"use strict";

var max = Math.max,
    min = Math.min;

module.exports.install = function() {
  // Public: Monkey-patches Number to have Rails-like //seconds() function.
  // Warning, due to the way the Javascript parser works, applying functions on
  // numbers is kind of weird. See examples for details.
  //
  // Examples
  //
  //   2.seconds()
  //   //=> SyntaxError: Unexpected token ILLEGAL
  //
  //   10..seconds()
  //   //=> 10000
  //
  //   (5).seconds()
  //   //=> 5000
  //   // This is the preferred way to represent numbers when calling these
  //   // methods on them
  //
  // Returns an integer representing time in milliseconds

  /**
   * Multiplies a number by 1000 to get time in milliseconds
   *
   * @example
   * (2).seconds(); //=> 2000
   * @return {Number} time in milliseconds
   */
  Number.prototype.seconds = function() {
    return this * 1000;
  };

  /**
   * Alias for Number.prototype.seconds
   *
   * @see Number.prototype.seconds
   * @example
   * (1).second(); //=> 1000
   * @return {Number} time in milliseconds
   */
  Number.prototype.second = Number.prototype.seconds;

  /**
   * Converts a number from a current scale to a 0 - 1 scale.
   *
   * @param {Number} start low point of scale to convert from
   * @param {Number} end high point of scale to convert from
   * @example
   * (5).fromScale(0, 10) //=> 0.5
   * @return {Number} the scaled value
   */
  Number.prototype.fromScale = function(start, end) {
    var val = (this - min(start, end)) / (max(start, end) - min(start, end));

    if (val > 1) {
      return 1;
    }

    if (val < 0){
      return 0;
    }

    return val;
  };

  /**
   * Converts a number from a 0 - 1 scale to the specified scale.
   *
   * @param {Number} start low point of scale to convert to
   * @param {Number} end high point of scale to convert to
   * @example
   * (0.5).toScale(0, 10) //=> 5
   * @return {Number} the scaled value
   */
  Number.prototype.toScale = function(start, end) {
    var i = this * (max(start, end) - min(start, end)) + min(start, end);

    if (i < start) {
      return start;
    }

    if (i > end) {
      return end;
    }

    return i;
  };
};