && routeController.guidancePhase === "driving") {
        // the guidance camera owns the viewport during a live trip — the
        // chain's fix refreshes marker/strip; the camera settles on the
        // next throttled ease (never a pose fight)
      } else {
        follow?.follow(fix);
      }
    }
    marker.setStale(false);
    recenter.setFixState("fresh");
    renderState({ kind: "live", fix });
    // Auto-consult (the state-coexistence law): the RoutingSource ladder is
    // consulted ONCE per boot, only when the location chain is live AND a
    // destination resolved — destination-unavailable and no-destination
    // boots never make a route request. A ?g= resume boot NEVER consults
    // (the envelope's route IS the trip); a failed resume stays honest
    // (no destination drawn). The consult waits for the map's load.
    if (destination !== null && !routeConsulted && resumeId === null) {
      routeConsulted = true;
      void mapLayersReady.then(() => routeController?.consult(fix, destination));
    }
    if (!tickStarted) startTick();
    // emitted UNCONDITIONALLY (outside the map guard above): a WebGL2-absent
    // device must still resolve the capture race, or its boot reads as failed
    console.log("ARAHARAH-LIVE fix=" + fix.source + " acc=" + String(fix.accuracyM));
  }

  // 10 — the 1s telemetry tick exists ONLY after live; staleness re-runs the
  //      chain (never a continuous poll — Phase 6 owns the cadence, D-05).
  function startTick(): void {
    tickStarted = true;
    setInterval(tick, 1000);
  }

  function tick(): void {
    if (lastFix === null) return;
    if (!isFixStale(lastFix, Date.now())) {
      renderState({ kind: "live", fix: lastFix }); // refresh ±M / FIX Ns AGO
      return;
    }
    if (staleHandled) return;
    staleHandled = true;
    marker.setStale(true);
    recenter.setFixState("lost");
    renderState({ kind: "stale", fix: lastFix });
    void runChain(); // re-acquire — the re-run refreshes, not the clock
  }

  // 11 — the chat-fallback trigger (D-06 and GEO-02): Requests the bot's
  //      keyboard so a Desktop user can send a pin (issue #77). A thrown
  //      request means the session expired (401, D-03): revalidate once,
  //      retry once; persistent failure returns to the denied card.
  async function askViaChat(): Promise<void> {
    let token = getSession();
    if (token === null || isSessionStale()) {
      renderState({ kind: "validating" });
      const res = await createSession(wa?.initData ?? "");
      if (!res.ok) {
        renderDenied();
        return;
      }
      token = res.token;
    }
    try {
      renderAwaitingPin();
      await requestChatFallback(token);
      await runChain();
    } catch {
      const res = await createSession(wa?.initData ?? "");
      if (res.ok) {
        try {
          renderAwaitingPin();
          await requestChatFallback(res.token);
          await runChain();
        } catch {
          renderAwaitingPin(); // the fallback request itself failed — AWAITING PIN is honest
        }
      } else {
        renderDenied();
      }
    }
  }
}