@mixin button($style: simple, $base-color: #4294f0, $text-size: inherit, $padding: 7px 18px) {

	@if type-of($style) == string and type-of($base-color) == color {
		@include buttonstyle($style, $base-color, $text-size, $padding);
	}

	@if type-of($style) == string and type-of($base-color) == number {
		$padding: $text-size;
		$text-size: $base-color;
		$base-color: #4294f0;

		@if $padding == inherit {
			$padding: 7px 18px;
		}

		@include buttonstyle($style, $base-color, $text-size, $padding);
	}

	@if type-of($style) == color and type-of($base-color) == color {
		$base-color: $style;
		$style: simple;
		@include buttonstyle($style, $base-color, $text-size, $padding);
	}

	@if type-of($style) == color and type-of($base-color) == number {
		$padding: $text-size;
		$text-size: $base-color;
		$base-color: $style;
		$style: simple;

		@if $padding == inherit {
			$padding: 7px 18px;
		}

		@include buttonstyle($style, $base-color, $text-size, $padding);
	}

	@if type-of($style) == number {
		$padding: $base-color;
		$text-size: $style;
		$base-color: #4294f0;
		$style: simple;

		@if $padding == #4294f0 {
			$padding: 7px 18px;
		}

		@include buttonstyle($style, $base-color, $text-size, $padding);
	}

	&:disabled {
		opacity: 0.5;
		cursor: not-allowed;
	}
}

// Selector Style Button
//************************************************************************//
@mixin buttonstyle($type, $b-color, $t-size, $pad) {
	// Grayscale button
	@if $type == simple and $b-color == grayscale($b-color) {
		@include simple($b-color, true, $t-size, $pad);
	}

	@if $type == shiny and $b-color == grayscale($b-color) {
		@include shiny($b-color, true, $t-size, $pad);
	}

	@if $type == pill and $b-color == grayscale($b-color) {
		@include pill($b-color, true, $t-size, $pad);
	}

	@if $type == flat and $b-color == grayscale($b-color) {
		@include flat($b-color, true, $t-size, $pad);
	}

	// Colored button
	@if $type == simple {
		@include simple($b-color, false, $t-size, $pad);
	} @else if $type == shiny {
		@include shiny($b-color, false, $t-size, $pad);
	} @else if $type == pill {
		@include pill($b-color, false, $t-size, $pad);
	} @else if $type == flat {
		@include flat($b-color, false, $t-size, $pad);
	}
}

// Simple Button
//************************************************************************//
@mixin simple($base-color, $grayscale: false, $textsize: inherit, $padding: 7px 18px) {
	$color: hsl(0, 0, 100%);
	$border: adjust-color($base-color, $saturation: 9%, $lightness: -14%);
	$inset-shadow: adjust-color($base-color, $saturation: -8%, $lightness: 15%);
	$stop-gradient: adjust-color($base-color, $saturation: 9%, $lightness: -11%);
	$text-shadow: adjust-color($base-color, $saturation: 15%, $lightness: -18%);

	@if is-light($base-color) {
		$color: hsl(0, 0, 20%);
		$text-shadow: adjust-color($base-color, $saturation: 10%, $lightness: 4%);
	}

	@if $grayscale == true {
		$border: grayscale($border);
		$inset-shadow: grayscale($inset-shadow);
		$stop-gradient: grayscale($stop-gradient);
		$text-shadow: grayscale($text-shadow);
	}

	border: 1px solid $border;
	border-radius: 3px;
	box-shadow: inset 0 1px 0 0 $inset-shadow;
	color: $color;
	display: inline-block;
	font-size: $textsize;
	font-weight: bold;
	@include linear-gradient ($base-color, $stop-gradient);
	padding: $padding;
	text-decoration: none;
	text-shadow: 0 1px 0 $text-shadow;
	background-clip: padding-box;

	&:hover:not(:disabled) {
		$base-color-hover: adjust-color($base-color, $saturation: -4%, $lightness: -5%);
		$inset-shadow-hover: adjust-color($base-color, $saturation: -7%, $lightness: 5%);
		$stop-gradient-hover: adjust-color($base-color, $saturation: 8%, $lightness: -14%);

		@if $grayscale == true {
			$base-color-hover: grayscale($base-color-hover);
			$inset-shadow-hover: grayscale($inset-shadow-hover);
			$stop-gradient-hover: grayscale($stop-gradient-hover);
		}

		box-shadow: inset 0 1px 0 0 $inset-shadow-hover;
		cursor: pointer;
		@include linear-gradient ($base-color-hover, $stop-gradient-hover);
	}

	&:active:not(:disabled),
	&:focus:not(:disabled) {
		$border-active: adjust-color($base-color, $saturation: 9%, $lightness: -14%);
		$inset-shadow-active: adjust-color($base-color, $saturation: 7%, $lightness: -17%);

		@if $grayscale == true {
			$border-active: grayscale($border-active);
			$inset-shadow-active: grayscale($inset-shadow-active);
		}

		border: 1px solid $border-active;
		box-shadow: inset 0 0 8px 4px $inset-shadow-active, inset 0 0 8px 4px $inset-shadow-active;
	}
}

// Shiny Button
//************************************************************************//
@mixin shiny($base-color, $grayscale: false, $textsize: inherit, $padding: 7px 18px) {
	$color: hsl(0, 0, 100%);
	$border: adjust-color($base-color, $red: -117, $green: -111, $blue: -81);
	$border-bottom: adjust-color($base-color, $red: -126, $green: -127, $blue: -122);
	$fourth-stop: adjust-color($base-color, $red: -79, $green: -70, $blue: -46);
	$inset-shadow: adjust-color($base-color, $red: 37, $green: 29, $blue: 12);
	$second-stop: adjust-color($base-color, $red: -56, $green: -50, $blue: -33);
	$text-shadow: adjust-color($base-color, $red: -140, $green: -141, $blue: -114);
	$third-stop: adjust-color($base-color, $red: -86, $green: -75, $blue: -48);

	@if is-light($base-color) {
		$color: hsl(0, 0, 20%);
		$text-shadow: adjust-color($base-color, $saturation: 10%, $lightness: 4%);
	}

	@if $grayscale == true {
		$border: grayscale($border);
		$border-bottom: grayscale($border-bottom);
		$fourth-stop: grayscale($fourth-stop);
		$inset-shadow: grayscale($inset-shadow);
		$second-stop: grayscale($second-stop);
		$text-shadow: grayscale($text-shadow);
		$third-stop: grayscale($third-stop);
	}

	border: 1px solid $border;
	border-bottom: 1px solid $border-bottom;
	border-radius: 5px;
	box-shadow: inset 0 1px 0 0 $inset-shadow;
	color: $color;
	display: inline-block;
	font-size: $textsize;
	font-weight: bold;
	@include linear-gradient(top, $base-color 0%, $second-stop 50%, $third-stop 50%, $fourth-stop 100%);
	padding: $padding;
	text-align: center;
	text-decoration: none;
	text-shadow: 0 -1px 1px $text-shadow;

	&:hover:not(:disabled) {
		$first-stop-hover: adjust-color($base-color, $red: -13, $green: -15, $blue: -18);
		$second-stop-hover: adjust-color($base-color, $red: -66, $green: -62, $blue: -51);
		$third-stop-hover: adjust-color($base-color, $red: -93, $green: -85, $blue: -66);
		$fourth-stop-hover: adjust-color($base-color, $red: -86, $green: -80, $blue: -63);

		@if $grayscale == true {
			$first-stop-hover: grayscale($first-stop-hover);
			$second-stop-hover: grayscale($second-stop-hover);
			$third-stop-hover: grayscale($third-stop-hover);
			$fourth-stop-hover: grayscale($fourth-stop-hover);
		}

		cursor: pointer;
		@include linear-gradient(top, $first-stop-hover 0%,
				$second-stop-hover 50%,
				$third-stop-hover 50%,
				$fourth-stop-hover 100%);
	}

	&:active:not(:disabled),
	&:focus:not(:disabled) {
		$inset-shadow-active: adjust-color($base-color, $red: -111, $green: -116, $blue: -122);

		@if $grayscale == true {
			$inset-shadow-active: grayscale($inset-shadow-active);
		}

		box-shadow: inset 0 0 20px 0 $inset-shadow-active;
	}
}

// Pill Button
//************************************************************************//
@mixin pill($base-color, $grayscale: false, $textsize: inherit, $padding: 7px 18px) {
	$color: hsl(0, 0, 100%);
	$border-bottom: adjust-color($base-color, $hue: 8, $saturation: -11%, $lightness: -26%);
	$border-sides: adjust-color($base-color, $hue: 4, $saturation: -21%, $lightness: -21%);
	$border-top: adjust-color($base-color, $hue: -1, $saturation: -30%, $lightness: -15%);
	$inset-shadow: adjust-color($base-color, $hue: -1, $saturation: -1%, $lightness: 7%);
	$stop-gradient: adjust-color($base-color, $hue: 8, $saturation: 14%, $lightness: -10%);
	$text-shadow: adjust-color($base-color, $hue: 5, $saturation: -19%, $lightness: -15%);

	@if is-light($base-color) {
		$color: hsl(0, 0, 20%);
		$text-shadow: adjust-color($base-color, $saturation: 10%, $lightness: 4%);
	}

	@if $grayscale == true {
		$border-bottom: grayscale($border-bottom);
		$border-sides: grayscale($border-sides);
		$border-top: grayscale($border-top);
		$inset-shadow: grayscale($inset-shadow);
		$stop-gradient: grayscale($stop-gradient);
		$text-shadow: grayscale($text-shadow);
	}

	border: 1px solid $border-top;
	border-color: $border-top $border-sides $border-bottom;
	border-radius: 16px;
	box-shadow: inset 0 1px 0 0 $inset-shadow;
	color: $color;
	display: inline-block;
	font-size: $textsize;
	font-weight: normal;
	line-height: 1;
	@include linear-gradient ($base-color, $stop-gradient);
	padding: $padding;
	text-align: center;
	text-decoration: none;
	text-shadow: 0 -1px 1px $text-shadow;
	background-clip: padding-box;

	&:hover:not(:disabled) {
		$base-color-hover: adjust-color($base-color, $lightness: -4.5%);
		$border-bottom: adjust-color($base-color, $hue: 8, $saturation: 13.5%, $lightness: -32%);
		$border-sides: adjust-color($base-color, $hue: 4, $saturation: -2%, $lightness: -27%);
		$border-top: adjust-color($base-color, $hue: -1, $saturation: -17%, $lightness: -21%);
		$inset-shadow-hover: adjust-color($base-color, $saturation: -1%, $lightness: 3%);
		$stop-gradient-hover: adjust-color($base-color, $hue: 8, $saturation: -4%, $lightness: -15.5%);
		$text-shadow-hover: adjust-color($base-color, $hue: 5, $saturation: -5%, $lightness: -22%);

		@if $grayscale == true {
			$base-color-hover: grayscale($base-color-hover);
			$border-bottom: grayscale($border-bottom);
			$border-sides: grayscale($border-sides);
			$border-top: grayscale($border-top);
			$inset-shadow-hover: grayscale($inset-shadow-hover);
			$stop-gradient-hover: grayscale($stop-gradient-hover);
			$text-shadow-hover: grayscale($text-shadow-hover);
		}

		border: 1px solid $border-top;
		border-color: $border-top $border-sides $border-bottom;
		box-shadow: inset 0 1px 0 0 $inset-shadow-hover;
		cursor: pointer;
		@include linear-gradient ($base-color-hover, $stop-gradient-hover);
		text-shadow: 0 -1px 1px $text-shadow-hover;
		background-clip: padding-box;
	}

	&:active:not(:disabled),
	&:focus:not(:disabled) {
		$active-color: adjust-color($base-color, $hue: 4, $saturation: -12%, $lightness: -10%);
		$border-active: adjust-color($base-color, $hue: 6, $saturation: -2.5%, $lightness: -30%);
		$border-bottom-active: adjust-color($base-color, $hue: 11, $saturation: 6%, $lightness: -31%);
		$inset-shadow-active: adjust-color($base-color, $hue: 9, $saturation: 2%, $lightness: -21.5%);
		$text-shadow-active: adjust-color($base-color, $hue: 5, $saturation: -12%, $lightness: -21.5%);

		@if $grayscale == true {
			$active-color: grayscale($active-color);
			$border-active: grayscale($border-active);
			$border-bottom-active: grayscale($border-bottom-active);
			$inset-shadow-active: grayscale($inset-shadow-active);
			$text-shadow-active: grayscale($text-shadow-active);
		}

		background: $active-color;
		border: 1px solid $border-active;
		border-bottom: 1px solid $border-bottom-active;
		box-shadow: inset 0 0 6px 3px $inset-shadow-active;
		text-shadow: 0 -1px 1px $text-shadow-active;
	}
}

// Flat Button
//************************************************************************//
@mixin flat($base-color, $grayscale: false, $textsize: inherit, $padding: 7px 18px) {
	$color: hsl(0, 0, 100%);

	@if is-light($base-color) {
		$color: hsl(0, 0, 20%);
	}

	background-color: $base-color;
	border-radius: 3px;
	border: none;
	color: $color;
	display: inline-block;
	font-size: inherit;
	font-weight: bold;
	padding: 7px 18px;
	text-decoration: none;
	background-clip: padding-box;

	&:hover:not(:disabled) {
		$base-color-hover: adjust-color($base-color, $saturation: 4%, $lightness: 5%);

		@if $grayscale == true {
			$base-color-hover: grayscale($base-color-hover);
		}

		background-color: $base-color-hover;
		cursor: pointer;
	}

	&:active:not(:disabled),
	&:focus:not(:disabled) {
		$base-color-active: adjust-color($base-color, $saturation: -4%, $lightness: -5%);

		@if $grayscale == true {
			$base-color-active: grayscale($base-color-active);
		}

		background-color: $base-color-active;
		cursor: pointer;
	}
}
