//--------------------------------------------------------------------------------
// functions
@function compact($vars...) {
  $separator: list-separator($vars);
  $list: ();
  @each $var in $vars {
    @if $var {
      $list: append($list, $var, $separator);
    }
  }
  @return $list;
}

@function first-value-of($list) {
  @return nth($list, 1);
}

@function -compass-space-list($item1, $item2:null, $item3:null, $item4:null, $item5:null, $item6:null, $item7:null, $item8:null, $item9:null) {
  $items: ();
  // Support for polymorphism.
  @if type-of($item1) == 'list' {
    // Passing a single array of properties.
    $items: $item1;
  } @else {
    $items: $item1 $item2 $item3 $item4 $item5 $item6 $item7 $item8 $item9;
  }

  $full: first-value-of($items);

  @for $i from 2 through length($items) {
    $item: nth($items, $i);
    @if $item != null {
      $full: $full $item;
    }
  }

  @return $full;
}

@function -compass-list-size($list) {
  @return length($list);
}

@function prefixed($prefix, $property1, $property2:null, $property3:null, $property4:null, $property5:null, $property6:null, $property7:null, $property8:null, $property9:null) {
  $properties: $property1, $property2, $property3, $property4, $property5, $property6, $property7, $property8, $property9;
  $prefixed: false;
  @each $item in $properties {
    @if type-of($item) == 'string' {
      $prefixed: $prefixed or str-index($item, 'url') != 1 and str-index($item, 'rgb') != 1 and str-index($item, '#') != 1;
    } @elseif type-of($item) == 'color' {
    } @elseif $item != null {
      $prefixed: true;
    }
  }
  @return $prefixed;
}

@function prefix($prefix, $property1, $property2:null, $property3:null, $property4:null, $property5:null, $property6:null, $property7:null, $property8:null, $property9:null) {
  $properties: "";

  // Support for polymorphism.
  @if type-of($property1) == 'list' {
    // Passing a single array of properties.
    $properties: $property1;
  } @else {
    // Passing multiple properties.
    $properties: $property1, $property2, $property3, $property4, $property5, $property6, $property7, $property8, $property9;
  }

  $props: false;
  @each $item in $properties {
    @if $item == null {}
    @else {
      @if prefixed($prefix, $item) {
        $item: #{$prefix}-#{$item};
      }
      @if $props {
        $props: $props, $item;
      }
      @else {
        $props: $item;
      }
    }
  }
  @return $props;
}

@function -svg($property1, $property2:null, $property3:null, $property4:null, $property5:null, $property6:null, $property7:null, $property8:null, $property9:null) {
  @return prefix('-svg', $property1, $property2, $property3, $property4, $property5, $property6, $property7, $property8, $property9);
}

@function -owg($property1, $property2:null, $property3:null, $property4:null, $property5:null, $property6:null, $property7:null, $property8:null, $property9:null) {
  @return prefix('-owg', $property1, $property2, $property3, $property4, $property5, $property6, $property7, $property8, $property9);
}

@function -webkit($property1, $property2:null, $property3:null, $property4:null, $property5:null, $property6:null, $property7:null, $property8:null, $property9:null) {
  @return prefix('-webkit', $property1, $property2, $property3, $property4, $property5, $property6, $property7, $property8, $property9);
}

@function -moz($property1, $property2:null, $property3:null, $property4:null, $property5:null, $property6:null, $property7:null, $property8:null, $property9:null) {
  @return prefix('-moz', $property1, $property2, $property3, $property4, $property5, $property6, $property7, $property8, $property9);
}

@function -o($property1, $property2:null, $property3:null, $property4:null, $property5:null, $property6:null, $property7:null, $property8:null, $property9:null) {
  @return prefix('-o', $property1, $property2, $property3, $property4, $property5, $property6, $property7, $property8, $property9);
}

@function -pie($property1, $property2:null, $property3:null, $property4:null, $property5:null, $property6:null, $property7:null, $property8:null, $property9:null) {
  @return prefix('-pie', $property1, $property2, $property3, $property4, $property5, $property6, $property7, $property8, $property9);
}

//--------------------------------------------------------------------------------
// mix-ins
$experimental-support-for-mozilla: true !default;
$experimental-support-for-webkit: true !default;
$support-for-original-webkit-gradients: true !default;
$experimental-support-for-opera: true !default;
$experimental-support-for-microsoft: true !default;
$experimental-support-for-khtml: false !default;
$experimental-support-for-svg: false !default;
$experimental-support-for-pie: false !default;

@mixin experimental($property, $value,
  $moz      : $experimental-support-for-mozilla,
  $webkit   : $experimental-support-for-webkit,
  $o        : $experimental-support-for-opera,
  $ms       : $experimental-support-for-microsoft,
  $khtml    : $experimental-support-for-khtml,
  $official : true
) {
  @if $webkit  and $experimental-support-for-webkit    { -webkit-#{$property} : $value; }
  @if $khtml   and $experimental-support-for-khtml     {  -khtml-#{$property} : $value; }
  @if $moz     and $experimental-support-for-mozilla   {    -moz-#{$property} : $value; }
  @if $ms      and $experimental-support-for-microsoft {     -ms-#{$property} : $value; }
  @if $o       and $experimental-support-for-opera     {      -o-#{$property} : $value; }
  @if $official                                        {         #{$property} : $value; }
}

//--------------------------------------------------------------------------------
// box-shadow
$_zm-default-box-shadow-color: #333333 !default;
$_zm-default-box-shadow-h-offset: 0px !default;
$_zm-default-box-shadow-v-offset: 0px !default;
$_zm-default-box-shadow-blur: 5px !default;
$_zm-default-box-shadow-spread : false !default;
$_zm-default-box-shadow-inset : false !default;

@mixin _zm-box-shadow(
  $shadow-1 : default,
  $shadow-2 : false,
  $shadow-3 : false,
  $shadow-4 : false,
  $shadow-5 : false,
  $shadow-6 : false,
  $shadow-7 : false,
  $shadow-8 : false,
  $shadow-9 : false,
  $shadow-10: false
) {
  @if $shadow-1 == default {
    $shadow-1 : -compass-space-list(compact(if($_zm-default-box-shadow-inset, inset, false), $_zm-default-box-shadow-h-offset, $_zm-default-box-shadow-v-offset, $_zm-default-box-shadow-blur, $_zm-default-box-shadow-spread, $_zm-default-box-shadow-color));
  }
  $shadow : compact($shadow-1, $shadow-2, $shadow-3, $shadow-4, $shadow-5, $shadow-6, $shadow-7, $shadow-8, $shadow-9, $shadow-10);
  @include experimental(box-shadow, $shadow,
          -moz, -webkit, not(-o), not(-ms), not(-khtml), official
  );
}

//--------------------------------------------------------------------------------
// images
@mixin _zm-background-image(
  $image-1,
  $image-2: false,
  $image-3: false,
  $image-4: false,
  $image-5: false,
  $image-6: false,
  $image-7: false,
  $image-8: false,
  $image-9: false,
  $image-10: false
) {
  $images: compact($image-1, $image-2, $image-3, $image-4, $image-5, $image-6, $image-7, $image-8, $image-9, $image-10);
  $add-pie-bg: prefixed(-pie,   $images) or -compass-list-size($images) > 1;

  @if $experimental-support-for-svg          and prefixed(-svg,    $images) { background-image:    -svg($images); background-size: 100%; }
  @if $support-for-original-webkit-gradients and prefixed(-owg,    $images) { background-image:    -owg($images); }
  @if $experimental-support-for-webkit       and prefixed(-webkit, $images) { background-image: -webkit($images); }
  @if $experimental-support-for-mozilla      and prefixed(-moz,    $images) { background-image:    -moz($images); }
  @if $experimental-support-for-opera        and prefixed(-o,      $images) { background-image:      -o($images); }
  @if $experimental-support-for-pie          and $add-pie-bg                { @warn "PIE does not support background-image. Use @include background(#{$images}) instead." }
  background-image:         $images ;
}

//--------------------------------------------------------------------------------
// Cheat lines
@mixin zurui-line-top($op1:.2,$op2:.3) {
  @include _zm-box-shadow(rgba(255, 255, 255, $op2) 0 1px 0 inset);
  border-top: 1px solid rgba(0, 0, 0, $op1);
}

@mixin zurui-line-left($op1:.2,$op2:.3) {
  @include _zm-box-shadow(rgba(255, 255, 255, $op2) -1px 0 0);
  border-left: 1px solid rgba(0, 0, 0, $op1);
}

@mixin zurui-line-right($op1:.2,$op2:.3) {
  @include _zm-box-shadow(rgba(255, 255, 255, $op2) -1px 0 0 inset);
  border-right: 1px solid rgba(0, 0, 0, $op1);
}

@mixin zurui-line-bottom($op1:.2,$op2:.3) {
  @include _zm-box-shadow(rgba(255, 255, 255, $op2) 0 1px 0);
  border-bottom: 1px solid rgba(0, 0, 0, $op1);
}

//--------------------------------------------------------------------------------
// Cheat font shadows
@mixin zurui-ts-000($op:.4) {
  text-shadow: 1px -1px rgba(0, 0, 0, $op);
}

@mixin zurui-ts-fff($op:.7) {
  text-shadow: -1px 1px rgba(255, 255, 255, $op);
}

//--------------------------------------------------------------------------------
// Cheat gradation
@mixin zurui-gradient-top-lighten($color:#666, $lighten:10%) {
  @include _zm-background-image(linear-gradient(lighten($color, $lighten) 0%, $color 100%));
  background-color: $color;
}

@mixin zurui-gradient-top-darken($color:#666, $darken:10%) {
  @include _zm-background-image(linear-gradient(darken($color, $darken) 0%, $color 100%));
  background-color: $color;
}

//--------------------------------------------------------------------------------
// Cheat box shadow
@mixin zurui-box-outer($op1:2px) {
  @include _zm-box-shadow(rgba(0, 0, 0, .15) 0 0 $op1);
}

@mixin zurui-box-inner($op1:20px) {
  @include _zm-box-shadow(rgba(0, 0, 0, .2) 0 0 $op1 inset);
}

@mixin zurui-box-deboss($border:.1, $shadow:.1, $highlight:1) {
  @include _zm-box-shadow(rgba(0, 0, 0, $shadow) -1px 1px 2px inset, rgba(255, 255, 255, $highlight) -1px 1px 0);
  border: 1px solid rgba(0, 0, 0, $border);
}

@mixin zurui-box-emboss($border:.15, $shadow:.05, $highlight:1) {
  @include _zm-box-shadow(rgba(0, 0, 0, $shadow) -1px 1px 0, rgba(255, 255, 255, $highlight) -1px 1px 0 inset);
  border: 1px solid rgba(0, 0, 0, $border);
}