//
// Navigation Bar
// ==============================




// Base
// ---------------------------

.NavigationBar {
	.box-sizing(content-box); // allows us to set a fixed height whilst growing when padding is applied
	.retina-1px-border-bottom( rgba(0, 0, 0, 0.28) );
	background-color: @headerbar-bg;
	line-height: @headerbar-height;
	height: @headerbar-height;
	position: relative;
	z-index: @view-transition-stack-top + 1;

	// make room for the iOS statusbar
	.device--iPhone & {
		padding-top: @statusbar-height;
	}
}




// Buttons - Common
// ---------------------------


/*
 * 1. force hardware accelaration - prepare for animation
 *    removes antialising artefacts left by transform/animation
 * 2. remove browser default styles from <button>
 *    button is used to leverage the [disabled] attribute
 * 3. stops overflow without having to apply overflow:hidden on the wrapper
 * 4. position and stack the element for layout
 **/

.NavigationBarLeftButton,
.NavigationBarRightButton {
	.transition( opacity 80ms );
	.translateZ(0); // 1
	background: none; // 2
	color: @headerbar-button-color;
	border: none; // 2
	bottom: 0;
	line-height: @headerbar-height; // 3
	height: @headerbar-height; // 3
	outline: none; // 2
	position: absolute; // 4
	z-index: 2; // 4
	-webkit-appearance: none; // 2

	&[disabled] {
		color: @headerbar-button-color-disabled;
	}

	&.Tappable-active {
		opacity: .5;
	}
}




// Left Button
// ---------------------------

// arrow and label position themselves

.NavigationBarLeftButton {}




// Left Icon / Back Chevron (child of left button)
// ---------------------------

// common

.NavigationBarLeftArrow,
.NavigationBarLeftIcon {
	.translateZ(0);
	bottom: 0;
	left: 0;
	line-height: inherit;
	position: absolute;
	text-align: center; // center the chevron
	vertical-align: top;
	width: @headerbar-left-arrow-with-gutter;
	z-index: 3; // should be the highest element in the navigation bar
}

// arrow

.NavigationBarLeftArrow {
	#gradient .horizontal(@headerbar-bg, fade(@headerbar-bg, 0%), 50%, 100%); // mask the label as it enters and leaves
	.ionicon(inherit, @ionicon-var-chevron-left, @icon-size-large);
	line-height: inherit;
}

// icon

.NavigationBarLeftIcon {
	display: none; // hide from iOS
	font-size: @icon-size-large;
}




// Left Label
// Child of Left Button
// ---------------------------

.NavigationBarLeftLabel {
	.translateZ(0);
	bottom: 0;
	color: inherit;
	display: inline-block;
	left: @gutter-sm;
	vertical-align: top;
	line-height: @headerbar-height;
	height: @headerbar-height;
	position: absolute;

	// FIXME: always offset the label to stop jank
	// .has-arrow & {
	// 	left: @headerbar-left-arrow-with-gutter;
	// }
	left: @headerbar-left-arrow-with-gutter;
}




// Title
// ---------------------------

.NavigationBarTitle {
	bottom: 0;
	font-weight: 500;
	height: @headerbar-height;
	left: 0;
	line-height: @headerbar-height;
	position: absolute;
	text-align: center;
	width: 100%;
	z-index: 1;
}




// Right Button
// ---------------------------

.NavigationBarRightButton {
	right: @gutter-sm;
}




// Right Icon
// ---------------------------

.NavigationBarRightIcon {
	font-size: @icon-size-large;
}




// Animation
// ---------------------------

// 1. set common duration
// 2. set common timing function
// 3. disable user interaction during transitions

.NavigationBarTransition-Instant-enter,
.NavigationBarTransition-Instant-leave,
.NavigationBarTransition-Fade-enter,
.NavigationBarTransition-Fade-leave,
.NavigationBarTransition-Forwards-enter,
.NavigationBarTransition-Forwards-leave,
.NavigationBarTransition-Backwards-enter,
.NavigationBarTransition-Backwards-leave {
	.animation-duration( @view-transition-duration ); // 1
	.animation-timing-function( @view-transition-timing-function ); // 2
	pointer-events: none; // 3
}

// set transition types

.NavigationBarTransition-Fade-enter {
	.animation-name( fadeIn );
}
.NavigationBarTransition-Fade-leave {
	.animation-name( fadeOut );
}
.NavigationBarTransition-Forwards-enter {
	.animation-name( NavigationBarTransitionForwardsEnter );
}
.NavigationBarTransition-Forwards-leave {
	.animation-name( NavigationBarTransitionForwardsLeave );
}
.NavigationBarTransition-Backwards-enter {
	.animation-name( NavigationBarTransitionBackwardsEnter );
}
.NavigationBarTransition-Backwards-leave {
	.animation-name( NavigationBarTransitionBackwardsLeave );
}

// instant is a special case. intentionally declared last

.NavigationBarTransition-Instant-enter {
	.animation( fadeIn 50ms linear );
}
.NavigationBarTransition-Instant-leave {
	.animation( fadeOut 50ms linear );
}


// Describe animation keyframes

// header element (forwards) - enter
@-webkit-keyframes NavigationBarTransitionForwardsEnter {
	from { opacity: 0; -webkit-transform: translate3d(@view-transition-distance, 0, 0); }
	to   { opacity: 1; -webkit-transform: translate3d(0, 0, 0); }
}
@keyframes NavigationBarTransitionForwardsEnter {
	from { opacity: 0; transform: translate3d(@view-transition-distance, 0, 0); }
	to   { opacity: 1; transform: translate3d(0, 0, 0); }
}

// header element (forwards) - leave
@-webkit-keyframes NavigationBarTransitionForwardsLeave {
	from { opacity: 1; -webkit-transform: translate3d(0, 0, 0); }
	to   { opacity: 0; -webkit-transform: translate3d(-@view-transition-distance, 0, 0); }
}
@keyframes NavigationBarTransitionForwardsLeave {
	from { opacity: 1; transform: translate3d(0, 0, 0); }
	to   { opacity: 0; transform: translate3d(-@view-transition-distance, 0, 0); }
}

// header element (backwards) - enter
@-webkit-keyframes NavigationBarTransitionBackwardsEnter {
	from { opacity: 0; -webkit-transform: translate3d(-@view-transition-distance, 0, 0); }
	to   { opacity: 1; -webkit-transform: translate3d(0, 0, 0); }
}
@keyframes NavigationBarTransitionBackwardsEnter {
	from { opacity: 0; transform: translate3d(-@view-transition-distance, 0, 0); }
	to   { opacity: 1; transform: translate3d(0, 0, 0); }
}

// header element (backwards) - leave
@-webkit-keyframes NavigationBarTransitionBackwardsLeave {
	from { opacity: 1; -webkit-transform: translate3d(0, 0, 0); }
	to   { opacity: 0; -webkit-transform: translate3d(@view-transition-distance, 0, 0); }
}
@keyframes NavigationBarTransitionBackwardsLeave {
	from { opacity: 1; transform: translate3d(0, 0, 0); }
	to   { opacity: 0; transform: translate3d(@view-transition-distance, 0, 0); }
}