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 );