<?php
/**
 * Order-state mirror: the backend tells the site which confirmation state an order reached.
 *
 * The state is written to the order meta `_cp_confirmation_state` and one order note is added
 * when it changes. The write is compare-then-set, so a repeated or concurrent call for the same
 * state leaves the order and its notes unchanged. This never affects customer messages or the
 * order's WooCommerce status.
 *
 * @package OrderPing
 */

defined( 'ABSPATH' ) || exit;

const ORDERPING_ORDER_STATE_PATH = '/wp-json/orderping/v1/order-state';
const ORDERPING_STATE_META       = '_cp_confirmation_state';

/**
 * Allowed states and the note text for each.
 *
 * @return array<string,string>
 */
function orderping_order_state_notes() {
	return array(
		'confirmed'   => 'CommercePing: customer confirmed this order on WhatsApp.',
		'cancelled'   => 'CommercePing: this order was cancelled (confirmation resolved as cancelled).',
		'unconfirmed' => 'CommercePing: this order is not confirmed (no reply before the deadline).',
	);
}

/**
 * Optional reason a state was reached, sent by backends that know it. A reason only changes the
 * note text; the state vocabulary is unchanged, so a plugin that predates reasons still accepts the
 * same request (it ignores the extra field and writes the deadline wording).
 *
 * @return array<string,array<string,string>> state => reason => note.
 */
function orderping_order_state_reason_notes() {
	return array(
		'unconfirmed' => array(
			'edited_after_confirmed' => 'CommercePing: this order was edited after the customer confirmed it, so it needs a fresh confirmation.',
		),
	);
}

/**
 * Note text for a state and optional reason. An unknown reason falls back to the state's note.
 *
 * @param string $state  Allowed state.
 * @param string $reason Reason or empty string.
 * @return string
 */
function orderping_order_state_note( $state, $reason ) {
	$notes   = orderping_order_state_notes();
	$reasons = orderping_order_state_reason_notes();
	return $reasons[ $state ][ $reason ] ?? $notes[ $state ];
}

/**
 * Sets the state meta when it differs. Returns 'applied' when it wrote, 'unchanged' when the
 * order already carried the state.
 *
 * @param WC_Order $order Order.
 * @param string   $state  One of the allowed states.
 * @param string   $reason Optional reason; selects the note text only.
 * @return string
 */
function orderping_apply_order_state( WC_Order $order, $state, $reason = '' ) {
	if ( (string) $order->get_meta( ORDERPING_STATE_META, true ) === $state ) {
		return 'unchanged';
	}
	$order->update_meta_data( ORDERPING_STATE_META, $state );
	$order->save_meta_data();
	$order->add_order_note( orderping_order_state_note( $state, $reason ) );
	return 'applied';
}

/**
 * Handles a signed order-state write.
 *
 * @param WP_REST_Request $request Request.
 * @return WP_REST_Response|WP_Error
 */
function orderping_rest_order_state( WP_REST_Request $request ) {
	$conn = orderping_connection();
	if ( null === $conn || $conn['id'] !== (string) $request->get_header( 'x_op_connection' ) ) {
		return new WP_Error( 'orderping_unauthorized', 'Unauthorized', array( 'status' => 401 ) );
	}
	$body    = $request->get_body();
	$verdict = orderping_verify(
		$conn['secret'],
		'cp-to-site',
		'POST',
		ORDERPING_ORDER_STATE_PATH,
		(string) $request->get_header( 'x_op_timestamp' ),
		(string) $request->get_header( 'x_op_nonce' ),
		(string) $request->get_header( 'x_op_signature' ),
		$body,
		time()
	);
	if ( true !== $verdict ) {
		return new WP_Error( 'orderping_unauthorized', 'Unauthorized', array( 'status' => 401 ) );
	}
	// Claim the nonce only after the signature is valid.
	if ( ! orderping_claim_nonce( (string) $request->get_header( 'x_op_nonce' ) ) ) {
		return new WP_Error( 'orderping_replayed', 'Unauthorized', array( 'status' => 401 ) );
	}

	$data = json_decode( $body, true );
	if (
		! is_array( $data )
		|| 1 !== ( $data['contract_version'] ?? null )
		|| ! is_string( $data['state'] ?? null ) || ! array_key_exists( $data['state'], orderping_order_state_notes() )
		|| ! is_string( $data['action_id'] ?? null ) || ! preg_match( '/^[A-Za-z0-9:_.-]{1,160}$/', $data['action_id'] )
		|| ! is_string( $data['order_id'] ?? null ) || ! preg_match( '/^\d{1,20}$/', $data['order_id'] )
	) {
		return new WP_Error( 'orderping_invalid', 'Invalid request', array( 'status' => 400 ) );
	}

	$order = orderping_fresh_order( (int) $data['order_id'] );
	// Pilot scope and capture first: nothing about any other order is read or written.
	if ( ! $order instanceof WC_Order || ! orderping_order_in_scope( $order ) || ! orderping_order_was_captured( $order->get_id() ) ) {
		return new WP_Error( 'orderping_not_found', 'Order not found', array( 'status' => 404 ) );
	}

	$reason = is_string( $data['reason'] ?? null ) ? $data['reason'] : '';
	$status = orderping_apply_order_state( $order, $data['state'], $reason );
	return new WP_REST_Response(
		array(
			'status' => $status,
			'state'  => $data['state'],
		),
		200
	);
}