learnpress / inc / AI / Assistant / LanguageResolver.php

LanguageResolver.php in LearnPress – WordPress LMS Plugin for Create and Sell Online Courses 4.4.7, at inc/AI/Assistant/LanguageResolver.php

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1	<?php
2
3	namespace LearnPress\AI\Assistant;
4
5	/**
6	* LanguageResolver — detects learner language and generates instruction for the model.
7	*
8	* Completely stateless utility; can be reused across Agent and QuickQuizEngine.
9	*
10	* @package LearnPress\AI\Assistant
11	* @since 4.3.5
12	*/
13	class LanguageResolver {
14
15	/**
16	* Build strict language guidance so the model replies in the learner's language.
17	*
18	* @param string $user_message Current learner input.
19	* @param array $history Conversation history.
20	* @param int $user_id Current user ID.
21	*
22	* @return string
23	*/
24	public function build_instruction( string $user_message, array $history, int $user_id ): string {
25
26	$sample = $this->resolve_language_sample( $user_message, $history );
27	$locale_hint = $this->resolve_locale_hint( $user_id );
28
29	if ( $sample !== '' ) {
30	return sprintf(
31	/* translators: 1: learner message sample, 2: locale hint. */
32	__( 'Language policy: reply strictly in the same language as the learner. Do not default to English. Learner sample: "%1$s". Locale fallback: %2$s.', 'learnpress' ),
33	$sample,
34	$locale_hint !== '' ? $locale_hint : 'n/a'
35	);
36	}
37
38	return sprintf(
39	/* translators: %s: locale hint. */
40	__( 'Language policy: reply strictly in the learner language and do not default to English. If the latest learner message is language-neutral, use locale fallback: %s.', 'learnpress' ),
41	$locale_hint !== '' ? $locale_hint : 'n/a'
42	);
43	}
44
45	// ----------------------------------------------------------------
46	// Private helpers
47	// ----------------------------------------------------------------
48
49	/**
50	* Pick the best text sample to infer learner language.
51	*
52	* Prefers the current message; falls back to previous user turns.
53	*
54	* @param string $user_message Current learner input.
55	* @param array $history Conversation history.
56	*
57	* @return string
58	*/
59	private function resolve_language_sample( string $user_message, array $history ): string {
60
61	$current = $this->trim_text_for_prompt( $user_message );
62	if ( $this->has_letters( $current ) && ! $this->is_language_neutral_command( $current ) ) {
63	return $current;
64	}
65
66	for ( $index = count( $history ) - 1; $index >= 0; $index-- ) {
67	$item = $history[ $index ] ?? array();
68	if ( ( $item['role'] ?? '' ) !== 'user' \|\| ! isset( $item['content'] ) ) {
69	continue;
70	}
71
72	$content = $this->trim_text_for_prompt( (string) $item['content'] );
73	if ( ! $this->has_letters( $content ) \|\| $this->is_language_neutral_command( $content ) ) {
74	continue;
75	}
76
77	return $content;
78	}
79
80	return '';
81	}
82
83	/**
84	* Resolve locale hint from WordPress user/site settings.
85	*
86	* @param int $user_id Current user ID.
87	*
88	* @return string
89	*/
90	private function resolve_locale_hint( int $user_id ): string {
91	$locale = (string) get_user_locale( $user_id );
92	if ( $locale !== '' ) {
93	return $locale;
94	}
95
96	$locale = (string) determine_locale();
97	if ( $locale !== '' ) {
98	return $locale;
99	}
100
101	return (string) get_locale();
102	}
103
104	/**
105	* Determine if input is a language-neutral command (e.g. /quick-quiz, "1", "A", ...).
106	*
107	* @param string $text Input text.
108	*
109	* @return bool
110	*/
111	private function is_language_neutral_command( string $text ): bool {
112
113	$normalized = trim( $text );
114	if ( $normalized === '' ) {
115	return true;
116	}
117
118	if ( str_starts_with( $normalized, '/' ) ) {
119	return true;
120	}
121
122	return preg_match( '/^[\d\W_]+$/u', $normalized ) === 1;
123	}
124
125	/**
126	* Check whether input contains at least one letter character.
127	*
128	* @param string $text Input text.
129	*
130	* @return bool
131	*/
132	private function has_letters( string $text ): bool {
133	return preg_match( '/\p{L}/u', $text ) === 1;
134	}
135
136	/**
137	* Trim and cap text length for safe system prompt injection.
138	*
139	* @param string $text Input text.
140	*
141	* @return string
142	*/
143	private function trim_text_for_prompt( string $text ): string {
144
145	$clean = trim( preg_replace( '/\s+/', ' ', $text ) ?? '' );
146	if ( $clean === '' ) {
147	return '';
148	}
149
150	return mb_substr( $clean, 0, 220, 'UTF-8' );
151	}
152	}
153