<?php
/**
 * WordPress privacy tools: export and erase (F-FORMS-05).
 *
 * @package ForensixDigital
 */

declare(strict_types=1);

namespace ForensixDigital\Apps\Forms;

defined( 'ABSPATH' ) || exit;

/**
 * Connects the entries to Tools > Export Personal Data and Erase Personal Data. An entry belongs
 * to a person when the first email field of its form holds their address.
 */
final class Privacy {

	private const PER_PAGE = 50;

	/**
	 * Creates the handler.
	 *
	 * @param EntryStore $entries Entries.
	 */
	public function __construct( private EntryStore $entries ) {}

	/**
	 * Hooks the exporter and eraser.
	 */
	public function register(): void {
		add_filter( 'wp_privacy_personal_data_exporters', array( $this, 'add_exporter' ) );
		add_filter( 'wp_privacy_personal_data_erasers', array( $this, 'add_eraser' ) );
	}

	/**
	 * Removes the hooks.
	 */
	public function unregister(): void {
		remove_filter( 'wp_privacy_personal_data_exporters', array( $this, 'add_exporter' ) );
		remove_filter( 'wp_privacy_personal_data_erasers', array( $this, 'add_eraser' ) );
	}

	/**
	 * Adds the exporter.
	 *
	 * @param mixed $exporters Registered exporters.
	 * @return mixed
	 */
	public function add_exporter( $exporters ) {
		if ( is_array( $exporters ) ) {
			$exporters['forensix-forms'] = array(
				'exporter_friendly_name' => __( 'Forensix form entries', 'forensix-digital' ),
				'callback'               => array( $this, 'export' ),
			);
		}
		return $exporters;
	}

	/**
	 * Adds the eraser.
	 *
	 * @param mixed $erasers Registered erasers.
	 * @return mixed
	 */
	public function add_eraser( $erasers ) {
		if ( is_array( $erasers ) ) {
			$erasers['forensix-forms'] = array(
				'eraser_friendly_name' => __( 'Forensix form entries', 'forensix-digital' ),
				'callback'             => array( $this, 'erase' ),
			);
		}
		return $erasers;
	}

	/**
	 * Exports the entries of an address.
	 *
	 * @param string $email Address.
	 * @param int    $page  Page, from 1.
	 * @return array{data: array<int, array<string, mixed>>, done: bool}
	 */
	public function export( string $email, int $page = 1 ): array {
		$ids  = $this->entries->ids_by_email( $email, $page, self::PER_PAGE );
		$data = array();
		foreach ( $ids as $id ) {
			$entry = $this->entries->find( $id );
			if ( null === $entry ) {
				continue;
			}
			$items = array();
			foreach ( (array) $entry['data'] as $row ) {
				$items[] = array(
					'name'  => (string) ( $row['label'] ?? '' ),
					'value' => (string) ( $row['value'] ?? '' ),
				);
			}
			$data[] = array(
				'group_id'    => 'forensix-form-entries',
				'group_label' => __( 'Form entries', 'forensix-digital' ),
				'item_id'     => 'forensix-entry-' . $id,
				'data'        => $items,
			);
		}
		return array(
			'data' => $data,
			'done' => count( $ids ) < self::PER_PAGE,
		);
	}

	/**
	 * Erases the entries of an address.
	 *
	 * @param string $email Address. WordPress also passes a page number; it is not needed, because each call erases the first page of what is left.
	 * @return array{items_removed: int, items_retained: int, messages: string[], done: bool}
	 */
	public function erase( string $email ): array {
		$ids = $this->entries->ids_by_email( $email, 1, self::PER_PAGE );
		foreach ( $ids as $id ) {
			$this->entries->delete( $id );
		}
		return array(
			'items_removed'  => count( $ids ),
			'items_retained' => 0,
			'messages'       => array(),
			'done'           => count( $ids ) < self::PER_PAGE,
		);
	}
}