<?php
/**
 * WordPress database evidence event store.
 *
 * @package Leanmerce\CommerceCompliance
 */

namespace Leanmerce\CommerceCompliance\Infrastructure\Evidence;

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

use Leanmerce\CommerceCompliance\Domain\Evidence\EvidenceEvent;
use Leanmerce\CommerceCompliance\Domain\Evidence\EvidenceEventStoreInterface;
use Leanmerce\CommerceCompliance\Infrastructure\Database\TableNames;

final class WpdbEvidenceEventStore implements EvidenceEventStoreInterface {
	public function append( EvidenceEvent $event ): bool {
		global $wpdb;

		$table = TableNames::get( 'events' );
		if ( '' === $table || ! isset( $wpdb ) ) {
			return false;
		}

		$idempotency_key = $event->idempotency_key();
		if ( null !== $idempotency_key && '' !== $idempotency_key ) {
			$existing = $this->find_by_idempotency_key( $table, $idempotency_key );
			if ( null !== $existing ) {
				return $this->same_event( $existing, $event );
			}
		}

		$uuid = function_exists( 'wp_generate_uuid4' ) ? wp_generate_uuid4() : $this->fallback_uuid();
		$json = wp_json_encode( $event->payload() );
		if ( ! is_string( $json ) ) {
			return false;
		}

		// phpcs:ignore WordPress.DB.DirectDatabaseQuery.DirectQuery -- Append-only writes target the plugin's own custom evidence table.
		$result = $wpdb->insert(
			$table,
			array(
				'uuid'            => $uuid,
				'order_id'        => $event->order_id(),
				'event_type'      => $event->event_type(),
				'idempotency_key' => $idempotency_key,
				'actor_type'      => 'system',
				'status'          => 'recorded',
				'payload_json'    => $json,
				'occurred_at'     => $event->occurred_at(),
				'created_at'      => current_time( 'mysql', true ),
			),
			array( '%s', '%d', '%s', '%s', '%s', '%s', '%s', '%s', '%s' )
		);

		if ( false !== $result ) {
			return true;
		}

		// A unique-key race is idempotent only if the winning row describes the
		// same immutable event. A conflicting reuse of the key must fail closed.
		if ( null !== $idempotency_key && '' !== $idempotency_key ) {
			$winner = $this->find_by_idempotency_key( $table, $idempotency_key );
			return null !== $winner && $this->same_event( $winner, $event );
		}
		return false;
	}

	public function for_order( int $order_id ): array {
		global $wpdb;

		$table = TableNames::get( 'events' );
		if ( '' === $table || ! isset( $wpdb ) || $order_id <= 0 ) {
			return array();
		}

		$rows   = $wpdb->get_results( $wpdb->prepare( "SELECT event_type, order_id, payload_json, occurred_at, idempotency_key FROM {$table} WHERE order_id = %d ORDER BY id ASC", $order_id ), ARRAY_A ); // phpcs:ignore WordPress.DB.PreparedSQL.InterpolatedNotPrepared,WordPress.DB.DirectDatabaseQuery.DirectQuery,WordPress.DB.DirectDatabaseQuery.NoCaching,PluginCheck.Security.DirectDB.UnescapedDBParameter -- Table is an internal allowlisted identifier; immutable evidence reads must bypass mutable object caches.
		$events = array();
		foreach ( is_array( $rows ) ? $rows : array() as $row ) {
			$payload  = json_decode( (string) $row['payload_json'], true );
			$events[] = new EvidenceEvent(
				(string) $row['event_type'],
				(int) $row['order_id'],
				is_array( $payload ) ? $payload : array(),
				(string) $row['occurred_at'],
				isset( $row['idempotency_key'] ) ? (string) $row['idempotency_key'] : null
			);
		}
		return $events;
	}

	/** @return array<string,mixed>|null */
	private function find_by_idempotency_key( string $table, string $idempotency_key ): ?array {
		global $wpdb;
		// phpcs:disable WordPress.DB.DirectDatabaseQuery.DirectQuery,WordPress.DB.DirectDatabaseQuery.NoCaching,WordPress.DB.PreparedSQL.InterpolatedNotPrepared,PluginCheck.Security.DirectDB.UnescapedDBParameter -- $table is resolved only from the internal TableNames allowlist; idempotency reads must see the authoritative custom table.
		$row = $wpdb->get_row(
			$wpdb->prepare(
				"SELECT event_type, order_id, payload_json FROM {$table} WHERE idempotency_key = %s LIMIT 1",
				$idempotency_key
			),
			ARRAY_A
		); // phpcs:ignore WordPress.DB.PreparedSQL.InterpolatedNotPrepared -- Table is internal allowlisted name.
		// phpcs:enable
		return is_array( $row ) ? $row : null;
	}

	/** @param array<string,mixed> $stored */
	private function same_event( array $stored, EvidenceEvent $candidate ): bool {
		if ( (string) ( $stored['event_type'] ?? '' ) !== $candidate->event_type()
			|| (int) ( $stored['order_id'] ?? 0 ) !== $candidate->order_id() ) {
			return false;
		}
		$payload = json_decode( (string) ( $stored['payload_json'] ?? '' ), true );
		if ( ! is_array( $payload ) ) {
			return false;
		}
		return $this->normalize( $payload ) === $this->normalize( $candidate->payload() );
	}

	/** @return mixed */
	private function normalize( $value ) {
		if ( ! is_array( $value ) ) {
			return $value;
		}
		if ( array_is_list( $value ) ) {
			return array_map( array( $this, 'normalize' ), $value );
		}
		$out = array();
		foreach ( $value as $key => $item ) {
			$out[ (string) $key ] = $this->normalize( $item );
		}
		ksort( $out, SORT_STRING );
		return $out;
	}

	private function fallback_uuid(): string {
		$bytes    = random_bytes( 16 );
		$bytes[6] = chr( ( ord( $bytes[6] ) & 0x0f ) | 0x40 );
		$bytes[8] = chr( ( ord( $bytes[8] ) & 0x3f ) | 0x80 );
		$hex      = bin2hex( $bytes );
		return substr( $hex, 0, 8 ) . '-' . substr( $hex, 8, 4 ) . '-' . substr( $hex, 12, 4 ) . '-' . substr( $hex, 16, 4 ) . '-' . substr( $hex, 20 );
	}
}