// Foundation for Sites by ZURB
// foundation.zurb.com
// Licensed under MIT Open Source

////
/// @group functions
////

/// Determine if a value is not falsey, in CSS terms. Falsey values are `null`, `none`, `0` with any unit, or an empty list.
///
/// @param {Mixed} $val - Value to check.
///
/// @returns {Boolean} `true` if `$val` is not falsey.
@function has-value($val) {
  @if $val == null or $val == none {
    @return false;
  }
  @if type-of($val) == 'number' and strip-unit($val) == 0 {
    @return false;
  }
  @if type-of($val) == 'list' and length($val) == 0 {
    @return false;
  }
  @return true;
}

/// Determine a top/right/bottom/right value on a padding, margin, etc. property, no matter how many values were passed in. Use this function if you need to know the specific side of a value, but don't know if the value is using a shorthand format.
///
/// @param {List|Number} $val - Value to analyze. Should be a shorthand sizing property, e.g. "1em 2em 1em"
/// @param {Keyword} $side - Side to return. Should be `top`, `right`, `bottom`, or `left`.
///
/// @returns {Number} A single value based on `$val` and `$side`.
@function get-side($val, $side) {
  $length: length($val);

  @if $length == 1 {
    @return $val;
  }
  @if $length == 2 {
    @return map-get((
      top: nth($val, 1),
      bottom: nth($val, 1),
      left: nth($val, 2),
      right: nth($val, 2),
    ), $side);
  }
  @if $length == 3 {
    @return map-get((
      top: nth($val, 1),
      left: nth($val, 2),
      right: nth($val, 2),
      bottom: nth($val, 3),
    ), $side);
  }
  @if $length == 4 {
    @return map-get((
      top: nth($val, 1),
      right: nth($val, 2),
      bottom: nth($val, 3),
      left: nth($val, 4),
    ), $side);
  }
}

/// Given border $val, find a specific element of the border, which is $elem. The possible values for $elem are width, style, and color.
///
/// @param {List} $val - Border value to find a value in.
/// @param {Keyword} $elem - Border component to extract.
///
/// @returns {Mixed} If the value exists, returns the value. If the value is not in the border definition, the function will return a 0px width, solid style, or black border.
@function get-border-value($val, $elem) {
  // Find the width, style, or color and return it
  @each $v in $val {
    $type: type-of($v);
    @if $elem == width and $type == 'number' {
      @return $v;
    }
    @if $elem == style and $type == 'string' {
      @return $v;
    }
    @if $elem == color and $type == 'color' {
      @return $v;
    }
  }

  // Defaults
  $defaults: (
    width: 0,
    style: solid,
    color: #000,
  );
  @return map-get($defaults, $elem);
}

/// Calculates x^y, where x is `$base` and y is `$power`.
/// @access private
///
/// @param {Number} $base - Base number (x).
/// @param {Number} $power - Exponent (y).
@function pow($base, $power) {
  @if $power == 0 { @return 1; }
  @return $base * pow($base, $power - 1);
}

// TODO: Remove this (it's used by the grid but is overkill)
/// Given a user-defined list of keywords and a list of possible keywords, find the ones that were passed in.
/// @access private
///
/// @param {List} $opts - List of values to find keywords in.
/// @param {List} $seeking - List of all possible keywords.
///
/// @returns {Map} A map of all keywords in $seeking. If a keyword was found in $opts, its value is true, otherwise false.
@function -zf-get-options($opts, $seeking) {
  @if type-of($opts) != 'list' {
    $opts: ($opts);
  }

  $map: ();
  @each $keyword in $seeking {
    $val: if(index($opts, $keyword) != null, true, false);
    $item: ($keyword: $val);
    $map: map-merge($map, $item);
  }

  @return $map;
}