Extract completer function into matchAutocompleters

packages/components/src/autocomplete/autocompleter-matcher.ts

@@ -0,0 +1,218 @@
+/**
+ * External dependencies
+ */
+import removeAccents from 'remove-accents';
+
+/**
+ * WordPress dependencies
+ */
+import { slice, getTextContent } from '@wordpress/rich-text';
+
+/**
+ * Internal dependencies
+ */
+import { getAutoCompleterUI } from './autocompleter-ui';
+import { escapeRegExp } from '../utils/strings';
+import type {
+	AutocompleterUIProps,
+	WPCompleter,
+	UseAutocompleteProps,
+} from './types';
+
+export interface AutocompleterMatchResult {
+	/** The matched completer, or null if no match */
+	completer: WPCompleter | null;
+	/** The filter value/query extracted from the text */
+	filterValue: string;
+	/** Whether the autocompleter should be reset */
+	shouldReset: boolean;
+	/** The AutocompleterUI component to use */
+	AutocompleterUI:
+		| ( ( props: AutocompleterUIProps ) => JSX.Element | null )
+		| null;
+}
+
+export interface AutocompleterMatchOptions {
+	/** The text content to match against */
+	textContent: string;
+	/** Array of available completers */
+	completers: WPCompleter[];
+	/** Length of currently filtered options (used to detect mismatch) */
+	currentFilteredOptionsLength: number;
+	/** Whether the user is currently backspacing */
+	isBackspacing: boolean;
+	/** The currently active autocompleter */
+	currentAutocompleter: WPCompleter | null;
+	/** The current AutocompleterUI component */
+	currentAutocompleterUI:
+		| ( ( props: AutocompleterUIProps ) => JSX.Element | null )
+		| null;
+	/** The record object for context checking */
+	record: UseAutocompleteProps[ 'record' ];
+}
+
+/**
+ * Matches text content against available completers and determines the appropriate
+ * autocompleter state. This function contains the core matching logic extracted
+ * from the useAutocomplete hook for better testability.
+ *
+ * @param options The matching options
+ * @return The matching result containing completer info and state updates
+ */
+export function matchAutocompleters(
+	options: AutocompleterMatchOptions
+): AutocompleterMatchResult {
+	const {
+		textContent,
+		completers,
+		currentFilteredOptionsLength,
+		isBackspacing,
+		currentAutocompleter,
+		currentAutocompleterUI,
+		record,
+	} = options;
+
+	// If no text content, reset
+	if ( ! textContent ) {
+		return {
+			completer: null,
+			filterValue: '',
+			shouldReset: true,
+			AutocompleterUI: null,
+		};
+	}
+
+	// Find the completer with the highest triggerPrefix index in the textContent
+	const completer = completers.reduce< WPCompleter | null >(
+		( lastTrigger, currentCompleter ) => {
+			const triggerIndex = textContent.lastIndexOf(
+				currentCompleter.triggerPrefix
+			);
+			const lastTriggerIndex =
+				lastTrigger !== null
+					? textContent.lastIndexOf( lastTrigger.triggerPrefix )
+					: -1;
+
+			return triggerIndex > lastTriggerIndex
+				? currentCompleter
+				: lastTrigger;
+		},
+		null
+	);
+
+	// If no completer found, reset
+	if ( ! completer ) {
+		return {
+			completer: null,
+			filterValue: '',
+			shouldReset: true,
+			AutocompleterUI: null,
+		};
+	}
+
+	const { allowContext, triggerPrefix } = completer;
+	const triggerIndex = textContent.lastIndexOf( triggerPrefix );
+	const textWithoutTrigger = textContent.slice(
+		triggerIndex + triggerPrefix.length
+	);
+
+	// Performance guard: prevent matching if too far from trigger
+	const tooDistantFromTrigger = textWithoutTrigger.length > 50;
+	if ( tooDistantFromTrigger ) {
+		return {
+			completer: null,
+			filterValue: '',
+			shouldReset: false, // Don't reset, just ignore this match attempt
+			AutocompleterUI: null,
+		};
+	}
+
+	const mismatch = currentFilteredOptionsLength === 0;
+	const wordsFromTrigger = textWithoutTrigger.split( /\s/ );
+
+	// Allow the effect to run when not backspacing and if there was a mismatch
+	// i.e when typing a trigger + the match string or when clicking in an
+	// existing trigger word on the page
+	const hasOneTriggerWord = wordsFromTrigger.length === 1;
+
+	// Allow the effect to run when backspacing and if "touching" a word that
+	// "belongs" to a trigger. We consider a "trigger word" any word up to the
+	// limit of 3 from the trigger character
+	const matchingWhileBackspacing =
+		isBackspacing && wordsFromTrigger.length <= 3;
+
+	// If there's a mismatch and we're not in a valid backspacing or single word scenario
+	if ( mismatch && ! ( matchingWhileBackspacing || hasOneTriggerWord ) ) {
+		return {
+			completer: null,
+			filterValue: '',
+			shouldReset: true,
+			AutocompleterUI: null,
+		};
+	}
+
+	// Check context constraints if allowContext is defined
+	if ( allowContext ) {
+		const textAfterSelection = getTextContent(
+			slice( record, undefined, getTextContent( record ).length )
+		);
+
+		if (
+			! allowContext(
+				textContent.slice( 0, triggerIndex ),
+				textAfterSelection
+			)
+		) {
+			return {
+				completer: null,
+				filterValue: '',
+				shouldReset: true,
+				AutocompleterUI: null,
+			};
+		}
+	}
+
+	// Validate text format - reject if starts or ends with problematic whitespace
+	if (
+		/^\s/.test( textWithoutTrigger ) ||
+		/\s\s+$/.test( textWithoutTrigger )
+	) {
+		return {
+			completer: null,
+			filterValue: '',
+			shouldReset: true,
+			AutocompleterUI: null,
+		};
+	}
+
+	// Validate character range
+	if ( ! /[\u0000-\uFFFF]*$/.test( textWithoutTrigger ) ) {
+		return {
+			completer: null,
+			filterValue: '',
+			shouldReset: true,
+			AutocompleterUI: null,
+		};
+	}
+
+	// Extract the query from the text
+	const safeTrigger = escapeRegExp( completer.triggerPrefix );
+	const text = removeAccents( textContent );
+	const match = text
+		.slice( text.lastIndexOf( completer.triggerPrefix ) )
+		.match( new RegExp( `${ safeTrigger }([\u0000-\uFFFF]*)$` ) );
+	const query = match && match[ 1 ];
+
+	// Determine the AutocompleterUI to use
+	const AutocompleterUI =
+		completer !== currentAutocompleter
+			? getAutoCompleterUI( completer )
+			: currentAutocompleterUI;
+
+	return {
+		completer,
+		filterValue: query === null ? '' : query,
+		shouldReset: false,
+		AutocompleterUI,
+	};
+}