function UIElement( dom ) {

	this.dom = dom;

}

UIElement.prototype = {

	add: function () {

		for ( var i = 0; i < arguments.length; i ++ ) {

			var argument = arguments[ i ];

			if ( argument instanceof UIElement ) {

				this.dom.appendChild( argument.dom );

			} else {

				console.error( 'UIElement:', argument, 'is not an instance of UIElement.' );

			}

		}

		return this;

	},

	remove: function () {

		for ( var i = 0; i < arguments.length; i ++ ) {

			var argument = arguments[ i ];

			if ( argument instanceof UIElement ) {

				this.dom.removeChild( argument.dom );

			} else {

				console.error( 'UIElement:', argument, 'is not an instance of UIElement.' );

			}

		}

		return this;

	},

	clear: function () {

		while ( this.dom.children.length ) {

			this.dom.removeChild( this.dom.lastChild );

		}

	},

	setId: function ( id ) {

		this.dom.id = id;

		return this;

	},

	getId: function () {

		return this.dom.id;

	},

	setClass: function ( name ) {

		this.dom.className = name;

		return this;

	},

	addClass: function ( name ) {

		this.dom.classList.add( name );

		return this;

	},

	removeClass: function ( name ) {

		this.dom.classList.remove( name );

		return this;

	},

	setStyle: function ( style, array ) {

		for ( var i = 0; i < array.length; i ++ ) {

			this.dom.style[ style ] = array[ i ];

		}

		return this;

	},

	setDisabled: function ( value ) {

		this.dom.disabled = value;

		return this;

	},

	setTextContent: function ( value ) {

		this.dom.textContent = value;

		return this;

	},

	getIndexOfChild: function ( element ) {

		return Array.prototype.indexOf.call( this.dom.children, element.dom );

	}

};

// properties

var properties = [ 'position', 'left', 'top', 'right', 'bottom', 'width', 'height', 'border', 'borderLeft',
	'borderTop', 'borderRight', 'borderBottom', 'borderColor', 'display', 'overflow', 'margin', 'marginLeft', 'marginTop', 'marginRight', 'marginBottom', 'padding', 'paddingLeft', 'paddingTop', 'paddingRight', 'paddingBottom', 'color',
	'background', 'backgroundColor', 'opacity', 'fontSize', 'fontWeight', 'textAlign', 'textDecoration', 'textTransform', 'cursor', 'zIndex' ];

properties.forEach( function ( property ) {

	var method = 'set' + property.substr( 0, 1 ).toUpperCase() + property.substr( 1, property.length );

	UIElement.prototype[ method ] = function () {

		this.setStyle( property, arguments );

		return this;

	};

} );

// events

var events = [ 'KeyUp', 'KeyDown', 'MouseOver', 'MouseOut', 'Click', 'DblClick', 'Change', 'Input' ];

events.forEach( function ( event ) {

	var method = 'on' + event;

	UIElement.prototype[ method ] = function ( callback ) {

		this.dom.addEventListener( event.toLowerCase(), callback.bind( this ), false );

		return this;

	};

} );

// UISpan

function UISpan() {

	UIElement.call( this );

	this.dom = document.createElement( 'span' );

	return this;

}

UISpan.prototype = Object.create( UIElement.prototype );
UISpan.prototype.constructor = UISpan;

// UIDiv

function UIDiv() {

	UIElement.call( this );

	this.dom = document.createElement( 'div' );

	return this;

}

UIDiv.prototype = Object.create( UIElement.prototype );
UIDiv.prototype.constructor = UIDiv;

// UIRow

function UIRow() {

	UIElement.call( this );

	var dom = document.createElement( 'div' );
	dom.className = 'Row';

	this.dom = dom;

	return this;

}

UIRow.prototype = Object.create( UIElement.prototype );
UIRow.prototype.constructor = UIRow;

// UIPanel

function UIPanel() {

	UIElement.call( this );

	var dom = document.createElement( 'div' );
	dom.className = 'Panel';

	this.dom = dom;

	return this;

}

UIPanel.prototype = Object.create( UIElement.prototype );
UIPanel.prototype.constructor = UIPanel;

// UIText

function UIText( text ) {

	UIElement.call( this );

	var dom = document.createElement( 'span' );
	dom.className = 'Text';
	dom.style.cursor = 'default';
	dom.style.display = 'inline-block';
	dom.style.verticalAlign = 'middle';

	this.dom = dom;
	this.setValue( text );

	return this;

}

UIText.prototype = Object.create( UIElement.prototype );
UIText.prototype.constructor = UIText;

UIText.prototype.getValue = function () {

	return this.dom.textContent;

};

UIText.prototype.setValue = function ( value ) {

	if ( value !== undefined ) {

		this.dom.textContent = value;

	}

	return this;

};


// UIInput

function UIInput( text ) {

	UIElement.call( this );

	var dom = document.createElement( 'input' );
	dom.className = 'Input';
	dom.style.padding = '2px';
	dom.style.border = '1px solid transparent';

	dom.addEventListener( 'keydown', function ( event ) {

		event.stopPropagation();

	}, false );

	this.dom = dom;
	this.setValue( text );

	return this;

}

UIInput.prototype = Object.create( UIElement.prototype );
UIInput.prototype.constructor = UIInput;

UIInput.prototype.getValue = function () {

	return this.dom.value;

};

UIInput.prototype.setValue = function ( value ) {

	this.dom.value = value;

	return this;

};


// UITextArea

function UITextArea() {

	UIElement.call( this );

	var dom = document.createElement( 'textarea' );
	dom.className = 'TextArea';
	dom.style.padding = '2px';
	dom.spellcheck = false;

	dom.addEventListener( 'keydown', function ( event ) {

		event.stopPropagation();

		if ( event.keyCode === 9 ) {

			event.preventDefault();

			var cursor = dom.selectionStart;

			dom.value = dom.value.substring( 0, cursor ) + '\t' + dom.value.substring( cursor );
			dom.selectionStart = cursor + 1;
			dom.selectionEnd = dom.selectionStart;

		}

	}, false );

	this.dom = dom;

	return this;

}

UITextArea.prototype = Object.create( UIElement.prototype );
UITextArea.prototype.constructor = UITextArea;

UITextArea.prototype.getValue = function () {

	return this.dom.value;

};

UITextArea.prototype.setValue = function ( value ) {

	this.dom.value = value;

	return this;

};


// UISelect

function UISelect() {

	UIElement.call( this );

	var dom = document.createElement( 'select' );
	dom.className = 'Select';
	dom.style.padding = '2px';

	this.dom = dom;

	return this;

}

UISelect.prototype = Object.create( UIElement.prototype );
UISelect.prototype.constructor = UISelect;

UISelect.prototype.setMultiple = function ( boolean ) {

	this.dom.multiple = boolean;

	return this;

};

UISelect.prototype.setOptions = function ( options ) {

	var selected = this.dom.value;

	while ( this.dom.children.length > 0 ) {

		this.dom.removeChild( this.dom.firstChild );

	}

	for ( var key in options ) {

		var option = document.createElement( 'option' );
		option.value = key;
		option.innerHTML = options[ key ];
		this.dom.appendChild( option );

	}

	this.dom.value = selected;

	return this;

};

UISelect.prototype.getValue = function () {

	return this.dom.value;

};

UISelect.prototype.setValue = function ( value ) {

	value = String( value );

	if ( this.dom.value !== value ) {

		this.dom.value = value;

	}

	return this;

};

// UICheckbox

function UICheckbox( boolean ) {

	UIElement.call( this );

	var dom = document.createElement( 'input' );
	dom.className = 'Checkbox';
	dom.type = 'checkbox';

	this.dom = dom;
	this.setValue( boolean );

	return this;

}

UICheckbox.prototype = Object.create( UIElement.prototype );
UICheckbox.prototype.constructor = UICheckbox;

UICheckbox.prototype.getValue = function () {

	return this.dom.checked;

};

UICheckbox.prototype.setValue = function ( value ) {

	if ( value !== undefined ) {

		this.dom.checked = value;

	}

	return this;

};


// UIColor

function UIColor() {

	UIElement.call( this );

	var dom = document.createElement( 'input' );
	dom.className = 'Color';
	dom.style.width = '32px';
	dom.style.height = '16px';
	dom.style.border = '0px';
	dom.style.padding = '2px';
	dom.style.backgroundColor = 'transparent';

	try {

		dom.type = 'color';
		dom.value = '#ffffff';

	} catch ( exception ) {}

	this.dom = dom;

	return this;

}

UIColor.prototype = Object.create( UIElement.prototype );
UIColor.prototype.constructor = UIColor;

UIColor.prototype.getValue = function () {

	return this.dom.value;

};

UIColor.prototype.getHexValue = function () {

	return parseInt( this.dom.value.substr( 1 ), 16 );

};

UIColor.prototype.setValue = function ( value ) {

	this.dom.value = value;

	return this;

};

UIColor.prototype.setHexValue = function ( hex ) {

	this.dom.value = '#' + ( '000000' + hex.toString( 16 ) ).slice( - 6 );

	return this;

};


// UINumber

function UINumber( number ) {

	UIElement.call( this );

	var scope = this;

	var dom = document.createElement( 'input' );
	dom.style.cursor = 'ns-resize';
	dom.className = 'Number';
	dom.value = '0.00';

	this.value = 0;

	this.min = - Infinity;
	this.max = Infinity;

	this.precision = 2;
	this.step = 1;
	this.unit = '';
	this.nudge = 0.01;

	this.dom = dom;

	this.setValue( number );

	var changeEvent = document.createEvent( 'HTMLEvents' );
	changeEvent.initEvent( 'change', true, true );

	var distance = 0;
	var onMouseDownValue = 0;

	var pointer = [ 0, 0 ];
	var prevPointer = [ 0, 0 ];

	function onMouseDown( event ) {

		event.preventDefault();

		distance = 0;

		onMouseDownValue = scope.value;

		prevPointer = [ event.clientX, event.clientY ];

		document.addEventListener( 'mousemove', onMouseMove, false );
		document.addEventListener( 'mouseup', onMouseUp, false );

	}

	function onMouseMove( event ) {

		var currentValue = scope.value;

		pointer = [ event.clientX, event.clientY ];

		distance += ( pointer[ 0 ] - prevPointer[ 0 ] ) - ( pointer[ 1 ] - prevPointer[ 1 ] );

		var value = onMouseDownValue + ( distance / ( event.shiftKey ? 5 : 50 ) ) * scope.step;
		value = Math.min( scope.max, Math.max( scope.min, value ) );

		if ( currentValue !== value ) {

			scope.setValue( value );
			dom.dispatchEvent( changeEvent );

		}

		prevPointer = [ event.clientX, event.clientY ];

	}

	function onMouseUp() {

		document.removeEventListener( 'mousemove', onMouseMove, false );
		document.removeEventListener( 'mouseup', onMouseUp, false );

		if ( Math.abs( distance ) < 2 ) {

			dom.focus();
			dom.select();

		}

	}

	function onTouchStart( event ) {

		if ( event.touches.length === 1 ) {

			distance = 0;

			onMouseDownValue = scope.value;

			prevPointer = [ event.touches[ 0 ].pageX, event.touches[ 0 ].pageY ];

			document.addEventListener( 'touchmove', onTouchMove, false );
			document.addEventListener( 'touchend', onTouchEnd, false );

		}

	}

	function onTouchMove( event ) {

		var currentValue = scope.value;

		pointer = [ event.touches[ 0 ].pageX, event.touches[ 0 ].pageY ];

		distance += ( pointer[ 0 ] - prevPointer[ 0 ] ) - ( pointer[ 1 ] - prevPointer[ 1 ] );

		var value = onMouseDownValue + ( distance / ( event.shiftKey ? 5 : 50 ) ) * scope.step;
		value = Math.min( scope.max, Math.max( scope.min, value ) );

		if ( currentValue !== value ) {

			scope.setValue( value );
			dom.dispatchEvent( changeEvent );

		}

		prevPointer = [ event.touches[ 0 ].pageX, event.touches[ 0 ].pageY ];

	}

	function onTouchEnd( event ) {

		if ( event.touches.length === 0 ) {

			document.removeEventListener( 'touchmove', onTouchMove, false );
			document.removeEventListener( 'touchend', onTouchEnd, false );

		}

	}

	function onChange() {

		scope.setValue( dom.value );

	}

	function onFocus() {

		dom.style.backgroundColor = '';
		dom.style.cursor = '';

	}

	function onBlur() {

		dom.style.backgroundColor = 'transparent';
		dom.style.cursor = 'ns-resize';

	}

	function onKeyDown( event ) {

		event.stopPropagation();

		switch ( event.keyCode ) {

			case 13: // enter
				dom.blur();
				break;

			case 38: // up
				event.preventDefault();
				scope.setValue( scope.getValue() + scope.nudge );
				dom.dispatchEvent( changeEvent );
				break;

			case 40: // down
				event.preventDefault();
				scope.setValue( scope.getValue() - scope.nudge );
				dom.dispatchEvent( changeEvent );
				break;

		}

	}

	onBlur();

	dom.addEventListener( 'keydown', onKeyDown, false );
	dom.addEventListener( 'mousedown', onMouseDown, false );
	dom.addEventListener( 'touchstart', onTouchStart, false );
	dom.addEventListener( 'change', onChange, false );
	dom.addEventListener( 'focus', onFocus, false );
	dom.addEventListener( 'blur', onBlur, false );

	return this;

}

UINumber.prototype = Object.create( UIElement.prototype );
UINumber.prototype.constructor = UINumber;

UINumber.prototype.getValue = function () {

	return this.value;

};

UINumber.prototype.setValue = function ( value ) {

	if ( value !== undefined ) {

		value = parseFloat( value );

		if ( value < this.min ) value = this.min;
		if ( value > this.max ) value = this.max;

		this.value = value;
		this.dom.value = value.toFixed( this.precision );

		if ( this.unit !== '' ) this.dom.value += ' ' + this.unit;

	}

	return this;

};

UINumber.prototype.setPrecision = function ( precision ) {

	this.precision = precision;

	return this;

};

UINumber.prototype.setStep = function ( step ) {

	this.step = step;

	return this;

};

UINumber.prototype.setNudge = function ( nudge ) {

	this.nudge = nudge;

	return this;

};

UINumber.prototype.setRange = function ( min, max ) {

	this.min = min;
	this.max = max;

	return this;

};

UINumber.prototype.setUnit = function ( unit ) {

	this.unit = unit;

	return this;

};

// UIInteger

function UIInteger( number ) {

	UIElement.call( this );

	var scope = this;

	var dom = document.createElement( 'input' );
	dom.style.cursor = 'ns-resize';
	dom.className = 'Number';
	dom.value = '0';

	this.value = 0;

	this.min = - Infinity;
	this.max = Infinity;

	this.step = 1;
	this.nudge = 1;

	this.dom = dom;

	this.setValue( number );

	var changeEvent = document.createEvent( 'HTMLEvents' );
	changeEvent.initEvent( 'change', true, true );

	var distance = 0;
	var onMouseDownValue = 0;

	var pointer = [ 0, 0 ];
	var prevPointer = [ 0, 0 ];

	function onMouseDown( event ) {

		event.preventDefault();

		distance = 0;

		onMouseDownValue = scope.value;

		prevPointer = [ event.clientX, event.clientY ];

		document.addEventListener( 'mousemove', onMouseMove, false );
		document.addEventListener( 'mouseup', onMouseUp, false );

	}

	function onMouseMove( event ) {

		var currentValue = scope.value;

		pointer = [ event.clientX, event.clientY ];

		distance += ( pointer[ 0 ] - prevPointer[ 0 ] ) - ( pointer[ 1 ] - prevPointer[ 1 ] );

		var value = onMouseDownValue + ( distance / ( event.shiftKey ? 5 : 50 ) ) * scope.step;
		value = Math.min( scope.max, Math.max( scope.min, value ) ) | 0;

		if ( currentValue !== value ) {

			scope.setValue( value );
			dom.dispatchEvent( changeEvent );

		}

		prevPointer = [ event.clientX, event.clientY ];

	}

	function onMouseUp() {

		document.removeEventListener( 'mousemove', onMouseMove, false );
		document.removeEventListener( 'mouseup', onMouseUp, false );

		if ( Math.abs( distance ) < 2 ) {

			dom.focus();
			dom.select();

		}

	}

	function onChange() {

		scope.setValue( dom.value );

	}

	function onFocus() {

		dom.style.backgroundColor = '';
		dom.style.cursor = '';

	}

	function onBlur() {

		dom.style.backgroundColor = 'transparent';
		dom.style.cursor = 'ns-resize';

	}

	function onKeyDown( event ) {

		event.stopPropagation();

		switch ( event.keyCode ) {

			case 13: // enter
				dom.blur();
				break;

			case 38: // up
				event.preventDefault();
				scope.setValue( scope.getValue() + scope.nudge );
				dom.dispatchEvent( changeEvent );
				break;

			case 40: // down
				event.preventDefault();
				scope.setValue( scope.getValue() - scope.nudge );
				dom.dispatchEvent( changeEvent );
				break;

		}

	}

	onBlur();

	dom.addEventListener( 'keydown', onKeyDown, false );
	dom.addEventListener( 'mousedown', onMouseDown, false );
	dom.addEventListener( 'change', onChange, false );
	dom.addEventListener( 'focus', onFocus, false );
	dom.addEventListener( 'blur', onBlur, false );

	return this;

}

UIInteger.prototype = Object.create( UIElement.prototype );
UIInteger.prototype.constructor = UIInteger;

UIInteger.prototype.getValue = function () {

	return this.value;

};

UIInteger.prototype.setValue = function ( value ) {

	if ( value !== undefined ) {

		value = parseInt( value );

		this.value = value;
		this.dom.value = value;

	}

	return this;

};

UIInteger.prototype.setStep = function ( step ) {

	this.step = parseInt( step );

	return this;

};

UIInteger.prototype.setNudge = function ( nudge ) {

	this.nudge = nudge;

	return this;

};

UIInteger.prototype.setRange = function ( min, max ) {

	this.min = min;
	this.max = max;

	return this;

};


// UIBreak

function UIBreak() {

	UIElement.call( this );

	var dom = document.createElement( 'br' );
	dom.className = 'Break';

	this.dom = dom;

	return this;

}

UIBreak.prototype = Object.create( UIElement.prototype );
UIBreak.prototype.constructor = UIBreak;


// UIHorizontalRule

function UIHorizontalRule() {

	UIElement.call( this );

	var dom = document.createElement( 'hr' );
	dom.className = 'HorizontalRule';

	this.dom = dom;

	return this;

}

UIHorizontalRule.prototype = Object.create( UIElement.prototype );
UIHorizontalRule.prototype.constructor = UIHorizontalRule;


// UIButton

function UIButton( value ) {

	UIElement.call( this );

	var dom = document.createElement( 'button' );
	dom.className = 'Button';

	this.dom = dom;
	this.dom.textContent = value;

	return this;

}

UIButton.prototype = Object.create( UIElement.prototype );
UIButton.prototype.constructor = UIButton;

UIButton.prototype.setLabel = function ( value ) {

	this.dom.textContent = value;

	return this;

};


// UITabbedPanel

function UITabbedPanel( ) {

	UIElement.call( this );

	var dom = document.createElement( 'div' );

	this.dom = dom;

	this.setClass( 'TabbedPanel' );

	this.tabs = [];
	this.panels = [];

	this.tabsDiv = new UIDiv();
	this.tabsDiv.setClass( 'Tabs' );

	this.panelsDiv = new UIDiv();
	this.panelsDiv.setClass( 'Panels' );

	this.add( this.tabsDiv );
	this.add( this.panelsDiv );

	this.selected = '';

	return this;

}

UITabbedPanel.prototype = Object.create( UIElement.prototype );
UITabbedPanel.prototype.constructor = UITabbedPanel;

UITabbedPanel.prototype.select = function ( id ) {

	var tab;
	var panel;
	var scope = this;

	// Deselect current selection
	if ( this.selected && this.selected.length ) {

		tab = this.tabs.find( function ( item ) {

			return item.dom.id === scope.selected;

		} );
		panel = this.panels.find( function ( item ) {

			return item.dom.id === scope.selected;

		} );

		if ( tab ) {

			tab.removeClass( 'selected' );

		}

		if ( panel ) {

			panel.setDisplay( 'none' );

		}

	}

	tab = this.tabs.find( function ( item ) {

		return item.dom.id === id;

	} );
	panel = this.panels.find( function ( item ) {

		return item.dom.id === id;

	} );

	if ( tab ) {

		tab.addClass( 'selected' );

	}

	if ( panel ) {

		panel.setDisplay( '' );

	}

	this.selected = id;

	return this;

};

UITabbedPanel.prototype.addTab = function ( id, label, items ) {

	var tab = new UITabbedPanel.Tab( label, this );
	tab.setId( id );
	this.tabs.push( tab );
	this.tabsDiv.add( tab );

	var panel = new UIDiv();
	panel.setId( id );
	panel.add( items );
	panel.setDisplay( 'none' );
	this.panels.push( panel );
	this.panelsDiv.add( panel );

	this.select( id );

};

UITabbedPanel.Tab = function ( text, parent ) {

	UIText.call( this, text );
	this.parent = parent;

	this.setClass( 'Tab' );

	var scope = this;

	this.dom.addEventListener( 'click', function () {

		scope.parent.select( scope.dom.id );

	} );

	return this;

};

UITabbedPanel.Tab.prototype = Object.create( UIText.prototype );
UITabbedPanel.Tab.prototype.constructor = UITabbedPanel.Tab;

// UIListbox
function UIListbox( ) {

	UIElement.call( this );

	var dom = document.createElement( 'div' );
	dom.className = 'Listbox';
	dom.tabIndex = 0;

	this.dom = dom;
	this.items = [];
	this.listitems = [];
	this.selectedIndex = 0;
	this.selectedValue = null;

	return this;

}

UIListbox.prototype = Object.create( UIElement.prototype );
UIListbox.prototype.constructor = UIListbox;

UIListbox.prototype.setItems = function ( items ) {

	if ( Array.isArray( items ) ) {

		this.items = items;

	}

	this.render();

};

UIListbox.prototype.render = function ( ) {

	while ( this.listitems.length ) {

		var item = this.listitems[ 0 ];

		item.dom.remove();

		this.listitems.splice( 0, 1 );

	}

	for ( var i = 0; i < this.items.length; i ++ ) {

		var item = this.items[ i ];

		var listitem = new UIListbox.ListboxItem( this );
		listitem.setId( item.id || `Listbox-${i}` );
		listitem.setTextContent( item.name || item.type );
		this.add( listitem );

	}

};

// Assuming user passes valid list items
UIListbox.prototype.add = function () {

	var items = Array.from( arguments );

	this.listitems = this.listitems.concat( items );

	UIElement.prototype.add.apply( this, items );

};

UIListbox.prototype.selectIndex = function ( index ) {

	if ( index >= 0 && index < this.items.length ) {

		this.setValue( this.listitems[ index ].getId() );

	}

	this.selectedIndex = index;

};

UIListbox.prototype.getValue = function () {

	return this.selectedValue;

};

UIListbox.prototype.setValue = function ( value ) {

	for ( var i = 0; i < this.listitems.length; i ++ ) {

		var element = this.listitems[ i ];

		if ( element.getId() === value ) {

			element.addClass( 'active' );

		} else {

			element.removeClass( 'active' );

		}

	}

	this.selectedValue = value;

	var changeEvent = document.createEvent( 'HTMLEvents' );
	changeEvent.initEvent( 'change', true, true );
	this.dom.dispatchEvent( changeEvent );

};

// Listbox Item
UIListbox.ListboxItem = function ( parent ) {

	UIElement.call( this );

	var dom = document.createElement( 'div' );
	dom.className = 'ListboxItem';

	this.parent = parent;
	this.dom = dom;

	var scope = this;

	function onClick() {

		if ( scope.parent ) {

			scope.parent.setValue( scope.getId( ) );

		}

	}

	dom.addEventListener( 'click', onClick, false );

	return this;

};

UIListbox.ListboxItem.prototype = Object.create( UIElement.prototype );
UIListbox.ListboxItem.prototype.constructor = UIListbox.ListboxItem;

export { UIElement, UISpan, UIDiv, UIRow, UIPanel, UIText, UIInput, UITextArea, UISelect, UICheckbox, UIColor, UINumber, UIInteger, UIBreak, UIHorizontalRule, UIButton, UITabbedPanel, UIListbox };