<?php
/**
 * Pairing with the CommercePing backend.
 *
 * 1. Connect (admin-post, capability + nonce): POST {site_url, instance_id,
 *    state, return_url} to /woo/pair/start, then send the admin to the
 *    returned approval page.
 * 2. The backend returns the admin to a nonce-protected admin-post URL.
 * 3. Complete (admin-post, capability + nonce): exchange the approved code and
 *    `state` for the per-store secret.
 *
 * @package OrderPing
 */

defined( 'ABSPATH' ) || exit;

/**
 * Posts JSON to a backend pairing endpoint.
 *
 * @param string $path Path, e.g. /woo/pair/start.
 * @param array  $body Payload.
 * @return array|null Decoded JSON body on HTTP 200, otherwise null.
 */
function orderping_pairing_request( $path, array $body ) {
	$response = wp_remote_post(
		orderping_backend_url() . $path,
		array(
			'timeout'     => 10,
			'redirection' => 0,
			'headers'     => array( 'Content-Type' => 'application/json' ),
			'body'        => wp_json_encode( $body ),
		)
	);
	if ( is_wp_error( $response ) || 200 !== (int) wp_remote_retrieve_response_code( $response ) ) {
		return null;
	}
	$decoded = json_decode( wp_remote_retrieve_body( $response ), true );
	return is_array( $decoded ) ? $decoded : null;
}

/**
 * Starts pairing and redirects the admin to the backend approval page.
 */
function orderping_handle_connect() {
	if ( ! current_user_can( 'manage_woocommerce' ) ) {
		wp_die( esc_html__( 'You do not have permission to do this.', 'commerceping' ), 403 );
	}
	check_admin_referer( 'orderping_connect' );
	// Explicit opt-in: nothing is sent to CommercePing until the admin ticks the consent box.
	if ( empty( $_POST['orderping_consent'] ) ) {
		orderping_redirect_to_settings( 'consent_required' );
	}

	$state  = bin2hex( random_bytes( 16 ) );
	// Built with add_query_arg: wp_nonce_url() HTML-escapes the ampersand.
	$return = add_query_arg( '_wpnonce', wp_create_nonce( 'orderping_complete' ), admin_url( 'admin-post.php?action=orderping_complete' ) );
	$result = orderping_pairing_request(
		'/woo/pair/start',
		array(
			'site_url'    => untrailingslashit( home_url() ),
			'instance_id' => orderping_instance_id(),
			'state'       => $state,
			'return_url'  => $return,
		)
	);
	$approve = is_array( $result ) && isset( $result['approve_url'], $result['code'] ) ? esc_url_raw( (string) $result['approve_url'] ) : '';
	// Only ever send the admin to the configured backend host.
	if ( '' === $approve || wp_parse_url( $approve, PHP_URL_HOST ) !== wp_parse_url( orderping_backend_url(), PHP_URL_HOST ) ) {
		orderping_redirect_to_settings( 'start_failed' );
	}
	update_option(
		ORDERPING_OPTION_PAIRING,
		array(
			'code'  => (string) $result['code'],
			'state' => $state,
		),
		false
	);
	// phpcs:ignore WordPress.Security.SafeRedirect.wp_redirect_wp_redirect -- external, host-checked above.
	wp_redirect( $approve );
	exit;
}

/**
 * Exchanges the approved code for the per-store secret.
 */
function orderping_handle_complete() {
	if ( ! current_user_can( 'manage_woocommerce' ) ) {
		wp_die( esc_html__( 'You do not have permission to do this.', 'commerceping' ), 403 );
	}
	check_admin_referer( 'orderping_complete' );

	$pending = get_option( ORDERPING_OPTION_PAIRING );
	// A completion link is single use: drop the pending pairing before the exchange.
	delete_option( ORDERPING_OPTION_PAIRING );
	if ( ! is_array( $pending ) || empty( $pending['code'] ) || empty( $pending['state'] ) ) {
		orderping_redirect_to_settings( 'no_pairing' );
	}
	$result = orderping_pairing_request(
		'/woo/pair/complete',
		array(
			'code'        => (string) $pending['code'],
			'instance_id' => orderping_instance_id(),
			'state'       => (string) $pending['state'],
		)
	);
	if ( ! is_array( $result ) || empty( $result['connection_id'] ) || empty( $result['secret'] ) || (int) ( $result['contract_version'] ?? 0 ) !== ORDERPING_CONTRACT_VERSION ) {
		orderping_redirect_to_settings( 'complete_failed' );
	}
	// A new pairing never inherits queued work from an earlier one.
	orderping_discard_queued_work();
	update_option(
		ORDERPING_OPTION_CONNECTION,
		array(
			'id'     => sanitize_text_field( (string) $result['connection_id'] ),
			'secret' => (string) $result['secret'],
			'epoch'  => (int) ( $result['connection_epoch'] ?? 1 ),
			'connected_at' => time(),
		),
		false
	);
	// Display-only; taken solely from the completion response, never invented. Absent means no email shown.
	$email = isset( $result['account_email'] ) && is_string( $result['account_email'] ) ? sanitize_email( $result['account_email'] ) : '';
	if ( '' !== $email ) {
		update_option( ORDERPING_OPTION_ACCOUNT_EMAIL, $email, false );
	} else {
		delete_option( ORDERPING_OPTION_ACCOUNT_EMAIL );
	}
	orderping_redirect_to_settings( 'connected' );
}

/**
 * Sends a signed ping so the admin can confirm the channel works.
 */
function orderping_handle_test_ping() {
	if ( ! current_user_can( 'manage_woocommerce' ) ) {
		wp_die( esc_html__( 'You do not have permission to do this.', 'commerceping' ), 403 );
	}
	check_admin_referer( 'orderping_test_ping' );
	$result = orderping_send_event(
		array(
			'type'             => 'ping',
			'event_id'         => bin2hex( random_bytes( 8 ) ),
			'contract_version' => ORDERPING_CONTRACT_VERSION,
			'plugin_version'   => ORDERPING_VERSION,
		)
	);
	orderping_redirect_to_settings( $result['ok'] ? 'ping_ok' : 'ping_failed' );
}

/**
 * Redirects to the settings page with a status code, then exits.
 *
 * @param string $notice Notice code.
 */
function orderping_redirect_to_settings( $notice ) {
	wp_safe_redirect( add_query_arg( 'orderping_notice', rawurlencode( $notice ), admin_url( 'admin.php?page=orderping' ) ) );
	exit;
}