import { useEffect, useState } from 'react';
import { Link } from 'react-router-dom';
import {
  ArrowRight,
  TrendingUp,
  TrendingDown,
  RefreshCw,
  CreditCard,
} from 'lucide-react';

import api, { type Account, type Transaction } from '../api';

function formatAmount(amount: number, currency: string) {
  const abs = Math.abs(amount);
  if (currency === 'USD') {
    return `$${abs.toLocaleString('en-US', { minimumFractionDigits: 2, maximumFractionDigits: 2 })}`;
  }
  return `₡${abs.toLocaleString('es-CR', { minimumFractionDigits: 2, maximumFractionDigits: 2 })}`;
}

function formatDate(dateStr: string) {
  return new Date(dateStr).toLocaleDateString('en-US', {
    month: 'short',
    day: 'numeric',
  });
}

export default function Dashboard() {
  const [accounts, setAccounts] = useState<Account[]>([]);
  const [recent, setRecent] = useState<Transaction[]>([]);
  const [loading, setLoading] = useState(true);

  const fetchData = async () => {
    setLoading(true);
    try {
      const [accRes, txRes] = await Promise.all([
        api.get('/accounts/'),
        api.get('/transactions/recent?limit=5'),
      ]);
      setAccounts(accRes.data);
      setRecent(txRes.data);
    } catch (e) {
      console.error(e);
    } finally {
      setLoading(false);
    }
  };

  useEffect(() => {
    fetchData();
  }, []);

  const totalCRC = accounts
    .filter((a) => a.currency === 'CRC')
    .reduce((s, a) => s + a.balance, 0);
  const totalUSD = accounts
    .filter((a) => a.currency === 'USD')
    .reduce((s, a) => s + a.balance, 0);

  return (
    <div className="space-y-6">
      {/* Header */}
      <div className="flex items-center justify-between">
        <div>
          <h1 className="text-2xl font-bold">Dashboard</h1>
          <p className="text-sm text-slate-500 mt-1">Financial overview</p>
        </div>
        <button
          onClick={fetchData}
          className="p-2 rounded-lg text-slate-500 hover:text-white hover:bg-slate-800/50 transition-colors"
        >
          <RefreshCw className={`w-4 h-4 ${loading ? 'animate-spin' : ''}`} />
        </button>
      </div>

      {/* Account balances */}
      <div className="grid grid-cols-1 sm:grid-cols-2 lg:grid-cols-4 gap-4">
        {accounts.map((account, i) => (
          <div
            key={account.id}
            className="relative group animate-fade-in"
          >
            <div className="absolute -inset-[1px] rounded-xl bg-gradient-to-br from-emerald-500/20 to-cyan-500/20 opacity-0 group-hover:opacity-100 transition-opacity" />
            <div className="relative bg-slate-900/60 border border-slate-800/60 rounded-xl p-5">
              <div className="flex items-center justify-between mb-3">
                <span className="text-xs font-medium text-slate-500 uppercase tracking-wider">
                  {account.label}
                </span>
                <span className="text-[10px] font-mono text-slate-600 bg-slate-800/60 px-2 py-0.5 rounded">
                  {account.bank}
                </span>
              </div>
              <p className="text-2xl font-bold font-mono tracking-tight">
                {formatAmount(account.balance, account.currency)}
              </p>
            </div>
          </div>
        ))}

        {/* Totals */}
        {accounts.length > 0 && (
          <>
            <div
              className="bg-gradient-to-br from-emerald-500/10 to-cyan-500/5 border border-emerald-500/20 rounded-xl p-5"
            >
              <span className="text-xs font-medium text-emerald-400/80 uppercase tracking-wider">
                Total CRC
              </span>
              <p className="text-2xl font-bold font-mono tracking-tight text-emerald-400 mt-3">
                {formatAmount(totalCRC, 'CRC')}
              </p>
            </div>
            <div
              className="bg-gradient-to-br from-cyan-500/10 to-emerald-500/5 border border-cyan-500/20 rounded-xl p-5 animate-fade-in"
            >
              <span className="text-xs font-medium text-cyan-400/80 uppercase tracking-wider">
                Total USD
              </span>
              <p className="text-2xl font-bold font-mono tracking-tight text-cyan-400 mt-3">
                {formatAmount(totalUSD, 'USD')}
              </p>
            </div>
          </>
        )}
      </div>

      {/* Recent transactions */}
      <div className="bg-slate-900/40 border border-slate-800/60 rounded-xl">
        <div className="flex items-center justify-between px-5 py-4 border-b border-slate-800/40">
          <div className="flex items-center gap-2">
            <CreditCard className="w-4 h-4 text-slate-500" />
            <h2 className="font-semibold text-sm">Recent Charges</h2>
          </div>
          <Link
            to="/transactions"
            className="flex items-center gap-1 text-xs font-medium text-emerald-400 hover:text-emerald-300 transition-colors"
          >
            View all
            <ArrowRight className="w-3 h-3" />
          </Link>
        </div>

        {recent.length === 0 && !loading ? (
          <div className="px-5 py-12 text-center text-slate-600 text-sm">
            No transactions yet. Add your first one!
          </div>
        ) : (
          <div className="divide-y divide-slate-800/40">
            {recent.map((tx, i) => (
              <div
                key={tx.id}
                className="flex items-center justify-between px-5 py-3.5 hover:bg-slate-800/20 transition-colors animate-fade-in"
              >
                <div className="flex items-center gap-3 min-w-0">
                  <div
                    className={`w-8 h-8 rounded-lg flex items-center justify-center flex-shrink-0 ${
                      tx.transaction_type === 'DEVOLUCION'
                        ? 'bg-emerald-500/10 text-emerald-400'
                        : 'bg-red-500/10 text-red-400'
                    }`}
                  >
                    {tx.transaction_type === 'DEVOLUCION' ? (
                      <TrendingUp className="w-4 h-4" />
                    ) : (
                      <TrendingDown className="w-4 h-4" />
                    )}
                  </div>
                  <div className="min-w-0">
                    <p className="text-sm font-medium truncate">{tx.merchant}</p>
                    <p className="text-xs text-slate-500">
                      {formatDate(tx.date)}
                      {tx.category && (
                        <span className="ml-2 text-slate-600">
                          {tx.category.name}
                        </span>
                      )}
                    </p>
                  </div>
                </div>
                <span
                  className={`font-mono text-sm font-medium flex-shrink-0 ml-4 ${
                    tx.transaction_type === 'DEVOLUCION'
                      ? 'text-emerald-400'
                      : 'text-white'
                  }`}
                >
                  {tx.transaction_type === 'DEVOLUCION' ? '+' : '-'}
                  {formatAmount(tx.amount, tx.currency)}
                </span>
              </div>
            ))}
          </div>
        )}
      </div>
    </div>
  );
}