<?php
namespace Advently\Data;

use Advently\Door\Contracts\SubscriberRepo;
use Advently\Security\SignedId;

defined( 'ABSPATH' ) || exit;

/**
 * Subscriber rows: one per (lower-cased) email, shared by email and login mode.
 */
final class Subscribers implements SubscriberRepo {

	/** @var SignedId */
	private $signer;

	public function __construct( SignedId $signer ) {
		$this->signer = $signer;
	}

	/**
	 * @param string $token The signed cookie value "id.signature".
	 */
	public function findByToken( string $token ): ?array {
		$id = $this->signer->verify( $token );
		return null === $id ? null : $this->find( $id );
	}

	public function find( int $id ): ?array {
		global $wpdb;
		// phpcs:ignore WordPress.DB.DirectDatabaseQuery.DirectQuery, WordPress.DB.DirectDatabaseQuery.NoCaching -- custom table, per-request lookup.
		$row = $wpdb->get_row( $wpdb->prepare( "SELECT id, email FROM {$wpdb->prefix}advently_subscribers WHERE id = %d", $id ), ARRAY_A );
		return $row ? self::shape( $row ) : null;
	}

	public function findByEmail( string $email ): ?array {
		global $wpdb;
		// phpcs:ignore WordPress.DB.DirectDatabaseQuery.DirectQuery, WordPress.DB.DirectDatabaseQuery.NoCaching -- custom table, per-request lookup.
		$row = $wpdb->get_row( $wpdb->prepare( "SELECT id, email FROM {$wpdb->prefix}advently_subscribers WHERE email = %s", strtolower( trim( $email ) ) ), ARRAY_A );
		return $row ? self::shape( $row ) : null;
	}

	/**
	 * Finds or creates the row for an email. Consent is recorded the first time it is given.
	 */
	public function subscribe( string $email, bool $consent, string $ipHash ): array {
		return $this->upsert( $email, null, $consent, $ipHash );
	}

	/**
	 * The subscriber row of a logged-in customer (login mode).
	 */
	public function forUser( \WP_User $user, string $ipHash ): ?array {
		if ( ! is_email( $user->user_email ) ) {
			return null;
		}
		return $this->upsert( $user->user_email, (int) $user->ID, false, $ipHash );
	}

	public function token( int $id ): string {
		return $this->signer->sign( $id );
	}

	private function upsert( string $email, ?int $userId, bool $consent, string $ipHash ): array {
		global $wpdb;
		$email = strtolower( trim( $email ) );
		$now   = current_time( 'mysql', true );

		// The unique email key makes this safe against two parallel first visits.
		// NULLIF turns the 0 / '' placeholders into real NULLs (prepare() has no NULL).
		// phpcs:ignore WordPress.DB.DirectDatabaseQuery.DirectQuery, WordPress.DB.DirectDatabaseQuery.NoCaching -- custom table write.
		$wpdb->query(
			$wpdb->prepare(
				"INSERT INTO {$wpdb->prefix}advently_subscribers (email, user_id, created_at, consent_at, ip_hash)
				VALUES (%s, NULLIF(%d, 0), %s, NULLIF(%s, ''), %s)
				ON DUPLICATE KEY UPDATE
					user_id = COALESCE(VALUES(user_id), user_id),
					consent_at = COALESCE(consent_at, VALUES(consent_at))",
				$email,
				(int) $userId,
				$now,
				$consent ? $now : '',
				$ipHash
			)
		);

		// phpcs:ignore WordPress.DB.DirectDatabaseQuery.DirectQuery, WordPress.DB.DirectDatabaseQuery.NoCaching -- custom table, read-after-write.
		$row = $wpdb->get_row( $wpdb->prepare( "SELECT id, email FROM {$wpdb->prefix}advently_subscribers WHERE email = %s", $email ), ARRAY_A );
		return self::shape( $row );
	}

	private static function shape( array $row ): array {
		return [
			'id'    => (int) $row['id'],
			'email' => (string) $row['email'],
		];
	}
}