"use client";

import { useCallback, useEffect, useRef, useState } from "react";
import { useRouter } from "next/navigation";
import { toast } from "sonner";
import { Clock, RefreshCw, X } from "lucide-react";
import { Button } from "@/components/ui/button";
import {
  COUNTDOWN_TICK_MS,
  SESSION_AUTO_CLOSE_MS,
  SESSION_WARN_THRESHOLD_MS,
  formatCountdown,
  sessionExpiryPhase,
  timeUntilExpiry,
  type SessionExpiryPhase,
} from "@/lib/session/countdown";
import { SESSION_EXTENDED_EVENT } from "@/hooks/useGameTick";

interface SessionExpiryBannerProps {
  /** Absolute expiry (ms since epoch), server-computed from the JWT `exp`. */
  sessionExp: number | null;
  /** How early (ms) to warn before expiry. Overrides the default for tests. */
  warnMs?: number;
  /** How long before expiry (ms) to auto-close the banner. Overrides default. */
  closeMs?: number;
}

/**
 * Pre-expiry warning + session-extend surface for logged-in users.
 *
 * The `payload-token` cookie is HttpOnly, so the browser can only see the
 * server-passed `sessionExp`. This component turns that into a live countdown:
 * it warns `warnMs` before expiry (firing one sonner toast), offers an
 * "Extend Session" button that calls Payload's built-in refresh endpoint to add
 * another token window, and auto-closes shortly before the hard cutoff. On
 * extend it dispatches `SESSION_EXTENDED_EVENT` so minigames un-lock and then
 * re-validates to pick up the refreshed cookie.
 */
export function SessionExpiryBanner({
  sessionExp,
  warnMs = SESSION_WARN_THRESHOLD_MS,
  closeMs = SESSION_AUTO_CLOSE_MS,
}: SessionExpiryBannerProps) {
  const router = useRouter();
  const [now, setNow] = useState(() => Date.now());
  const [dismissed, setDismissed] = useState(false);
  const [extending, setExtending] = useState(false);
  const [error, setError] = useState<string | null>(null);
  const toastFiredRef = useRef(false);

  // Live clock so the countdown ticks every second.
  useEffect(() => {
    const timer = window.setInterval(() => setNow(Date.now()), COUNTDOWN_TICK_MS);
    return () => window.clearInterval(timer);
  }, []);

  // Each new expiry window (after an Extend) re-arms the one-shot toast.
  useEffect(() => {
    toastFiredRef.current = false;
  }, [sessionExp]);

  const remainingMs = timeUntilExpiry(sessionExp, now);
  const phase: SessionExpiryPhase =
    remainingMs == null ? "idle" : sessionExpiryPhase(remainingMs, warnMs, closeMs);
  const visible = phase === "warn" && !dismissed;

  // Fire the heads-up toast once when we first enter the warn window.
  const fireToast = useCallback(() => {
    if (toastFiredRef.current) return;
    toastFiredRef.current = true;
    const minutes = Math.round(warnMs / 60_000);
    toast.info(`Your session expires in about ${minutes} min.`, {
      action: {
        label: "Extend",
        onClick: () => void extendSession(),
      },
      duration: Infinity,
    });
    // eslint-disable-next-line react-hooks/exhaustive-deps
  }, [warnMs]);

  useEffect(() => {
    if (phase === "warn") fireToast();
  }, [phase, warnMs, fireToast]);

  const extendSession = useCallback(async () => {
    setExtending(true);
    setError(null);
    try {
      const response = await fetch("/api/users/refresh-token", {
        method: "POST",
        credentials: "same-origin",
      });
      if (!response.ok) {
        throw new Error(`Session refresh failed (HTTP ${response.status}).`);
      }
      // Unlock minigames that locked when the session neared expiry, then
      // re-validate so the refreshed cookie is picked up and the countdown
      // resumes from the new expiry.
      window.dispatchEvent(new CustomEvent(SESSION_EXTENDED_EVENT));
      router.refresh();
    } catch (e) {
      const message = e instanceof Error ? e.message : "Could not extend session.";
      setError(message);
      toast.error(message);
    } finally {
      setExtending(false);
    }
  }, [router]);

  if (!visible) return null;

  const minutesLeft = Math.round(warnMs / 60_000);

  return (
    <div
      className="flex flex-wrap items-center justify-between gap-3 border-b border-white/15 bg-slate-900/90 px-4 py-2 text-sm text-white/90 backdrop-blur-sm"
      role="status"
      aria-live="polite"
    >
      <div className="flex items-center gap-3">
        <Clock className="size-4 shrink-0 text-white/60" aria-hidden="true" />
        <span>
          Session expires in{" "}
          <span className="font-mono tabular-nums text-white">{formatCountdown((remainingMs ?? 0) / 1000)}</span>.{" "}
          Extend to stay signed in for another {minutesLeft} min.
        </span>
      </div>
      <div className="flex items-center gap-2">
        <Button
          type="button"
          variant="outline"
          size="sm"
          onClick={() => void extendSession()}
          disabled={extending}
          className="h-7 border-white/30 bg-transparent text-white hover:bg-white/10 hover:text-white"
        >
          <RefreshCw className={`size-3.5 ${extending ? "animate-spin" : ""}`} aria-hidden="true" />
          {extending ? "Extending..." : "Extend"}
        </Button>
        <Button
          type="button"
          variant="ghost"
          size="sm"
          onClick={() => setDismissed(true)}
          className="h-7 text-white/70 hover:bg-white/10 hover:text-white"
        >
          <X className="size-3.5" aria-hidden="true" />
          <span className="sr-only">Dismiss</span>
        </Button>
      </div>
      {error && <p className="absolute -bottom-6 left-4 text-xs text-red-400">{error}</p>}
    </div>
  );
}