import { raceColor } from '../utils/colors.js'
import { POOL_BY_SEX_ARREST_THRESHOLD } from '../utils/pooling.js'

/**
 * The results page's first block: what was actually observed, before any
 * modelling. One row per student group plus a district total.
 *
 * The table doubles as the legend and the control for the density panel — each
 * row carries the checkbox that adds or removes that group's curve, and the
 * colour swatch is the same hue the curve is drawn in. That's deliberate:
 * a separate legend plus a separate group picker would make the reader hold
 * three mappings in their head instead of one.
 *
 * @param {{
 *   groups: Array<{key:string, race:string, sex:string|null, label:string,
 *     enroll:number, observed:number, rate:number}>,
 *   selectedKeys: string[],
 *   onToggleGroup: (key: string) => void,
 *   pooled: boolean,
 *   autoPooled: boolean,
 *   onPooledChange: (pooled: boolean) => void,
 *   selectionIsEnrollmentFallback: boolean,
 * }} props
 */
export default function DistrictSummaryTable({
  groups,
  selectedKeys,
  onToggleGroup,
  pooled,
  autoPooled,
  onPooledChange,
  selectionIsEnrollmentFallback,
}) {
  if (!groups?.length) {
    return (
      <div className="cv-card" style={{ padding: 'var(--space-2)' }}>
        <h3 style={cardTitle}>Reported arrests and enrollment</h3>
        <p style={{ color: 'var(--cv-ink-3)', margin: 0 }}>
          No student-group data is available for this district in 2021–22.
        </p>
      </div>
    )
  }

  const selected = new Set(selectedKeys)
  const totalEnroll = groups.reduce((sum, g) => sum + g.enroll, 0)
  const totalObserved = groups.reduce((sum, g) => sum + g.observed, 0)
  const totalRate = totalEnroll > 0 ? (totalObserved / totalEnroll) * 1000 : 0

  return (
    <div className="cv-card" style={{ padding: 'var(--space-2)' }}>
      <h3 style={cardTitle}>Reported arrests and enrollment, 2021–22</h3>
      <p style={{ fontSize: '0.8rem', color: 'var(--cv-ink-3)', margin: '0 0 var(--space-2)' }}>
        Check a group to show its modelled arrest-rate distribution in the chart below.
      </p>

      {pooled && (
        <PoolingBanner autoPooled={autoPooled} totalObserved={totalObserved} onPooledChange={onPooledChange} />
      )}

      {selectionIsEnrollmentFallback && (
        <p style={noteStyle}>
          No group in this district reported an arrest in 2021–22, so the two largest groups by
          enrollment are shown by default.
        </p>
      )}

      <div style={{ overflowX: 'auto' }}>
        <table style={tableStyle}>
          <caption style={{ captionSide: 'bottom', textAlign: 'left', paddingTop: 'var(--space-1)', fontSize: '0.75rem', color: 'var(--cv-ink-3)' }}>
            Students counted are those in the four modelled race groups (American Indian / Alaska
            Native, Black, Hispanic, White) — not the district&rsquo;s total enrollment, which also
            includes groups this model does not estimate.
          </caption>
          <thead>
            <tr>
              <th scope="col" style={{ ...thStyle, textAlign: 'left' }}>Student group</th>
              <th scope="col" style={thStyle}>Students</th>
              <th scope="col" style={thStyle}>Observed arrests</th>
              <th scope="col" style={thStyle}>Rate per 1,000</th>
            </tr>
          </thead>
          <tbody>
            {groups.map((g) => (
              <GroupRow
                key={g.key}
                group={g}
                checked={selected.has(g.key)}
                onToggle={() => onToggleGroup(g.key)}
              />
            ))}
          </tbody>
          <tfoot>
            <tr>
              <th scope="row" style={{ ...tdStyle, textAlign: 'left', fontWeight: 700, borderTop: '2px solid var(--cv-ink)' }}>
                All modelled groups
              </th>
              <td style={{ ...numStyle, fontWeight: 700, borderTop: '2px solid var(--cv-ink)' }}>
                {totalEnroll.toLocaleString()}
              </td>
              <td style={{ ...numStyle, fontWeight: 700, borderTop: '2px solid var(--cv-ink)' }}>
                {totalObserved.toLocaleString()}
              </td>
              <td style={{ ...numStyle, fontWeight: 700, borderTop: '2px solid var(--cv-ink)' }}>
                {formatRate(totalRate)}
              </td>
            </tr>
          </tfoot>
        </table>
      </div>

      {!pooled && (
        <label style={{ ...toggleLabel, marginTop: 'var(--space-2)' }}>
          <input type="checkbox" checked={false} onChange={() => onPooledChange(true)} />
          <span>Combine Female and Male within each race</span>
        </label>
      )}
    </div>
  )
}

function GroupRow({ group, checked, onToggle }) {
  const zero = group.observed === 0
  const inputId = `group-toggle-${group.key}`
  return (
    <tr style={{ opacity: zero ? 0.62 : 1 }}>
      <td style={{ ...tdStyle, textAlign: 'left' }}>
        <label htmlFor={inputId} style={{ display: 'flex', alignItems: 'center', gap: '0.5rem', cursor: 'pointer' }}>
          <input id={inputId} type="checkbox" checked={checked} onChange={onToggle} />
          <span
            aria-hidden="true"
            style={{
              width: '11px',
              height: '11px',
              borderRadius: '3px',
              flexShrink: 0,
              // Hollow when deselected: the swatch tracks whether that curve is
              // on screen, so the table stays a truthful legend.
              background: checked ? raceColor(group.race) : 'transparent',
              border: `2px solid ${raceColor(group.race)}`,
            }}
          />
          <span>{group.label}</span>
        </label>
      </td>
      <td style={numStyle}>{group.enroll.toLocaleString()}</td>
      <td style={numStyle}>{group.observed.toLocaleString()}</td>
      <td style={numStyle}>{formatRate(group.rate)}</td>
    </tr>
  )
}

function PoolingBanner({ autoPooled, totalObserved, onPooledChange }) {
  return (
    <div style={bannerStyle}>
      <p style={{ margin: 0, fontSize: '0.82rem' }}>
        {autoPooled ? (
          <>
            This district reported {totalObserved.toLocaleString()} arrests in total — fewer than{' '}
            {POOL_BY_SEX_ARREST_THRESHOLD} — so Female and Male students are combined within each
            race to give each estimate more data to stand on.
          </>
        ) : (
          <>Female and Male students are combined within each race.</>
        )}
      </p>
      <label style={toggleLabel}>
        <input type="checkbox" checked onChange={() => onPooledChange(false)} />
        <span>Combined — uncheck to show Female and Male separately</span>
      </label>
    </div>
  )
}

function formatRate(rate) {
  if (!(rate > 0)) return '0.0'
  return rate.toLocaleString(undefined, { minimumFractionDigits: 1, maximumFractionDigits: 1 })
}

const cardTitle = { fontSize: '0.85rem', marginBottom: 'var(--space-1)', color: 'var(--cv-ink-2)' }

const tableStyle = {
  width: '100%',
  borderCollapse: 'collapse',
  fontSize: '0.85rem',
  fontVariantNumeric: 'tabular-nums',
}

const thStyle = {
  textAlign: 'right',
  padding: '0.35rem 0.5rem',
  borderBottom: '1px solid var(--cv-rule-strong)',
  fontSize: '0.72rem',
  fontWeight: 600,
  textTransform: 'uppercase',
  letterSpacing: '0.06em',
  color: 'var(--cv-ink-3)',
  whiteSpace: 'nowrap',
}

const tdStyle = {
  padding: '0.35rem 0.5rem',
  borderBottom: '1px solid var(--cv-rule)',
}

const numStyle = { ...tdStyle, textAlign: 'right', whiteSpace: 'nowrap' }

const bannerStyle = {
  background: 'var(--cv-paper-2)',
  border: '1px solid var(--cv-rule)',
  borderLeft: '3px solid var(--cv-accent)',
  borderRadius: 'var(--radius-md)',
  padding: 'var(--space-1) var(--space-2)',
  marginBottom: 'var(--space-2)',
  display: 'flex',
  flexDirection: 'column',
  gap: '0.4rem',
}

const toggleLabel = {
  display: 'inline-flex',
  alignItems: 'center',
  gap: '0.45rem',
  fontSize: '0.78rem',
  color: 'var(--cv-ink-2)',
  cursor: 'pointer',
}

const noteStyle = {
  fontSize: '0.78rem',
  fontStyle: 'italic',
  color: 'var(--cv-ink-3)',
  margin: '0 0 var(--space-2)',
}