// @category  utilities/targeting

@function _isLegacySupported($vendor, $comparator, $version) {
  // we currently only check for legacy IE support
  @if $vendor != ie { @return true; }
  $compass-not-legacy-ie-version: 9; // the version if IE that Compass starts considering `legacy`
  $min-ie-legacy-support: 999;
  @if($legacy-support-for-ie8) { $min-ie-legacy-support: 8; }
  @if($legacy-support-for-ie7) { $min-ie-legacy-support: 7; }
  @if($legacy-support-for-ie6) { $min-ie-legacy-support: 6; }
  @return ($version >= $min-ie-legacy-support);
}

// given a list of browsers and versions, this will consolidate them into a
// normalized list of targeted browsers
// @function  _getTargetedBrowsers
// @private
// @param     $browsers {List} the browsers/versions to target
// @param     $using {String} an optional string to append to the end of each item
// @param     $vendors {List} the list of supported vendors for class targeting
// @return    $list {List} the normalized list of targeted browsers
// @usage:
// _getTargetedBrowsers(ie) => (.ie)
// _getTargetedBrowsers(ie lte 7) => (.ie.lte7)
// _getTargetedBrowsers(ie 6 7) => (.ie.ie6, .ie.ie7)
// _getTargetedBrowsers(ie 10 lt 9) => (.ie.ie10, .ie.lte8)
// _getTargetedBrowsers(ie 6, $using: '&') => (.ie.ie6&) // e.g. for merging with other selectors
@function _getTargetedBrowsers($browsers, $using: '', $vendors: $CONFIG_BROWSER_VENDORS_CLASS) {
  $browsers: -compass-list($browsers);
  $vendors: -compass-list($vendors);
  $comparators: (eq lt lte);
  $comparator: false;
  $vendor: false;
  $list: ();
  $unversioned: ();
  $version-adjust: 0;
  @each $item in $browsers {
    // if it's a comparator, update it
    @if(index($comparators, $item)) {
      // since we don't support, lt on class names, we augment the version number and use lte
      @if($item == lt) {
        $version-adjust: -1;
        $item: lte;
      }
      $comparator: $item;
    }
    // otherwise check if it's a browser vendor
    @else if(index(-compass-list($vendors), $item)) {
      $vendor: $item;
      // keep track of unversioned vendors
      $unversioned: append($unversioned, unquote('.#{$vendor}#{$using}'), comma);
    }
    // otherwise assume it's a version
    @else if(type-of($item) == number) {
      $unversioned: list-remove($unversioned, index($unversioned, '.#{$vendor}#{$using}'));
      $tmp: $item;
      // if it's equalitative, prefix the vendor onto the version
      @if(not $comparator or $comparator == eq) {
        $item: #{$vendor}#{$item};
      }
      // otherwise use the comparator as the prefix
      @else {
        $item: #{$comparator}#{($item + $version-adjust)};
      }
      @if($vendor and _isLegacySupported($vendor, $comparator, $tmp)) {
        $item: '.#{$vendor}.#{$item}#{$using}';
        $list: append($list, unquote($item), comma);
      }
      // restore temps
      $version-adjust: 0;
      $comparator: false;
    }
  }
  // take any unused vendors and stick them back onto the list
  @if(length($unversioned) > 0) {
    $list: join($list, $unversioned, comma);
  }
  @return $list;
}

// mixin to target a specific browser using either class names or hacks
// @mixin     target-browser
// @param     $browsers {List} the List of browsers to target
// @param     $property {String} the CSS property
// @param     $value {*} the CSS value
// @param     $merge {Bool} should the class name be merged e.g. `.ie8.example` vs `.ie8 .example`
// @param     $inline {Bool} if set to false, don't use inline hacks even if available
// @usage:
// =target-browser(ie 8, border, 10px);
// =target-browser(ie lte 7, padding, 0);
@mixin target-browser($browsers, $property: nil, $value: nil, $merge: false, $inline: true) {
  @if($CONFIG_BROWSER_ALLOW_HACKS) {
    // target webkit, Safari3+, Chrome1+
    @if(index2($browsers, associative($CONFIG_BROWSER_VENDORS_HACK, webkit-all) )) {
      @if $CONFIG_BROWSER_WARN_ON_HACK {
        @warn "using hack for webkit-all";
      }
      // @link http://paulirish.com/2009/browser-specific-css-hacks/
      @media screen and (-webkit-min-device-pixel-ratio:0) {
        & {
          @include debug-message("[archetype:target-browser:begin] --- webkit ---");
          @include output-style($property, $value);
          @if archetype-version('sass >= 3.2') {
            @content;
          }
          @include debug-message("[archetype:target-browser:end]   --- webkit ---");
        }
      }
    }
    // target gecko
    @if(index2($browsers, associative($CONFIG_BROWSER_VENDORS_HACK, gecko-all) )) {
      @if $CONFIG_BROWSER_WARN_ON_HACK {
        @warn "using hack for gecko-all";
      }
      // @link http://paulirish.com/2009/browser-specific-css-hacks/
      &, x:-moz-any-link {
        @include debug-message("[archetype:target-browser:begin] --- gecko ---");
        @include output-style($property, $value);
        @if archetype-version('sass >= 3.2') {
          @content;
        }
        @include debug-message("[archetype:target-browser:end]   --- gecko ---");
      }
    }
    // target opera
    @if(index2($browsers, associative($CONFIG_BROWSER_VENDORS_HACK, opera-all) )) {
      @if $CONFIG_BROWSER_WARN_ON_HACK {
        @warn "using hack for opera-all";
      }
      // @link http://paulirish.com/2009/browser-specific-css-hacks/
      &, x:-o-prefocus {
        @include debug-message("[archetype:target-browser:begin] --- opera ---");
        @include output-style($property, $value);
        @if archetype-version('sass >= 3.2') {
          @content;
        }
        @include debug-message("[archetype:target-browser:end]   --- opera ---");
      }
    }
    // if there's only one target browser and it's IE6 or IE lte 7, we can use an inline hack
    @if($inline) {
      $tmp: _getTargetedBrowsers($browsers);
      @if(length($tmp) == 1) {
        $support: ();
        @if($legacy-support-for-ie6) { $support: append($support, '.ie.ie6'); }
        @if($legacy-support-for-ie6 or $legacy-support-for-ie7) { $support: append($support, '.ie.lte7'); }
        $idx: index2($support, $tmp);
        @if($idx) {
          $prefix: nth(('_', '*'), $idx);
          $value: if(index($CORE_CSS_RTL_VALUE_SUPPORT, $property), rtl($value, $property), $value);
          // NOTE: RTL support on properties like `border-left-width` won't fully work until Compass/Sass support string replace methods
          @include debug-message("[archetype:target-browser:begin] --- #{$browsers} ---");
          @include output-style(#{$prefix}#{rtl($property)}, $value);
          @include debug-message("[archetype:target-browser:end]   --- #{$browsers} ---");
          $value: nil;
        }
      }
    }
  }
  // target via class names
  $classes: _getTargetedBrowsers($browsers, $using: if($merge, '&', ' &'));
  @if(length($classes) > 0) {
    #{$classes} {
      @include debug-message("[archetype:target-browser:begin] --- #{$browsers} ---");
      @include output-style($property, $value);
      @if archetype-version('sass >= 3.2') {
        @content;
      }
      @include debug-message("[archetype:target-browser:end]   --- #{$browsers} ---");
    }
  }
}

// target specific operating systems based on a class name
// @mixin     target-os
// @param     $os {List} the List of operating systems to target
// @param     $property {String} the CSS property
// @param     $value {*} the CSS value
// @param     $merge {Bool} should the class name be merged e.g. `.os-win.example` vs `.os-win .example`
@mixin target-os($os: (), $property: nil, $value: nil, $merge: false) {
  $os: -compass-list($os);
  $using: if($merge, '&', ' &');
  $classes: ();
  // if `default` is in the list of OS's, then output without a prefix
  @if(index($os, default)) {
    $classes: append($classes, unquote('&'), comma);
  }
  // step through the list of vendor OS's
  @each $vendor in $CONFIG_OS_VENDORS_CLASS {
    // if it matches the requested os
    @if index2(nth($vendor, 2), $os) {
      $item: unquote('.#{nth($vendor, 1)}#{$using}');
      // if it's not already on the stack, push it
      @if(not index($classes, $item)) {
        $classes: append($classes, $item, comma);
      }
    }
  }
  @if(length($classes) > 0) {
    #{$classes} {
      @include debug-message("[archetype:target-os:begin] --- #{$os} ---");
      @include output-style($property, $value);
      @if archetype-version('sass >= 3.2') {
        @content;
      }
      @include debug-message("[archetype:target-os:end]   --- #{$os} ---");
    }
  }
}