import { useState, useEffect } from 'react'
import { Link } from 'react-router-dom'
import dayjs from 'dayjs'
import { api } from '../../utils/api'
import { getBfCategory } from '../../utils/calc'
import { useProfile } from '../../context/ProfileContext'
import { KPI_KCAL_WINDOW_DEFAULT } from '../../widgetSystem/bodyChartDays'

const MAX_KPI = 9

function formatRefVal(row) {
  if (row.value_numeric != null && row.value_numeric !== '') {
    const n = Number(row.value_numeric)
    return Number.isFinite(n) ? String(n) : String(row.value_numeric)
  }
  return row.value_text != null ? String(row.value_text) : '–'
}

/**
 * KPIs: Referenzwerte (Layer-1-Summary) + Körperfett % + Ø Kalorien (Fenster konfigurierbar) — max. 9 Kacheln.
 */
export default function PilotKpiBoard({ refreshTick = 0, kcalWindowDays = KPI_KCAL_WINDOW_DEFAULT }) {
  const { activeProfile } = useProfile()
  const sex = activeProfile?.sex || 'm'
  const [refs, setRefs] = useState([])
  const [bf, setBf] = useState(null)
  const [avgKcal, setAvgKcal] = useState(null)
  const [loading, setLoading] = useState(true)
  const [err, setErr] = useState(null)

  useEffect(() => {
    let cancelled = false
    ;(async () => {
      try {
        setLoading(true)
        const nutrLimit = Math.min(2000, Math.max(60, kcalWindowDays * 5))
        const [summary, calipers, nutrition] = await Promise.all([
          api.listProfileReferenceValuesSummary().catch(() => ({ tiles: [] })),
          api.listCaliper(3).catch(() => []),
          api.listNutrition(nutrLimit).catch(() => []),
        ])
        if (cancelled) return
        const tiles = Array.isArray(summary?.tiles) ? summary.tiles.filter((t) => t?.latest) : []
        const latestCal = Array.isArray(calipers) && calipers[0]?.body_fat_pct != null ? calipers[0] : null
        const recentNutr = (nutrition || []).filter(
          (n) => n.date >= dayjs().subtract(kcalWindowDays, 'day').format('YYYY-MM-DD'),
        })
        const kcal =
          recentNutr.length > 0
            ? Math.round(recentNutr.reduce((s, n) => s + (n.kcal || 0), 0) / recentNutr.length)
            : null

        const wantBf = !!latestCal?.body_fat_pct
        const wantKcal = kcal != null && kcal > 0
        const extra = (wantBf ? 1 : 0) + (wantKcal ? 1 : 0)
        const refCap = Math.max(0, MAX_KPI - extra)
        setRefs(tiles.slice(0, refCap))
        setBf(
          wantBf
            ? {
                pct: latestCal.body_fat_pct,
                cat: getBfCategory(latestCal.body_fat_pct, sex),
                date: latestCal.date,
              }
            : null,
        )
        setAvgKcal(wantKcal ? kcal : null)
        setErr(null)
      } catch (e) {
        if (!cancelled) {
          setErr(e.message || 'KPIs konnten nicht geladen werden')
          setRefs([])
        }
      } finally {
        if (!cancelled) setLoading(false)
      }
    })()
    return () => {
      cancelled = true
    }
  }, [refreshTick, sex, kcalWindowDays])

  if (loading) {
    return (
      <div className="card section-gap" style={{ textAlign: 'center', padding: 24 }}>
        <div className="spinner" />
      </div>
    )
  }
  if (err) {
    return (
      <div className="card section-gap" style={{ color: 'var(--danger)', fontSize: 13 }}>
        {err}
      </div>
    )
  }

  const tiles = []

  refs.forEach((tile) => {
    const l = tile.latest
    tiles.push(
      <div key={`ref-${tile.type_key}`} className="card" style={{ margin: 0, padding: 12, boxSizing: 'border-box' }}>
        <div style={{ fontSize: 11, fontWeight: 600, color: 'var(--text3)' }}>{tile.type_label}</div>
        <div style={{ fontSize: 17, fontWeight: 700, marginTop: 4 }}>
          {formatRefVal(l)}
          {l.unit ? (
            <span style={{ fontSize: 13, fontWeight: 600, color: 'var(--text2)', marginLeft: 4 }}>{l.unit}</span>
          ) : null}
        </div>
        <div style={{ fontSize: 10, color: 'var(--text3)', marginTop: 4 }}>Ref.wert</div>
      </div>,
    )
  })

  if (bf) {
    tiles.push(
      <div key="kpi-bf" className="card" style={{ margin: 0, padding: 12, boxSizing: 'border-box' }}>
        <div style={{ fontSize: 11, fontWeight: 600, color: 'var(--text3)' }}>Körperfett</div>
        <div style={{ fontSize: 17, fontWeight: 700, marginTop: 4, color: bf.cat?.color || 'var(--text1)' }}>
          {bf.pct}%
        </div>
        <div style={{ fontSize: 10, color: 'var(--text3)', marginTop: 4 }}>{bf.cat?.label || 'Caliper'}</div>
      </div>,
    )
  }

  if (avgKcal != null) {
    tiles.push(
      <div key="kpi-kcal" className="card" style={{ margin: 0, padding: 12, boxSizing: 'border-box' }}>
        <div style={{ fontSize: 11, fontWeight: 600, color: 'var(--text3)' }}>
          Ø Kalorien ({kcalWindowDays}T)
        </div>
        <div style={{ fontSize: 17, fontWeight: 700, marginTop: 4, color: '#EF9F27' }}>{avgKcal} kcal</div>
        <div style={{ fontSize: 10, color: 'var(--text3)', marginTop: 4 }}>Ernährung</div>
      </div>,
    )
  }

  if (tiles.length === 0) {
    return (
      <div className="card section-gap">
        <div className="card-title">Kennzahlen</div>
        <p style={{ fontSize: 13, color: 'var(--text2)', margin: 0 }}>
          Noch keine Daten.{' '}
          <Link to="/settings/reference-values" style={{ color: 'var(--accent)' }}>
            Referenzwerte
          </Link>
          ,{' '}
          <Link to="/caliper" style={{ color: 'var(--accent)' }}>
            Caliper
          </Link>
          ,{' '}
          <Link to="/nutrition" style={{ color: 'var(--accent)' }}>
            Ernährung
          </Link>
          .
        </p>
      </div>
    )
  }

  return (
    <div className="card section-gap">
      <div className="card-title">Kennzahlen</div>
      <p style={{ fontSize: 12, color: 'var(--text2)', marginBottom: 12, lineHeight: 1.5 }}>
        Referenzwerte (bis {MAX_KPI} gesamt inkl. KF% und Ø-Kalorien). Fehlende Typen werden automatisch weggelassen.
      </p>
      <div className="ref-value-tiles-grid">{tiles}</div>
    </div>
  )
}