import { api } from "@/lib/api-client";
import { useSession } from "@/lib/auth-client";
import { useTranslation } from "@/lib/i18n";
import { capture } from "@/lib/posthog";
import { Button } from "@sase/ui";
import { useQuery } from "@tanstack/react-query";
import { Link } from "@tanstack/react-router";
import { Sparkles, X } from "lucide-react";
import { useCallback, useEffect, useRef, useState } from "react";

interface Subscription {
  status: string;
  plan?: { name: string; key: string };
  billingPeriod: string;
  endDate?: string;
}

// Early, value-framed conversion nudge that fills the dead zone the urgency
// banner leaves: the 30-day trial only shows the (red) urgency banner in its
// final week, so for ~3 weeks there is no in-app push at all — and ~98% of
// trials never reach checkout. This banner instead fires on PROVEN VALUE (the
// user has decoded >= VALUE_THRESHOLD customer vehicles) and only outside the
// urgency window, so the two never overlap and the tone stays positive.
const VALUE_THRESHOLD = 3;
// Urgency banner owns days <= 7; this one owns days > 7 (no overlap).
const URGENCY_WINDOW_DAYS = 7;

function dismissStorageKey(userId: string | null | undefined, endDate: string): string {
  return `trialValueUpsellDismissed-${userId ?? "anon"}-${endDate}`;
}

export function TrialValueUpsell() {
  const { t } = useTranslation();
  const { data: session } = useSession();
  const userId = session?.user?.id ?? null;
  const [dismissed, setDismissed] = useState(false);
  const [mounted, setMounted] = useState(false);
  const viewedRef = useRef(false);

  const { data: subData, isLoading: subLoading } = useQuery({
    queryKey: ["subscription", "me"],
    queryFn: () =>
      api.get<{ subscription: Subscription | null; eligibleForTrial: boolean }>(
        "/subscriptions/me",
      ),
  });

  const subscription = subData?.subscription;
  const endDate = subscription?.endDate;
  const days =
    subscription?.status === "trial" && endDate
      ? Math.max(0, Math.ceil((new Date(endDate).getTime() - Date.now()) / (1000 * 60 * 60 * 24)))
      : null;
  // Only outside the urgency window, so the urgency banner stays the sole voice
  // in the final week.
  const inWindow = !subLoading && days !== null && days > URGENCY_WINDOW_DAYS;

  // Server-truth value signal: how many customer vehicles this trial user has
  // decoded. Requesting exactly VALUE_THRESHOLD rows is enough to answer
  // ">= threshold" without a COUNT endpoint. Gated so non-eligible users never
  // pay for the request.
  const { data: history } = useQuery({
    queryKey: ["vehicles", "history", "value-probe", VALUE_THRESHOLD],
    queryFn: () => api.get<unknown[]>(`/vehicles/history?limit=${VALUE_THRESHOLD}`),
    enabled: inWindow,
    staleTime: 5 * 60 * 1000,
  });
  const hasProvenValue = Array.isArray(history) && history.length >= VALUE_THRESHOLD;

  const dismissKey = endDate ? dismissStorageKey(userId, endDate) : null;

  useEffect(() => {
    setMounted(true);
  }, []);

  useEffect(() => {
    if (!mounted || !dismissKey) return;
    if (localStorage.getItem(dismissKey) === "true") setDismissed(true);
  }, [mounted, dismissKey]);

  const visible = inWindow && hasProvenValue && !dismissed;

  useEffect(() => {
    if (!visible || viewedRef.current || days === null) return;
    viewedRef.current = true;
    capture("trial_value_upsell_viewed", {
      days_remaining: days,
      plan_name: subscription?.plan?.name,
      billing_period: subscription?.billingPeriod,
    });
  }, [visible, days, subscription?.plan?.name, subscription?.billingPeriod]);

  const handleCTAClick = useCallback(() => {
    capture("trial_value_upsell_cta_clicked", {
      days_remaining: days,
      plan_name: subscription?.plan?.name,
      billing_period: subscription?.billingPeriod,
    });
  }, [days, subscription?.plan?.name, subscription?.billingPeriod]);

  if (!visible || !dismissKey) return null;

  const handleDismiss = () => {
    capture("trial_value_upsell_dismissed", {
      days_remaining: days,
      plan_name: subscription?.plan?.name,
      billing_period: subscription?.billingPeriod,
    });
    localStorage.setItem(dismissKey, "true");
    setDismissed(true);
  };

  return (
    <section
      aria-label={t("subscription.valueUpsell.title")}
      className="flex items-start gap-3 border-b border-brand/20 bg-brand/5 px-4 py-3 sm:items-center sm:px-6"
    >
      <Sparkles className="mt-0.5 size-5 shrink-0 text-brand sm:mt-0" />

      <div className="flex flex-1 flex-col gap-1 sm:flex-row sm:items-center sm:gap-4">
        <div>
          <p className="text-sm font-semibold text-foreground">
            {t("subscription.valueUpsell.title")}
          </p>
          <p className="text-xs text-muted-foreground">
            {t("subscription.valueUpsell.description")}
          </p>
        </div>

        <Link to="/dashboard/subscription" className="shrink-0" onClick={handleCTAClick}>
          <Button size="sm" className="bg-brand text-white hover:bg-brand/90">
            {t("subscription.valueUpsell.cta")}
          </Button>
        </Link>
      </div>

      <button
        type="button"
        onClick={handleDismiss}
        className="flex size-8 shrink-0 items-center justify-center rounded-md text-muted-foreground transition-colors hover:bg-brand/10 hover:text-foreground"
        aria-label={t("common.close")}
      >
        <X className="size-4" />
      </button>
    </section>
  );
}