'use client';
import React, { useState, useEffect, useCallback } from 'react';
import Link from 'next/link';
import { useAuth } from '@/contexts/AuthContext';
import { useRouter } from 'next/navigation';

function fmt(cents: number) { return '$' + (cents / 100).toLocaleString('en-US', { minimumFractionDigits: 2 }); }

export default function ReconciliationPage() {
  const { user, loading } = useAuth();
  const router = useRouter();
  const [transactions, setTransactions] = useState<any[]>([]);
  const [loadingData, setLoadingData] = useState(false);
  const [uploading, setUploading] = useState(false);
  const [summary, setSummary] = useState<{ matched: number; unmatched: number } | null>(null);

  useEffect(() => { if (!loading && !user) router.push('/login?next=' + encodeURIComponent(window.location.pathname)); }, [user, loading, router]);

  const load = useCallback(async () => {
    setLoadingData(true);
    const r = await fetch('/api/accounting/reconciliation');
    const d = await r.json();
    setTransactions(d.transactions ?? []);
    setSummary(d.summary ?? null);
    setLoadingData(false);
  }, []);

  useEffect(() => { if (user) load(); }, [user, load]);

  async function handleUpload(e: React.ChangeEvent<HTMLInputElement>) {
    const file = e.target.files?.[0];
    if (!file) return;
    setUploading(true);
    const text = await file.text();
    const r = await fetch('/api/accounting/reconciliation', {
      method: 'POST', headers: { 'Content-Type': 'application/json' }, body: JSON.stringify({ csv: text }),
    });
    const d = await r.json();
    setSummary(d.summary ?? null);
    setUploading(false);
    load();
  }

  async function handleManualMatch(txId: string, invoiceId: string) {
    await fetch('/api/accounting/reconciliation/match', {
      method: 'POST', headers: { 'Content-Type': 'application/json' }, body: JSON.stringify({ transaction_id: txId, invoice_id: invoiceId }),
    });
    load();
  }

  if (loading) return <div className="min-h-screen bg-[#0a0a0a] flex items-center justify-center"><div className="w-8 h-8 border-2 border-[#1D4ED8] border-t-transparent rounded-full animate-spin" /></div>;
  if (!user) return null;

  return (
    <div className="min-h-screen bg-[#0a0a0a] text-white p-6">
      <div className="max-w-6xl mx-auto space-y-4">
        <div className="flex items-center justify-between">
          <div>
            <h1 className="text-xl font-bold">Bank Reconciliation</h1>
            <Link href="/admin/accounting" className="text-xs text-[#555] hover:text-[#888]">← Accounting</Link>
          </div>
          <label className={`px-3 py-1.5 bg-[#1D4ED8] rounded text-xs font-medium hover:bg-blue-500 cursor-pointer ${uploading ? 'opacity-50' : ''}`}>
            {uploading ? 'Uploading…' : 'Upload Bank CSV'}
            <input type="file" accept=".csv" className="hidden" onChange={handleUpload} disabled={uploading} />
          </label>
        </div>

        {summary && (
          <div className="grid grid-cols-2 gap-3">
            <div className="bg-green-400/10 border border-green-400/20 rounded-lg p-4">
              <p className="text-2xl font-bold text-green-400">{summary.matched}</p>
              <p className="text-xs text-[#888] mt-1">Auto-matched transactions</p>
            </div>
            <div className="bg-yellow-400/10 border border-yellow-400/20 rounded-lg p-4">
              <p className="text-2xl font-bold text-yellow-400">{summary.unmatched}</p>
              <p className="text-xs text-[#888] mt-1">Need review</p>
            </div>
          </div>
        )}

        <div className="bg-[#111] border border-[#DCE6F2] rounded-lg overflow-x-auto">
          <table className="w-full text-sm">
            <thead>
              <tr className="border-b border-[#FFFFFF]">
                {['Date','Description','Amount','Type','Matched To','Reconciled','Action'].map(h => (
                  <th key={h} className="px-3 py-2 text-left text-xs text-[#555] font-medium">{h}</th>
                ))}
              </tr>
            </thead>
            <tbody>
              {loadingData ? (
                <tr><td colSpan={7} className="px-4 py-8 text-center text-[#555] text-xs">Loading…</td></tr>
              ) : transactions.length === 0 ? (
                <tr><td colSpan={7} className="px-4 py-8 text-center text-[#555] text-xs">No transactions. Upload a CSV to begin.</td></tr>
              ) : transactions.map((tx: any) => (
                <tr key={tx.id} className="border-b border-[#FFFFFF] hover:bg-[#FFFFFF]">
                  <td className="px-3 py-2 text-[#888] text-xs">{tx.transaction_date}</td>
                  <td className="px-3 py-2 text-white text-xs max-w-xs truncate">{tx.description}</td>
                  <td className={`px-3 py-2 text-xs font-medium ${tx.type === 'credit' ? 'text-green-400' : 'text-red-400'}`}>{fmt(Math.abs(tx.amount_cents ?? 0))}</td>
                  <td className="px-3 py-2 text-[#888] text-xs capitalize">{tx.type}</td>
                  <td className="px-3 py-2 text-[#555] text-xs">{tx.matched_invoice_id ? `Invoice ${tx.matched_invoice_id.slice(0, 8)}…` : tx.matched_expense_id ? `Expense` : '—'}</td>
                  <td className="px-3 py-2">
                    <span className={`px-2 py-0.5 rounded-full text-xs ${tx.reconciled ? 'bg-green-400/10 text-green-400' : 'bg-yellow-400/10 text-yellow-400'}`}>{tx.reconciled ? 'Yes' : 'No'}</span>
                  </td>
                  <td className="px-3 py-2">
                    {!tx.reconciled && <span className="text-xs text-[#555]">Manual match</span>}
                  </td>
                </tr>
              ))}
            </tbody>
          </table>
        </div>
      </div>
    </div>
  );
}
