feat(query): add more like this query

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

Author: Spamercz

doc/02-query-objects.md

@@ -504,6 +504,21 @@ new \Spameri\ElasticQuery\Query\ScriptScore(
 );
 ```
 
+##### MoreLikeThis Query
+Find documents similar to provided text or document references.
+- Class: `\Spameri\ElasticQuery\Query\MoreLikeThis`
+- [Documentation](https://www.elastic.co/guide/en/elasticsearch/reference/current/query-dsl-mlt-query.html)
+- [Implementation](https://github.com/Spameri/ElasticQuery/blob/master/src/Query/MoreLikeThis.php)
+
+```php
+new \Spameri\ElasticQuery\Query\MoreLikeThis(
+	fields: ['title', 'body'],
+	like: ['quick brown fox', ['_index' => 'imdb', '_id' => '1']],
+	minTermFreq: 1,
+	maxQueryTerms: 12,
+);
+```
+
 ##### Script Query
 Filter documents with a Painless boolean script.
 - Class: `\Spameri\ElasticQuery\Query\Script`

src/Query/MoreLikeThis.php

@@ -0,0 +1,78 @@
+<?php
+
+declare(strict_types = 1);
+
+namespace Spameri\ElasticQuery\Query;
+
+/**
+ * @see https://www.elastic.co/guide/en/elasticsearch/reference/current/query-dsl-mlt-query.html
+ */
+class MoreLikeThis implements \Spameri\ElasticQuery\Query\LeafQueryInterface
+{
+
+	/**
+	 * @param array<int, string> $fields
+	 * @param array<int, string|array<string, mixed>> $like Texts or doc refs (['_index' => ..., '_id' => ...]).
+	 * @param array<int, string|array<string, mixed>> $unlike
+	 */
+	public function __construct(
+		private array $fields,
+		private array $like,
+		private array $unlike = [],
+		private int|null $minTermFreq = null,
+		private int|null $maxQueryTerms = null,
+		private int|string|null $minimumShouldMatch = null,
+	)
+	{
+		if ($fields === []) {
+			throw new \Spameri\ElasticQuery\Exception\InvalidArgumentException(
+				'MoreLikeThis query requires at least one field.',
+			);
+		}
+
+		if ($like === []) {
+			throw new \Spameri\ElasticQuery\Exception\InvalidArgumentException(
+				'MoreLikeThis query requires at least one like value.',
+			);
+		}
+	}
+
+
+	public function key(): string
+	{
+		return 'more_like_this_' . \implode('-', $this->fields);
+	}
+
+
+	/**
+	 * @return array<string, array<string, mixed>>
+	 */
+	public function toArray(): array
+	{
+		$body = [
+			'fields' => $this->fields,
+			'like' => $this->like,
+		];
+
+		if ($this->unlike !== []) {
+			$body['unlike'] = $this->unlike;
+		}
+
+		if ($this->minTermFreq !== null) {
+			$body['min_term_freq'] = $this->minTermFreq;
+		}
+
+		if ($this->maxQueryTerms !== null) {
+			$body['max_query_terms'] = $this->maxQueryTerms;
+		}
+
+		if ($this->minimumShouldMatch !== null) {
+			$body['minimum_should_match'] = $this->minimumShouldMatch;
+		}
+
+		return [
+			'more_like_this' => $body,
+		];
+	}
+
+}

tests/SpameriTests/ElasticQuery/Query/MoreLikeThis.phpt

@@ -0,0 +1,85 @@
+<?php declare(strict_types = 1);
+
+namespace SpameriTests\ElasticQuery\Query;
+
+require_once __DIR__ . '/../../bootstrap.php';
+
+
+class MoreLikeThis extends \Tester\TestCase
+{
+
+	private const INDEX = 'spameri_test_query_mlt';
+
+
+	public function setUp(): void
+	{
+		$ch = \curl_init();
+		\curl_setopt($ch, \CURLOPT_URL, \ELASTICSEARCH_HOST . '/' . self::INDEX);
+		\curl_setopt($ch, \CURLOPT_RETURNTRANSFER, 1);
+		\curl_setopt($ch, \CURLOPT_CUSTOMREQUEST, 'PUT');
+		\curl_setopt($ch, \CURLOPT_HTTPHEADER, ['Content-Type: application/json']);
+
+		\curl_exec($ch);
+	}
+
+
+	public function testToArray(): void
+	{
+		$mlt = new \Spameri\ElasticQuery\Query\MoreLikeThis(
+			fields: ['title', 'body'],
+			like: ['quick brown fox', ['_index' => 'imdb', '_id' => '1']],
+			minTermFreq: 1,
+			maxQueryTerms: 12,
+		);
+
+		$array = $mlt->toArray();
+
+		\Tester\Assert::same(['title', 'body'], $array['more_like_this']['fields']);
+		\Tester\Assert::same(1, $array['more_like_this']['min_term_freq']);
+	}
+
+
+	public function testRequiresFields(): void
+	{
+		\Tester\Assert::exception(
+			static function (): void {
+				new \Spameri\ElasticQuery\Query\MoreLikeThis([], ['foo']);
+			},
+			\Spameri\ElasticQuery\Exception\InvalidArgumentException::class,
+		);
+	}
+
+
+	public function testRequiresLike(): void
+	{
+		\Tester\Assert::exception(
+			static function (): void {
+				new \Spameri\ElasticQuery\Query\MoreLikeThis(['f'], []);
+			},
+			\Spameri\ElasticQuery\Exception\InvalidArgumentException::class,
+		);
+	}
+
+
+	public function testKey(): void
+	{
+		$mlt = new \Spameri\ElasticQuery\Query\MoreLikeThis(['title'], ['foo']);
+
+		\Tester\Assert::same('more_like_this_title', $mlt->key());
+	}
+
+
+	public function tearDown(): void
+	{
+		$ch = \curl_init();
+		\curl_setopt($ch, \CURLOPT_URL, \ELASTICSEARCH_HOST . '/' . self::INDEX);
+		\curl_setopt($ch, \CURLOPT_RETURNTRANSFER, 1);
+		\curl_setopt($ch, \CURLOPT_CUSTOMREQUEST, 'DELETE');
+		\curl_setopt($ch, \CURLOPT_HTTPHEADER, ['Content-Type: application/json']);
+
+		\curl_exec($ch);
+	}
+
+}
+
+(new MoreLikeThis())->run();