<?php
/**
 * @package PlugixaCrm
 */

declare( strict_types = 1 );

namespace PlugixaCrm\Modules\DocumentLibrary\Repositories;

use PlugixaCrm\Core\Database\Schema;

if ( ! defined( 'ABSPATH' ) ) {
	exit;
}

/**
 * The document⇄record junction.
 *
 * A PLAIN repository, on purpose — NOT a {@see \PlugixaCrm\Core\Database\Repository}. A link has no
 * lifecycle of its own: it is created when you associate a document with a record and gone when you
 * un-associate them, with no soft-delete stage in between. Extending the base Repository would drag in the
 * five audit columns and the soft-delete machinery that a pure junction has no use for (and that SchemaTest
 * would then demand it carry). So this talks to $wpdb directly.
 *
 * It is polymorphic like the attachment table: `entity_type` + `entity_id` let one table link documents to
 * accounts, opportunities, contacts and leads without a column per type.
 */
final class DocumentLinkRepository {

	private function table(): string {
		return Schema::table( 'document_links' );
	}

	/**
	 * The records a document is linked to.
	 *
	 * @param int $document_id Document.
	 *
	 * @return array<int, array{entity_type: string, entity_id: int}>
	 */
	public function for_document( int $document_id ): array {
		global $wpdb;

		$table = $this->table();

		// phpcs:ignore WordPress.DB.DirectDatabaseQuery.DirectQuery, WordPress.DB.DirectDatabaseQuery.NoCaching -- custom table, no object cache to read from.
		$rows = $wpdb->get_results(
			$wpdb->prepare( "SELECT entity_type, entity_id FROM %i WHERE document_id = %d ORDER BY id ASC", $table, $document_id ),
			ARRAY_A
		);

		return array_map(
			static fn( array $row ): array => array(
				'entity_type' => (string) $row['entity_type'],
				'entity_id'   => (int) $row['entity_id'],
			),
			is_array( $rows ) ? $rows : array()
		);
	}

	/**
	 * The document ids linked to a record.
	 *
	 * @param string $entity_type Record type.
	 * @param int    $entity_id   Record id.
	 *
	 * @return int[]
	 */
	public function for_record( string $entity_type, int $entity_id ): array {
		global $wpdb;

		$table = $this->table();

		// phpcs:ignore WordPress.DB.DirectDatabaseQuery.DirectQuery, WordPress.DB.DirectDatabaseQuery.NoCaching -- custom table, no object cache to read from.
		$ids = $wpdb->get_col(
			$wpdb->prepare(
				"SELECT document_id FROM %i WHERE entity_type = %s AND entity_id = %d ORDER BY id DESC",
				$table,
				$entity_type,
				$entity_id
			)
		);

		return array_map( 'intval', is_array( $ids ) ? $ids : array() );
	}

	/**
	 * Associate a document with a record. Idempotent — the UNIQUE key absorbs a repeat.
	 *
	 * @param int    $document_id Document.
	 * @param string $entity_type Record type.
	 * @param int    $entity_id   Record id.
	 */
	public function link( int $document_id, string $entity_type, int $entity_id ): void {
		global $wpdb;

		$table = $this->table();

		// INSERT IGNORE: a link that already exists is not an error, it is the desired state.
		// phpcs:ignore WordPress.DB.DirectDatabaseQuery.DirectQuery, WordPress.DB.DirectDatabaseQuery.NoCaching -- custom table, no object cache to read from.
		$wpdb->query(
			$wpdb->prepare(
				"INSERT IGNORE INTO %i (document_id, entity_type, entity_id, created_at, created_by) VALUES (%d, %s, %d, %s, %d)",
				$table,
				$document_id,
				$entity_type,
				$entity_id,
				current_time( 'mysql', true ),
				get_current_user_id()
			)
		);
	}

	/**
	 * Remove one association.
	 *
	 * @param int    $document_id Document.
	 * @param string $entity_type Record type.
	 * @param int    $entity_id   Record id.
	 */
	public function unlink( int $document_id, string $entity_type, int $entity_id ): void {
		global $wpdb;

		// phpcs:ignore WordPress.DB.DirectDatabaseQuery.DirectQuery, WordPress.DB.DirectDatabaseQuery.NoCaching -- custom table, no object cache to read from.
		$wpdb->delete(
			$this->table(),
			array(
				'document_id' => $document_id,
				'entity_type' => $entity_type,
				'entity_id'   => $entity_id,
			)
		);
	}

	/**
	 * Drop every link a document has — called when the document is purged.
	 *
	 * @param int $document_id Document.
	 */
	public function purge_for_document( int $document_id ): void {
		global $wpdb;

		// phpcs:ignore WordPress.DB.DirectDatabaseQuery.DirectQuery, WordPress.DB.DirectDatabaseQuery.NoCaching -- custom table, no object cache to read from.
		$wpdb->delete( $this->table(), array( 'document_id' => $document_id ) );
	}

	/**
	 * Drop every link pointing at a record — called when that record is purged.
	 *
	 * The documents themselves are left alone: a document is first-class and may be linked to several
	 * records, so one record's destruction is not the document's.
	 *
	 * @param string $entity_type Record type.
	 * @param int    $entity_id   Record id.
	 */
	public function purge_for_record( string $entity_type, int $entity_id ): void {
		global $wpdb;

		// phpcs:ignore WordPress.DB.DirectDatabaseQuery.DirectQuery, WordPress.DB.DirectDatabaseQuery.NoCaching -- custom table, no object cache to read from.
		$wpdb->delete(
			$this->table(),
			array(
				'entity_type' => $entity_type,
				'entity_id'   => $entity_id,
			)
		);
	}
}