////
/// @group BEM
///
/// @access public
////

/// 
/// Generate a new suffix.
///
/// @param {string} $name - Suffix name
///
/// @content
///
/// @throw If the element is not preceded by a block or modifier.
///
/// @example scss - Using a suffix
///   @include iro-bem-utility('hidden') {
///     display: none;
///     
///     @media (max-width: 320px) {
///       @include iro-bem-suffix('phone') {
///         display: none;
///       }
///     }
///     
///     @media (max-width: 768px) {
///       @include iro-bem-suffix('tablet') {
///         display: none;
///       }
///     }
///   }
///   
///   // Generates:
///   
///   .u-hidden {
///     display: none;
///   }
///   
///   @media (max-width: 320px) {
///     .u-hidden@phone {
///       display: none;
///     }
///   }
///   
///   @media (max-width: 768px) {
///     .u-hidden@tablet {
///       display: none;
///     }
///   }
///
@mixin iro-bem-suffix($name) {
    $result:   iro-bem-suffix($name);
    $selector: nth($result, 1);
    $context:  nth($result, 2);

    @include iro-bem-validate(
        'suffix',
        (name: $name),
        $selector,
        $context
    );

    @include iro-context-push($iro-bem-context-id, $context...);
    @at-root #{$selector} {
        @content;
    }
    @include iro-context-pop($iro-bem-context-id);
}

///
/// Generate a new suffix. Check the respective mixin documentation for more information.
/// 
/// @return {list} A list with two items: 1. selector, 2. context or `null`
///
/// @see {mixin} iro-bem-suffix
///
@function iro-bem-suffix($name) {
    //
    // Suffixes can be used on block, element and modifier.
    //

    $noop: iro-context-assert-stack-count($iro-bem-context-id, $iro-bem-max-depth);
    $noop: iro-context-assert-stack-must-contain($iro-bem-context-id, 'block');
    $noop: iro-context-assert-stack-must-not-contain($iro-bem-context-id, 'suffix');

    $parent-context:  iro-context-get($iro-bem-context-id, 'block' 'element' 'modifier');
    $parent-selector: map-get(nth($parent-context, 2), 'selector');

    @if not iro-selector-suffix-match(&, $parent-selector) {
        //
        // The current selector doesn't match the parent selector.
        // The user manually added a selector between parent context and this suffix call.
        // This case is forbidden because any outcome semantically wouldn't make sense:
        //   - {b,e,m} [manual selector] {b,e,m}@suffix
        //   - {b,e,m}@suffix [manual selector]
        // The first case would make the modifier behave like an element.
        // The second case is unintuitive, the code would be more clear by nesting the manual
        // selector in the suffix instead.
        //

        @error 'A suffix must be an immediate child of the parent context';
    }

    //
    // The suffix part can simply be appended.
    // Possible outcomes:
    //   - {b,e,m}@suffix
    //

    $selector: selector-append(&, $iro-bem-suffix-separator + $name);

    $context: 'suffix', (
        'name':     $name,
        'selector': $selector
    );

    @return $selector $context;
}