import { useMemo, useState } from 'react';
import {
  Building2, ChevronRight, ChevronDown, Search, Filter, Plus, Download,
  ExternalLink, Copy, MoreHorizontal
} from 'lucide-react';
import { sampleAccounts } from '../data/portalData';
import type { Account, AccountType } from '../types/portal';
import { useOnChainBalances } from '../hooks/useOnChainBalances';
import type { OnChainBalance } from '../services/chain138';
import OnChainBalanceTag from '../components/portal/OnChainBalanceTag';
import { explorerAddressUrl } from '../services/explorer';

const typeColors: Record<AccountType, string> = {
  operating: '#3b82f6', reserve: '#22c55e', custody: '#a855f7', escrow: '#f97316',
  settlement: '#06b6d4', nostro: '#eab308', vostro: '#ec4899', collateral: '#6366f1',
  treasury: '#14b8a6', crypto_wallet: '#8b5cf6', stablecoin: '#10b981', omnibus: '#64748b',
};

const formatBalance = (amount: number, currency: string) => {
  if (currency === 'BTC') return `${amount.toFixed(4)} BTC`;
  if (currency === 'USDC') return `$${amount.toLocaleString()}`;
  const sym = currency === 'USD' ? '$' : currency === 'EUR' ? '€' : currency === 'GBP' ? '£' : '';
  if (Math.abs(amount) >= 1_000_000) return `${sym}${(amount / 1_000_000).toFixed(2)}M`;
  return `${sym}${amount.toLocaleString(undefined, { minimumFractionDigits: 2, maximumFractionDigits: 2 })}`;
};

interface AccountRowProps {
  account: Account;
  level?: number;
  onChainBalances: Record<string, OnChainBalance>;
  balancesLoading: boolean;
}

function AccountRow({ account, level = 0, onChainBalances, balancesLoading }: AccountRowProps) {
  const [expanded, setExpanded] = useState(false);
  const hasChildren = account.subaccounts && account.subaccounts.length > 0;
  const onChain = account.walletAddress ? onChainBalances[account.walletAddress] : undefined;

  return (
    <>
      <div className={`account-table-row level-${level}`} style={{ paddingLeft: `${16 + level * 24}px` }}>
        <div className="account-table-name">
          {hasChildren ? (
            <button className="expand-btn" onClick={() => setExpanded(!expanded)}>
              {expanded ? <ChevronDown size={14} /> : <ChevronRight size={14} />}
            </button>
          ) : (
            <span className="expand-placeholder" />
          )}
          <span className="account-type-dot" style={{ background: typeColors[account.type] }} />
          <div>
            <span className="account-name-text">{account.name}</span>
            <span className="account-type-label">{account.type.replace('_', ' ')}</span>
            {account.walletAddress && (
              <span style={{ display: 'block', marginTop: 2 }}>
                <OnChainBalanceTag
                  address={account.walletAddress}
                  balance={onChain}
                  loading={balancesLoading}
                  compact
                />
              </span>
            )}
          </div>
        </div>
        <div className="account-table-cell currency">{account.currency}</div>
        <div className="account-table-cell mono balance">{formatBalance(account.balance, account.currency)}</div>
        <div className="account-table-cell mono available">{formatBalance(account.availableBalance, account.currency)}</div>
        <div className="account-table-cell">
          <span className={`account-status-badge ${account.status}`}>{account.status}</span>
        </div>
        <div className="account-table-cell identifier">
          {account.iban && <span className="mono small">{account.iban}</span>}
          {account.walletAddress && (
            <a
              href={explorerAddressUrl(account.walletAddress)}
              target="_blank"
              rel="noreferrer"
              className="mono small"
              title="View on SolaceScan"
              style={{ color: 'inherit', textDecoration: 'underline dotted' }}
            >
              {account.walletAddress.slice(0, 10)}…
            </a>
          )}
          {account.swift && <span className="swift-badge">{account.swift}</span>}
        </div>
        <div className="account-table-cell">
          <span className="mono small">{account.lastActivity.toLocaleTimeString([], { hour: '2-digit', minute: '2-digit' })}</span>
        </div>
        <div className="account-table-cell actions">
          <button className="row-action-btn" title="View Details"><ExternalLink size={12} /></button>
          <button className="row-action-btn" title="Copy ID"><Copy size={12} /></button>
          <button className="row-action-btn" title="More"><MoreHorizontal size={12} /></button>
        </div>
      </div>
      {expanded && hasChildren && account.subaccounts!.map(sub => (
        <AccountRow key={sub.id} account={sub} level={level + 1} onChainBalances={onChainBalances} balancesLoading={balancesLoading} />
      ))}
    </>
  );
}

export default function AccountsPage() {
  const [search, setSearch] = useState('');
  const [typeFilter, setTypeFilter] = useState<string>('all');
  const [view, setView] = useState<'tree' | 'flat'>('tree');

  const onChainAddresses = useMemo(
    () => sampleAccounts
      .flatMap(a => [a, ...(a.subaccounts || [])])
      .filter(a => !!a.walletAddress)
      .map(a => a.walletAddress as string),
    [],
  );
  const { balances: onChainBalances, loading: balancesLoading } = useOnChainBalances(onChainAddresses);

  const allAccounts = view === 'flat'
    ? sampleAccounts.flatMap(a => [a, ...(a.subaccounts || [])])
    : sampleAccounts;

  const filtered = allAccounts.filter(a => {
    const matchSearch = a.name.toLowerCase().includes(search.toLowerCase()) ||
      a.currency.toLowerCase().includes(search.toLowerCase()) ||
      a.type.includes(search.toLowerCase());
    const matchType = typeFilter === 'all' || a.type === typeFilter;
    return matchSearch && matchType && (view === 'flat' || !a.parentId);
  });

  const totalBalance = sampleAccounts.reduce((sum, a) => {
    if (a.currency === 'USD' || a.currency === 'USDC') return sum + a.balance;
    if (a.currency === 'EUR') return sum + a.balance * 1.08;
    if (a.currency === 'GBP') return sum + a.balance * 1.27;
    if (a.currency === 'BTC') return sum + a.balance * 67_000;
    return sum;
  }, 0);

  return (
    <div className="accounts-page">
      <div className="page-header">
        <div>
          <h1><Building2 size={24} /> Account Management</h1>
          <p className="page-subtitle">Multi-account and subaccount structures with consolidated views</p>
        </div>
        <div className="page-header-actions">
          <button className="btn-secondary"><Download size={14} /> Export</button>
          <button className="btn-primary"><Plus size={14} /> New Account</button>
        </div>
      </div>

      {/* Summary Cards */}
      <div className="accounts-summary">
        <div className="summary-card">
          <span className="summary-label">Total Accounts</span>
          <span className="summary-value">{sampleAccounts.length + sampleAccounts.reduce((c, a) => c + (a.subaccounts?.length || 0), 0)}</span>
        </div>
        <div className="summary-card">
          <span className="summary-label">Consolidated Balance (USD eq.)</span>
          <span className="summary-value">${(totalBalance / 1_000_000).toFixed(2)}M</span>
        </div>
        <div className="summary-card">
          <span className="summary-label">Active</span>
          <span className="summary-value green">{sampleAccounts.filter(a => a.status === 'active').length}</span>
        </div>
        <div className="summary-card">
          <span className="summary-label">Frozen</span>
          <span className="summary-value orange">{sampleAccounts.filter(a => a.status === 'frozen').length}</span>
        </div>
      </div>

      {/* Toolbar */}
      <div className="table-toolbar">
        <div className="table-toolbar-left">
          <div className="search-input-wrapper">
            <Search size={14} />
            <input
              type="text"
              placeholder="Search accounts..."
              value={search}
              onChange={e => setSearch(e.target.value)}
            />
          </div>
          <div className="filter-group">
            <Filter size={14} />
            <select value={typeFilter} onChange={e => setTypeFilter(e.target.value)}>
              <option value="all">All Types</option>
              <option value="operating">Operating</option>
              <option value="treasury">Treasury</option>
              <option value="custody">Custody</option>
              <option value="settlement">Settlement</option>
              <option value="nostro">Nostro</option>
              <option value="escrow">Escrow</option>
              <option value="collateral">Collateral</option>
              <option value="stablecoin">Stablecoin</option>
            </select>
          </div>
        </div>
        <div className="table-toolbar-right">
          <div className="view-toggle">
            <button className={view === 'tree' ? 'active' : ''} onClick={() => setView('tree')}>Tree</button>
            <button className={view === 'flat' ? 'active' : ''} onClick={() => setView('flat')}>Flat</button>
          </div>
        </div>
      </div>

      {/* Account Table */}
      <div className="account-table">
        <div className="account-table-header">
          <div className="account-table-name">Account</div>
          <div className="account-table-cell currency">Currency</div>
          <div className="account-table-cell balance">Balance</div>
          <div className="account-table-cell available">Available</div>
          <div className="account-table-cell">Status</div>
          <div className="account-table-cell identifier">Identifier</div>
          <div className="account-table-cell">Last Activity</div>
          <div className="account-table-cell actions" />
        </div>
        <div className="account-table-body">
          {filtered.map(acc => (
            <AccountRow
              key={acc.id}
              account={acc}
              onChainBalances={onChainBalances}
              balancesLoading={balancesLoading}
            />
          ))}
        </div>
      </div>
    </div>
  );
}