'use client';

import { useEffect, useMemo, useState } from 'react';
import Link from 'next/link';
import { apiUrl } from '@/lib/constants';

interface ClipboardSummary {
  id: string;
  createdAt: string;
  lastActivity: string;
  hasPassword: boolean;
  entryCount: number;
  fileCount: number;
  ttl: number | null;
}

export default function AdminDashboard() {
  const [token, setToken] = useState('');
  const [inputToken, setInputToken] = useState('');
  const [clipboards, setClipboards] = useState<ClipboardSummary[]>([]);
  const [loading, setLoading] = useState(false);
  const [error, setError] = useState('');

  useEffect(() => {
    const saved = localStorage.getItem('adminToken');
    if (saved) {
      setToken(saved);
      setInputToken(saved);
    }
  }, []);

  useEffect(() => {
    if (token) {
      fetchClipboards();
    }
  // eslint-disable-next-line react-hooks/exhaustive-deps
  }, [token]);

  const fetchClipboards = async () => {
    setLoading(true);
    setError('');

    try {
      const response = await fetch(`${apiUrl}/admin/clipboards`, {
        headers: { 'x-admin-token': token },
      });

      if (response.status === 401) {
        setError('Invalid token. Please log in again.');
        return;
      }

      if (!response.ok) {
        throw new Error('Failed to fetch clipboards');
      }

      const data = await response.json();
      setClipboards(data);
    } catch (err) {
      setError(err instanceof Error ? err.message : 'Unknown error');
    } finally {
      setLoading(false);
    }
  };

  const handleLogin = () => {
    if (!inputToken) {
      setError('Please enter an admin token');
      return;
    }

    localStorage.setItem('adminToken', inputToken);
    setToken(inputToken);
    setError('');
  };

  const handleDelete = async (roomCode: string) => {
    if (!confirm(`Delete clipboard ${roomCode}? This cannot be undone.`)) {
      return;
    }

    try {
      const response = await fetch(`${apiUrl}/admin/clipboards/${roomCode}`, {
        method: 'DELETE',
        headers: { 'x-admin-token': token },
      });

      if (!response.ok) {
        throw new Error('Failed to delete clipboard');
      }

      await fetchClipboards();
    } catch (err) {
      setError(err instanceof Error ? err.message : 'Unknown error');
    }
  };

  const tokenValid = useMemo(() => Boolean(token), [token]);

  return (
    <div className="w-full max-w-6xl mx-auto p-6 md:p-10">
      <div className="flex items-center justify-between mb-6">
        <div>
          <h1 className="text-3xl font-bold">Admin Dashboard</h1>
          <p className="text-text-secondary">Manage clipboards and inspect activity</p>
        </div>
        <Link href="/" className="btn btn-ghost">
          Back to Home
        </Link>
      </div>

      <div className="card mb-6">
        <div className="flex flex-col sm:flex-row sm:items-end gap-4">
          <div className="flex-1">
            <label className="block text-sm text-text-secondary mb-2">Admin Token</label>
            <input
              type="password"
              value={inputToken}
              onChange={(e) => setInputToken(e.target.value)}
              className="input w-full"
              placeholder="Enter admin token"
            />
          </div>
          <button className="btn btn-primary self-start sm:self-auto" onClick={handleLogin}>
            {tokenValid ? 'Update Token' : 'Login'}
          </button>
        </div>
        {error && <p className="text-red-400 text-sm mt-2">{error}</p>}
      </div>

      {tokenValid && (
        <div className="card">
          <div className="flex items-center justify-between mb-4">
            <h2 className="text-xl font-semibold">Clipboards</h2>
            <div className="flex gap-2">
              <button className="btn btn-ghost" onClick={fetchClipboards} disabled={loading}>
                Refresh
              </button>
            </div>
          </div>
          {loading ? (
            <p className="text-text-secondary">Loading clipboards...</p>
          ) : (
            <div className="overflow-x-auto">
              <table className="min-w-full text-sm">
                <thead className="text-left text-text-secondary border-b border-surface-hover">
                  <tr>
                    <th className="py-2 pr-4">ID</th>
                    <th className="py-2 pr-4">Entries</th>
                    <th className="py-2 pr-4">Files</th>
                    <th className="py-2 pr-4">Password</th>
                    <th className="py-2 pr-4">TTL</th>
                    <th className="py-2 pr-4">Last Activity</th>
                    <th className="py-2 pr-4 text-right">Actions</th>
                  </tr>
                </thead>
                <tbody>
                  {clipboards.length === 0 && (
                    <tr>
                      <td className="py-4 text-text-secondary" colSpan={7}>
                        No clipboards found.
                      </td>
                    </tr>
                  )}
                  {clipboards.map((clipboard) => (
                    <tr key={clipboard.id} className="border-b border-surface-hover">
                      <td className="py-3 pr-4 font-mono">{clipboard.id}</td>
                      <td className="py-3 pr-4">{clipboard.entryCount}</td>
                      <td className="py-3 pr-4">{clipboard.fileCount}</td>
                      <td className="py-3 pr-4">{clipboard.hasPassword ? 'Yes' : 'No'}</td>
                      <td className="py-3 pr-4">{formatTTL(clipboard.ttl)}</td>
                      <td className="py-3 pr-4 text-text-secondary">{new Date(clipboard.lastActivity).toLocaleString()}</td>
                      <td className="py-3 pr-4 text-right">
                        <div className="flex justify-end gap-2">
                          <Link href={`/admin/${clipboard.id}`} className="btn btn-secondary btn-sm">
                            View
                          </Link>
                          <button className="btn btn-ghost btn-sm" onClick={() => handleDelete(clipboard.id)}>
                            Delete
                          </button>
                        </div>
                      </td>
                    </tr>
                  ))}
                </tbody>
              </table>
            </div>
          )}
        </div>
      )}
    </div>
  );
}

function formatTTL(ttl: number | null): string {
  if (ttl === null) return 'None';
  if (ttl < 60) return `${ttl}s`;
  if (ttl < 3600) return `${Math.round(ttl / 60)}m`;
  const hours = Math.round(ttl / 3600);
  return `${hours}h`;
}