import { router } from "expo-router";
import { useEffect, useRef } from "react";

import { fetchAPI } from "@/lib/fetch";
import type { CallRecord, ChatActiveRide } from "@/types/type";

// Listens for an incoming WebRTC call (a 'ringing' call row this user did not
// place) and routes the user to the call screen — regardless of which tab is
// open. Rendered once at the root layout level; emits no UI.
//
// It only polls while an active ride exists (the only window in which a call
// can happen). To avoid re-navigating on every poll, it remembers the call id
// it already handed off to the call screen and resets once that call goes
// terminal.

const ACTIVE_POLL_MS = 5000;
const CALL_POLL_MS = 3000;

const CallWatcher = () => {
  // The ride we're watching for an incoming call on.
  const rideIdRef = useRef<number | null>(null);
  // The call id we've already navigated to, so we don't re-push the screen.
  const handledCallIdRef = useRef<number | null>(null);

  useEffect(() => {
    let cancelled = false;

    // Refresh which ride (if any) is active for this user, then poll its call
    // row. Both run on intervals; the call poll no-ops until a rideId is known.
    const activeTimer = setInterval(async () => {
      try {
        const res = await fetchAPI("/(api)/chat/active");
        const active = (res.data ?? null) as ChatActiveRide | null;
        if (cancelled) return;
        rideIdRef.current = active?.ride_id ?? null;
      } catch (err) {
        console.log("[CALL_WATCHER_ACTIVE]: ", err);
      }
    }, ACTIVE_POLL_MS);

    const callTimer = setInterval(async () => {
      const rideId = rideIdRef.current;
      if (rideId === null) return;
      try {
        const res = await fetchAPI(`/(api)/ride/${rideId}/call`);
        const call = (res.data ?? null) as CallRecord | null;
        if (cancelled || !call) return;

        // A terminal call clears the handled marker so the next incoming call
        // can navigate again.
        if (
          call.status === "ended" ||
          call.status === "declined" ||
          call.status === "missed"
        ) {
          if (handledCallIdRef.current === call.id) {
            handledCallIdRef.current = null;
          }
          return;
        }

        // An incoming ringing call we didn't place: hand off to the call
        // screen, once per call id.
        if (call.status === "ringing" && !call.is_caller) {
          if (handledCallIdRef.current === call.id) return;
          handledCallIdRef.current = call.id;
          router.push({
            pathname: "/(root)/call",
            params: { rideId: String(rideId), mode: "incoming" },
          });
        }
      } catch (err) {
        console.log("[CALL_WATCHER_CALL]: ", err);
      }
    }, CALL_POLL_MS);

    // Kick the active poll immediately so an incoming call on a freshly
    // matched ride is noticed without waiting for the first interval.
    void (async () => {
      try {
        const res = await fetchAPI("/(api)/chat/active");
        if (cancelled) return;
        rideIdRef.current =
          ((res.data ?? null) as ChatActiveRide | null)?.ride_id ?? null;
      } catch {
        // ignore — the interval will retry
      }
    })();

    return () => {
      cancelled = true;
      clearInterval(activeTimer);
      clearInterval(callTimer);
    };
  }, []);

  return null;
};

export default CallWatcher;