//
// Copyright 2017 Google Inc. All Rights Reserved.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//      http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
//

@import "@material/theme/variables";
@import "./variables";

// Applies the correct CSS rules to an element to give it the elevation specified by $z-value.
// The $z-value must be between 0 and 24.
// If $color has an alpha channel, it will be ignored and overridden. To increase the opacity of the shadow, use
// $opacity-boost.
@mixin mdc-elevation($z-value, $color: $mdc-elevation-baseline-color, $opacity-boost: 0) {
  @if type-of($z-value) != number or not unitless($z-value) {
    @error "$z-value must be a unitless number, but received '#{$z-value}'";
  }

  @if $z-value < 0 or $z-value > 24 {
    @error "$z-value must be between 0 and 24, but received '#{$z-value}'";
  }

  $color: mdc-theme-prop-value($color);

  $umbra-z-value: map-get($mdc-elevation-umbra-map, $z-value);
  $penumbra-z-value: map-get($mdc-elevation-penumbra-map, $z-value);
  $ambient-z-value: map-get($mdc-elevation-ambient-map, $z-value);

  $umbra-color: rgba($color, $mdc-elevation-umbra-opacity + $opacity-boost);
  $penumbra-color: rgba($color, $mdc-elevation-penumbra-opacity + $opacity-boost);
  $ambient-color: rgba($color, $mdc-elevation-ambient-opacity + $opacity-boost);

  box-shadow:
    #{"#{$umbra-z-value} #{$umbra-color}"},
    #{"#{$penumbra-z-value} #{$penumbra-color}"},
    #{$ambient-z-value} $ambient-color;
}

// Returns a string that can be used as the value for a `transition` property for elevation.
// Calling this function directly is useful in situations where a component needs to transition
// more than one property.
//
// ```scss
// .foo {
//   transition: mdc-elevation-transition-value(), opacity 100ms ease;
//   will-change: $mdc-elevation-property, opacity;
// }
// ```
@function mdc-elevation-transition-value(
  $duration: $mdc-elevation-transition-duration,
  $easing: $mdc-elevation-transition-timing-function) {
  @return #{$mdc-elevation-property} #{$duration} #{$easing};
}