<?php
/**
 * Qdrant vector store.
 *
 * Qdrant requires point IDs to be unsigned 64-bit integers or UUIDs, so string IDs
 * are hashed into numbers while the original value is kept in the payload.
 *
 * @package AI House
 */

defined( 'ABSPATH' ) || exit;

/**
 * Class MYBOT_Vector_Qdrant
 */
class MYBOT_Vector_Qdrant implements MYBOT_Vector_Store {

	/**
	 * Cluster URL, for example https://xyz.aws.cloud.qdrant.io
	 *
	 * @var string
	 */
	protected $url;

	/**
	 * API key.
	 *
	 * @var string
	 */
	protected $key;

	/**
	 * Collection name.
	 *
	 * @var string
	 */
	protected $collection;

	/**
	 * Constructor.
	 *
	 * @param string $url        URL.
	 * @param string $key        API key.
	 * @param string $collection Collection name.
	 */
	public function __construct( $url, $key, $collection = 'mybot' ) {
		$this->url        = rtrim( (string) $url, '/' );
		$this->key        = (string) $key;
		$this->collection = preg_replace( '/[^a-zA-Z0-9_\-]/', '', (string) $collection );
	}

	/**
	 * Store ID.
	 *
	 * @return string
	 */
	public function get_id() {
		return 'qdrant';
	}

	/**
	 * Display name.
	 *
	 * @return string
	 */
	public function get_label() {
		return 'Qdrant';
	}

	/**
	 * Whether the store is configured.
	 *
	 * @return bool
	 */
	public function is_configured() {
		return '' !== $this->url && '' !== $this->key && '' !== $this->collection;
	}

	/**
	 * Authentication headers.
	 *
	 * @return array
	 */
	protected function headers() {
		return array( 'api-key' => $this->key );
	}

	/**
	 * Collection URL.
	 *
	 * @return string
	 */
	protected function collection_url() {
		return $this->url . '/collections/' . rawurlencode( $this->collection );
	}

	/**
	 * Converts a string ID into a 63-bit integer.
	 *
	 * @param string $id Original ID.
	 * @return int
	 */
	protected function numeric_id( $id ) {
		$hex = substr( hash( 'sha256', (string) $id ), 0, 15 );

		return (int) hexdec( $hex );
	}

	/**
	 * Writes vectors.
	 *
	 * @param array $records List of records.
	 * @return true|WP_Error
	 */
	public function upsert( $records ) {
		if ( ! $this->is_configured() ) {
			return new WP_Error( 'mybot_vector_unconfigured', __( 'Qdrant is not configured.', 'aihouse' ) );
		}

		if ( empty( $records ) ) {
			return true;
		}

		$points = array();

		foreach ( $records as $record ) {
			$metadata              = isset( $record['metadata'] ) && is_array( $record['metadata'] ) ? $record['metadata'] : array();
			$metadata['content']   = isset( $record['content'] ) ? (string) $record['content'] : '';
			$metadata['source_id'] = isset( $metadata['source_id'] ) ? (int) $metadata['source_id'] : 0;

			$points[] = array(
				'id'      => $this->numeric_id( $record['id'] ),
				'vector'  => isset( $record['values'] ) ? $record['values'] : array(),
				'payload' => $metadata,
			);
		}

		$response = MYBOT_HTTP::post_json(
			$this->collection_url() . '/points?wait=true',
			array( 'points' => $points ),
			$this->headers(),
			20,
			1
		);

		return is_wp_error( $response ) ? $response : true;
	}

	/**
	 * Queries vectors.
	 *
	 * @param array $vector    Query vector.
	 * @param int   $top_k     Number of results.
	 * @param float $min_score Score threshold.
	 * @return array|WP_Error
	 */
	public function query( $vector, $top_k = 4, $min_score = 0.0 ) {
		if ( ! $this->is_configured() ) {
			return new WP_Error( 'mybot_vector_unconfigured', __( 'Qdrant is not configured.', 'aihouse' ) );
		}

		$body = array(
			'vector'          => $vector,
			'limit'           => max( 1, (int) $top_k ),
			'with_payload'    => true,
			'score_threshold' => (float) $min_score,
		);

		$response = MYBOT_HTTP::post_json(
			$this->collection_url() . '/points/search',
			$body,
			$this->headers(),
			15
		);

		if ( is_wp_error( $response ) ) {
			return $response;
		}

		$rows    = isset( $response['result'] ) && is_array( $response['result'] ) ? $response['result'] : array();
		$results = array();

		foreach ( $rows as $row ) {
			$payload = isset( $row['payload'] ) && is_array( $row['payload'] ) ? $row['payload'] : array();
			$content = isset( $payload['content'] ) ? (string) $payload['content'] : '';
			unset( $payload['content'] );

			$results[] = array(
				'id'       => isset( $row['id'] ) ? (string) $row['id'] : '',
				'score'    => isset( $row['score'] ) ? (float) $row['score'] : 0.0,
				'content'  => $content,
				'metadata' => $payload,
			);
		}

		return $results;
	}

	/**
	 * Deletes by a list of IDs.
	 *
	 * @param array $ids List of IDs.
	 * @return true|WP_Error
	 */
	public function delete( $ids ) {
		$ids = array_values( array_filter( array_map( 'strval', (array) $ids ), 'strlen' ) );

		if ( empty( $ids ) ) {
			return true;
		}

		$numeric = array();

		foreach ( $ids as $id ) {
			$numeric[] = $this->numeric_id( $id );
		}

		return $this->delete_request( array( 'points' => $numeric ) );
	}

	/**
	 * Deletes every vector that belongs to a post.
	 *
	 * @param int $source_id Post ID.
	 * @return true|WP_Error
	 */
	public function delete_by_source( $source_id ) {
		return $this->delete_request(
			array(
				'filter' => array(
					'must' => array(
						array(
							'key'   => 'source_id',
							'match' => array( 'value' => (int) absint( $source_id ) ),
						),
					),
				),
			)
		);
	}

	/**
	 * Sends a delete request.
	 *
	 * @param array $body Request body.
	 * @return true|WP_Error
	 */
	protected function delete_request( $body ) {
		if ( ! $this->is_configured() ) {
			return new WP_Error( 'mybot_vector_unconfigured', __( 'Qdrant is not configured.', 'aihouse' ) );
		}

		$response = MYBOT_HTTP::post_json(
			$this->collection_url() . '/points/delete?wait=true',
			$body,
			$this->headers(),
			15
		);

		return is_wp_error( $response ) ? $response : true;
	}
}