frontend/src/components/EventTimeline.jsx

import { useState, useEffect } from 'react';
import { fetchEvents } from '../api';

const TYPE_STYLE = {
  geopolitical: { color: '#ef4444', bg: 'rgba(239,68,68,.12)', label: '地缘' },
  supply:       { color: '#10b981', bg: 'rgba(16,185,129,.12)', label: '供给' },
  demand:       { color: '#f59e0b', bg: 'rgba(245,158,11,.12)', label: '需求' },
  macro:        { color: '#3b82f6', bg: 'rgba(59,130,246,.12)', label: '宏观' },
  policy:       { color: '#8b5cf6', bg: 'rgba(139,92,246,.12)', label: '政策' },
};

const IMPACT_COLOR = { bullish: '#10b981', bearish: '#ef4444', neutral: '#94a3b8' };
const IMPACT_LABEL = { bullish: '利多', bearish: '利空', neutral: '中性' };

const FACTOR_ZH = {
  vix_lag1: 'VIX', usd_index: 'USD指数', supply_saudi: '沙特产量',
  Brent_spot: 'Brent', mom1m_lag1: '动量', natgas_spot_henry: '天然气',
  pmi_us_mfg: 'PMI制造', ipi_us: '工业产出', rig_count_us_new: '钻井数',
  news_oil_sentiment: '新闻情绪', news_geo_tone: '地缘情绪',
};

export default function EventTimeline({ limit = 5 }) {
  const [events, setEvents] = useState([]);
  const [expanded, setExpanded] = useState(null);
  const [filter, setFilter] = useState('all');

  useEffect(() => {
    fetchEvents().then(d => {
      if (Array.isArray(d)) {
        d.sort((a, b) => b.date.localeCompare(a.date));
        setEvents(d);
      }
    }).catch(() => {});
  }, []);

  const filtered = filter === 'all' ? events : events.filter(e => e.type === filter);
  const shown = filtered.slice(0, expanded !== null ? 50 : limit);

  if (!events.length) return null;

  return (
    <div className="card" style={{ padding: '1.2rem' }}>
      <div style={{ display: 'flex', justifyContent: 'space-between', alignItems: 'center', marginBottom: '.8rem' }}>
        <h3 style={{ margin: 0 }}>
          🔗 因果叙事链
          <span style={{ fontSize: '.75rem', fontWeight: 400, color: 'var(--muted)', marginLeft: 8 }}>
            事件 → 因子异动 → 风险信号 → 对冲建议
          </span>
        </h3>
        <div style={{ display: 'flex', gap: 6 }}>
          {[['all', '全部'], ...Object.entries(TYPE_STYLE).map(([k, v]) => [k, v.label])].map(([k, label]) => (
            <button key={k}
              onClick={() => setFilter(k)}
              style={{
                background: filter === k ? (TYPE_STYLE[k]?.bg || 'rgba(99,102,241,.15)') : 'rgba(255,255,255,.04)',
                color: filter === k ? (TYPE_STYLE[k]?.color || 'var(--accent)') : 'var(--muted)',
                border: `1px solid ${filter === k ? (TYPE_STYLE[k]?.color || 'var(--accent)') + '44' : 'transparent'}`,
                borderRadius: 12, padding: '3px 10px', fontSize: '.75rem', cursor: 'pointer',
              }}>
              {label}
            </button>
          ))}
        </div>
      </div>

      {/* Timeline */}
      <div style={{ position: 'relative', paddingLeft: 24 }}>
        {/* Vertical line */}
        <div style={{
          position: 'absolute', left: 9, top: 8, bottom: 8, width: 2,
          background: 'linear-gradient(to bottom, rgba(99,102,241,.4), rgba(99,102,241,.05))',
        }} />

        {shown.map((ev, i) => {
          const ts = TYPE_STYLE[ev.type] || TYPE_STYLE.macro;
          const isOpen = expanded === i;
          return (
            <div key={i} style={{ position: 'relative', marginBottom: isOpen ? 16 : 10 }}>
              {/* Dot on timeline */}
              <div style={{
                position: 'absolute', left: -20, top: 6, width: 14, height: 14,
                borderRadius: '50%', background: ts.color,
                border: '2px solid #0d1117', zIndex: 1,
                boxShadow: isOpen ? `0 0 8px ${ts.color}88` : 'none',
              }} />

              {/* Event card */}
              <div
                onClick={() => setExpanded(isOpen ? null : i)}
                style={{
                  background: isOpen ? ts.bg : 'rgba(255,255,255,.02)',
                  border: `1px solid ${isOpen ? ts.color + '33' : 'rgba(255,255,255,.06)'}`,
                  borderRadius: 10, padding: '10px 14px', cursor: 'pointer',
                  transition: 'all .2s ease',
                }}>
                {/* Header row */}
                <div style={{ display: 'flex', alignItems: 'center', gap: 8 }}>
                  <span style={{ fontSize: '1.1rem' }}>{ev.icon}</span>
                  <span style={{ fontWeight: 600, fontSize: '.9rem' }}>{ev.title}</span>
                  <span style={{
                    fontSize: '.7rem', padding: '1px 8px', borderRadius: 8,
                    background: IMPACT_COLOR[ev.impact] + '22', color: IMPACT_COLOR[ev.impact],
                    fontWeight: 600,
                  }}>
                    {IMPACT_LABEL[ev.impact]}
                  </span>
                  <span style={{ marginLeft: 'auto', fontSize: '.75rem', color: 'var(--muted)' }}>
                    {ev.date}
                  </span>
                </div>

                {/* Expanded content: causal chain */}
                {isOpen && (
                  <div style={{ marginTop: 12 }}>
                    {/* Narrative */}
                    <div style={{ fontSize: '.85rem', color: 'var(--muted)', lineHeight: 1.6, marginBottom: 12 }}>
                      {ev.narrative}
                    </div>

                    {/* Causal chain visualization */}
                    <div style={{
                      display: 'grid', gridTemplateColumns: 'repeat(4, 1fr)', gap: 8,
                      background: 'rgba(0,0,0,.2)', borderRadius: 8, padding: 12,
                    }}>
                      {/* Step 1: Event */}
                      <div style={{ textAlign: 'center' }}>
                        <div style={{ fontSize: '.65rem', color: ts.color, fontWeight: 600, marginBottom: 4 }}>① 事件触发</div>
                        <div style={{ fontSize: '1.3rem' }}>{ev.icon}</div>
                        <div style={{ fontSize: '.75rem', marginTop: 4 }}>{ev.title.slice(0, 12)}</div>
                      </div>

                      {/* Step 2: Factor changes */}
                      <div style={{ textAlign: 'center' }}>
                        <div style={{ fontSize: '.65rem', color: '#3b82f6', fontWeight: 600, marginBottom: 4 }}>② 因子异动</div>
                        {ev.factor_changes && Object.entries(ev.factor_changes).slice(0, 3).map(([k, v]) => (
                          <div key={k} style={{ fontSize: '.75rem', lineHeight: 1.6 }}>
                            {FACTOR_ZH[k] || k}{' '}
                            <span style={{ color: v > 0 ? '#10b981' : '#ef4444', fontWeight: 700 }}>
                              {v > 0 ? '↑' : '↓'}{Math.abs(v).toFixed(1)}
                            </span>
                          </div>
                        ))}
                      </div>

                      {/* Step 3: Risk signal */}
                      <div style={{ textAlign: 'center' }}>
                        <div style={{ fontSize: '.65rem', color: '#f59e0b', fontWeight: 600, marginBottom: 4 }}>③ 风险信号</div>
                        <div style={{ fontSize: '.75rem', lineHeight: 1.5, color: 'var(--muted)' }}>
                          {ev.risk_signal}
                        </div>
                      </div>

                      {/* Step 4: Hedging action */}
                      <div style={{ textAlign: 'center' }}>
                        <div style={{ fontSize: '.65rem', color: '#10b981', fontWeight: 600, marginBottom: 4 }}>④ 对冲建议</div>
                        <div style={{ fontSize: '.75rem', lineHeight: 1.5, color: 'var(--muted)' }}>
                          {ev.hedging_action}
                        </div>
                      </div>
                    </div>

                    {/* Arrow chain */}
                    <div style={{
                      display: 'flex', justifyContent: 'center', gap: 4, marginTop: 6,
                      fontSize: '.7rem', color: 'var(--muted)',
                    }}>
                      <span style={{ color: ts.color }}>事件</span> →
                      <span style={{ color: '#3b82f6' }}>因子</span> →
                      <span style={{ color: '#f59e0b' }}>信号</span> →
                      <span style={{ color: '#10b981' }}>对冲</span>
                    </div>
                  </div>
                )}
              </div>
            </div>
          );
        })}
      </div>

      {/* Show more */}
      {filtered.length > limit && expanded === null && (
        <div style={{ textAlign: 'center', marginTop: 8 }}>
          <button
            onClick={() => setExpanded(-1)}
            style={{
              background: 'none', border: '1px solid rgba(99,102,241,.3)',
              color: 'var(--accent)', borderRadius: 8, padding: '4px 16px',
              fontSize: '.8rem', cursor: 'pointer',
            }}>
            查看全部 {filtered.length} 个事件
          </button>
        </div>
      )}
    </div>
  );
}