<?php
namespace Patchwork\Split;

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

class REST_Controller {

    const NS = 'patchwork-split/v1';

    public function __construct() {
        add_action( 'rest_api_init', [ $this, 'register_routes' ] );
    }

    public function register_routes(): void {
        // GET order items — used by the manager on the edit screen and the preview modal
        register_rest_route( self::NS, '/orders/(?P<id>\d+)/items', [
            'methods'             => 'GET',
            'callback'            => [ $this, 'get_items' ],
            'permission_callback' => [ self::class, 'check_permission' ],
        ] );

        // POST one batch of split / unable lines
        register_rest_route( self::NS, '/orders/(?P<id>\d+)/split', [
            'methods'             => 'POST',
            'callback'            => [ $this, 'split' ],
            'permission_callback' => [ self::class, 'check_permission' ],
        ] );
    }

    /**
     * Permission for every /orders/{id}/… route: the user must be allowed to
     * edit that specific order. A missing order gets the 404 from the callback
     * only if the user could split orders at all.
     */
    public static function check_permission( \WP_REST_Request $request ): bool {
        if ( ! Settings::current_user_can_split() ) return false;
        $order = wc_get_order( absint( $request['id'] ) );
        if ( ! $order ) return true;
        return Settings::current_user_can_edit_order( $order );
    }

    // ─── GET items ────────────────────────────────────────────────────────────

    public function get_items( \WP_REST_Request $request ): \WP_REST_Response {
        $order = wc_get_order( absint( $request['id'] ) );
        if ( ! $order || $order->get_type() !== 'shop_order' ) {
            return $this->error( 'pwsplit_no_order', __( 'Order not found.', 'patchwork-order-split' ), 404 );
        }

        $items     = [];
        $backorder = Backorders::units( $order );
        foreach ( $order->get_items( 'line_item' ) as $item_id => $item ) {
            $product = $item->get_product();
            $qty     = (int) $item->get_quantity();
            $total   = (float) $item->get_total() + (float) $item->get_total_tax();
            $items[] = [
                'order_item_id' => (int) $item_id,
                'title'         => $item->get_name(),
                'sku'           => $product ? $product->get_sku() : '',
                'qty'           => $qty,
                'price'         => $total,
                'unit_price'    => $qty > 0 ? $total / $qty : 0,
                'refunded'      => (int) $order->get_qty_refunded_for_item( $item_id ) !== 0 || $order->get_total_refunded_for_item( $item_id ) > 0,
                'backorder'     => (int) ( $backorder[ $item_id ] ?? 0 ),
            ];
        }

        $shipping_total = (float) $order->get_shipping_total() + (float) $order->get_shipping_tax();
        $problem        = Splitter::order_problem( $order );

        return new \WP_REST_Response( [
            'success'        => true,
            'order_id'       => $order->get_id(),
            'order_number'   => $order->get_order_number(),
            'status'         => $order->get_status(),
            'paid'           => Splitter::is_paid( $order ),
            'payment_method' => $order->get_payment_method_title(),
            'items'          => $items,
            'shipping_total' => $shipping_total,
            'currency'       => html_entity_decode( get_woocommerce_currency_symbol( $order->get_currency() ) ),
            'blocked'        => $problem ? $problem->get_error_message() : '',
        ], 200 );
    }

    // ─── POST split ───────────────────────────────────────────────────────────

    public function split( \WP_REST_Request $request ): \WP_REST_Response {
        $order = wc_get_order( absint( $request['id'] ) );
        if ( ! $order || $order->get_type() !== 'shop_order' ) {
            return $this->error( 'pwsplit_no_order', __( 'Order not found.', 'patchwork-order-split' ), 404 );
        }

        $params = (array) $request->get_json_params();
        $lines  = isset( $params['lines'] ) && is_array( $params['lines'] ) ? $params['lines'] : [];
        $args   = array_intersect_key( $params, array_flip( [ 'shipping', 'child_status', 'child_date', 'notify_customer', 'refund_via_gateway' ] ) );

        $result = ( new Splitter() )->split( $order, $lines, $args );
        if ( is_wp_error( $result ) ) {
            return $this->error( $result->get_error_code(), $result->get_error_message(), 400 );
        }

        $result['success']    = true;
        $result['parent_url'] = $order->get_edit_order_url();
        $result['child_url']  = $result['child_id']  ? wc_get_order( $result['child_id'] )->get_edit_order_url()  : '';
        $result['unable_url'] = $result['unable_id'] ? wc_get_order( $result['unable_id'] )->get_edit_order_url() : '';

        return new \WP_REST_Response( $result, 200 );
    }

    private function error( string $code, string $message, int $status ): \WP_REST_Response {
        return new \WP_REST_Response( [ 'success' => false, 'code' => $code, 'message' => $message ], $status );
    }
}