import assertionWrapper from './assertion-wrapper.js'

const NEAR_ZERO = 5e-6 // 0.000005, Firefox fails at higher levels of precision.

/**
 * Checks that the supplied values are equal with a high though not absolute degree of precision.
 * @param {Float} actual
 * @param {Float} expected
 * @param {string} message
 * @returns {void}
 */
function almostEquals (actual, expected, message) {
  message = message || (actual + ' did not equal ' + expected)
  const result = Math.abs(actual - expected) < NEAR_ZERO
  return { result, message, actual, expected }
}

/**
 * @param {external:chai} _chai
 * @param {external:chai_utils} utils
 * @returns {void}
 */
function setAssertionMethods (_chai, utils) {
  const wrap = assertionWrapper(_chai, utils)

  assert.almostEquals = wrap(almostEquals)
}

export default setAssertionMethods