// breakpoint mixins
@function breakpoint-next($name, $grid-breakpoints: $grid-breakpoints, $breakpoint-names: map-keys($grid-breakpoints)) {
  $n: index($breakpoint-names, $name);
  @return if($n != null and $n < length($breakpoint-names), nth($breakpoint-names, $n + 1), null);
}

@function breakpoint-min($name, $grid-breakpoints: $grid-breakpoints) {
  $min: map-get($grid-breakpoints, $name);
  @return if($min != 0, $min, null);
}

@function breakpoint-max($name, $grid-breakpoints: $grid-breakpoints) {
  $next: breakpoint-next($name, $grid-breakpoints);
  @return if($next, breakpoint-min($next, $grid-breakpoints) - .02, null);
}

@function breakpoint-infix($name, $grid-breakpoints: $grid-breakpoints) {
  @return if(breakpoint-min($name, $grid-breakpoints) == null, "", "-#{$name}");
}


// breakpoint mixins responisve
@mixin media-breakpoint-up($name, $grid-breakpoints: $grid-breakpoints) {
  $min: breakpoint-min($name, $grid-breakpoints);
  @if $min {
    @media (min-width: $min) {
      @content;
    }
  } @else {
    @content;
  }
}

@mixin media-breakpoint-down($name, $grid-breakpoints: $grid-breakpoints) {
  $max: breakpoint-max($name, $grid-breakpoints);
  @if $max {
    @media (max-width: $max) {
      @content;
    }
  } @else {
    @content;
  }
}

//
//  Breakpoint ABOVE
//––––––––––––––––––––––––––––––––––––––––––––––––––

// @include breakpoint-above(sm) {}
@mixin breakpoint-above($breakpoint) {

  // If the breakpoint exists in the map.
  @if map-has-key($grid-breakpoints, $breakpoint) {

    // Get the breakpoint value.
    $breakpoint-value: map-get($grid-breakpoints, $breakpoint);

    // Write the media query.
    @media (min-width: $breakpoint-value) {
      @content;
    }
  
  // If the breakpoint doesn't exist in the map.
  } @else {

    // Log a warning.
    @warn 'Invalid breakpoint: #{$breakpoint}.';
  }
}


//
//  breakpoint BELOW
//––––––––––––––––––––––––––––––––––––––––––––––––––

// @include breakpoint-below(sm) {}
@mixin breakpoint-below($breakpoint) {

  // If the breakpoint exists in the map.
  @if map-has-key($grid-breakpoints, $breakpoint) {

    // Get the breakpoint value.
    $breakpoint-value: map-get($grid-breakpoints, $breakpoint);

    // Write the media query.
    @media (max-width: ($breakpoint-value - 1)) {
      @content;
    }
  
  // If the breakpoint doesn't exist in the map.
  } @else {

    // Log a warning.
    @warn 'Invalid breakpoint: #{$breakpoint}.';
  }
}


//
//  breakpoint BETWEEN
//––––––––––––––––––––––––––––––––––––––––––––––––––

// @include breakpoint-between(sm, md) {}
@mixin breakpoint-between($lower, $upper) {

  // If both the lower and upper breakpoints exist in the map.
  @if map-has-key($grid-breakpoints, $lower) and map-has-key($grid-breakpoints, $upper) {

    // Get the lower and upper breakpoints.
    $lower-breakpoint: map-get($grid-breakpoints, $lower);
    $upper-breakpoint: map-get($grid-breakpoints, $upper);

    // Write the media query.
    @media (min-width: $lower-breakpoint) and (max-width: ($upper-breakpoint - 1)) {
      @content;
    }
  
  // If one or both of the breakpoints don't exist.
  } @else {

    // If lower breakpoint is invalid.
    @if (map-has-key($grid-breakpoints, $lower) == false) {

      // Log a warning.
      @warn 'Your lower breakpoint was invalid: #{$lower}.';
    }

    // If upper breakpoint is invalid.
    @if (map-has-key($grid-breakpoints, $upper) == false) {

      // Log a warning.
      @warn 'Your upper breakpoint was invalid: #{$upper}.';
    }
  }
}