import BN from "bn.js";

/**
 * WAD Arithmetic Module
 *
 * Fixed-point arithmetic with 10^18 precision.
 * All functions operate on BN values to avoid JavaScript's 53-bit limitation.
 */

/**
 * Convert lamports (9 decimals) to WAD format (18 decimals)
 */
export function toWad(lamports: BN): BN {
  return lamports.mul(new BN(1_000_000_000));
}

/**
 * Convert WAD to lamports (floor rounding)
 */
export function fromWadFloor(wad: BN): BN {
  return wad.div(new BN(1_000_000_000));
}

/**
 * Convert WAD to lamports (ceiling rounding)
 */
export function fromWadCeil(wad: BN): BN {
  const divisor = new BN(1_000_000_000);
  return wad.add(divisor.sub(new BN(1))).div(divisor);
}

/**
 * Multiply two WAD values: (a * b) / WAD
 */
export function multiplyWad(a: BN, b: BN): BN {
  const WAD = new BN("1000000000000000000");
  return a.mul(b).div(WAD);
}

/**
 * Divide two WAD values: (a * WAD) / b
 */
export function divideWad(a: BN, b: BN): BN {
  const WAD = new BN("1000000000000000000");
  return a.mul(WAD).div(b);
}