export function asNumber(value: string | number | null | undefined) {
  if (value === null || value === undefined) {
    return 0;
  }

  const parsed = typeof value === 'number' ? value : Number(value);
  return Number.isFinite(parsed) ? parsed : 0;
}

type NumberScale = {
  divisor: number;
  suffix: string;
};

const NUMBER_SCALES: NumberScale[] = [
  { divisor: 1, suffix: '' },
  { divisor: 1_000, suffix: 'K' },
  { divisor: 1_000_000, suffix: 'M' },
  { divisor: 1_000_000_000, suffix: 'B' }
];

type FormatScaledNumberOptions = {
  minimumFractionDigits?: number;
  maximumFractionDigits?: number;
};

export function formatScaledNumber(
  value: string | number | null | undefined,
  options: FormatScaledNumberOptions = {}
) {
  const {
    minimumFractionDigits = 0,
    maximumFractionDigits = 1
  } = options;

  const numeric = asNumber(value);
  const absolute = Math.abs(numeric);

  let scaleIndex = 0;
  if (absolute >= 1_000_000_000) {
    scaleIndex = 3;
  } else if (absolute >= 1_000_000) {
    scaleIndex = 2;
  } else if (absolute >= 1_000) {
    scaleIndex = 1;
  }

  let scaledAbsolute = absolute / NUMBER_SCALES[scaleIndex].divisor;

  if (
    Number(scaledAbsolute.toFixed(maximumFractionDigits)) >= 1_000
    && scaleIndex < NUMBER_SCALES.length - 1
  ) {
    scaleIndex += 1;
    scaledAbsolute = absolute / NUMBER_SCALES[scaleIndex].divisor;
  }

  const scaled = numeric < 0 ? -scaledAbsolute : scaledAbsolute;
  const formatted = new Intl.NumberFormat('en-US', {
    minimumFractionDigits,
    maximumFractionDigits
  }).format(scaled);

  return `${formatted}${NUMBER_SCALES[scaleIndex].suffix}`;
}

export function formatCurrency(value: string | number | null | undefined) {
  return new Intl.NumberFormat('en-US', {
    style: 'currency',
    currency: 'USD',
    maximumFractionDigits: 2
  }).format(asNumber(value));
}

export function formatPercent(value: string | number | null | undefined) {
  return `${asNumber(value).toFixed(2)}%`;
}

export function formatCompactCurrency(value: string | number | null | undefined) {
  return new Intl.NumberFormat('en-US', {
    style: 'currency',
    currency: 'USD',
    notation: 'compact',
    maximumFractionDigits: 2
  }).format(asNumber(value));
}