brk/website_next/explore/block/fee-rates.js

export const FEE_RATE_PERCENTILES = /** @type {const} */ ([
  0,
  10,
  25,
  50,
  75,
  90,
  100,
]);

export const FEE_RATE_STOPS = /** @type {const} */ ([
  { label: "min", color: "var(--emerald)" },
  { label: "10%", color: "var(--green)" },
  { label: "25%", color: "var(--lime)" },
  { label: "50%", color: "var(--yellow)" },
  { label: "75%", color: "var(--amber)" },
  { label: "90%", color: "var(--orange)" },
  { label: "max", color: "var(--red)" },
]);

/**
 * @param {number[]} values
 * @param {number} percentile
 */
function percentileValue(values, percentile) {
  return values[Math.round((percentile / 100) * (values.length - 1))];
}

/** @param {number[]} feeRates */
export function createFeeRateRange(feeRates) {
  const values = feeRates.toSorted((a, b) => a - b);

  return FEE_RATE_PERCENTILES.map((percentile) => {
    return percentileValue(values, percentile);
  });
}

/**
 * @param {number} index
 * @param {number} count
 */
export function getFeeRateStopByRank(index, count) {
  const percentile = count === 1 ? 100 : 100 - (index / (count - 1)) * 100;

  for (let stopIndex = 0; stopIndex < FEE_RATE_PERCENTILES.length; stopIndex += 1) {
    if (percentile <= FEE_RATE_PERCENTILES[stopIndex]) {
      return FEE_RATE_STOPS[stopIndex];
    }
  }

  return FEE_RATE_STOPS[FEE_RATE_STOPS.length - 1];
}

/**
 * @param {number} feeRate
 * @param {number[]} ranges
 */
export function getFeeRateStop(feeRate, ranges) {
  for (let index = 0; index < ranges.length; index += 1) {
    if (feeRate <= ranges[index]) return FEE_RATE_STOPS[index];
  }

  return FEE_RATE_STOPS[FEE_RATE_STOPS.length - 1];
}

/**
 * @param {number} feeRate
 * @param {number[]} ranges
 */
export function getFeeRateColor(feeRate, ranges) {
  if (feeRate <= ranges[0]) return FEE_RATE_STOPS[0].color;

  for (let index = 1; index < ranges.length; index += 1) {
    if (feeRate > ranges[index]) continue;

    const previousRate = ranges[index - 1];
    const nextRate = ranges[index];
    const span = nextRate - previousRate;
    const ratio = span ? (feeRate - previousRate) / span : 0;
    const previousShare = ((1 - ratio) * 100).toFixed(2);
    const nextShare = (ratio * 100).toFixed(2);

    return `color-mix(in oklch, ${FEE_RATE_STOPS[index - 1].color} ${previousShare}%, ${FEE_RATE_STOPS[index].color} ${nextShare}%)`;
  }

  return FEE_RATE_STOPS[FEE_RATE_STOPS.length - 1].color;
}