// Drawing mixins

// generic drawing of more complex things

@function _widget_edge($c:$borders_edge) {
// outer highlight "used" on most widgets
  @return 0 1px $c;
}

// provide font size in rem, with px fallback
@mixin fontsize($size: 24, $base: 16) {
  font-size: round($size) + pt;
  //font-size: ($size / $base) * 1rem;
}

@mixin _shadows($shadow1, $shadow2:none, $shadow3:none, $shadow4:none) {
//
// Helper function to stack up to 4 box-shadows;
//
  @if $shadow4!=none { box-shadow: $shadow1, $shadow2, $shadow3, $shadow4; }
  @else if $shadow3!=none { box-shadow: $shadow1, $shadow2, $shadow3; }
  @else if $shadow2!=none { box-shadow: $shadow1, $shadow2; }
  @else { box-shadow: $shadow1; }
}

// entries

@mixin entry($t, $fc:$selected_bg_color, $edge: $borders_edge) {
//
// Entries drawing function
//
// $t: entry type
// $fc: focus color
// $edge: set to none to not draw the bottom edge or specify a color to not
//        use the default one
//
// possible $t values:
// normal, focus, insensitive
//
  $_inner_shadows: inset 0 2px 4px transparentize(black, 0.6);

  @if $t==normal {
    background-color: $base_color;
    border-color: $borders_color;
    @include _shadows($_inner_shadows);

  }
  @if $t==focus {
    @include _shadows($_inner_shadows);
    border-color: if($fc==$selected_bg_color,
                     $selected_borders_color,
                     darken($fc,35%));
  }
  @if $t==hover { }
  @if $t==insensitive {
    color: $insensitive_fg_color;
    border-color: $insensitive_bg_color;
    box-shadow: none;
  }
}

// buttons

@function _border_color ($c) { @return darken($c,25%); } // colored buttons want
                                                         // the border form the
                                                         // base color

@function _text_shadow_color ($tc:$fg_color, $bg:$bg_color) {
//
// calculate the color of text shadows
//
// $tc is the text color
// $bg is the background color
//
  $_lbg: lightness($bg)/100%;
  @if lightness($tc)<50% { @return transparentize(white,1-$_lbg/($_lbg*1.3)); }
  @else { @return transparentize(black,$_lbg*0.8); }
}

@function _button_hilight_color($c) {
//
// calculate the right top hilight color for buttons
//
// $c: base color;
//
  @if lightness($c)>90% { @return white; }
  @else if lightness($c)>80% { @return transparentize(white, 0.3); }
  @else if lightness($c)>50% { @return transparentize(white, 0.5); }
  @else if lightness($c)>40% { @return transparentize(white, 0.7); }
  @else { @return transparentize(white, 0.9); }
}

@mixin _button_text_shadow ($tc:$fg_color, $bg:$bg_color) {
//
// helper function for the text emboss effect
//
// $tc is the optional text color, not the shadow color
//
// TODO: this functions needs a way to deal with special cases
//

  $_shadow: _text_shadow_color($tc, $bg);

  @if lightness($tc)<50% {
    text-shadow: 0 1px $_shadow;
    icon-shadow: 0 1px $_shadow;
  }
  @else {
    text-shadow: 0 -1px $_shadow;
    icon-shadow: 0 -1px $_shadow;
  }
}

@function _border_color($c, $darker: false) {
  @if $darker == true { @return darken($c, 20%); }
  @else { @return darken($c, 10%); }
}

@function _text_shadow_color ($tc: $fg_color, $bg: $bg_color) {
//
// calculate the color of text shadows
//
// $tc is the text color
// $bg is the background color
//
  $_lbg: lightness($bg)/100%;
  @if lightness($tc)<50% { @return transparentize(white, 1-$_lbg/($_lbg*1.3)); }
  @else { @return transparentize(black, $_lbg*0.8); }
}

@function _button_hilight_color($c) {
//
// calculate the right top hilight color for buttons
//
// $c: base color;
//
  @if lightness($c)>95% { @return white; }
  @else if lightness($c)>90% { @return transparentize(white, 0.2); }
  @else if lightness($c)>80% { @return transparentize(white, 0.5); }
  @else if lightness($c)>50% { @return transparentize(white, 0.8); }
  @else if lightness($c)>40% { @return transparentize(white, 0.9); }
  @else { @return transparentize(white, 0.98); }
}

@mixin _button_text_shadow ($tc:$fg_color, $bg:$bg_color) {
//
// helper function for the text emboss effect
//
// $tc is the optional text color, not the shadow color
//
// TODO: this functions needs a way to deal with special cases
//

  $_shadow: _text_shadow_color($tc, $bg);

  @if lightness($tc)<50% {
    text-shadow: 0 1px $_shadow;
    -gtk-icon-shadow: 0 1px $_shadow;
  }
  @else {
    text-shadow: 0 -1px $_shadow;
    -gtk-icon-shadow: 0 -1px $_shadow;
  }
}

@mixin button($t, $c:$bg_color, $tc:$fg_color, $edge: none) {
//
// Button drawing function
//
// $t:    button type,
// $c:    base button color for colored* types
// $tc:   optional text color for colored* types
// $edge: set to none to not draw the bottom edge or specify a color to not
//        use the default one
//
// possible $t values:
// normal, hover, active, insensitive, insensitive-active,
// backdrop, backdrop-active, backdrop-insensitive, backdrop-insensitive-active,
// osd, osd-hover, osd-active, osd-insensitive, osd-backdrop, undecorated
//
// This mixin sets the $button_fill global variable which containts the button background-image
//
  $_hilight_color: _button_hilight_color($c);
  $_button_edge: if($edge == none, none, _widget_edge($edge));
  $_blank_edge: if($edge == none, none, _widget_edge(transparentize($edge,1)));
  $_button_shadow: 0 1px 2px transparentize($shadow_color, 0.03);

  @if $t==normal {
  //
  // normal button
  //
    color: $tc;
    outline-color: transparentize($tc, 0.7);
    border-color: if($c != $bg_color, _border_color($c), $borders_color);
    border-bottom-color: if($c != $bg_color, _border_color($c, true), $alt_borders_color);
    $button_fill: if($variant == 'light', linear-gradient(to top, darken($c, 4%) 2px, $c),
                                          linear-gradient(to top, darken($c,1%) 2px, $c)) !global;
    background-image: $button_fill;
    @include _button_text_shadow($tc, $c);
    @include _shadows(inset 0 1px $_hilight_color, $_button_edge, $_button_shadow);
  }

  @else if $t==hover {
  //
  // hovered button
  //
    color: $tc;
    outline-color: transparentize($tc, 0.7);
    border-color: if($c != $bg_color, _border_color($c), $borders_color);
    border-bottom-color: if($c != $bg_color, _border_color($c, true), $alt_borders_color);
    @if $variant == 'light' {
      $button_fill: linear-gradient(to top, $c, lighten($c, 1%) 1px) !global;
      @include _button_text_shadow($tc, lighten($c, 6%));
      @include _shadows(inset 0 1px _button_hilight_color(lighten($c, 6%)), $_button_edge, $_button_shadow);
    }
    @else {
      $button_fill: linear-gradient(to top, darken($c,1%), lighten($c, 1%) 1px) !global;
      @include _button_text_shadow($tc,lighten($c, 6%));
      @include _shadows(inset 0 1px _button_hilight_color(darken($c, 2%)), $_button_edge, $_button_shadow);
    }
    background-image: $button_fill;
  }

  @if $t==normal-alt {
  //
  // normal button alternative look
  //
    color: $tc;
    outline-color: transparentize($tc, 0.7);
    border-color: if($c != $bg_color, _border_color($c, true), $alt_borders_color);
    @include _button_text_shadow($tc, $c);
    @if $variant == 'light' {
      background-image: linear-gradient(to bottom, lighten($c, 5%) 20%, $c 90%);
       @include _shadows(inset 0 1px _button_hilight_color(lighten($c, 6%)),
                        $_button_edge, $_button_shadow);
    }
    @else {
      background-image: linear-gradient(to bottom, darken($c, 3%) 20%, darken($c, 6%) 90%);
      @include _shadows(inset 0 1px $_hilight_color,
                        $_button_edge, $_button_shadow);
    }
  }

  @else if $t==hover-alt {
  //
  // hovered button alternative look
  //
    color: $tc;
    outline-color: transparentize($tc, 0.7);
    border-color: if($c != $bg_color, _border_color($c, true), $alt_borders_color);
    @if $variant == 'light' {
      $button_fill: linear-gradient(to bottom, lighten($c, 9%) 10%, lighten($c, 4%) 90%) !global;
      @include _shadows(inset 0 1px _button_hilight_color(lighten($c, 6%)),
                        $_button_edge, $_button_shadow);
    }
    @else {
      $button_fill: linear-gradient(to bottom, $c 20%, darken($c, 4%) 90%) !global;
      @include _shadows(inset 0 1px $_hilight_color,
                        $_button_edge, $_button_shadow);
    }
    background-image: $button_fill;
  }

  @else if $t==active {
  //
  // pushed button
  //
    color: $tc;
    outline-color: transparentize($tc, 0.7);
    border-color: if($c != $bg_color, _border_color($c), $borders_color);
    $button_fill: if($variant == 'light', image(darken($c, 14%)), image(darken($c, 9%))) !global;
    background-image: $button_fill;
    @include _shadows(inset 0 1px transparentize($_hilight_color, 1), $_button_edge);

    text-shadow: none;
    -gtk-icon-shadow: none;
  }

  @else if $t==insensitive {
  //
  // insensitive button
  //
    $_bg: if($c != $bg_color, mix($c, $base_color, 85%), $insensitive_bg_color);

    label, & { color: if($tc != $fg_color, mix($tc, $_bg, 50%), $insensitive_fg_color); }

    border-color: if($c != $bg_color, _border_color($c), $insensitive_borders_color);
    $button_fill: image($_bg) !global;
    background-image: $button_fill;
    text-shadow: none;
    -gtk-icon-shadow: none;
    // white with 0 alpha to avoid an ugly transition, since no color means
    // black with 0 alpha
    @include _shadows(inset 0 1px transparentize(white, 1), $_button_edge);
  }

  @else if $t==insensitive-active {
  //
  // insensitive pushed button
  //
    $_bg: if($variant == 'light', darken(mix($c, $base_color, 85%), 8%), darken(mix($c, $base_color, 85%), 6%));
    $_bc: if($c != $bg_color, _border_color($c), $insensitive_borders_color);

    label, & { color: if($c != $bg_color, mix($tc, $_bg, 60%), $insensitive_fg_color); }

    border-color: $_bc;
    $button_fill: image($_bg) !global;
    background-image: $button_fill;
    // white with 0 alpha to avoid an ugly transition, since no color means
    // black with 0 alpha
    @include _shadows(inset 0 1px transparentize(white, 1), $_button_edge);
  }

  
  @else if $t==osd {
  //
  // normal osd button
  //
    $_bg: if($c != $bg_color, transparentize($c, 0.5), $osd_bg_color);

    color: $osd_fg_color;
    border-color: $osd_borders_color;
    background-color: transparent;
    $button_fill: image($_bg) !global;
    background-image: $button_fill;
    background-clip: padding-box;
    box-shadow: inset 0 1px transparentize(white, 0.9);
    text-shadow: 0 1px black;
    -gtk-icon-shadow: 0 1px black;
    outline-color: transparentize($osd_fg_color, 0.7);
  }

  @else if $t==osd-hover {
  //
  // active osd button
  //
    $_bg: if($c != $bg_color, transparentize($c, 0.3), lighten($osd_bg_color, 12%));

    color: white;
    border-color: $osd_borders_color;
    background-color: transparent;
    $button_fill: image($_bg) !global;
    background-image: $button_fill;
    background-clip: padding-box;
    box-shadow: inset 0 1px transparentize(white, 0.9);
    text-shadow: 0 1px black;
    -gtk-icon-shadow: 0 1px black;
    outline-color: transparentize($osd_fg_color, 0.7);
  }

  @else if $t==osd-active {
  //
  // active osd button
  //
    $_bg: if($c != $bg_color, $c, $osd_borders_color);

    color: white;
    border-color: $osd_borders_color;
    background-color: transparent;
    $button_fill: image($_bg) !global;
    background-image: $button_fill;
    background-clip: padding-box;
    box-shadow: none;
    text-shadow: none;
    -gtk-icon-shadow: none;
    outline-color: transparentize($osd_fg_color, 0.7);
  }

  @else if $t==osd-insensitive {
  //
  // insensitive osd button
  //
    color: $osd_insensitive_fg_color;
    border-color: $osd_borders_color;
    background-color: transparent;
    $button_fill: image($osd_insensitive_bg_color) !global;
    background-image: $button_fill;
    background-clip: padding-box;
    box-shadow: none;
    text-shadow: none;
    -gtk-icon-shadow: none;
  }

  
  @else if $t==undecorated {
  //
  // reset
  //
    border-color: transparent;
    background-color: transparent;
    $button_fill: none !global;
    background-image: $button_fill;

    @include _shadows(inset 0 1px transparentize(white, 1), $_blank_edge);

    text-shadow: none;
    -gtk-icon-shadow: none;
  }
}