// SPDX-FileCopyrightText: 2024 LiveKit, Inc.
//
// SPDX-License-Identifier: Apache-2.0

/** convert bigints to numbers preserving undefined values */
export function bigIntToNumber<T extends bigint | undefined>(
  value: T,
): T extends bigint ? number : undefined {
  return (value !== undefined ? Number(value) : undefined) as T extends bigint ? number : undefined;
}

/** convert numbers to bigints preserving undefined values */
export function numberToBigInt<T extends number | undefined>(
  value: T,
): T extends number ? bigint : undefined {
  return (value !== undefined ? BigInt(value) : undefined) as T extends number ? bigint : undefined;
}

export function splitUtf8(s: string, n: number): Uint8Array[] {
  if (n < 4) {
    throw new Error('n must be at least 4 due to utf8 encoding rules');
  }
  // adapted from https://stackoverflow.com/a/6043797
  const result: Uint8Array[] = [];
  let encoded = new TextEncoder().encode(s);
  while (encoded.length > n) {
    let k = n;
    while (k > 0) {
      const byte = encoded[k];
      if (byte !== undefined && (byte & 0xc0) !== 0x80) {
        break;
      }
      k--;
    }
    result.push(encoded.slice(0, k));
    encoded = encoded.slice(k);
  }
  if (encoded.length > 0) {
    result.push(encoded);
  }
  return result;
}