'use client';

import { useCallback, useEffect, useState } from 'react';
import { useRouter } from 'next/navigation';
import { Ban, Bot, CheckCircle2, Loader2, MessageSquare, Search, Users } from 'lucide-react';
import { AdminShell } from '@/components/id/admin-shell';
import { useAuth } from '@/components/id/auth-provider';
import { useToast } from '@/components/id/toast-provider';
import { Button } from '@/components/ui/button';
import { Input } from '@/components/ui/input';
import { Table, TableBody, TableCell, TableHead, TableHeader, TableRow } from '@/components/ui/table';
import {
  AdminBotMetrics,
  ManagedBot,
  fetchAdminBotMetrics,
  fetchAdminBots,
  setAdminBotActive
} from '@/lib/api';
import { getAdminLandingPath } from '@/lib/admin-access';

export default function AdminBotsPage() {
  const router = useRouter();
  const { token, user: currentUser } = useAuth();
  const { showToast } = useToast();
  const [bots, setBots] = useState<ManagedBot[]>([]);
  const [total, setTotal] = useState(0);
  const [metrics, setMetrics] = useState<AdminBotMetrics | null>(null);
  const [search, setSearch] = useState('');
  const [page, setPage] = useState(1);
  const [loading, setLoading] = useState(true);
  const [actionBotId, setActionBotId] = useState<string | null>(null);

  const loadBots = useCallback(async () => {
    if (!token) return;
    setLoading(true);
    try {
      const [botsResponse, metricsResponse] = await Promise.all([
        fetchAdminBots({ search, page, limit: 20 }, token),
        fetchAdminBotMetrics(token)
      ]);
      setBots(botsResponse.bots ?? []);
      setTotal(botsResponse.total ?? 0);
      setMetrics(metricsResponse);
    } catch (error) {
      showToast(error instanceof Error ? error.message : 'Не удалось загрузить ботов');
    } finally {
      setLoading(false);
    }
  }, [page, search, showToast, token]);

  useEffect(() => {
    if (!currentUser) return;
    if (!currentUser.canManageBots && !currentUser.isSuperAdmin) {
      router.replace(getAdminLandingPath(currentUser));
    }
  }, [currentUser, router]);

  useEffect(() => {
    if (!currentUser?.canManageBots && !currentUser?.isSuperAdmin) return;
    void loadBots();
  }, [currentUser?.canManageBots, currentUser?.isSuperAdmin, loadBots]);

  async function handleToggleActive(bot: ManagedBot) {
    if (!token) return;
    setActionBotId(bot.id);
    try {
      await setAdminBotActive(bot.id, !bot.isActive, token);
      showToast(bot.isActive ? 'Бот заблокирован' : 'Бот разблокирован');
      await loadBots();
    } catch (error) {
      showToast(error instanceof Error ? error.message : 'Не удалось изменить статус бота');
    } finally {
      setActionBotId(null);
    }
  }

  const totalPages = Math.max(1, Math.ceil(total / 20));

  return (
    <AdminShell active="/admin/bots">
      <h2 className="mb-4 text-2xl font-medium tracking-tight">Telegram-боты</h2>
      <div className="mb-6 grid gap-3 sm:grid-cols-2 lg:grid-cols-4">
        <MetricCard label="Всего ботов" value={metrics?.totalBots ?? 0} icon={Bot} />
        <MetricCard label="Активных" value={metrics?.activeBots ?? 0} icon={CheckCircle2} accent="text-emerald-600" />
        <MetricCard label="Заблокированных" value={metrics?.blockedBots ?? 0} icon={Ban} accent="text-rose-600" />
        <MetricCard label="Сообщений" value={metrics?.totalMessages ?? 0} icon={MessageSquare} />
      </div>

      <div className="mb-4 flex flex-wrap items-center gap-3">
        <div className="relative min-w-[240px] flex-1">
          <Search className="pointer-events-none absolute left-3 top-1/2 h-4 w-4 -translate-y-1/2 text-[#667085]" />
          <Input
            className="rounded-xl pl-9"
            placeholder="Поиск по названию или @username"
            value={search}
            onChange={(event) => {
              setSearch(event.target.value);
              setPage(1);
            }}
          />
        </div>
        <p className="text-sm text-[#667085]">Найдено: {total}</p>
      </div>

      <div className="overflow-hidden rounded-2xl border border-[#eceef4] bg-white">
        <Table>
          <TableHeader>
            <TableRow>
              <TableHead>Бот</TableHead>
              <TableHead>Владелец</TableHead>
              <TableHead>Статус</TableHead>
              <TableHead className="text-right">Действия</TableHead>
            </TableRow>
          </TableHeader>
          <TableBody>
            {loading ? (
              <TableRow>
                <TableCell colSpan={4} className="py-10 text-center text-[#667085]">
                  <Loader2 className="mx-auto h-5 w-5 animate-spin" />
                </TableCell>
              </TableRow>
            ) : bots.length ? (
              bots.map((bot) => (
                <TableRow key={bot.id}>
                  <TableCell>
                    <div className="flex items-center gap-3">
                      <div className="flex h-10 w-10 items-center justify-center rounded-full bg-[#eef4ff] text-[#3390ec]">
                        <Bot className="h-5 w-5" />
                      </div>
                      <div>
                        <p className="font-medium">{bot.name}</p>
                        <p className="text-sm text-[#667085]">@{bot.username}</p>
                        {bot.isSystemBot ? <p className="text-xs text-[#3390ec]">Системный</p> : null}
                      </div>
                    </div>
                  </TableCell>
                  <TableCell>
                    <div className="flex items-center gap-2">
                      <Users className="h-4 w-4 text-[#667085]" />
                      <div>
                        <p className="text-sm font-medium">{bot.owner?.displayName ?? '—'}</p>
                        {bot.owner?.username ? <p className="text-xs text-[#667085]">@{bot.owner.username}</p> : null}
                      </div>
                    </div>
                  </TableCell>
                  <TableCell>
                    <span
                      className={
                        bot.isActive
                          ? 'inline-flex rounded-full bg-emerald-50 px-2.5 py-1 text-xs font-medium text-emerald-700'
                          : 'inline-flex rounded-full bg-rose-50 px-2.5 py-1 text-xs font-medium text-rose-700'
                      }
                    >
                      {bot.isActive ? 'Активен' : 'Заблокирован'}
                    </span>
                  </TableCell>
                  <TableCell className="text-right">
                    {!bot.isSystemBot ? (
                      <Button
                        variant="outline"
                        size="sm"
                        className="rounded-xl"
                        disabled={actionBotId === bot.id}
                        onClick={() => void handleToggleActive(bot)}
                      >
                        {actionBotId === bot.id ? (
                          <Loader2 className="h-4 w-4 animate-spin" />
                        ) : bot.isActive ? (
                          'Заблокировать'
                        ) : (
                          'Разблокировать'
                        )}
                      </Button>
                    ) : (
                      <span className="text-xs text-[#667085]">—</span>
                    )}
                  </TableCell>
                </TableRow>
              ))
            ) : (
              <TableRow>
                <TableCell colSpan={4} className="py-10 text-center text-[#667085]">
                  Боты не найдены
                </TableCell>
              </TableRow>
            )}
          </TableBody>
        </Table>
      </div>

      {totalPages > 1 ? (
        <div className="mt-4 flex items-center justify-center gap-2">
          <Button variant="outline" size="sm" className="rounded-xl" disabled={page <= 1} onClick={() => setPage((value) => value - 1)}>
            Назад
          </Button>
          <span className="text-sm text-[#667085]">
            {page} / {totalPages}
          </span>
          <Button
            variant="outline"
            size="sm"
            className="rounded-xl"
            disabled={page >= totalPages}
            onClick={() => setPage((value) => value + 1)}
          >
            Вперёд
          </Button>
        </div>
      ) : null}
    </AdminShell>
  );
}

function MetricCard({
  label,
  value,
  icon: Icon,
  accent
}: {
  label: string;
  value: number;
  icon: typeof Bot;
  accent?: string;
}) {
  return (
    <div className="rounded-2xl border border-[#eceef4] bg-white p-4">
      <div className="mb-2 flex items-center gap-2 text-sm text-[#667085]">
        <Icon className={`h-4 w-4 ${accent ?? ''}`} />
        {label}
      </div>
      <p className="text-2xl font-semibold">{value.toLocaleString('ru-RU')}</p>
    </div>
  );
}