/**
* Default settings for jQuery UI Autocomplete for use with non-hierarchical taxonomies.
*
* @output wp-admin/js/tags-suggest.js
*/
( function( $ ) {
var tempID = 0;
var separator = wp.i18n._x( ',', 'tag delimiter' ) || ',';
var __ = wp.i18n.__,
_n = wp.i18n._n,
sprintf = wp.i18n.sprintf;

function split( val ) {
return val.split( new RegExp( separator + '\\s*' ) );
}

function getLast( term ) {
return split( term ).pop();
}

/**
* Add UI Autocomplete to an input or textarea element with presets for use
* with non-hierarchical taxonomies.
*
* Example: `$( element ).wpTagsSuggest( options )`.
*
* The taxonomy can be passed in a `data-wp-taxonomy` attribute on the element or
* can be in `options.taxonomy`.
*
* @since 4.7.0
*
* @param {Object} options Options that are passed to UI Autocomplete. Can be used to override the default settings.
* @return {Object} jQuery instance.
*/
$.fn.wpTagsSuggest = function( options ) {
var cache;
var last;
var $element = $( this );

// Do not initialize if the element doesn't exist.
if ( ! $element.length ) {
return this;
}

options = options || {};

var taxonomy = options.taxonomy || $element.attr( 'data-wp-taxonomy' ) || 'post_tag';

delete( options.taxonomy );

options = $.extend( {
source: function( request, response ) {
var term;

if ( last === request.term ) {
response( cache );
return;
}

term = getLast( request.term );

$.get( window.ajaxurl, {
action: 'ajax-tag-search',
tax: taxonomy,
q: term,
number: 20
} ).always( function() {
$element.removeClass( 'ui-autocomplete-loading' ); // UI fails to remove this sometimes?
} ).done( function( data ) {
var tagName;
var tags = [];

if ( data ) {
data = data.split( '\n' );

for ( tagName in data ) {
var id = ++tempID;

tags.push({
id: id,
name: data[tagName]
});
}

cache = tags;
response( tags );
} else {
response( tags );
}
} );

last = request.term;
},
focus: function( event, ui ) {
$element.attr( 'aria-activedescendant', 'wp-tags-autocomplete-' + ui.item.id );

// Don't empty the input field when using the arrow keys
// to highlight items. See api.jqueryui.com/autocomplete/#event-focus
event.preventDefault();
},
select: function( event, ui ) {
var tags = split( $element.val() );
// Remove the last user input.
tags.pop();
// Append the new tag and an empty element to get one more separator at the end.
tags.push( ui.item.name, '' );

$element.val( tags.join( separator + ' ' ) );

if ( $.ui.keyCode.TAB === event.keyCode ) {
// Audible confirmation message when a tag has been selected.
window.wp.a11y.speak( wp.i18n.__( 'Term selected.' ), 'assertive' );
event.preventDefault();
} else if ( $.ui.keyCode.ENTER === event.keyCode ) {
// If we're in the edit post Tags meta box, add the tag.
if ( window.tagBox ) {
window.tagBox.userAction = 'add';
window.tagBox.flushTags( $( this ).closest( '.tagsdiv' ) );
}

// Do not close Quick Edit / Bulk Edit.
event.preventDefault();
event.stopPropagation();
}

return false;
},
open: function() {
$element.attr( 'aria-expanded', 'true' );
},
close: function() {
$element.attr( 'aria-expanded', 'false' );
},
minLength: 2,
position: {
my: 'left top+2',
at: 'left bottom',
collision: 'none'
},
messages: {
noResults: __( 'No results found.' ),
results: function( number ) {
return sprintf(
/* translators: %d: Number of search results found. */
_n(
'%d result found. Use up and down arrow keys to navigate.',
'%d results found. Use up and down arrow keys to navigate.',
number
),
number
);
}
}
}, options );

$element.on( 'keydown', function() {
$element.removeAttr( 'aria-activedescendant' );
} );

$element.autocomplete( options );

// Ensure the autocomplete instance exists.
if ( ! $element.autocomplete( 'instance' ) ) {
return this;
}

$element.autocomplete( 'instance' )._renderItem = function( ul, item ) {
return $( '<li role="option" id="wp-tags-autocomplete-' + item.id + '">' )
.text( item.name )
.appendTo( ul );
};

$element.attr( {
'role': 'combobox',
'aria-autocomplete': 'list',
'aria-expanded': 'false',
'aria-owns': $element.autocomplete( 'widget' ).attr( 'id' )
} )
.on( 'focus', function() {
var inputValue = split( $element.val() ).pop();

// Don't trigger a search if the field is empty.
// Also, avoids screen readers announce `No search results`.
if ( inputValue ) {
$element.autocomplete( 'search' );
}
} );

// Returns a jQuery object containing the menu element.
$element.autocomplete( 'widget' )
.addClass( 'wp-tags-autocomplete' )
.attr( 'role', 'listbox' )
.removeAttr( 'tabindex' ) // Remove the `tabindex=0` attribute added by jQuery UI.

/*
* Looks like Safari and VoiceOver need an `aria-selected` attribute. See ticket #33301.
* The `menufocus` and `menublur` events are the same events used to add and remove
* the `ui-state-focus` CSS class on the menu items. See jQuery UI Menu Widget.
*/
.on( 'menufocus', function( event, ui ) {
ui.item.attr( 'aria-selected', 'true' );
})
.on( 'menublur', function() {
// The `menublur` event returns an object where the item is `null`,
// so we need to find the active item with other means.
$( this ).find( '[aria-selected="true"]' ).removeAttr( 'aria-selected' );
});

return this;
};

}( jQuery ) );