text: if ( 'undefined' === typeof window.wp ) {
  	window.wp = {};
  }
  if ( 'undefined' === typeof window.wp.codeEditor ) {
  	window.wp.codeEditor = {};
  }
  
  ( function( $, wp ) {
  	'use strict';
  
  	/**
  	 * Default settings for code editor.
  	 *
  	 * @since 4.9.0
  	 * @type {object}
  	 */
  	wp.codeEditor.defaultSettings = {
  		codemirror: {},
  		csslint: {},
  		htmlhint: {},
  		jshint: {},
  		onTabNext: function() {},
  		onTabPrevious: function() {},
  		onChangeLintingErrors: function() {},
  		onUpdateErrorNotice: function() {}
  	};
  
  	/**
  	 * Configure linting.
  	 *
  	 * @param {CodeMirror} editor - Editor.
  	 * @param {object}     settings - Code editor settings.
  	 * @param {object}     settings.codeMirror - Settings for CodeMirror.
  	 * @param {Function}   settings.onChangeLintingErrors - Callback for when there are changes to linting errors.
  	 * @param {Function}   settings.onUpdateErrorNotice - Callback to update error notice.
  	 * @returns {void}
  	 */
  	function configureLinting( editor, settings ) { // eslint-disable-line complexity
  		var currentErrorAnnotations = [], previouslyShownErrorAnnotations = [];
  
  		/**
  		 * Call the onUpdateErrorNotice if there are new errors to show.
  		 *
  		 * @returns {void}
  		 */
  		function updateErrorNotice() {
  			if ( settings.onUpdateErrorNotice && ! _.isEqual( currentErrorAnnotations, previouslyShownErrorAnnotations ) ) {
  				settings.onUpdateErrorNotice( currentErrorAnnotations, editor );
  				previouslyShownErrorAnnotations = currentErrorAnnotations;
  			}
  		}
  
  		/**
  		 * Get lint options.
  		 *
  		 * @returns {object} Lint options.
  		 */
  		function getLintOptions() { // eslint-disable-line complexity
  			var options = editor.getOption( 'lint' );
  
  			if ( ! options ) {
  				return false;
  			}
  
  			if ( true === options ) {
  				options = {};
  			} else if ( _.isObject( options ) ) {
  				options = $.extend( {}, options );
  			}
  
  			// Note that rules must be sent in the "deprecated" lint.options property to prevent linter from complaining about unrecognized options. See <https://github.com/codemirror/CodeMirror/pull/4944>.
  			if ( ! options.options ) {
  				options.options = {};
  			}
  
  			// Configure JSHint.
  			if ( 'javascript' === settings.codemirror.mode && settings.jshint ) {
  				$.extend( options.options, settings.jshint );
  			}
  
  			// Configure CSSLint.
  			if ( 'css' === settings.codemirror.mode && settings.csslint ) {
  				$.extend( options.options, settings.csslint );
  			}
  
  			// Configure HTMLHint.
  			if ( 'htmlmixed' === settings.codemirror.mode && settings.htmlhint ) {
  				options.options.rules = $.extend( {}, settings.htmlhint );
  
  				if ( settings.jshint ) {
  					options.options.rules.jshint = settings.jshint;
  				}
  				if ( settings.csslint ) {
  					options.options.rules.csslint = settings.csslint;
  				}
  			}
  
  			// Wrap the onUpdateLinting CodeMirror event to route to onChangeLintingErrors and onUpdateErrorNotice.
  			options.onUpdateLinting = (function( onUpdateLintingOverridden ) {
  				return function( annotations, annotationsSorted, cm ) {
  					var errorAnnotations = _.filter( annotations, function( annotation ) {
  						return 'error' === annotation.severity;
  					} );
  
  					if ( onUpdateLintingOverridden ) {
  						onUpdateLintingOverridden.apply( annotations, annotationsSorted, cm );
  					}
  
  					// Skip if there are no changes to the errors.
  					if ( _.isEqual( errorAnnotations, currentErrorAnnotations ) ) {
  						return;
  					}
  
  					currentErrorAnnotations = errorAnnotations;
  
  					if ( settings.onChangeLintingErrors ) {
  						settings.onChangeLintingErrors( errorAnnotations, annotations, annotationsSorted, cm );
  					}
  
  					/*
  					 * Update notifications when the editor is not focused to prevent error message
  					 * from overwhelming the user during input, unless there are now no errors or there
  					 * were previously errors shown. In these cases, update immediately so they can know
  					 * that they fixed the errors.
  					 */
  					if ( ! editor.state.focused || 0 === currentErrorAnnotations.length || previouslyShownErrorAnnotations.length > 0 ) {
  						updateErrorNotice();
  					}
  				};
  			})( options.onUpdateLinting );
  
  			return options;
  		}
  
  		editor.setOption( 'lint', getLintOptions() );
  
  		// Keep lint options populated.
  		editor.on( 'optionChange', function( cm, option ) {
  			var options, gutters, gutterName = 'CodeMirror-lint-markers';
  			if ( 'lint' !== option ) {
  				return;
  			}
  			gutters = editor.getOption( 'gutters' ) || [];
  			options = editor.getOption( 'lint' );
  			if ( true === options ) {
  				if ( ! _.contains( gutters, gutterName ) ) {
  					editor.setOption( 'gutters', [ gutterName ].concat( gutters ) );
  				}
  				editor.setOption( 'lint', getLintOptions() ); // Expand to include linting options.
  			} else if ( ! options ) {
  				editor.setOption( 'gutters', _.without( gutters, gutterName ) );
  			}
  
  			// Force update on error notice to show or hide.
  			if ( editor.getOption( 'lint' ) ) {
  				editor.performLint();
  			} else {
  				currentErrorAnnotations = [];
  				updateErrorNotice();
  			}
  		} );
  
  		// Update error notice when leaving the editor.
  		editor.on( 'blur', updateErrorNotice );
  
  		// Work around hint selection with mouse causing focus to leave editor.
  		editor.on( 'startCompletion', function() {
  			editor.off( 'blur', updateErrorNotice );
  		} );
  		editor.on( 'endCompletion', function() {
  			var editorRefocusWait = 500;
  			editor.on( 'blur', updateErrorNotice );
  
  			// Wait for editor to possibly get re-focused after selection.
  			_.delay( function() {
  				if ( ! editor.state.focused ) {
  					updateErrorNotice();
  				}
  			}, editorRefocusWait );
  		});
  
  		/*
  		 * Make sure setting validities are set if the user tries to click Publish
  		 * while an autocomplete dropdown is still open. The Customizer will block
  		 * saving when a setting has an error notifications on it. This is only
  		 * necessary for mouse interactions because keyboards will have already
  		 * blurred the field and cause onUpdateErrorNotice to have already been
  		 * called.
  		 */
  		$( document.body ).on( 'mousedown', function( event ) {
  			if ( editor.state.focused && ! $.contains( editor.display.wrapper, event.target ) && ! $( event.target ).hasClass( 'CodeMirror-hint' ) ) {
  				updateErrorNotice();
  			}
  		});
  	}
  
  	/**
  	 * Configure tabbing.
  	 *
  	 * @param {CodeMirror} codemirror - Editor.
  	 * @param {object}     settings - Code editor settings.
  	 * @param {object}     settings.codeMirror - Settings for CodeMirror.
  	 * @param {Function}   settings.onTabNext - Callback to handle tabbing to the next tabbable element.
  	 * @param {Function}   settings.onTabPrevious - Callback to handle tabbing to the previous tabbable element.
  	 * @returns {void}
  	 */
  	function configureTabbing( codemirror, settings ) {
  		var $textarea = $( codemirror.getTextArea() );
  
  		codemirror.on( 'blur', function() {
  			$textarea.data( 'next-tab-blurs', false );
  		});
  		codemirror.on( 'keydown', function onKeydown( editor, event ) {
  			var tabKeyCode = 9, escKeyCode = 27;
  
  			// Take note of the ESC keypress so that the next TAB can focus outside the editor.
  			if ( escKeyCode === event.keyCode ) {
  				$textarea.data( 'next-tab-blurs', true );
  				return;
  			}
  
  			// Short-circuit if tab key is not being pressed or the tab key press should move focus.
  			if ( tabKeyCode !== event.keyCode || ! $textarea.data( 'next-tab-blurs' ) ) {
  				return;
  			}
  
  			// Focus on previous or next focusable item.
  			if ( event.shiftKey ) {
  				settings.onTabPrevious( codemirror, event );
  			} else {
  				settings.onTabNext( codemirror, event );
  			}
  
  			// Reset tab state.
  			$textarea.data( 'next-tab-blurs', false );
  
  			// Prevent tab character from being added.
  			event.preventDefault();
  		});
  	}
  
  	/**
  	 * @typedef {object} CodeEditorInstance
  	 * @property {object} settings - The code editor settings.
  	 * @property {CodeMirror} codemirror - The CodeMirror instance.
  	 */
  
  	/**
  	 * Initialize Code Editor (CodeMirror) for an existing textarea.
  	 *
  	 * @since 4.9.0
  	 *
  	 * @param {string|jQuery|Element} textarea - The HTML id, jQuery object, or DOM Element for the textarea that is used for the editor.
  	 * @param {object}                [settings] - Settings to override defaults.
  	 * @param {Function}              [settings.onChangeLintingErrors] - Callback for when the linting errors have changed.
  	 * @param {Function}              [settings.onUpdateErrorNotice] - Callback for when error notice should be displayed.
  	 * @param {Function}              [settings.onTabPrevious] - Callback to handle tabbing to the previous tabbable element.
  	 * @param {Function}              [settings.onTabNext] - Callback to handle tabbing to the next tabbable element.
  	 * @param {object}                [settings.codemirror] - Options for CodeMirror.
  	 * @param {object}                [settings.csslint] - Rules for CSSLint.
  	 * @param {object}                [settings.htmlhint] - Rules for HTMLHint.
  	 * @param {object}                [settings.jshint] - Rules for JSHint.
  	 * @returns {CodeEditorInstance} Instance.
  	 */
  	wp.codeEditor.initialize = function initialize( textarea, settings ) {
  		var $textarea, codemirror, instanceSettings, instance;
  		if ( 'string' === typeof textarea ) {
  			$textarea = $( '#' + textarea );
  		} else {
  			$textarea = $( textarea );
  		}
  
  		instanceSettings = $.extend( {}, wp.codeEditor.defaultSettings, settings );
  		instanceSettings.codemirror = $.extend( {}, instanceSettings.codemirror );
  
  		codemirror = wp.CodeMirror.fromTextArea( $textarea[0], instanceSettings.codemirror );
  
  		configureLinting( codemirror, instanceSettings );
  
  		instance = {
  			settings: instanceSettings,
  			codemirror: codemirror
  		};
  
  		if ( codemirror.showHint ) {
  			codemirror.on( 'keyup', function( editor, event ) { // eslint-disable-line complexity
  				var shouldAutocomplete, isAlphaKey = /^[a-zA-Z]$/.test( event.key ), lineBeforeCursor, innerMode, token;
  				if ( codemirror.state.completionActive && isAlphaKey ) {
  					return;
  				}
  
  				// Prevent autocompletion in string literals or comments.
  				token = codemirror.getTokenAt( codemirror.getCursor() );
  				if ( 'string' === token.type || 'comment' === token.type ) {
  					return;
  				}
  
  				innerMode = wp.CodeMirror.innerMode( codemirror.getMode(), token.state ).mode.name;
  				lineBeforeCursor = codemirror.doc.getLine( codemirror.doc.getCursor().line ).substr( 0, codemirror.doc.getCursor().ch );
  				if ( 'html' === innerMode || 'xml' === innerMode ) {
  					shouldAutocomplete =
  						'<' === event.key ||
  						'/' === event.key && 'tag' === token.type ||
  						isAlphaKey && 'tag' === token.type ||
  						isAlphaKey && 'attribute' === token.type ||
  						'=' === token.string && token.state.htmlState && token.state.htmlState.tagName;
  				} else if ( 'css' === innerMode ) {
  					shouldAutocomplete =
  						isAlphaKey ||
  						':' === event.key ||
  						' ' === event.key && /:\s+$/.test( lineBeforeCursor );
  				} else if ( 'javascript' === innerMode ) {
  					shouldAutocomplete = isAlphaKey || '.' === event.key;
  				} else if ( 'clike' === innerMode && 'application/x-httpd-php' === codemirror.options.mode ) {
  					shouldAutocomplete = 'keyword' === token.type || 'variable' === token.type;
  				}
  				if ( shouldAutocomplete ) {
  					codemirror.showHint( { completeSingle: false } );
  				}
  			});
  		}
  
  		// Facilitate tabbing out of the editor.
  		configureTabbing( codemirror, settings );
  
  		return instance;
  	};
  
  })( window.jQuery, window.wp );
  