import {
  Area,
  AreaChart,
  Bar,
  BarChart,
  CartesianGrid,
  ResponsiveContainer,
  Tooltip,
  XAxis,
  YAxis,
} from 'recharts'
import {
  ArrowRight,
  Building2,
  CalendarClock,
  CircleAlert,
  Euro,
  Megaphone,
  TicketCheck,
  Users,
  Wallet,
  Wrench,
} from 'lucide-react'
import { Link } from 'react-router'
import { useStore, fmtEUR } from '../store/store'
import { fmtDatum } from '../lib/format'

const monthShort = ['Jan', 'Feb', 'Mär', 'Apr', 'Mai', 'Jun', 'Jul', 'Aug', 'Sep', 'Okt', 'Nov', 'Dez']

function StatCard({
  icon: Icon,
  label,
  value,
  sub,
  tone = 'teal',
}: {
  icon: React.ElementType
  label: string
  value: string
  sub?: string
  tone?: 'teal' | 'amber' | 'red' | 'blue'
}) {
  const tones = {
    teal: 'bg-teal-50 text-teal-700',
    amber: 'bg-amber-50 text-amber-700',
    red: 'bg-red-50 text-red-600',
    blue: 'bg-blue-50 text-blue-700',
  }
  return (
    <div className="rounded-2xl border bg-white p-5 shadow-sm">
      <div className={`mb-3 inline-flex rounded-xl p-2.5 ${tones[tone]}`}>
        <Icon className="h-5 w-5" />
      </div>
      <div className="text-2xl font-bold tracking-tight">{value}</div>
      <div className="mt-0.5 text-sm text-slate-500">{label}</div>
      {sub && <div className="mt-1 text-xs text-slate-400">{sub}</div>}
    </div>
  )
}

function TenantDashboard() {
  const { meineEinheit: demoUnit, me, transactions, tickets, threads, announcements, mieter } = useStore()
  const myTx = transactions.filter((t) => t.unitId === demoUnit.id)
  const openTx = myTx.filter((t) => t.status !== 'bezahlt')
  const myTickets = tickets.filter((t) => t.unitId === demoUnit.id)
  const unread = threads.filter((t) => t.unreadByTenant)
  const meinMieter = mieter.find((m) => m.unitId === demoUnit.id)

  const chartData = monthShort.slice(0, 10).map((m, i) => ({
    m,
    Betrag: myTx.filter((t) => t.year === 2026 && myTx.indexOf(t) % 12 === i).reduce((s, t) => s + (t.status === 'bezahlt' ? t.amount : 0), 0),
  }))

  return (
    <div className="space-y-6">
      <div className="flex flex-wrap items-end justify-between gap-3">
        <div>
          <h1 className="text-2xl font-bold tracking-tight">Hallo, {me?.name}</h1>
          <p className="text-sm text-slate-500">
            {demoUnit.building} · Wohnung {demoUnit.number} · {demoUnit.size} m²
          </p>
        </div>
        <div className="rounded-xl bg-amber-50 px-4 py-2 text-sm text-amber-800">
          <CalendarClock className="mr-2 inline h-4 w-4" />
          Nächste Zahlung: Oktober-Miete bis 03.10.2026
        </div>
      </div>

      <div className="grid gap-4 sm:grid-cols-2 xl:grid-cols-4">
        <StatCard
          icon={Wallet}
          label="Monatliche Warmmiete"
          value={meinMieter ? fmtEUR.format(meinMieter.warmmiete) : '–'}
          sub={meinMieter ? `Kaltmiete ${fmtEUR.format(meinMieter.kaltmiete)} + NK` : 'Mieterdaten folgen'}
        />
        <StatCard
          icon={Euro}
          label={openTx.length > 0 ? 'Offene Forderungen' : 'Keine offenen Forderungen'}
          value={openTx.length > 0 ? fmtEUR.format(openTx.reduce((s, t) => s + t.amount, 0)) : '0,00 €'}
          tone={openTx.length > 0 ? 'amber' : 'teal'}
          sub={openTx.length > 0 ? `${openTx.length} Posten zu zahlen` : 'Alles bezahlt – danke!'}
        />
        <StatCard
          icon={Wrench}
          label="Meine Schadensmeldungen"
          value={`${myTickets.length}`}
          tone="blue"
          sub={`${myTickets.filter((t) => t.status !== 'erledigt').length} in Bearbeitung`}
        />
        <StatCard
          icon={TicketCheck}
          label="Mietverhältnis seit"
          value={meinMieter?.mietbeginnAm ? fmtDatum(meinMieter.mietbeginnAm) : '–'}
          sub={meinMieter ? `Kaution: ${fmtEUR.format(meinMieter.kautionHoehe)} hinterlegt` : 'Mieterdaten folgen'}
        />
      </div>

      <div className="grid gap-4 lg:grid-cols-3">
        <div className="rounded-2xl border bg-white p-5 shadow-sm lg:col-span-2">
          <div className="mb-4 flex items-center justify-between">
            <h2 className="font-semibold">Gezahlte Miete 2026</h2>
            <Link to="/mietkonto" className="flex items-center gap-1 text-sm font-medium text-teal-700 hover:underline">
              Zum Mietkonto <ArrowRight className="h-3.5 w-3.5" />
            </Link>
          </div>
          <div className="h-56">
            <ResponsiveContainer width="100%" height="100%">
              <BarChart data={chartData}>
                <CartesianGrid strokeDasharray="3 3" stroke="#e2e8f0" />
                <XAxis dataKey="m" tick={{ fontSize: 12 }} stroke="#94a3b8" />
                <YAxis tick={{ fontSize: 12 }} stroke="#94a3b8" width={70} />
                <Tooltip formatter={(v) => fmtEUR.format(Number(v))} />
                <Bar dataKey="Betrag" fill="#0d9488" radius={[6, 6, 0, 0]} isAnimationActive={false} />
              </BarChart>
            </ResponsiveContainer>
          </div>
        </div>

        <div className="rounded-2xl border bg-white p-5 shadow-sm">
          <div className="mb-3 flex items-center gap-2">
            <Megaphone className="h-4.5 w-4.5 text-teal-700" />
            <h2 className="font-semibold">Ankündigungen</h2>
          </div>
          <ul className="space-y-3">
            {announcements.slice(0, 3).map((a) => (
              <li key={a.id} className="rounded-xl bg-slate-50 p-3">
                <div className="flex items-center justify-between gap-2">
                  <span className="text-xs font-semibold uppercase tracking-wide text-teal-700">
                    {a.tag}
                  </span>
                  <span className="text-xs text-slate-400">{fmtDatum(a.date)}</span>
                </div>
                <div className="mt-1 text-sm font-medium">{a.title}</div>
                <div className="mt-0.5 line-clamp-2 text-xs text-slate-500">{a.text}</div>
              </li>
            ))}
          </ul>
        </div>
      </div>

      <div className="grid gap-4 lg:grid-cols-2">
        <div className="rounded-2xl border bg-white p-5 shadow-sm">
          <div className="mb-3 flex items-center justify-between">
            <h2 className="font-semibold">Offene Schadensmeldungen</h2>
            <Link to="/schadensmeldungen" className="flex items-center gap-1 text-sm font-medium text-teal-700 hover:underline">
              Alle anzeigen <ArrowRight className="h-3.5 w-3.5" />
            </Link>
          </div>
          {myTickets.filter((t) => t.status !== 'erledigt').length === 0 ? (
            <p className="text-sm text-slate-500">Aktuell keine offenen Meldungen.</p>
          ) : (
            <ul className="space-y-2">
              {myTickets
                .filter((t) => t.status !== 'erledigt')
                .map((t) => (
                  <li key={t.id} className="flex items-center justify-between rounded-xl bg-slate-50 px-4 py-3">
                    <div>
                      <div className="text-sm font-medium">{t.title}</div>
                      <div className="text-xs text-slate-400">{t.category} · {fmtDatum(t.createdAt)}</div>
                    </div>
                    <span className={`rounded-full px-2.5 py-1 text-xs font-semibold ${
                      t.status === 'offen' ? 'bg-amber-100 text-amber-800' : 'bg-blue-100 text-blue-800'
                    }`}>
                      {t.status}
                    </span>
                  </li>
                ))}
            </ul>
          )}
        </div>

        <div className="rounded-2xl border bg-white p-5 shadow-sm">
          <div className="mb-3 flex items-center justify-between">
            <h2 className="font-semibold">Nachrichten</h2>
            <Link to="/nachrichten" className="flex items-center gap-1 text-sm font-medium text-teal-700 hover:underline">
              Posteingang <ArrowRight className="h-3.5 w-3.5" />
            </Link>
          </div>
          {unread.length === 0 ? (
            <p className="text-sm text-slate-500">Keine ungelesenen Nachrichten.</p>
          ) : (
            <ul className="space-y-2">
              {unread.map((t) => (
                <li key={t.id} className="rounded-xl bg-teal-50 px-4 py-3">
                  <div className="text-sm font-medium">{t.subject}</div>
                  <div className="mt-0.5 line-clamp-1 text-xs text-slate-500">
                    {t.messages[t.messages.length - 1]?.text}
                  </div>
                </li>
              ))}
            </ul>
          )}
        </div>
      </div>
    </div>
  )
}

function AdminDashboard() {
  const { units, transactions, tickets, announcements, buildings: gebaeude, mieter } = useStore()
  const rented = units.filter((u) => u.status === 'vermietet')
  const occupancy = units.length ? Math.round((rented.length / units.length) * 100) : 0
  const monthlyIncome = mieter.reduce((s, m) => s + m.warmmiete, 0)
  const openTickets = tickets.filter((t) => t.status === 'offen')
  const overdue = transactions.filter((t) => t.status === 'überfällig')

  const incomeData = monthShort.slice(0, 10).map((m, i) => ({
    m,
    Einnahmen: transactions
      .filter((t) => t.month === ['Januar','Februar','März','April','Mai','Juni','Juli','August','September','Oktober'][i] && t.status === 'bezahlt')
      .reduce((s, t) => s + t.amount, 0),
  }))

  const buildings = gebaeude.map((g) => {
    const us = units.filter((u) => u.building === g.name)
    return {
      name: g.name,
      Vermietet: us.filter((u) => u.status === 'vermietet').length,
      Leerstand: us.filter((u) => u.status === 'leerstand').length,
    }
  })

  return (
    <div className="space-y-6">
      <div>
        <h1 className="text-2xl font-bold tracking-tight">Verwaltungs-Dashboard</h1>
        <p className="text-sm text-slate-500">
          Bestand: {buildings.length} {buildings.length === 1 ? 'Haus' : 'Häuser'} · {units.length} Wohneinheiten · {rented.length} vermietet
        </p>
      </div>

      <div className="grid gap-4 sm:grid-cols-2 xl:grid-cols-4">
        <StatCard icon={Building2} label="Wohneinheiten gesamt" value={String(units.length)} sub={`${units.filter((u) => u.status === 'leerstand').length} aktuell im Leerstand`} />
        <StatCard icon={Users} label="Vermietungsquote" value={`${occupancy} %`} sub={`${rented.length} von ${units.length} Wohneinheiten`} />
        <StatCard icon={Euro} label="Monatliche Warmmiete (Soll)" value={fmtEUR.format(monthlyIncome)} sub="Summe aller vermieteten Einheiten" />
        <StatCard
          icon={CircleAlert}
          label="Aufmerksam erforderlich"
          value={`${openTickets.length} Meldungen · ${overdue.length} überfällig`}
          tone={openTickets.length + overdue.length > 0 ? 'red' : 'teal'}
          sub="Offene Schäden und rückständige Zahlungen"
        />
      </div>

      <div className="grid gap-4 lg:grid-cols-3">
        <div className="rounded-2xl border bg-white p-5 shadow-sm lg:col-span-2">
          <h2 className="mb-4 font-semibold">Eingänge 2026 (bezahlte Mieten)</h2>
          <div className="h-56">
            <ResponsiveContainer width="100%" height="100%">
              <AreaChart data={incomeData}>
                <defs>
                  <linearGradient id="gIncome" x1="0" y1="0" x2="0" y2="1">
                    <stop offset="0%" stopColor="#0d9488" stopOpacity={0.35} />
                    <stop offset="100%" stopColor="#0d9488" stopOpacity={0.02} />
                  </linearGradient>
                </defs>
                <CartesianGrid strokeDasharray="3 3" stroke="#e2e8f0" />
                <XAxis dataKey="m" tick={{ fontSize: 12 }} stroke="#94a3b8" />
                <YAxis tick={{ fontSize: 12 }} stroke="#94a3b8" width={80} />
                <Tooltip formatter={(v) => fmtEUR.format(Number(v))} />
                <Area type="monotone" dataKey="Einnahmen" stroke="#0d9488" fill="url(#gIncome)" strokeWidth={2.5} isAnimationActive={false} />
              </AreaChart>
            </ResponsiveContainer>
          </div>
        </div>

        <div className="rounded-2xl border bg-white p-5 shadow-sm">
          <h2 className="mb-4 font-semibold">Belegung pro Haus</h2>
          <div className="h-56">
            <ResponsiveContainer width="100%" height="100%">
              <BarChart data={buildings} layout="vertical" margin={{ left: 8 }}>
                <CartesianGrid strokeDasharray="3 3" stroke="#e2e8f0" horizontal={false} />
                <XAxis type="number" tick={{ fontSize: 11 }} stroke="#94a3b8" />
                <YAxis type="category" dataKey="name" tick={{ fontSize: 11 }} stroke="#94a3b8" width={95} />
                <Tooltip />
                <Bar dataKey="Vermietet" stackId="a" fill="#0d9488" radius={[0, 0, 0, 0]} isAnimationActive={false} />
                <Bar dataKey="Leerstand" stackId="a" fill="#f59e0b" radius={[0, 6, 6, 0]} isAnimationActive={false} />
              </BarChart>
            </ResponsiveContainer>
          </div>
          <div className="mt-2 flex gap-4 text-xs text-slate-500">
            <span className="flex items-center gap-1.5"><span className="h-2.5 w-2.5 rounded-sm bg-teal-600" /> vermietet</span>
            <span className="flex items-center gap-1.5"><span className="h-2.5 w-2.5 rounded-sm bg-amber-500" /> Leerstand</span>
          </div>
        </div>
      </div>

      <div className="grid gap-4 lg:grid-cols-2">
        <div className="rounded-2xl border bg-white p-5 shadow-sm">
          <div className="mb-3 flex items-center justify-between">
            <h2 className="font-semibold">Neueste Schadensmeldungen</h2>
            <Link to="/schadensmeldungen" className="flex items-center gap-1 text-sm font-medium text-teal-700 hover:underline">
              Alle anzeigen <ArrowRight className="h-3.5 w-3.5" />
            </Link>
          </div>
          <ul className="space-y-2">
            {tickets.slice(0, 4).map((t) => (
              <li key={t.id} className="flex items-center justify-between gap-3 rounded-xl bg-slate-50 px-4 py-3">
                <div className="min-w-0">
                  <div className="truncate text-sm font-medium">{t.title}</div>
                  <div className="text-xs text-slate-400">
                    {units.find((u) => u.id === t.unitId)?.building}, Whg. {units.find((u) => u.id === t.unitId)?.number} · {t.tenant}
                  </div>
                </div>
                <span className={`shrink-0 rounded-full px-2.5 py-1 text-xs font-semibold ${
                  t.status === 'offen' ? 'bg-amber-100 text-amber-800'
                  : t.status === 'in Bearbeitung' ? 'bg-blue-100 text-blue-800'
                  : 'bg-emerald-100 text-emerald-800'
                }`}>
                  {t.status}
                </span>
              </li>
            ))}
          </ul>
        </div>

        <div className="rounded-2xl border bg-white p-5 shadow-sm">
          <h2 className="mb-3 font-semibold">Letzte Ankündigung</h2>
          <div className="rounded-xl bg-teal-50 p-4">
            <div className="flex items-center justify-between">
              <span className="text-xs font-semibold uppercase tracking-wide text-teal-700">{announcements[0].tag}</span>
              <span className="text-xs text-slate-400">{announcements[0].date}</span>
            </div>
            <div className="mt-1 font-medium">{announcements[0].title}</div>
            <p className="mt-1 text-sm text-slate-600">{announcements[0].text}</p>
          </div>
          <p className="mt-3 text-xs text-slate-400">
            Ankündigungen sind im Mieter-Dashboard sowie als Nachricht sichtbar.
          </p>
        </div>
      </div>
    </div>
  )
}

export default function Dashboard() {
  const { role } = useStore()
  return role === 'tenant' ? <TenantDashboard /> : <AdminDashboard />
}