export function formatValue(value: number): string {
  if (Math.abs(value) >= 1_000_000) return `${(value / 1_000_000).toFixed(1)}M`;
  if (Math.abs(value) >= 1_000) return `${(value / 1_000).toFixed(1)}k`;
  if (Number.isInteger(value)) return value.toLocaleString();
  return value.toFixed(1);
}

export function formatFilterValue(value: number): string {
  if (Math.abs(value) >= 1_000_000) return `${(value / 1_000_000).toFixed(1)}M`;
  if (Math.abs(value) >= 1_000) return `${(value / 1_000).toFixed(1)}k`;
  if (Number.isInteger(value)) return value.toString();
  return value.toFixed(2);
}

export function formatDuration(d: string): string {
  if (d === 'F') return 'Freehold';
  if (d === 'L') return 'Leasehold';
  return d;
}

export function formatAge(value: number, approximate = true): string {
  if (value >= 1000) return approximate ? `~${Math.round(value)}` : `${Math.round(value)}`;
  return Math.round(value).toString();
}

// Format number with optional decimals, used in PropertyCard
export function formatNumber(value: number | undefined, decimals = 0): string {
  if (value === undefined) return '';
  return decimals > 0 ? value.toFixed(decimals) : Math.round(value).toLocaleString();
}

// Calculate weighted mean from histogram
export function calculateHistogramMean(histogram: {
  min: number;
  bin_width: number;
  counts: number[];
}): number | undefined {
  if (!histogram.counts.length) return undefined;
  const totalCount = histogram.counts.reduce((a, b) => a + b, 0);
  if (totalCount === 0) return undefined;

  let weightedSum = 0;
  for (let i = 0; i < histogram.counts.length; i++) {
    const binCenter = histogram.min + (i + 0.5) * histogram.bin_width;
    weightedSum += binCenter * histogram.counts[i];
  }
  return weightedSum / totalCount;
}