import { useState } from 'react';
import { useTradingDecisions } from '../../api/tradingHooks';
import type { TradingDecision } from '../../api/tradingHooks';
import { Card, LoadingSpinner } from '../../components/ui';
import { DataTable, type Column } from '../../components/DataTable';

function fmtUsd(v: number | null | undefined) {
  if (v == null) return '—';
  return `$${v.toLocaleString(undefined, { minimumFractionDigits: 2, maximumFractionDigits: 2 })}`;
}

function pnlColor(v: number | null | undefined) {
  if (v == null) return 'text-gray-400';
  return v >= 0 ? 'text-green-400' : 'text-red-400';
}

const PAGE_SIZE = 25;

const columns: Column<TradingDecision>[] = [
  {
    key: 'ticker',
    header: 'Ticker',
    className: 'font-mono font-semibold text-brand-300',
  },
  {
    key: 'decision',
    header: 'Decision',
    render: (r) => <span className="capitalize">{r.decision}</span>,
  },
  {
    key: 'computed_share_quantity',
    header: 'Shares',
    render: (r) => <span>{r.computed_share_quantity ?? '—'}</span>,
  },
  {
    key: 'computed_position_size',
    header: 'Position Size',
    render: (r) => <span>{fmtUsd(r.computed_position_size)}</span>,
  },
  {
    key: 'risk_tier_at_decision',
    header: 'Risk Tier',
    render: (r) => <span className="capitalize">{r.risk_tier_at_decision}</span>,
  },
  {
    key: 'portfolio_heat_at_decision',
    header: 'Heat',
    render: (r) => (
      <span className={pnlColor(r.portfolio_heat_at_decision)}>
        {r.portfolio_heat_at_decision != null ? `${(r.portfolio_heat_at_decision * 100).toFixed(1)}%` : '—'}
      </span>
    ),
  },
  {
    key: 'is_micro_trade',
    header: 'Micro',
    render: (r) => <span>{r.is_micro_trade ? 'Yes' : 'No'}</span>,
  },
  {
    key: 'created_at',
    header: 'Date',
    render: (r) => <span className="text-xs">{new Date(r.created_at).toLocaleString()}</span>,
  },
];

export function TradeHistory() {
  const [tickerFilter, setTickerFilter] = useState('');
  const [page, setPage] = useState(0);

  const { data, isLoading } = useTradingDecisions({
    ticker: tickerFilter || undefined,
    limit: PAGE_SIZE,
    offset: page * PAGE_SIZE,
  });

  if (isLoading) return <LoadingSpinner />;

  return (
    <div className="space-y-4">
      <Card>
        <div className="mb-3 flex items-center justify-between">
          <h2 className="text-sm font-medium text-gray-400">Trade History</h2>
          <input
            type="text"
            placeholder="Filter by ticker…"
            value={tickerFilter}
            onChange={(e) => {
              setTickerFilter(e.target.value.toUpperCase());
              setPage(0);
            }}
            className="w-32 rounded-md border border-surface-700 bg-surface-950 px-2 py-1 text-xs text-gray-200 placeholder-gray-500 focus:border-brand-500 focus:outline-none"
            aria-label="Filter by ticker"
          />
        </div>
        <DataTable<TradingDecision>
          data={data ?? []}
          columns={columns}
          keyField="id"
          pageSize={PAGE_SIZE}
          emptyMessage="No trading decisions found"
        />
        {/* Server-side pagination controls */}
        <div className="mt-2 flex items-center justify-end gap-2 text-xs text-gray-500">
          <button
            onClick={() => setPage((p) => Math.max(0, p - 1))}
            disabled={page === 0}
            className="rounded px-2 py-1 hover:bg-surface-800 disabled:opacity-30"
            aria-label="Previous page"
          >
            Prev
          </button>
          <span>Page {page + 1}</span>
          <button
            onClick={() => setPage((p) => p + 1)}
            disabled={(data?.length ?? 0) < PAGE_SIZE}
            className="rounded px-2 py-1 hover:bg-surface-800 disabled:opacity-30"
            aria-label="Next page"
          >
            Next
          </button>
        </div>
      </Card>
    </div>
  );
}