// When color definition differs for dark and light variant,
// it gets @if ed depending on $variant

@import 'color-palette';

@function gtkalpha($c, $a) {
  @return unquote("alpha(#{$c}, #{$a})");
}

@function on($color, $state: 'primary') {
  // Allow 'light' or 'dark' to $color
  @if ($color == 'light') { $color: white; }
  @if ($color == 'dark') { $color: black; }

  // Calculate color brightness according to https://www.w3.org/TR/AERT/#color-contrast
  $brightness: (red($color) * 299 + green($color) * 587 + blue($color) * 114) / 1000;

  @if ($brightness >= 128) {
    @if ($state == 'primary') { @return rgba(black, 0.87); }
    @if ($state == 'secondary') { @return rgba(black, 0.54); }
    @if ($state == 'disabled') { @return rgba(black, 0.38); }
    @if ($state == 'secondary-disabled') { @return rgba(black, 0.26); }
    @if ($state == 'track') { @return rgba(black, 0.26); }
    @if ($state == 'track-disabled') { @return rgba(black, 0.12); }
    @if ($state == 'divider') { @return rgba(black, 0.12); }
    @if ($state == 'fill') { @return rgba(black, 0.04); }
  } @else {
    @if ($state == 'primary') { @return white; }
    @if ($state == 'secondary') { @return rgba(white, 0.7); }
    @if ($state == 'disabled') { @return rgba(white, 0.5); }
    @if ($state == 'secondary-disabled') { @return rgba(white, 0.3); }
    @if ($state == 'track') { @return rgba(white, 0.3); }
    @if ($state == 'track-disabled') { @return rgba(white, 0.12); }
    @if ($state == 'divider') { @return rgba(white, 0.12); }
    @if ($state == 'fill') { @return rgba(white, 0.04); }
  }
}

@function highlight($color) {
  @if (lightness($color) >= 80%) { @return rgba(white, 0.4); }
  @else if (lightness($color) >= 40%) { @return rgba(white, 0.2); }
  @else { @return rgba(white, 0.1); }
}

//
// Basic colors
//

$blue:                                  #4285F4;
$green:                                 #34A853;
$yellow:                                #FBBC05;
$red:                                   #EA4335;

$primary:                               $blue;
$primary-alt:                           #7BAAF7;

$background:                            if($variant == 'light', #F2F2F2, #282828);
$surface:                               if($variant == 'light', #FFFFFF, #424242);
$base:                                  if($variant == 'light', #FFFFFF, #303030); // semi-surface with no elevation
$base-alt:                              if($variant == 'light', #FAFAFA, #2C2C2C);

$os-background:                         #303030;
$tooltip:                               rgba(#616161, 0.9);
$scrim:                                 rgba(black, 0.6);
$scrim-alt:                             rgba(black, 0.3);
$scrim-inverse:                         rgba(white, 0.1);
$titlebar:                              if($topbar == 'dark', #383838, #E0E0E0);
$panel:                                 if($topbar == 'dark', #212121, $scrim);
$panel-solid:                           if($topbar == 'dark', #212121, #CBCBCB); // for Unity panel which doesn't allow translucent colors

//
// Misc colors
//

$link:                                  $primary;
$link-visited:                          $purple-a200;

$warning:                               $yellow;
$error:                                 $red;
$success:                               $green;

$suggested:                             $primary;
$destructive:                           $error;

$infobar-info:                          $green;
$infobar-question:                      $blue;
$infobar-warning:                       $warning;
$infobar-error:                         $error;

$frame:                                 if($variant == 'light', rgba(black, 0.12), rgba(black, 0.26)); // instead of shadows
$border-alt:                            rgba(black, 0.26); // darker border color for Chrome and Firefox
$titlebar-indicator:                    if($topbar == 'dark', currentColor, $primary);

//
// Overlay state colors
//

$overlay-hover:                         gtkalpha(currentColor, 0.08);
$overlay-focus:                         gtkalpha(currentColor, 0.12);
$overlay-focus-hover:                   gtkalpha(currentColor, 0.16);
$overlay-active:                        gtkalpha(currentColor, 0.12);
$overlay-checked:                       gtkalpha(currentColor, 0.12);
$overlay-selected:                      rgba($primary, 0.24);

//
// Text and derivative colors
//

$text:                                  on($background);
$text-secondary:                        on($background, secondary);
$text-disabled:                         on($background, disabled);
$text-secondary-disabled:               on($background, secondary-disabled);
$track:                                 on($background, track);
$track-disabled:                        on($background, track-disabled);
$divider:                               on($background, divider);
$fill:                                  on($background, fill);

$titlebar-text:                         on($titlebar);
$titlebar-text-secondary:               on($titlebar, secondary);
$titlebar-text-disabled:                on($titlebar, disabled);
$titlebar-text-secondary-disabled:      on($titlebar, secondary-disabled);
$titlebar-track:                        on($titlebar, track);
$titlebar-track-disabled:               on($titlebar, track-disabled);
$titlebar-divider:                      on($titlebar, divider);
$titlebar-fill:                         on($titlebar, fill);

// workaround for GTK3 @placeholder_text_color which doesn't allow translucent colors
$placeholder_text_color:                if($variant == 'light', $grey-600, mix($white, $base, percentage(0.7)));