'use client';

/**
 * Realtime panel - Umami's "what's happening RIGHT NOW" view, surfaced
 * as a collapsible card at the top of the website-analytics page.
 *
 * Folds in five things from Umami's /api/realtime/<id> endpoint:
 *   - Totals strip (visitors / views / events / countries in the last 30m)
 *   - Top URLs being viewed
 *   - Top countries
 *   - Top referrers
 *   - Recent event stream (pageviews + named events as they arrive)
 *
 * Polling pauses when the card is collapsed so we're not hammering
 * Umami at 5 s intervals while no one is looking.
 */

import { useState } from 'react';
import { ChevronDown, ChevronUp, Globe, Activity, MapPin, ExternalLink } from 'lucide-react';

import { Card, CardContent } from '@/components/ui/card';
import { Skeleton } from '@/components/ui/skeleton';
import { CountryFlag } from '@/components/shared/country-flag';
import { getCountryName } from '@/lib/i18n/countries';
import { useUmamiRealtime } from './use-website-analytics';

export function RealtimePanel() {
  const [open, setOpen] = useState(false);
  const query = useUmamiRealtime(open);
  const data = query.data?.data ?? null;

  // Hide the entire bar when Umami reports a quiet 30-minute window -
  // a "Live activity (0 visitors)" header is just noise. We still poll
  // every 60 s while hidden so the bar reappears the moment traffic
  // arrives.
  const isQuiet = !!data && data.totals.visitors === 0 && data.events.length === 0;
  if (isQuiet && !open) return null;

  return (
    <Card className="overflow-hidden">
      <button
        type="button"
        onClick={() => setOpen((v) => !v)}
        className="flex w-full items-center justify-between gap-3 px-4 py-3 text-left transition hover:bg-muted/40 sm:px-5"
        aria-expanded={open}
      >
        <div className="flex items-center gap-3">
          <span className="relative flex h-2.5 w-2.5">
            <span className="absolute inline-flex h-full w-full animate-ping rounded-full bg-emerald-400 opacity-75" />
            <span className="relative inline-flex h-2.5 w-2.5 rounded-full bg-emerald-500" />
          </span>
          <div>
            <div className="text-sm font-semibold">Live activity</div>
            <div className="text-xs text-muted-foreground">
              {open
                ? 'Auto-refreshing every 5s · last 30 minutes'
                : 'Click to expand - top pages, countries, and a live event stream'}
            </div>
          </div>
        </div>
        {open ? (
          <ChevronUp className="size-4 text-muted-foreground" aria-hidden />
        ) : (
          <ChevronDown className="size-4 text-muted-foreground" aria-hidden />
        )}
      </button>

      {open ? (
        <CardContent className="border-t border-border pt-4 sm:pt-6">
          {query.isLoading ? (
            <Skeleton className="h-[300px] w-full" />
          ) : !data ? (
            <div className="py-6 text-center text-sm text-muted-foreground">
              No realtime data available.
            </div>
          ) : (
            <div className="space-y-4">
              {/* Totals strip */}
              <div className="grid grid-cols-2 gap-3 sm:grid-cols-4">
                <Stat label="Visitors" value={data.totals.visitors} />
                <Stat label="Pageviews" value={data.totals.views} />
                <Stat label="Events" value={data.totals.events} />
                <Stat label="Countries" value={data.totals.countries} />
              </div>

              {/* Three-column ranked-list strip */}
              <div className="grid gap-4 sm:grid-cols-3">
                <RankList
                  icon={<ExternalLink className="size-3.5" aria-hidden />}
                  title="Top pages right now"
                  rows={recordToRows(data.urls).map((r) => ({
                    ...r,
                    label: r.label === '/' ? 'Homepage' : r.label,
                  }))}
                  emptyLabel="No pageviews yet"
                />
                <RankList
                  icon={<MapPin className="size-3.5" aria-hidden />}
                  title="Top countries"
                  rows={recordToRows(data.countries).map((r) => ({
                    ...r,
                    label: getCountryName(r.label, 'en') || r.label || 'Unknown',
                  }))}
                  emptyLabel="No country data yet"
                />
                <RankList
                  icon={<Globe className="size-3.5" aria-hidden />}
                  title="Top referrers"
                  rows={recordToRows(data.referrers).map((r) => ({
                    ...r,
                    label: r.label || '(direct)',
                  }))}
                  emptyLabel="No referrers yet"
                />
              </div>

              {/* Recent event stream */}
              <div>
                <h3 className="mb-2 flex items-center gap-1.5 text-sm font-medium">
                  <Activity className="size-3.5 text-muted-foreground" aria-hidden />
                  Recent activity
                </h3>
                {data.events.length === 0 ? (
                  <div className="rounded-md border border-dashed border-border py-6 text-center text-xs text-muted-foreground">
                    No events in the last 30 minutes.
                  </div>
                ) : (
                  <ol className="space-y-1.5 text-xs">
                    {data.events.slice(0, 20).map((ev, i) => (
                      <li
                        key={`${ev.createdAt}-${i}`}
                        className="flex items-baseline justify-between gap-2 rounded-md bg-muted/40 px-2 py-1.5"
                      >
                        <div className="min-w-0 flex-1 truncate">
                          <span className="font-medium">
                            {ev.eventName
                              ? `Event: ${ev.eventName}`
                              : !ev.urlPath || ev.urlPath === '/'
                                ? 'Homepage'
                                : ev.urlPath}
                          </span>
                          <span className="ml-2 inline-flex items-center gap-1.5 text-muted-foreground">
                            {ev.country ? (
                              <CountryFlag code={ev.country} className="h-2.5 w-3.5" decorative />
                            ) : null}
                            <span>
                              {[
                                ev.country && getCountryName(ev.country, 'en'),
                                ev.browser,
                                ev.device,
                              ]
                                .filter(Boolean)
                                .join(' · ')}
                            </span>
                          </span>
                        </div>
                        <span className="shrink-0 tabular-nums text-muted-foreground">
                          {fmtAgo(ev.createdAt)}
                        </span>
                      </li>
                    ))}
                  </ol>
                )}
              </div>
            </div>
          )}
        </CardContent>
      ) : null}
    </Card>
  );
}

function Stat({ label, value }: { label: string; value: number }) {
  return (
    <div className="rounded-lg border border-border bg-card px-3 py-2">
      <div className="text-[10px] font-medium uppercase tracking-wide text-muted-foreground">
        {label}
      </div>
      <div className="mt-0.5 text-xl font-semibold tabular-nums">{value.toLocaleString()}</div>
    </div>
  );
}

interface RankRow {
  label: string;
  value: number;
}

function RankList({
  icon,
  title,
  rows,
  emptyLabel,
}: {
  icon: React.ReactNode;
  title: string;
  rows: RankRow[];
  emptyLabel: string;
}) {
  const max = rows[0]?.value ?? 1;
  return (
    <div>
      <h3 className="mb-2 flex items-center gap-1.5 text-xs font-medium uppercase tracking-wide text-muted-foreground">
        {icon}
        {title}
      </h3>
      {rows.length === 0 ? (
        <div className="rounded-md border border-dashed border-border py-3 text-center text-xs text-muted-foreground">
          {emptyLabel}
        </div>
      ) : (
        <ul className="space-y-1 text-xs">
          {rows.slice(0, 5).map((r) => {
            const pct = (r.value / max) * 100;
            return (
              <li key={r.label}>
                <div className="flex items-baseline justify-between gap-2">
                  <span className="min-w-0 flex-1 truncate font-medium">{r.label}</span>
                  <span className="shrink-0 tabular-nums text-muted-foreground">
                    {r.value.toLocaleString()}
                  </span>
                </div>
                <div className="mt-0.5 h-1 w-full rounded-full bg-muted">
                  <div
                    className="h-1 rounded-full bg-brand"
                    style={{ width: `${Math.max(2, pct)}%` }}
                    aria-hidden
                  />
                </div>
              </li>
            );
          })}
        </ul>
      )}
    </div>
  );
}

function recordToRows(rec: Record<string, number>): RankRow[] {
  return Object.entries(rec)
    .map(([label, value]) => ({ label, value }))
    .sort((a, b) => b.value - a.value);
}

function fmtAgo(iso: string): string {
  const t = new Date(iso).getTime();
  if (isNaN(t)) return iso;
  const diff = Date.now() - t;
  const seconds = Math.max(1, Math.round(diff / 1000));
  if (seconds < 60) return `${seconds}s ago`;
  const minutes = Math.round(seconds / 60);
  if (minutes < 60) return `${minutes}m ago`;
  const hours = Math.round(minutes / 60);
  return `${hours}h ago`;
}