/*
from: https://github.com/twbs/bootstrap/blob/v4-dev/
*/

// @include include-grid
$enable-grid-classes: true !default;
$grid-columns: 12 !default;
$grid-gutter-width-base: 30px !default;
$grid-gutter-widths: (
  xs: $grid-gutter-width-base,
  sm: $grid-gutter-width-base,
  md: $grid-gutter-width-base,
  lg: $grid-gutter-width-base,
  xl: $grid-gutter-width-base
) !default;
$grid-breakpoints: (
  xs: 0,
  sm: 576px,
  md: 768px,
  lg: 992px,
  xl: 1200px
) !default;
$container-max-widths: (
  sm: 540px,
  md: 720px,
  lg: 960px,
  xl: 1140px
) !default;

@mixin include-grid {

  @at-root {
    // Container widths
    //
    // Set the container width, and override it for fixed navbars in media queries.

    @if $enable-grid-classes {
      .container {
        @include make-container();
        @include make-container-max-widths();
      }
    }

    // Fluid container
    //
    // Utilizes the mixin meant for fixed width containers, but without any defined
    // width for fluid, full width layouts.

    @if $enable-grid-classes {
      .container-fluid {
        @include make-container();
      }
    }

    // Row
    //
    // Rows contain and clear the floats of your columns.

    @if $enable-grid-classes {
      .row {
        @include make-row();
      }

      // Remove the negative margin from default .row, then the horizontal padding
      // from all immediate children columns (to prevent runaway style inheritance).
      .no-gutters {
        margin-right: 0;
        margin-left: 0;

        > .col,
        > [class*="col-"] {
          padding-right: 0;
          padding-left: 0;
        }
      }
    }

    // Columns
    //
    // Common styles for small and large grid columns

    @if $enable-grid-classes {
      @include make-grid-columns();
    }
  }
}

// Breakpoint viewport sizes and media queries.
//
// Breakpoints are defined as a map of (name: minimum width), order from small to large:
//
//    (xs: 0, sm: 576px, md: 768px, lg: 992px, xl: 1200px)
//
// The map defined in the `$grid-breakpoints` global variable is used as the `$breakpoints` argument by default.

// Name of the next breakpoint, or null for the last breakpoint.
//
//    >> breakpoint-next(sm)
//    md
//    >> breakpoint-next(sm, (xs: 0, sm: 576px, md: 768px, lg: 992px, xl: 1200px))
//    md
//    >> breakpoint-next(sm, $breakpoint-names: (xs sm md lg xl))
//    md
@function breakpoint-next($name, $breakpoints: $grid-breakpoints, $breakpoint-names: map-keys($breakpoints)) {
  $n: index($breakpoint-names, $name);
  @return if($n < length($breakpoint-names), nth($breakpoint-names, $n + 1), null);
}

// Minimum breakpoint width. Null for the smallest (first) breakpoint.
//
//    >> breakpoint-min(sm, (xs: 0, sm: 576px, md: 768px, lg: 992px, xl: 1200px))
//    576px
@function breakpoint-min($name, $breakpoints: $grid-breakpoints) {
  $min: map-get($breakpoints, $name);
  @return if($min != 0, $min, null);
}

// Maximum breakpoint width. Null for the largest (last) breakpoint.
// The maximum value is calculated as the minimum of the next one less 0.1.
//
//    >> breakpoint-max(sm, (xs: 0, sm: 576px, md: 768px, lg: 992px, xl: 1200px))
//    767px
@function breakpoint-max($name, $breakpoints: $grid-breakpoints) {
  $next: breakpoint-next($name, $breakpoints);
  @return if($next, breakpoint-min($next, $breakpoints) - 1px, null);
}

// Returns a blank string if smallest breakpoint, otherwise returns the name with a dash infront.
// Useful for making responsive utilities.
//
//    >> breakpoint-infix(xs, (xs: 0, sm: 576px, md: 768px, lg: 992px, xl: 1200px))
//    ""  (Returns a blank string)
//    >> breakpoint-infix(sm, (xs: 0, sm: 576px, md: 768px, lg: 992px, xl: 1200px))
//    "-sm"
@function breakpoint-infix($name, $breakpoints: $grid-breakpoints) {
  @return if(breakpoint-min($name, $breakpoints) == null, "", "-#{$name}");
}


// Framework grid generation
//
// Used only by Bootstrap to generate the correct number of grid classes given
// any value of `$grid-columns`.

@mixin make-grid-columns($columns: $grid-columns, $gutters: $grid-gutter-widths, $breakpoints: $grid-breakpoints) {
  // Common properties for all breakpoints
  %grid-column {
    position: relative;
    width: 100%;
    min-height: 1px; // Prevent columns from collapsing when empty

    @include make-gutters($gutters);
  }

  @each $breakpoint in map-keys($breakpoints) {
    $infix: breakpoint-infix($breakpoint, $breakpoints);

    // Allow columns to stretch full width below their breakpoints
    @for $i from 1 through $columns {
      .col#{$infix}-#{$i} {
        @extend %grid-column;
      }
    }
    .col#{$infix} {
      @extend %grid-column;
    }

    @include media-breakpoint-up($breakpoint, $breakpoints) {
      // Provide basic `.col-{bp}` classes for equal-width flexbox columns
      .col#{$infix} {
        flex-basis: 0;
        flex-grow: 1;
        max-width: 100%;
      }
      .col#{$infix}-auto {
        flex: 0 0 auto;
        width: auto;
      }

      @for $i from 1 through $columns {
        .col#{$infix}-#{$i} {
          @include make-col($i, $columns);
        }
      }

      @each $modifier in (pull, push) {
        @for $i from 0 through $columns {
          .#{$modifier}#{$infix}-#{$i} {
            @include make-col-modifier($modifier, $i, $columns)
          }
        }
      }

      // `$columns - 1` because offsetting by the width of an entire row isn't possible
      @for $i from 0 through ($columns - 1) {
        @if not ($infix == "" and $i == 0) { // Avoid emitting useless .offset-xs-0
          .offset#{$infix}-#{$i} {
            @include make-col-modifier(offset, $i, $columns)
          }
        }
      }
    }
  }
}

// Media of at least the minimum breakpoint width. No query for the smallest breakpoint.
// Makes the @content apply to the given breakpoint and wider.
@mixin media-breakpoint-up($name, $breakpoints: $grid-breakpoints) {
  $min: breakpoint-min($name, $breakpoints);
  @if $min {
    @media (min-width: $min) {
      @content;
    }
  } @else {
    @content;
  }
}

// Media of at most the maximum breakpoint width. No query for the largest breakpoint.
// Makes the @content apply to the given breakpoint and narrower.
@mixin media-breakpoint-down($name, $breakpoints: $grid-breakpoints) {
  $max: breakpoint-max($name, $breakpoints);
  @if $max {
    @media (max-width: $max) {
      @content;
    }
  } @else {
    @content;
  }
}

// Media that spans multiple breakpoint widths.
// Makes the @content apply between the min and max breakpoints
@mixin media-breakpoint-between($lower, $upper, $breakpoints: $grid-breakpoints) {
  @include media-breakpoint-up($lower, $breakpoints) {
    @include media-breakpoint-down($upper, $breakpoints) {
      @content;
    }
  }
}

/// Grid system
//
// Generate semantic grid columns with these mixins.

@mixin make-container($gutters: $grid-gutter-widths) {
  position: relative;
  margin-right: auto;
  margin-left: auto;
  box-sizing: border-box;

  @each $breakpoint in map-keys($gutters) {
    @include media-breakpoint-up($breakpoint) {
      $gutter: map-get($gutters, $breakpoint);
      padding-right: ($gutter / 2);
      padding-left:  ($gutter / 2);
    }
  }
}

// For each breakpoint, define the maximum width of the container in a media query
@mixin make-container-max-widths($max-widths: $container-max-widths, $breakpoints: $grid-breakpoints) {
  @each $breakpoint, $container-max-width in $max-widths {
    @include media-breakpoint-up($breakpoint, $breakpoints) {
      width: $container-max-width;
      max-width: 100%;
      box-sizing: border-box;
    }
  }
}

@mixin make-gutters($gutters: $grid-gutter-widths) {
  @each $breakpoint in map-keys($gutters) {
    @include media-breakpoint-up($breakpoint) {
      $gutter: map-get($gutters, $breakpoint);
      padding-right: ($gutter / 2);
      padding-left:  ($gutter / 2);
      box-sizing: border-box;
    }
  }
}

@mixin make-row($gutters: $grid-gutter-widths) {
  display: flex;
  flex-wrap: wrap;
  box-sizing: border-box;

  @each $breakpoint in map-keys($gutters) {
    @include media-breakpoint-up($breakpoint) {
      $gutter: map-get($gutters, $breakpoint);
      margin-right: ($gutter / -2);
      margin-left:  ($gutter / -2);
    }
  }
}

@mixin make-col-ready($gutters: $grid-gutter-widths) {
  position: relative;
  // Prevent columns from becoming too narrow when at smaller grid tiers by
  // always setting `width: 100%;`. This works because we use `flex` values
  // later on to override this initial width.
  width: 100%;
  min-height: 1px; // Prevent collapsing

  @each $breakpoint in map-keys($gutters) {
    @include media-breakpoint-up($breakpoint) {
      $gutter: map-get($gutters, $breakpoint);
      padding-right: ($gutter / 2);
      padding-left:  ($gutter / 2);
    }
  }
}

@mixin make-col($size, $columns: $grid-columns) {
  flex: 0 0 percentage($size / $columns);
  // width: percentage($size / $columns);
  // Add a `max-width` to ensure content within each column does not blow out
  // the width of the column. Applies to IE10+ and Firefox. Chrome and Safari
  // do not appear to require this.
  max-width: percentage($size / $columns);
}

@mixin make-col-offset($size, $columns: $grid-columns) {
  margin-left: percentage($size / $columns);
}

@mixin make-col-push($size, $columns: $grid-columns) {
  left: if($size > 0, percentage($size / $columns), auto);
}

@mixin make-col-pull($size, $columns: $grid-columns) {
  right: if($size > 0, percentage($size / $columns), auto);
}

@mixin make-col-modifier($type, $size, $columns) {
  // Work around the lack of dynamic mixin @include support (https://github.com/sass/sass/issues/626)
  @if $type == push {
    @include make-col-push($size, $columns);
  } @else if $type == pull {
    @include make-col-pull($size, $columns);
  } @else if $type == offset {
    @include make-col-offset($size, $columns);
  }
}