// Cold Spot Detector / Atmospheric Disturbance Index — the per-device
// visual layer over lib/coldSpot.ts's pure classifiers. DevicesPage.tsx
// owns and updates the rolling-baseline state as `reading` frames arrive
// (mirrors GhostLog.tsx owning tell history and handing the *result* of
// computeEvilMeter down to its gauge); this component is purely
// presentational — given a device's current temperature/pressure readouts
// (or null, if that sensor_type has never reported), it renders the
// frost/ripple treatments, callouts, sparkline and composite gauge, and
// renders nothing for a sensor that has never reported. A device with
// neither sensor renders nothing at all.

import { useId } from 'react'
import { useTranslation } from 'react-i18next'
import { disturbanceIndex, disturbanceLabel } from '../lib/coldSpot'
import './ColdSpotPanel.css'

export type TemperatureReadout = {
  value: number
  unit: string
  deviation: number | null
  isColdSpot: boolean
  severity: number
}

export type PressureReadout = {
  value: number
  unit: string
  deviation: number | null
  isPressureAnomaly: boolean
  severity: number
  direction: 'rise' | 'drop'
}

type ColdSpotPanelProps = {
  temperature: TemperatureReadout | null
  pressure: PressureReadout | null
  /** Recent temperature samples, oldest first — see lib/coldSpot.ts's
   * pushSample/SPARKLINE_SAMPLE_CAP. */
  tempSparkline: readonly number[]
}

function clamp01(n: number): number {
  return Math.min(1, Math.max(0, n))
}

export function ColdSpotPanel({ temperature, pressure, tempSparkline }: ColdSpotPanelProps) {
  if (!temperature && !pressure) return null

  const bothReported = temperature !== null && pressure !== null

  return (
    <div className="coldspot-panel" data-testid="coldspot-panel">
      {temperature && <TemperatureReadoutRow readout={temperature} sparkline={tempSparkline} />}
      {pressure && <PressureReadoutRow readout={pressure} />}
      {bothReported && (
        <DisturbanceGauge
          index={disturbanceIndex(temperature!.severity, pressure!.severity)}
          correlated={temperature!.isColdSpot && pressure!.isPressureAnomaly}
        />
      )}
    </div>
  )
}

export default ColdSpotPanel

// ---- temperature: frost treatment + sparkline ----

function Sparkline({ samples, width = 96, height = 22 }: { samples: readonly number[]; width?: number; height?: number }) {
  if (samples.length === 0) return null
  let points: string
  if (samples.length === 1) {
    points = `0,${height / 2} ${width},${height / 2}`
  } else {
    const min = Math.min(...samples)
    const max = Math.max(...samples)
    const range = max - min || 1 // avoid a degenerate 0-range when every sample is equal
    const stepX = width / (samples.length - 1)
    points = samples
      .map((v, i) => {
        const x = i * stepX
        const norm = (v - min) / range
        const y = height - norm * height
        return `${x.toFixed(2)},${y.toFixed(2)}`
      })
      .join(' ')
  }
  return (
    <svg
      className="coldspot-sparkline"
      viewBox={`0 0 ${width} ${height}`}
      preserveAspectRatio="none"
      aria-hidden="true"
    >
      <polyline points={points} className="coldspot-sparkline-line" />
    </svg>
  )
}

function TemperatureReadoutRow({
  readout,
  sparkline,
}: {
  readout: TemperatureReadout
  sparkline: readonly number[]
}) {
  const { t } = useTranslation()
  const { value, unit, deviation, isColdSpot } = readout

  return (
    <div className={`sensor-row coldspot-temp-row${isColdSpot ? ' is-cold-spot' : ''}`}>
      <div className="coldspot-row-main">
        <span className="sensor-type">
          {isColdSpot && (
            <span className="coldspot-frost-glyph" aria-hidden="true">
              ❄
            </span>
          )}
          temperature
        </span>
        <span className="sensor-value flicker-soft">
          {Number(value.toFixed(3))} <span className="sensor-unit">{unit}</span>
        </span>
      </div>
      <Sparkline samples={sparkline} />
      {isColdSpot && deviation !== null && (
        <p className="coldspot-callout" data-testid="cold-spot-callout" role="status">
          {t('devices.dashboard.coldSpot.callout', {
            deviation: Math.abs(deviation).toFixed(1),
            unit,
            defaultValue: 'COLD SPOT — {{deviation}} {{unit}} below baseline',
          })}
        </p>
      )}
    </div>
  )
}

// ---- pressure: ripple treatment ----

function PressureReadoutRow({ readout }: { readout: PressureReadout }) {
  const { t } = useTranslation()
  const { value, unit, deviation, isPressureAnomaly } = readout

  return (
    <div className={`sensor-row coldspot-pressure-row${isPressureAnomaly ? ' is-pressure-anomaly' : ''}`}>
      <div className="coldspot-row-main">
        <span className="sensor-type">
          {isPressureAnomaly && (
            <span className="coldspot-ripple-glyph" aria-hidden="true">
              ◎
            </span>
          )}
          pressure
        </span>
        <span className="sensor-value flicker-soft">
          {Number(value.toFixed(3))} <span className="sensor-unit">{unit}</span>
        </span>
      </div>
      {isPressureAnomaly && deviation !== null && (
        <p className="coldspot-callout" data-testid="pressure-anomaly-callout" role="status">
          {t('devices.dashboard.pressureAnomaly.callout', {
            magnitude: Math.abs(deviation).toFixed(1),
            unit,
            defaultValue: 'PRESSURE ANOMALY — {{magnitude}} {{unit}} swing, atmosphere shifting',
          })}
        </p>
      )}
    </div>
  )
}

// ---- composite: Atmospheric Disturbance Index, a crescent arc gauge ----
// (structurally the same polar-arc technique as GhostLog.tsx's evil-meter
// gauge — a family resemblance for the "hacker witch" visual language —
// but a single filled sweep rather than a belief band, since there's no
// uncertainty-spread concept here, just one 0..100 score.)

const CX = 50
const CY = 44
const R = 32
const BAND_THICKNESS = 10

function angleForValue(v: number): number {
  return 180 - clamp01(v) * 180
}

function polar(radius: number, angleDeg: number): { x: number; y: number } {
  const rad = (angleDeg * Math.PI) / 180
  return { x: CX + radius * Math.cos(rad), y: CY - radius * Math.sin(rad) }
}

function DisturbanceGauge({ index, correlated }: { index: number; correlated: boolean }) {
  const { t } = useTranslation()
  const gaugeId = useId()
  const label = disturbanceLabel(index, correlated)
  const value = clamp01(index / 100)

  const outerR = R + BAND_THICKNESS / 2
  const innerR = R - BAND_THICKNESS / 2
  const startAngle = 180
  const endAngle = angleForValue(value)

  const outerStart = polar(outerR, startAngle)
  const outerEnd = polar(outerR, endAngle)
  const innerEnd = polar(innerR, endAngle)
  const innerStart = polar(innerR, startAngle)

  const bandPath = [
    `M ${outerStart.x} ${outerStart.y}`,
    `A ${outerR} ${outerR} 0 0 1 ${outerEnd.x} ${outerEnd.y}`,
    `L ${innerEnd.x} ${innerEnd.y}`,
    `A ${innerR} ${innerR} 0 0 0 ${innerStart.x} ${innerStart.y}`,
    'Z',
  ].join(' ')

  const trackStart = polar(R, 180)
  const trackEnd = polar(R, 0)
  const trackPath = `M ${trackStart.x} ${trackStart.y} A ${R} ${R} 0 0 1 ${trackEnd.x} ${trackEnd.y}`

  const bucketClass = correlated && index >= 40 ? 'converging' : index >= 70 ? 'severe' : index >= 40 ? 'rising' : index >= 15 ? 'faint' : 'calm'

  return (
    <div
      className={`disturbance-gauge disturbance-gauge--${bucketClass}`}
      data-testid="disturbance-gauge"
    >
      <p className="coldspot-section-title">
        {t('devices.dashboard.disturbance.title', {
          defaultValue: 'ATMOSPHERIC DISTURBANCE',
        })}
      </p>
      <svg
        viewBox="0 0 100 50"
        className="disturbance-gauge-svg"
        role="meter"
        aria-label={t('devices.dashboard.disturbance.ariaLabel', {
          defaultValue: 'atmospheric disturbance index',
        })}
        aria-valuemin={0}
        aria-valuemax={100}
        aria-valuenow={index}
        aria-valuetext={label}
      >
        <defs>
          <linearGradient id={gaugeId} x1="0%" y1="0%" x2="100%" y2="0%">
            <stop offset="0%" className="disturbance-gauge-stop-start" />
            <stop offset="100%" className="disturbance-gauge-stop-end" />
          </linearGradient>
        </defs>
        <path d={trackPath} className="disturbance-gauge-track" />
        <path d={bandPath} fill={`url(#${gaugeId})`} className="disturbance-gauge-band" />
      </svg>
      <div className="disturbance-gauge-readout">
        <span className="disturbance-gauge-index">{index}</span>
        <span className="disturbance-gauge-label">{label}</span>
      </div>
    </div>
  )
}