/*
 * chat-pin.ts — source 3: the chat-keyboard pin relay (GEO-02).
 * -----------------------------------------------------------
 * Telegram has no push channel from chat → WebView, so the app POLLS
 * GET /api/location with its memory-held Bearer token until the user
 * taps the request_location keyboard in chat and the bot relays the
 * pin into TTL KV.
 *
 * The poll is BOUNDED (60s): AWAITING PIN can never persist forever —
 * the bounded poll is what returns the UI to the denied card instead
 * of wedging (RESEARCH §Pattern 3). requestChatFallback (the ASK VIA
 * CHAT trigger) POSTs to /api/location-fallback — implemented in plan
 * 03-01 task 3 Step D as handleLocationFallback. The pathname is a
 * CONTRACT with 03-01, not a guess; if 03-01 ever renames the route,
 * both plans change together. The route is gated identically to the
 * poll: a 401 means the session expired and the caller must
 * revalidate (D-03) via createSession, not retry blindly — so this
 * function THROWS rather than silently leaving the user on a card
 * whose button appears to do nothing.
 */
import type { Fix } from "./types.ts";

export const CHAT_PIN_POLL_MS = 2000;
export const CHAT_PIN_TIMEOUT_MS = 60000;

export async function fetchChatPin(token: string): Promise<Fix | null> {
  const res = await fetch("/api/location", {
    method: "GET",
    headers: { authorization: `Bearer ${token}` },
  });
  if (!res.ok) return null; // 401 (expired session) and 405 both read as "no pin yet"; caller revalidates on the denied path
  const body: unknown = await res.json();
  const pin = (body as { pin?: { latitude?: number; longitude?: number; horizontal_accuracy?: number | null } }).pin;
  if (!pin || typeof pin.latitude !== "number" || typeof pin.longitude !== "number") return null;
  return {
    lat: pin.latitude,
    lng: pin.longitude,
    accuracyM: pin.horizontal_accuracy ?? null,
    headingDeg: null,
    ts: Date.now(),
    source: "chat-pin",
  };
}

export async function pollChatPin(
  token: string,
  options: { timeoutMs?: number; pollMs?: number; sleep?: (ms: number) => Promise<void> } = {},
): Promise<Fix | null> {
  const timeoutMs = options.timeoutMs ?? CHAT_PIN_TIMEOUT_MS;
  const pollMs = options.pollMs ?? CHAT_PIN_POLL_MS;
  const sleep = options.sleep ?? ((ms) => new Promise((r) => setTimeout(r, ms)));
  const deadline = Date.now() + timeoutMs;
  while (Date.now() < deadline) {
    const fix = await fetchChatPin(token);
    if (fix !== null) return fix;
    await sleep(pollMs);
  }
  return null; // bounded — returns to the denied card, never wedges AWAITING PIN
}

export async function requestChatFallback(token: string): Promise<void> {
  const res = await fetch("/api/location-fallback", {
    method: "POST",
    headers: { authorization: `Bearer ${token}` },
  });
  if (!res.ok) throw new Error("location-fallback-request-failed");
}