var binaryIndexBy = require('./binaryIndexBy'),
    identity = require('../utility/identity');

/** Used as references for the maximum length and index of an array. */
var MAX_ARRAY_LENGTH = Math.pow(2, 32) - 1,
    HALF_MAX_ARRAY_LENGTH = MAX_ARRAY_LENGTH >>> 1;

/**
 * Performs a binary search of `array` to determine the index at which `value`
 * should be inserted into `array` in order to maintain its sort order.
 *
 * @private
 * @param {Array} array The sorted array to inspect.
 * @param {*} value The value to evaluate.
 * @param {boolean} [retHighest] Specify returning the highest, instead
 *  of the lowest, index at which a value should be inserted into `array`.
 * @returns {number} Returns the index at which `value` should be inserted
 *  into `array`.
 */
function binaryIndex(array, value, retHighest) {
  var low = 0,
      high = array ? array.length : low;

  if (typeof value == 'number' && value === value && high <= HALF_MAX_ARRAY_LENGTH) {
    while (low < high) {
      var mid = (low + high) >>> 1,
          computed = array[mid];

      if (retHighest ? (computed <= value) : (computed < value)) {
        low = mid + 1;
      } else {
        high = mid;
      }
    }
    return high;
  }
  return binaryIndexBy(array, value, identity, retHighest);
}

module.exports = binaryIndex;
