<?php
/**
 * Stored connection and backend request helpers.
 *
 * The per-store secret lives in a single non-autoloaded option and is never
 * rendered, logged or returned.
 *
 * @package OrderPing
 */

defined( 'ABSPATH' ) || exit;

// The plugin owns its custom tables (outbox, confirmation, actions, nonces): direct queries are the only way to use them.
// The interpolated names are internal, prefixed constants and never user input; every value goes through $wpdb->prepare().
// phpcs:disable WordPress.DB.DirectDatabaseQuery, WordPress.DB.PreparedSQL.NotPrepared, WordPress.DB.PreparedSQL.InterpolatedNotPrepared, PluginCheck.Security.DirectDB.UnescapedDBParameter

const ORDERPING_OPTION_CONNECTION = 'orderping_connection';
const ORDERPING_OPTION_INSTANCE   = 'orderping_instance_id';
const ORDERPING_OPTION_PAIRING    = 'orderping_pairing';
// Set when the backend refused this plugin's contract version; holds that version.
const ORDERPING_OPTION_UPDATE_REQUIRED = 'orderping_update_required';
const ORDERPING_OPTION_PLUGIN_VERSION  = 'orderping_plugin_version';
// Display-only CommercePing account email, stored only from the pairing completion response.
const ORDERPING_OPTION_ACCOUNT_EMAIL   = 'orderping_account_email';
const ORDERPING_TRANSIENT_ACTIVATED    = 'orderping_activation_redirect';

/**
 * Whether the backend has refused this plugin's event contract, so sending is blocked
 * until the plugin is updated. The flag is tied to the contract version it was set
 * for, so an update that bumps the contract clears it by itself.
 *
 * @return bool
 */
function orderping_update_required() {
	return (int) get_option( ORDERPING_OPTION_UPDATE_REQUIRED, 0 ) === ORDERPING_CONTRACT_VERSION;
}

/**
 * Backend base URL. Override with ORDERPING_BACKEND_URL in wp-config.php.
 *
 * @return string
 */
function orderping_backend_url() {
	$url = defined( 'ORDERPING_BACKEND_URL' ) ? ORDERPING_BACKEND_URL : 'https://app.commerceping.com';
	/**
	 * Filters the CommercePing backend base URL (staging, local rigs). Production is the default.
	 *
	 * @param string $url Base URL.
	 */
	$url = apply_filters( 'orderping_backend_base', $url );
	return untrailingslashit( esc_url_raw( (string) $url ) );
}

/**
 * Stable per-install identifier, created on first use.
 *
 * @return string
 */
function orderping_instance_id() {
	$id = get_option( ORDERPING_OPTION_INSTANCE );
	if ( ! is_string( $id ) || ! preg_match( '/^[A-Za-z0-9_-]{8,128}$/', $id ) ) {
		$id = wp_generate_uuid4();
		update_option( ORDERPING_OPTION_INSTANCE, $id, false );
	}
	return $id;
}

/**
 * Paired connection, or null when not connected.
 *
 * @return array{id:string,secret:string,epoch:int}|null
 */
function orderping_connection() {
	$conn = get_option( ORDERPING_OPTION_CONNECTION );
	if ( is_array( $conn ) && ! empty( $conn['id'] ) && ! empty( $conn['secret'] ) ) {
		return array(
			'id'     => (string) $conn['id'],
			'secret' => (string) $conn['secret'],
			'epoch'  => (int) ( $conn['epoch'] ?? 1 ),
		);
	}
	return null;
}

/**
 * Sends a signed JSON event to the backend.
 *
 * @param array $event Event payload.
 * @param array $bound Optional connection the event was captured under (id, epoch); a different
 *                     current connection means the event is stale and nothing is sent.
 * @return array{ok:bool,status:int,error?:string}
 */
function orderping_send_event( array $event, array $bound = array() ) {
	$conn = orderping_connection();
	if ( null === $conn ) {
		return array( 'ok' => false, 'status' => 0, 'error' => 'not_connected' );
	}
	if ( orderping_update_required() ) {
		return array( 'ok' => false, 'status' => 0, 'error' => 'update_required' );
	}
	if ( $bound && ( $bound['id'] !== $conn['id'] || (int) $bound['epoch'] !== $conn['epoch'] ) ) {
		return array( 'ok' => false, 'status' => 0, 'error' => 'stale_connection' );
	}
	$body      = wp_json_encode( $event );
	$path      = '/woo/events';
	$timestamp = time();
	$nonce     = bin2hex( random_bytes( 16 ) );
	$response  = wp_remote_post(
		orderping_backend_url() . $path,
		array(
			'timeout'     => 10,
			'redirection' => 0,
			'headers'     => array(
				'Content-Type'    => 'application/json',
				'X-OP-Connection' => $conn['id'],
				'X-OP-Timestamp'  => (string) $timestamp,
				'X-OP-Nonce'      => $nonce,
				'X-OP-Signature'  => orderping_sign( $conn['secret'], 'site-to-cp', 'POST', $path, $timestamp, $nonce, $body ),
			),
			'body'        => $body,
		)
	);
	if ( is_wp_error( $response ) ) {
		return array( 'ok' => false, 'status' => 0, 'error' => 'transport' );
	}
	$status = (int) wp_remote_retrieve_response_code( $response );
	if ( 426 === $status ) {
		// The backend no longer accepts this plugin's contract version: block sending, show update guidance.
		update_option( ORDERPING_OPTION_UPDATE_REQUIRED, ORDERPING_CONTRACT_VERSION, false );
		return array( 'ok' => false, 'status' => 426, 'error' => 'update_required' );
	}
	return array( 'ok' => 200 === $status, 'status' => $status );
}

/**
 * Nonce table name.
 *
 * @return string
 */
function orderping_nonce_table() {
	global $wpdb;
	return $wpdb->prefix . 'orderping_nonces';
}

/**
 * Creates the plugin tables (nonce and outbox). The nonce UNIQUE key is what makes a claim atomic.
 */
function orderping_install_tables() {
	global $wpdb;
	require_once ABSPATH . 'wp-admin/includes/upgrade.php';
	$table   = orderping_nonce_table();
	$charset = $wpdb->get_charset_collate();
	dbDelta(
		"CREATE TABLE {$table} (
			nonce_hash char(64) NOT NULL,
			expires_at bigint(20) unsigned NOT NULL,
			PRIMARY KEY  (nonce_hash),
			UNIQUE KEY nonce_hash_unique (nonce_hash),
			KEY expires_at (expires_at)
		) {$charset};"
	);
	orderping_install_outbox_table();
	orderping_install_confirmation_tables();
	orderping_install_cancel_tables();
}

/**
 * Atomically claims a backend-request nonce: an insert against a unique key
 * that must affect exactly one row. A duplicate or any DB error is a failed claim.
 *
 * @param string $nonce Nonce header value (already validated).
 * @return bool True when the nonce was unused.
 */
function orderping_claim_nonce( $nonce ) {
	global $wpdb;
	$suppress = $wpdb->suppress_errors( true );
	// phpcs:ignore WordPress.DB.DirectDatabaseQuery.DirectQuery, WordPress.DB.DirectDatabaseQuery.NoCaching
	$rows = $wpdb->insert(
		orderping_nonce_table(),
		array(
			'nonce_hash' => hash( 'sha256', $nonce ),
			'expires_at' => time() + ORDERPING_NONCE_TTL,
		),
		array( '%s', '%d' )
	);
	$wpdb->suppress_errors( $suppress );
	return 1 === $rows && 1 === (int) $wpdb->rows_affected;
}

/**
 * Daily cleanup of expired nonces.
 */
function orderping_prune_nonces() {
	global $wpdb;
	$table = orderping_nonce_table();
	// phpcs:ignore WordPress.DB.DirectDatabaseQuery.DirectQuery, WordPress.DB.DirectDatabaseQuery.NoCaching, WordPress.DB.PreparedSQL.InterpolatedNotPrepared
	$wpdb->query( $wpdb->prepare( "DELETE FROM {$table} WHERE expires_at < %d", time() ) );
}