@use 'sass:math';
@use '@angular/cdk';

@use '../core/style/button-common';
@use '../core/tokens/token-utils';
@use './m3-datepicker';

$calendar-body-label-padding-start: 5% !default;
// We don't want the label to jump around when we switch between month and year views, so we use
// the same amount of padding regardless of the number of columns. We align the header label with
// the one third mark of the first cell, this was chosen somewhat arbitrarily to make it look
// roughly like the mock. Half way is too far since the cell text is center aligned.
$calendar-body-label-side-padding: math.div(33%, 7) !default;
$calendar-body-cell-min-size: 32px !default;
$calendar-body-cell-content-margin: 5% !default;
$calendar-body-cell-content-border-width: 1px !default;
$calendar-body-cell-radius: 999px !default;
$calendar-body-preview-cell-border: dashed 1px;

$calendar-body-min-size: 7 * $calendar-body-cell-min-size !default;
$calendar-body-cell-content-size: 100% - $calendar-body-cell-content-margin * 2 !default;

$calendar-range-end-body-cell-size:
    $calendar-body-cell-content-size + $calendar-body-cell-content-margin !default;

$fallbacks: m3-datepicker.get-tokens();

// Styles for a highlighted calendar cell (e.g. hovered or focused).
@mixin _highlighted-cell($token-name) {
  & > .mat-calendar-body-cell-content {
    @include _unselected-cell {
      background-color: token-utils.slot($token-name, $fallbacks);
    }
  }
}

// Utility mixin to target cells that aren't selected. Used to make selector easier to follow.
@mixin _unselected-cell {
  &:not(.mat-calendar-body-selected):not(.mat-calendar-body-comparison-identical) {
    @content;
  }
}

.mat-calendar-body {
  min-width: $calendar-body-min-size;
}

.mat-calendar-body-today {
  @include _unselected-cell {
    border-color: token-utils.slot(datepicker-calendar-date-today-outline-color, $fallbacks);
  }
}

.mat-calendar-body-label {
  height: 0;
  line-height: 0;
  text-align: start;
  padding-left: $calendar-body-label-side-padding;
  padding-right: $calendar-body-label-side-padding;

  font-size: token-utils.slot(datepicker-calendar-body-label-text-size, $fallbacks);
  font-weight: token-utils.slot(datepicker-calendar-body-label-text-weight, $fallbacks);
  color: token-utils.slot(datepicker-calendar-body-label-text-color, $fallbacks);
}

// Label that is not rendered and removed from the accessibility tree.
.mat-calendar-body-hidden-label {
  display: none;
}

.mat-calendar-body-cell-container {
  position: relative;
  height: 0;
  line-height: 0;
}

.mat-calendar-body-cell {
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  background: none;
  text-align: center;
  outline: none;
  margin: 0;

  // Needs to be repeated here in order to override the user agent styles.
  font-family: token-utils.slot(datepicker-calendar-text-font, $fallbacks);
  font-size: token-utils.slot(datepicker-calendar-text-size, $fallbacks);

  @include button-common.reset();
}

// We use ::before to apply a background to the body cell, because we need to apply a border
// radius to the start/end which means that part of the element will be cut off, making hovering
// through all the cells look glitchy. We can't do it on the cell itself, because it's the one
// that has the event listener and it can't be on the cell content, because it always has a
// border radius. Note that this and the selectors below can be much simpler if we were to use
// two separate elements for the main and comparison ranges, like we're doing for the preview
// range. We don't follow the simpler approach, because the range colors usually have some
// kind of opacity, which means that they'll start mixing when they're layered on top of each
// other, making the calendar look messy.
.mat-calendar-body-cell::before,
.mat-calendar-body-cell::after,
.mat-calendar-body-cell-preview {
  content: '';
  position: absolute;
  top: $calendar-body-cell-content-margin;
  left: 0;
  z-index: 0;
  box-sizing: border-box;
  display: block;

  // We want the range background to be slightly shorter than the cell so
  // that there's a gap when the range goes across multiple rows.
  height: $calendar-body-cell-content-size;
  width: 100%;
}

.mat-calendar-body-range-start:not(.mat-calendar-body-in-comparison-range)::before,
.mat-calendar-body-range-start::after,
.mat-calendar-body-comparison-start:not(.mat-calendar-body-comparison-bridge-start)::before,
.mat-calendar-body-comparison-start::after,
.mat-calendar-body-preview-start .mat-calendar-body-cell-preview {
  // Since the range background isn't a perfect circle, we need to size
  // and offset the start so that it aligns with the main circle.
  left: $calendar-body-cell-content-margin;
  width: $calendar-range-end-body-cell-size;
  border-top-left-radius: $calendar-body-cell-radius;
  border-bottom-left-radius: $calendar-body-cell-radius;

  [dir='rtl'] & {
    left: 0;
    border-radius: 0;
    border-top-right-radius: $calendar-body-cell-radius;
    border-bottom-right-radius: $calendar-body-cell-radius;
  }
}

@mixin _range-right-radius {
  // Since the range background isn't a perfect circle, we need to
  // resize the end so that it aligns with the main circle.
  width: $calendar-range-end-body-cell-size;
  border-top-right-radius: $calendar-body-cell-radius;
  border-bottom-right-radius: $calendar-body-cell-radius;
}

.mat-calendar-body-range-end:not(.mat-calendar-body-in-comparison-range)::before,
.mat-calendar-body-range-end::after,
.mat-calendar-body-comparison-end:not(.mat-calendar-body-comparison-bridge-end)::before,
.mat-calendar-body-comparison-end::after,
.mat-calendar-body-preview-end .mat-calendar-body-cell-preview {
  @include _range-right-radius;

  [dir='rtl'] & {
    left: $calendar-body-cell-content-margin;
    border-radius: 0;
    border-top-left-radius: $calendar-body-cell-radius;
    border-bottom-left-radius: $calendar-body-cell-radius;
  }
}

// Styles necessary to make RTL work.
[dir='rtl'] {
  .mat-calendar-body-comparison-bridge-start.mat-calendar-body-range-end::after,
  .mat-calendar-body-comparison-bridge-end.mat-calendar-body-range-start::after {
    @include _range-right-radius;
  }
}

// Prevents the extra overlap range indication from showing up when it's not supposed to.
.mat-calendar-body-comparison-start.mat-calendar-body-range-end::after,
.mat-calendar-body-comparison-end.mat-calendar-body-range-start::after {
  // Note that the RTL selector here is redundant, but we need to keep it in order to
  // raise the specificity since it can be overridden by some of the styles from above.
  &, [dir='rtl'] & {
    width: $calendar-body-cell-content-size;
  }
}

.mat-calendar-body-in-preview {
  color: token-utils.slot(datepicker-calendar-date-preview-state-outline-color, $fallbacks);

  .mat-calendar-body-cell-preview {
    border-top: $calendar-body-preview-cell-border;
    border-bottom: $calendar-body-preview-cell-border;
  }
}

.mat-calendar-body-preview-start .mat-calendar-body-cell-preview {
  border-left: $calendar-body-preview-cell-border;

  [dir='rtl'] & {
    border-left: 0;
    border-right: $calendar-body-preview-cell-border;
  }
}

.mat-calendar-body-preview-end .mat-calendar-body-cell-preview {
  border-right: $calendar-body-preview-cell-border;

  [dir='rtl'] & {
    border-right: 0;
    border-left: $calendar-body-preview-cell-border;
  }
}

.mat-calendar-body-disabled {
  cursor: default;

  & > .mat-calendar-body-cell-content {
    @include _unselected-cell {
      color: token-utils.slot(datepicker-calendar-date-disabled-state-text-color, $fallbacks);
    }
  }

  & > .mat-calendar-body-today {
    @include _unselected-cell {
      border-color: token-utils.slot(datepicker-calendar-date-today-disabled-state-outline-color,
          $fallbacks);
    }
  }

  // Fade out the disabled cells so that they can be distinguished from the enabled ones. Note that
  // ideally we'd use `color: GreyText` here which is what the browser uses for disabled buttons,
  // but we can't because Firefox doesn't recognize it.
  @include cdk.high-contrast {
    opacity: 0.5;
  }
}

.mat-calendar-body-cell-content {
  top: $calendar-body-cell-content-margin;
  left: $calendar-body-cell-content-margin;
  z-index: 1;

  display: flex;
  align-items: center;
  justify-content: center;

  box-sizing: border-box;
  width: $calendar-body-cell-content-size;
  height: $calendar-body-cell-content-size;

  // Prevents text being off-center on Android.
  line-height: 1;

  border-width: $calendar-body-cell-content-border-width;
  border-style: solid;

  // Choosing a value clearly larger than the height ensures we get the correct capsule shape.
  border-radius: $calendar-body-cell-radius;

  color: token-utils.slot(datepicker-calendar-date-text-color, $fallbacks);
  border-color: token-utils.slot(datepicker-calendar-date-outline-color, $fallbacks);

  // Increase specificity because focus indicator styles are part of the `mat-core` mixin and can
  // potentially overwrite the absolute position of the container.
  &.mat-focus-indicator {
    position: absolute;
  }

  @include cdk.high-contrast {
    border: none;
  }
}

.mat-calendar-body-active {
  .cdk-keyboard-focused &, .cdk-program-focused & {
    @include _highlighted-cell(datepicker-calendar-date-focus-state-background-color);
  }
}

@media (hover: hover) {
  .mat-calendar-body-cell:not(.mat-calendar-body-disabled):hover {
    @include _highlighted-cell(datepicker-calendar-date-hover-state-background-color);
  }
}

.mat-calendar-body-selected {
  background-color: token-utils.slot(datepicker-calendar-date-selected-state-background-color,
      $fallbacks);
  color: token-utils.slot(datepicker-calendar-date-selected-state-text-color, $fallbacks);

  .mat-calendar-body-disabled > & {
    background-color: token-utils.slot(
        datepicker-calendar-date-selected-disabled-state-background-color, $fallbacks);
  }

  &.mat-calendar-body-today {
    $shadow: token-utils.slot(datepicker-calendar-date-today-selected-state-outline-color,
      $fallbacks);
    box-shadow: inset 0 0 0 1px #{$shadow};
  }
}

$range-color:
  token-utils.slot(datepicker-calendar-date-in-range-state-background-color, $fallbacks);
$comparison-color:
  token-utils.slot(datepicker-calendar-date-in-comparison-range-state-background-color, $fallbacks);

.mat-calendar-body-in-range::before {
  background: token-utils.slot(datepicker-calendar-date-in-range-state-background-color,
      $fallbacks);
}

.mat-calendar-body-comparison-identical,
.mat-calendar-body-in-comparison-range::before {
  background: token-utils.slot(datepicker-calendar-date-in-comparison-range-state-background-color,
      $fallbacks);
}

.mat-calendar-body-comparison-identical,
.mat-calendar-body-in-comparison-range::before {
 background: token-utils.slot(datepicker-calendar-date-in-comparison-range-state-background-color,
      $fallbacks);
}

.mat-calendar-body-comparison-bridge-start::before,
[dir='rtl'] .mat-calendar-body-comparison-bridge-end::before {
  background: linear-gradient(to right, $range-color 50%, $comparison-color 50%);
}

.mat-calendar-body-comparison-bridge-end::before,
[dir='rtl'] .mat-calendar-body-comparison-bridge-start::before {
  background: linear-gradient(to left, $range-color 50%, $comparison-color 50%);
}

.mat-calendar-body-in-range > .mat-calendar-body-comparison-identical,
.mat-calendar-body-in-comparison-range.mat-calendar-body-in-range::after {
  background: token-utils.slot(datepicker-calendar-date-in-overlap-range-state-background-color,
      $fallbacks);
}

.mat-calendar-body-comparison-identical.mat-calendar-body-selected,
.mat-calendar-body-in-comparison-range > .mat-calendar-body-selected {
  background: token-utils.slot(
      datepicker-calendar-date-in-overlap-range-selected-state-background-color, $fallbacks);
}

@include cdk.high-contrast {
  $main-range-border: solid 1px;
  $comparison-range-border: dashed 1px;

  .mat-datepicker-popup:not(:empty),
  .mat-calendar-body-cell:not(.mat-calendar-body-in-range) .mat-calendar-body-selected {
    outline: solid 1px;
  }

  .mat-calendar-body-today {
    outline: dotted 1px;
  }

  // These backgrounds need to be removed, because they'll block the date ranges.
  .mat-calendar-body-cell::before,
  .mat-calendar-body-cell::after,
  .mat-calendar-body-selected {
    background: none;
  }

  .mat-calendar-body-in-range::before,
  .mat-calendar-body-comparison-bridge-start::before,
  .mat-calendar-body-comparison-bridge-end::before {
    border-top: $main-range-border;
    border-bottom: $main-range-border;
  }

  .mat-calendar-body-range-start::before {
    border-left: $main-range-border;

    [dir='rtl'] & {
      border-left: 0;
      border-right: $main-range-border;
    }
  }

  .mat-calendar-body-range-end::before {
    border-right: $main-range-border;

    [dir='rtl'] & {
      border-right: 0;
      border-left: $main-range-border;
    }
  }

  .mat-calendar-body-in-comparison-range::before {
    border-top: $comparison-range-border;
    border-bottom: $comparison-range-border;
  }

  .mat-calendar-body-comparison-start::before {
    border-left: $comparison-range-border;

    [dir='rtl'] & {
      border-left: 0;
      border-right: $comparison-range-border;
    }
  }

  .mat-calendar-body-comparison-end::before {
    border-right: $comparison-range-border;

    [dir='rtl'] & {
      border-right: 0;
      border-left: $comparison-range-border;
    }
  }
}
