Function computeLineChartAnalysis

app/utils/charts.ts:176–413

(values: Array<number | null>)

 * @returns LineChartAnalysis object with statistics and qualitative interpretation
 */
export function computeLineChartAnalysis(values: Array<number | null>): LineChartAnalysis {
  const indexedValues: Array<{ value: number; index: number }> = []

  for (let i = 0; i < values.length; i += 1) {
    const v = values[i]
    if (v === null || v === undefined) continue
    indexedValues.push({ value: v, index: i })
  }

  const n = indexedValues.length

  if (n === 0) {
    return {
      mean: 0,
      standardDeviation: 0,
      coefficientOfVariation: null,
      slope: 0,
      rSquared: null,
      interpretation: {
        volatility: 'undefined',
        trend: 'undefined',
      },
    }
  }

  if (n === 1) {
    const onlyValue = indexedValues[0]?.value ?? 0
    return {
      mean: onlyValue,
      standardDeviation: 0,
      coefficientOfVariation: null,
      slope: 0,
      rSquared: null,
      interpretation: {
        volatility: 'very_stable',
        trend: 'none',
      },
    }
  }

  let _sum = 0
  for (const entry of indexedValues) {
    _sum += entry.value
  }
  const mean = _sum / n

  let varianceSum = 0
  for (const entry of indexedValues) {
    const diff = entry.value - mean
    varianceSum += diff * diff
  }
  const standardDeviation = Math.sqrt(varianceSum / n)

  const coefficientOfVariation = mean === 0 ? null : standardDeviation / mean

  const originalYValues: number[] = []
  for (const entry of indexedValues) {
    originalYValues.push(entry.value)