<?php

namespace FluentCart\App\Modules\MCP\Tools;

use FluentCart\App\Helpers\Helper;
use FluentCart\App\Helpers\Status;
use FluentCart\App\Models\Order;
use FluentCart\App\Models\OrderTransaction;
use FluentCart\App\Modules\MCP\Support\MCPHelper;
use FluentCart\App\Modules\MCP\Support\PermissionGate;
use FluentCart\App\Modules\MCP\Support\WriteGuard;
use FluentCart\App\Services\Payments\Refund;
use FluentCart\Api\Resource\OrderResource;

/**
 * Order tools — find orders, then load one fully.
 *
 * Read surface (this file): list-orders (compact, filterable), get-order
 * (one order, include[]-driven), get-order-activity (the audit timeline).
 *
 * Parameter design notes for the agent's sake:
 *  - list-orders takes FLAT, enum-constrained filters (status, payment_status,
 *    …) rather than a freeform query object — the model negotiates against the
 *    schema at selection time, so flat + enum means fewer wrong calls.
 *  - Every filter is optional; omitting all returns the latest orders. Money
 *    filters (min_total/max_total) are in store-currency decimals, not cents —
 *    the agent thinks in dollars, we convert.
 *  - get-order accepts a numeric order_id (what list-orders returns) OR a
 *    uuid / invoice_no, so the agent never has to translate identifiers.
 *  - get-order is lean by default (items + customer); heavier sections
 *    (transactions, refunds, coupons, subscriptions, addresses) are opt-in via
 *    include[] so one order can't silently flood the context window.
 */
class OrderTools
{
    public static function definitions()
    {
        $orderStatuses    = ContextTools::ENUMS['order_statuses'];
        $paymentStatuses  = ContextTools::ENUMS['payment_statuses'];
        $shippingStatuses = ContextTools::ENUMS['shipping_statuses'];
        // change-order-status cannot set an order back to "no shipping required".
        $shippingWritable = array_values(array_diff($shippingStatuses, ['none']));
        // Only the statuses core actually accepts for a manual change — a subset
        // of the full order_statuses enum used for filtering (no draft/pending/
        // refunded/partial-refund: those are reached via payment/refund flows).
        $orderWritable    = array_keys(Status::getEditableOrderStatuses());
        $orderTypes       = ContextTools::ENUMS['order_types'];

        return [
            'fluent-cart/list-orders' => [
                'label'       => __('List Orders', 'fluent-cart'),
                'description' => __('Find and filter orders. Returns compact rows (id, number, customer, total, statuses, date, plus an items list: each line item\'s product, title and quantity) — call get-order for the full money/refund breakdown. All filters optional; combine freely. For one customer\'s orders, pass customer_email or customer_id here. Money filters are in store currency (e.g. 49.99), not cents.', 'fluent-cart'),
                'input_schema' => [
                    'type'       => 'object',
                    'properties' => [
                        'status'          => ['type' => 'string', 'enum' => $orderStatuses, 'description' => 'Order fulfillment/lifecycle status.'],
                        'payment_status'  => ['type' => 'string', 'enum' => $paymentStatuses],
                        'shipping_status' => ['type' => 'string', 'enum' => $shippingStatuses],
                        'type'            => ['type' => 'string', 'enum' => $orderTypes, 'description' => 'payment = first purchase, renewal = subscription renewal.'],
                        'customer_id'     => ['type' => 'integer'],
                        'customer_email'  => ['type' => 'string', 'description' => 'Exact email — the most reliable customer filter.'],
                        'product_id'      => ['type' => 'integer', 'description' => 'Orders containing this product.'],
                        'coupon_code'     => ['type' => 'string'],
                        'country'         => ['type' => 'string', 'description' => 'ISO-2 country code on the billing address.'],
                        'currency'        => ['type' => 'string', 'description' => 'ISO currency code.'],
                        'min_total'       => ['type' => 'number', 'description' => 'Minimum order total in store currency.'],
                        'max_total'       => ['type' => 'number', 'description' => 'Maximum order total in store currency.'],
                        'created_after'   => ['type' => 'string', 'description' => 'YYYY-MM-DD or ISO 8601, UTC.'],
                        'created_before'  => ['type' => 'string', 'description' => 'YYYY-MM-DD or ISO 8601, UTC.'],
                        'mode'            => ['type' => 'string', 'enum' => ['live', 'test'], 'description' => 'Defaults to all modes.'],
                        'search'          => ['type' => 'string', 'description' => 'Matches invoice/receipt number, order uuid, and customer name/email.'],
                        'sort_by'         => ['type' => 'string', 'enum' => ['id', 'created_at', 'completed_at', 'total_amount'], 'default' => 'id'],
                        'sort_type'       => ['type' => 'string', 'enum' => ['ASC', 'DESC'], 'default' => 'DESC'],
                        'page'            => ['type' => 'integer', 'default' => 1],
                        'per_page'        => ['type' => 'integer', 'default' => 15, 'description' => 'Max 100.'],
                    ],
                ],
                'execute_callback'    => [self::class, 'listOrders'],
                'permission_callback' => function () {
                    return PermissionGate::can('orders/view');
                },
                'annotations' => ['readonly' => true],
            ],

            'fluent-cart/get-order' => [
                'label'       => __('Get Order', 'fluent-cart'),
                'description' => __('Full detail for one order: money breakdown, line items, and customer by default. Add include[] for transactions, refunds, addresses, coupons, subscriptions. Identify the order by order_id (numeric, from list-orders) OR uuid OR invoice_no.', 'fluent-cart'),
                'input_schema' => [
                    'type'       => 'object',
                    'properties' => [
                        'order_id'   => ['type' => 'integer', 'description' => 'Numeric order id as returned by list-orders.'],
                        'uuid'       => ['type' => 'string'],
                        'invoice_no' => ['type' => 'string'],
                        'include'    => [
                            'type'        => 'array',
                            'description' => 'Optional heavier sections. items + customer are always included.',
                            'items'       => ['type' => 'string', 'enum' => ['transactions', 'refunds', 'addresses', 'coupons', 'subscriptions']],
                        ],
                    ],
                ],
                'execute_callback'    => [self::class, 'getOrder'],
                'permission_callback' => function () {
                    return PermissionGate::can('orders/view');
                },
                'annotations' => ['readonly' => true],
            ],

            'fluent-cart/get-order-activity' => [
                'label'       => __('Get Order Activity', 'fluent-cart'),
                'description' => __('Audit timeline for one order — status changes, payments, refunds, notes, emails sent: who did what and when. Use after get-order when you need history, not just current state.', 'fluent-cart'),
                'input_schema' => [
                    'type'       => 'object',
                    'properties' => [
                        'order_id' => ['type' => 'integer'],
                        'limit'    => ['type' => 'integer', 'default' => 30, 'description' => 'Max 100.'],
                    ],
                    'required' => ['order_id'],
                ],
                'execute_callback'    => [self::class, 'getOrderActivity'],
                'permission_callback' => function () {
                    return PermissionGate::can('orders/view');
                },
                'annotations' => ['readonly' => true],
            ],

            'fluent-cart/change-order-status' => [
                'label'       => __('Change Order Status', 'fluent-cart'),
                'description' => __('Change an order status or shipping status. Pass order_id and at least one of order_status or shipping_status. A no-op is returned if the order is already in that status. To refund, use refund-order instead.', 'fluent-cart'),
                'input_schema' => [
                    'type'       => 'object',
                    'properties' => [
                        'order_id'        => ['type' => 'integer'],
                        'order_status'    => ['type' => 'string', 'enum' => $orderWritable, 'description' => 'New order lifecycle status. Only these are manually settable; refunded/partial-refund come from the refund flow, draft/pending/failed from payment.'],
                        'shipping_status' => ['type' => 'string', 'enum' => $shippingWritable, 'description' => 'New shipping status. Setting shipped/delivered marks items fulfilled.'],
                    ],
                    'required' => ['order_id'],
                ],
                'execute_callback'    => [self::class, 'changeOrderStatus'],
                'permission_callback' => function () {
                    return PermissionGate::can('orders/manage_statuses');
                },
            ],

            'fluent-cart/add-order-note' => [
                'label'       => __('Add Order Note', 'fluent-cart'),
                'description' => __('Add an internal note to an order activity log. Visible to staff, not the customer.', 'fluent-cart'),
                'input_schema' => [
                    'type'       => 'object',
                    'properties' => [
                        'order_id' => ['type' => 'integer'],
                        'note'     => ['type' => 'string', 'description' => 'Note text. Plain text or simple HTML.'],
                    ],
                    'required' => ['order_id', 'note'],
                ],
                'execute_callback'    => [self::class, 'addOrderNote'],
                'permission_callback' => function () {
                    return PermissionGate::can('orders/manage');
                },
            ],

            'fluent-cart/refund-order' => [
                'label'       => __('Refund Order', 'fluent-cart'),
                'description' => __('Refund an order through its payment gateway. ALWAYS call with dry_run:true first to preview the refundable amount and receive a confirm_token, then call again with that confirm_token plus an idempotency_key to execute. Without an idempotency_key a repeated execute could double-refund. amount is in store currency; omit to refund the full remaining balance. The preview reports payment_mode and live_gateway_action; executing a LIVE refund requires the operator to opt in (test-mode always works).', 'fluent-cart'),
                'input_schema' => [
                    'type'       => 'object',
                    'properties' => [
                        'order_id'        => ['type' => 'integer'],
                        'amount'          => ['type' => 'number', 'description' => 'Amount to refund in store currency. Omit for the full remaining balance.'],
                        'transaction_id'  => ['type' => 'integer', 'description' => 'Charge transaction to refund against. Omit to use the latest successful charge.'],
                        'reason'          => ['type' => 'string'],
                        'dry_run'         => ['type' => 'boolean', 'description' => 'Preview without refunding. Returns a confirm_token. Do this first.'],
                        'confirm_token'   => ['type' => 'string', 'description' => 'From a prior dry_run. Required to execute.'],
                        'idempotency_key' => ['type' => 'string', 'description' => 'A unique string for this refund. Prevents double-refund on retry.'],
                    ],
                    'required' => ['order_id'],
                ],
                'execute_callback'    => [self::class, 'refundOrder'],
                'permission_callback' => function () {
                    return PermissionGate::can('orders/can_refund');
                },
                'annotations' => ['destructive' => true],
            ],
        ];
    }

    // -----------------------------------------------------------------
    // list-orders
    // -----------------------------------------------------------------

    public static function listOrders($params = [])
    {
        $paging = MCPHelper::pagination($params);

        // Eager-load customer plus a TRIMMED order_items relation — only the
        // columns needed for a "what's in this order" preview, never the full
        // money/refund/fulfillment row (that's get-order's job). formatRow caps
        // the preview, so even a large multi-item order can't flood the payload.
        // The product_id filter uses whereHas (a join), independent of this load.
        $query = Order::query()->with([
            'customer',
            'order_items' => function ($q) {
                $q->select(['id', 'order_id', 'post_id', 'post_title', 'title', 'quantity']);
            },
        ]);

        $filterError = self::applyFilters($query, $params);
        if (is_wp_error($filterError)) {
            return $filterError;
        }

        $sortBy   = self::allowed($params, 'sort_by', ['id', 'created_at', 'completed_at', 'total_amount'], 'id');
        $sortType = strtoupper(isset($params['sort_type']) ? $params['sort_type'] : 'DESC') === 'ASC' ? 'ASC' : 'DESC';

        // Deterministic total order: tie-break on id so identical calls and
        // cursor paging never reshuffle rows.
        $query->orderBy($sortBy, $sortType);
        if ($sortBy !== 'id') {
            $query->orderBy('id', 'DESC');
        }

        $paginator = $query->paginate($paging['per_page'], ['*'], 'page', $paging['page']);
        $total     = self::total($paginator);

        $rows = [];
        foreach (MCPHelper::paginatorItems($paginator) as $order) {
            $rows[] = self::formatRow($order);
        }

        return MCPHelper::envelope(
            sprintf(
                /* translators: %d: number of matching orders */
                _n('%d order found.', '%d orders found.', $total, 'fluent-cart'),
                $total
            ),
            ['orders' => $rows],
            MCPHelper::pagingMeta($paginator)
        );
    }

    private static function applyFilters($query, $params)
    {
        foreach (['status', 'payment_status', 'type', 'currency', 'mode'] as $col) {
            if (!empty($params[$col])) {
                $query->where($col, sanitize_text_field($params[$col]));
            }
        }

        // shipping_status: the reported 'none' maps to the empty/NULL stored value.
        if (!empty($params['shipping_status'])) {
            $shipping = sanitize_text_field($params['shipping_status']);
            if ($shipping === 'none') {
                $query->where(function ($q) {
                    $q->whereNull('shipping_status')->orWhere('shipping_status', '');
                });
            } else {
                $query->where('shipping_status', $shipping);
            }
        }

        if (!empty($params['customer_id'])) {
            $query->where('customer_id', (int) $params['customer_id']);
        }

        if (!empty($params['customer_email'])) {
            $email = sanitize_email($params['customer_email']);
            $query->whereHas('customer', function ($q) use ($email) {
                $q->where('email', $email);
            });
        }

        if (!empty($params['product_id'])) {
            $productId = (int) $params['product_id'];
            $query->whereHas('order_items', function ($q) use ($productId) {
                $q->where('post_id', $productId);
            });
        }

        if (!empty($params['coupon_code'])) {
            $code = sanitize_text_field($params['coupon_code']);
            $query->whereHas('appliedCoupons', function ($q) use ($code) {
                $q->where('code', $code);
            });
        }

        if (!empty($params['country'])) {
            $country = sanitize_text_field($params['country']);
            $query->whereHas('billing_address', function ($q) use ($country) {
                $q->where('country', $country);
            });
        }

        if (isset($params['min_total'])) {
            $query->where('total_amount', '>=', Helper::toCent($params['min_total']));
        }
        if (isset($params['max_total'])) {
            $query->where('total_amount', '<=', Helper::toCent($params['max_total']));
        }

        foreach (['created_after' => '>=', 'created_before' => '<='] as $field => $op) {
            if (empty($params[$field])) {
                continue;
            }
            $date = self::toDbDate($params[$field]);
            if ($date === null) {
                return self::invalidDateError($field);
            }
            $query->where('created_at', $op, $date);
        }

        if (!empty($params['search'])) {
            $term = sanitize_text_field($params['search']);
            $like = '%' . $term . '%';
            $query->where(function ($q) use ($like) {
                $q->where('invoice_no', 'LIKE', $like)
                    ->orWhere('receipt_number', 'LIKE', $like)
                    ->orWhere('uuid', 'LIKE', $like)
                    ->orWhereHas('customer', function ($cq) use ($like) {
                        $cq->where('email', 'LIKE', $like)
                            ->orWhere('first_name', 'LIKE', $like)
                            ->orWhere('last_name', 'LIKE', $like);
                    });
            });
        }
    }

    /**
     * Refund timestamp. Falls back to the latest refund transaction's date when
     * the order's own refunded_at column is empty but money was refunded — some
     * refund paths don't stamp the column.
     */
    private static function refundedAt($order)
    {
        if ($order->refunded_at) {
            return MCPHelper::toIso8601($order->refunded_at);
        }
        if ((int) $order->total_refund > 0) {
            $txn = OrderTransaction::query()
                ->where('order_id', $order->id)
                ->where('transaction_type', 'refund')
                ->orderBy('id', 'DESC')
                ->first();
            if ($txn && $txn->created_at) {
                return MCPHelper::toIso8601($txn->created_at);
            }
        }
        return null;
    }

    /**
     * Report the shipping status, mapping an empty/NULL stored value to 'none'
     * (no shipping required — e.g. digital orders) so the value is always a
     * member of the advertised enum.
     */
    private static function shippingStatusOut($order)
    {
        return ($order->shipping_status !== null && $order->shipping_status !== '') ? $order->shipping_status : 'none';
    }

    /** Compact list row — only what's needed to scan and decide which to open. */
    private static function formatRow($order)
    {
        $customer = ($order->relationLoaded('customer') && $order->customer) ? $order->customer : null;

        return [
            'order_id'        => (int) $order->id,
            'number'          => $order->invoice_no ? $order->invoice_no : (string) $order->id,
            'label'           => self::label($order, $customer),
            'status'          => $order->status,
            'payment_status'  => $order->payment_status,
            'shipping_status' => self::shippingStatusOut($order),
            'type'            => $order->type,
            'total'           => MCPHelper::moneyCompact($order->total_amount),
            'customer'        => $customer ? [
                'id'    => (int) $customer->id,
                'name'  => MCPHelper::personName($customer),
                'email' => $customer->email,
            ] : null,
            'items'           => self::itemsSummary($order),
            'created_at'      => MCPHelper::toIso8601($order->created_at),
        ];
    }

    /**
     * Compact "what was ordered" list for list rows: every line item as
     * product_id, display title (incl. variation), and quantity — enough for the
     * agent to recognize an order's contents without a get-order round-trip.
     * Prices and refund/fulfillment detail stay in get-order. Uncapped: a single
     * order won't realistically carry enough lines to bloat the payload.
     */
    private static function itemsSummary($order)
    {
        if (!$order->relationLoaded('order_items')) {
            return [];
        }

        $items = [];
        foreach ($order->order_items as $item) {
            $items[] = [
                'product_id' => (int) $item->post_id,
                'title'      => $item->getDisplayTitle(),
                'quantity'   => (int) $item->quantity,
            ];
        }

        return $items;
    }

    /** Human-readable one-liner: "Order INV-1042 — Jane Doe — $89.00 — paid". */
    private static function label($order, $customer)
    {
        $number = $order->invoice_no ? $order->invoice_no : ('#' . $order->id);
        $name   = $customer ? MCPHelper::personName($customer) : __('Guest', 'fluent-cart');
        $total  = MCPHelper::displayAmount((int) $order->total_amount, $order->currency);

        return sprintf(
            /* translators: 1: order number, 2: customer name, 3: order total, 4: payment status */
            __('Order %1$s — %2$s — %3$s — %4$s', 'fluent-cart'),
            $number,
            $name,
            $total,
            $order->payment_status
        );
    }

    // -----------------------------------------------------------------
    // get-order
    // -----------------------------------------------------------------

    public static function getOrder($params = [])
    {
        $order = self::resolveOrder($params);
        if (is_wp_error($order)) {
            return $order;
        }

        $include = isset($params['include']) ? (array) $params['include'] : [];

        $order->load('customer', 'order_items');

        $data = [
            'order_id'        => (int) $order->id,
            'uuid'            => $order->uuid,
            'number'          => $order->invoice_no,
            'receipt_number'  => $order->receipt_number,
            'status'          => $order->status,
            'payment_status'  => $order->payment_status,
            'shipping_status' => self::shippingStatusOut($order),
            'type'            => $order->type,
            'mode'            => $order->mode,
            'currency'        => $order->currency,
            'totals'          => self::totals($order),
            'customer'        => self::customerBlock($order),
            'items'           => self::itemsBlock($order),
            'created_at'      => MCPHelper::toIso8601($order->created_at),
            'completed_at'    => MCPHelper::toIso8601($order->completed_at),
            'refunded_at'     => self::refundedAt($order),
        ];

        if (in_array('addresses', $include, true)) {
            $data['addresses'] = self::addressesBlock($order);
        }
        if (in_array('transactions', $include, true)) {
            $data['transactions'] = self::transactionsBlock($order, false);
        }
        if (in_array('refunds', $include, true)) {
            $data['refunds'] = self::transactionsBlock($order, true);
        }
        if (in_array('coupons', $include, true)) {
            $data['coupons'] = self::couponsBlock($order);
        }
        if (in_array('subscriptions', $include, true)) {
            $data['subscriptions'] = self::subscriptionsBlock($order);
        }

        return MCPHelper::envelope(self::label($order, $order->customer), $data);
    }

    private static function resolveOrder($params)
    {
        if (!empty($params['order_id'])) {
            $order = Order::query()->where('id', (int) $params['order_id'])->first();
        } elseif (!empty($params['uuid'])) {
            $order = Order::query()->where('uuid', sanitize_text_field($params['uuid']))->first();
        } elseif (!empty($params['invoice_no'])) {
            $order = Order::query()->where('invoice_no', sanitize_text_field($params['invoice_no']))->first();
        } else {
            return MCPHelper::error(
                'missing_identifier',
                __('Provide order_id, uuid, or invoice_no.', 'fluent-cart'),
                ['fields' => ['order_id', 'uuid', 'invoice_no'], 'hint' => 'Use list-orders to find an order_id.']
            );
        }

        if (!$order) {
            return MCPHelper::error('order_not_found', __('No order found for the given identifier.', 'fluent-cart'));
        }

        return $order;
    }

    /** Full money breakdown — every line a money object (decimal + cents + display). */
    private static function totals($order)
    {
        $currency = $order->currency;
        return [
            'subtotal'              => MCPHelper::money($order->subtotal, $currency),
            'manual_discount_total' => MCPHelper::money($order->manual_discount_total, $currency),
            'coupon_discount_total' => MCPHelper::money($order->coupon_discount_total, $currency),
            'tax_total'             => MCPHelper::money($order->tax_total, $currency),
            'shipping_total'        => MCPHelper::money($order->shipping_total, $currency),
            'fee_total'             => MCPHelper::money($order->fee_total, $currency),
            'total_amount'          => MCPHelper::money($order->total_amount, $currency),
            'total_paid'            => MCPHelper::money($order->total_paid, $currency),
            'total_refund'          => MCPHelper::money($order->total_refund, $currency),
        ];
    }

    private static function customerBlock($order)
    {
        if (!$order->customer) {
            return null;
        }
        $c = $order->customer;
        return [
            'id'    => (int) $c->id,
            'name'  => MCPHelper::personName($c),
            'email' => $c->email,
        ];
    }

    private static function itemsBlock($order)
    {
        $items = [];
        if (!$order->relationLoaded('order_items')) {
            return $items;
        }
        foreach ($order->order_items as $item) {
            $items[] = [
                'id'            => (int) $item->id,
                'product_id'    => (int) $item->post_id,
                'variation_id'  => (int) $item->object_id,
                'title'         => $item->post_title ? $item->post_title : $item->title,
                'quantity'      => (int) $item->quantity,
                'fulfilled_qty' => (int) $item->fulfilled_quantity,
                'unit_price'    => MCPHelper::money($item->unit_price, $order->currency),
                'line_total'    => MCPHelper::money($item->line_total, $order->currency),
                'refund_total'  => MCPHelper::money($item->refund_total, $order->currency),
            ];
        }
        return $items;
    }

    private static function addressesBlock($order)
    {
        $order->load('order_addresses');
        $out = ['billing' => null, 'shipping' => null];
        if (!$order->relationLoaded('order_addresses')) {
            return $out;
        }
        foreach ($order->order_addresses as $addr) {
            $block = [
                'name'      => $addr->name,
                'address_1' => $addr->address_1,
                'address_2' => $addr->address_2,
                'city'      => $addr->city,
                'state'     => $addr->state,
                'postcode'  => $addr->postcode,
                'country'   => $addr->country,
                'phone'     => $addr->phone,
                'email'     => $addr->email,
            ];
            if ($addr->type === 'shipping') {
                $out['shipping'] = $block;
            } else {
                $out['billing'] = $block;
            }
        }
        return $out;
    }

    private static function transactionsBlock($order, $refundsOnly)
    {
        $order->load('transactions');
        $out = [];
        if (!$order->relationLoaded('transactions')) {
            return $out;
        }
        foreach ($order->transactions as $txn) {
            $isRefund = $txn->transaction_type === 'refund';
            if ($refundsOnly !== $isRefund) {
                continue;
            }
            $currency = $txn->currency ? $txn->currency : $order->currency;
            $out[] = [
                'id'               => (int) $txn->id,
                'type'             => $txn->transaction_type,
                'status'           => $txn->status,
                'payment_method'   => $txn->payment_method,
                'amount'           => MCPHelper::money($txn->total, $currency),
                'card_last_4'      => $txn->card_last_4,
                'card_brand'       => $txn->card_brand,
                'vendor_charge_id' => $txn->vendor_charge_id,
                'created_at'       => MCPHelper::toIso8601($txn->created_at),
            ];
        }
        return $out;
    }

    private static function couponsBlock($order)
    {
        $order->load('appliedCoupons');
        $out = [];
        if (!$order->relationLoaded('appliedCoupons')) {
            return $out;
        }
        foreach ($order->appliedCoupons as $coupon) {
            $out[] = [
                'code'   => $coupon->code,
                'amount' => MCPHelper::money($coupon->amount, $order->currency),
            ];
        }
        return $out;
    }

    private static function subscriptionsBlock($order)
    {
        $order->load('subscriptions');
        $out = [];
        if (!$order->relationLoaded('subscriptions')) {
            return $out;
        }
        foreach ($order->subscriptions as $sub) {
            $out[] = [
                'id'                => (int) $sub->id,
                'status'            => $sub->status,
                'item_name'         => $sub->item_name,
                'recurring_total'   => MCPHelper::money($sub->recurring_total, $order->currency),
                'billing_interval'  => $sub->billing_interval,
                'next_billing_date' => MCPHelper::toIso8601($sub->next_billing_date),
            ];
        }
        return $out;
    }

    // -----------------------------------------------------------------
    // get-order-activity
    // -----------------------------------------------------------------

    public static function getOrderActivity($params = [])
    {
        if (empty($params['order_id'])) {
            return MCPHelper::error('missing_identifier', __('order_id is required.', 'fluent-cart'));
        }

        $orderId = (int) $params['order_id'];
        $limit   = isset($params['limit']) ? min(max((int) $params['limit'], 1), 100) : 30;

        $order = Order::query()->where('id', $orderId)->first();
        if (!$order) {
            return MCPHelper::error('order_not_found', __('No order found for the given order_id.', 'fluent-cart'));
        }

        $events = [];

        // Logged activity: status changes, notes, emails — all written to
        // fct_activity. Fetch up to $limit; the merge below trims to $limit total.
        if (class_exists('\FluentCart\App\Models\Activity')) {
            $rows = \FluentCart\App\Models\Activity::query()
                ->where('module_id', $orderId)
                ->where(function ($q) {
                    $q->where('module_type', Order::class)->orWhere('module_name', 'order');
                })
                ->orderBy('id', 'DESC')
                ->limit($limit)
                ->get();

            foreach ($rows as $row) {
                $events[] = [
                    '_sort'          => (string) $row->created_at,
                    'event'          => self::activityEvent($row),
                    'source'         => 'activity',
                    'title'          => $row->title,
                    'status'         => $row->status,
                    'content'        => MCPHelper::htmlToText($row->content),
                    'by'             => $row->created_by,
                    'amount'         => null,
                    'payment_method' => null,
                    'reference'      => null,
                    'created_at'     => MCPHelper::toIso8601($row->created_at),
                ];
            }
        }

        // Money events: charges and refunds from the transactions ledger. These
        // are the payment/refund timeline entries the activity log doesn't carry.
        $order->load('transactions');
        if ($order->relationLoaded('transactions')) {
            foreach ($order->transactions as $txn) {
                $type  = $txn->transaction_type ? $txn->transaction_type : 'charge';
                $event = ($type === 'refund') ? 'refund' : (($type === 'charge') ? 'payment' : $type);
                $events[] = [
                    '_sort'          => (string) $txn->created_at,
                    'event'          => $event,
                    'source'         => 'transaction',
                    'title'          => self::txnTitle($type, $txn),
                    'status'         => $txn->status,
                    'content'        => null,
                    'by'             => null,
                    'amount'         => MCPHelper::money($txn->total, $txn->currency ? $txn->currency : null),
                    'payment_method' => $txn->payment_method ? $txn->payment_method : null,
                    'reference'      => $txn->vendor_charge_id ? $txn->vendor_charge_id : null,
                    'created_at'     => MCPHelper::toIso8601($txn->created_at),
                ];
            }
        }

        // Merge both streams most-recent-first, then cap at $limit.
        usort($events, function ($a, $b) {
            return strcmp($b['_sort'], $a['_sort']);
        });
        $events = array_slice($events, 0, $limit);
        foreach ($events as &$event) {
            unset($event['_sort']);
        }
        unset($event);

        return MCPHelper::envelope(
            sprintf(
                /* translators: 1: number of timeline entries, 2: order id */
                _n('%1$d timeline entry for order #%2$d.', '%1$d timeline entries for order #%2$d.', count($events), 'fluent-cart'),
                count($events),
                $orderId
            ),
            ['timeline' => $events]
        );
    }

    /** Classify an activity-log row into a coarse timeline event kind. */
    private static function activityEvent($row)
    {
        $title = strtolower((string) $row->title);
        if (strpos($title, 'email') !== false) {
            return 'email';
        }
        if (strpos($title, 'status') !== false || strpos($title, 'refund') !== false) {
            return 'status';
        }
        if ($row->log_type === 'api') {
            return 'api';
        }
        return 'note';
    }

    /** Human-readable title for a transaction timeline entry. */
    private static function txnTitle($type, $txn)
    {
        $method = $txn->payment_method ? $txn->payment_method : __('gateway', 'fluent-cart');
        if ($type === 'refund') {
            /* translators: 1: payment method, 2: status */
            return sprintf(__('Refund via %1$s — %2$s', 'fluent-cart'), $method, $txn->status);
        }
        if ($type === 'charge') {
            /* translators: 1: payment method, 2: status */
            return sprintf(__('Payment via %1$s — %2$s', 'fluent-cart'), $method, $txn->status);
        }
        /* translators: 1: transaction type, 2: payment method, 3: status */
        return sprintf(__('%1$s via %2$s — %3$s', 'fluent-cart'), $type, $method, $txn->status);
    }

    // -----------------------------------------------------------------
    // change-order-status (write)
    // -----------------------------------------------------------------

    public static function changeOrderStatus($params = [])
    {
        if (empty($params['order_id'])) {
            return MCPHelper::error('missing_identifier', __('order_id is required.', 'fluent-cart'));
        }
        $orderId = (int) $params['order_id'];
        $order   = Order::query()->where('id', $orderId)->first();
        if (!$order) {
            return MCPHelper::error('order_not_found', __('No order found for the given order_id.', 'fluent-cart'));
        }

        $targetOrderStatus = isset($params['order_status']) ? sanitize_text_field($params['order_status']) : null;
        $targetShipStatus  = isset($params['shipping_status']) ? sanitize_text_field($params['shipping_status']) : null;

        if ($targetOrderStatus === null && $targetShipStatus === null) {
            return MCPHelper::error('missing_param', __('Provide order_status and/or shipping_status.', 'fluent-cart'), ['fields' => ['order_status', 'shipping_status']]);
        }

        // Validate server-side against the statuses core actually accepts, so a
        // client that ignores the advertised enum gets a precise error rather
        // than a generic core rejection or a silent no-op.
        $editableOrder = array_keys(Status::getEditableOrderStatuses());
        if ($targetOrderStatus !== null && !in_array($targetOrderStatus, $editableOrder, true)) {
            return MCPHelper::error(
                'invalid_param',
                sprintf(
                    /* translators: 1: rejected status, 2: allowed statuses */
                    __('order_status "%1$s" cannot be set manually. Allowed: %2$s.', 'fluent-cart'),
                    $targetOrderStatus,
                    implode(', ', $editableOrder)
                ),
                ['fields' => ['order_status'], 'allowed' => $editableOrder]
            );
        }
        $editableShip = array_keys(Status::getEditableShippingStatuses());
        if ($targetShipStatus !== null && !in_array($targetShipStatus, $editableShip, true)) {
            return MCPHelper::error(
                'invalid_param',
                sprintf(
                    /* translators: 1: rejected status, 2: allowed statuses */
                    __('shipping_status "%1$s" is not settable. Allowed: %2$s.', 'fluent-cart'),
                    $targetShipStatus,
                    implode(', ', $editableShip)
                ),
                ['fields' => ['shipping_status'], 'allowed' => $editableShip]
            );
        }

        $changed   = [];
        $noChange  = [];
        $notApplied = [];

        if ($targetOrderStatus !== null) {
            if ($order->status === $targetOrderStatus) {
                $noChange[] = 'order_status';
            } else {
                $res = OrderResource::updateStatuses([
                    'order'    => $order,
                    'action'   => 'change_order_status',
                    'statuses' => ['order_status' => $targetOrderStatus],
                ]);
                if (is_wp_error($res)) {
                    return $res;
                }
                // Confirm the change actually took: core can no-op without error.
                $order = Order::query()->where('id', $orderId)->first();
                if ($order->status === $targetOrderStatus) {
                    $changed[] = 'order_status';
                } else {
                    $notApplied[] = 'order_status';
                }
            }
        }

        if ($targetShipStatus !== null) {
            $order = Order::query()->where('id', $orderId)->first();
            if ($order->shipping_status === $targetShipStatus) {
                $noChange[] = 'shipping_status';
            } else {
                $res = OrderResource::updateStatuses([
                    'order'    => $order,
                    'action'   => 'change_shipping_status',
                    'statuses' => ['shipping_status' => $targetShipStatus],
                ]);
                if (is_wp_error($res)) {
                    // Partial failure: report what already changed so the agent
                    // doesn't blindly re-apply the whole call (side effects fired).
                    if ($changed) {
                        $order = Order::query()->where('id', $orderId)->first();
                        return MCPHelper::error(
                            'partial_failure',
                            sprintf(
                                /* translators: 1: fields already changed, 2: error message */
                                __('Applied %1$s, but the shipping status change failed: %2$s. Do not re-run the whole call — retry only shipping_status.', 'fluent-cart'),
                                implode(', ', $changed),
                                $res->get_error_message()
                            ),
                            [
                                'order_id'        => $orderId,
                                'changed'         => $changed,
                                'failed'          => ['field' => 'shipping_status', 'error' => $res->get_error_message()],
                                'status'          => $order->status,
                                'shipping_status' => self::shippingStatusOut($order),
                            ]
                        );
                    }
                    return $res;
                }
                $order = Order::query()->where('id', $orderId)->first();
                if (self::shippingStatusOut($order) === $targetShipStatus) {
                    $changed[] = 'shipping_status';
                } else {
                    $notApplied[] = 'shipping_status';
                }
            }
        }

        $order = Order::query()->where('id', $orderId)->first();

        $summary = $changed
            ? sprintf(
                /* translators: 1: fields changed, 2: order id */
                __('Updated %1$s on order #%2$d.', 'fluent-cart'),
                implode(', ', $changed),
                $orderId
            )
            : __('No change — the order is already in the requested status.', 'fluent-cart');

        return MCPHelper::envelope($summary, [
            'order_id'        => $orderId,
            'status'          => $order->status,
            'shipping_status' => self::shippingStatusOut($order),
            'changed'         => $changed,
            'no_change'       => $noChange,
            'not_applied'     => $notApplied,
        ]);
    }

    // -----------------------------------------------------------------
    // add-order-note (write)
    // -----------------------------------------------------------------

    public static function addOrderNote($params = [])
    {
        if (empty($params['order_id']) || empty($params['note'])) {
            return MCPHelper::error('missing_param', __('order_id and note are required.', 'fluent-cart'), ['fields' => ['order_id', 'note']]);
        }
        $orderId = (int) $params['order_id'];
        $order   = Order::query()->where('id', $orderId)->first();
        if (!$order) {
            return MCPHelper::error('order_not_found', __('No order found for the given order_id.', 'fluent-cart'));
        }

        $note = wp_kses_post($params['note']);

        $log = fluent_cart_add_log(
            __('Note added via AI assistant', 'fluent-cart'),
            $note,
            'info',
            [
                'module_name' => 'order',
                'module_id'   => $orderId,
                'module_type' => Order::class,
                'log_type'    => 'activity',
            ]
        );

        // Confirm the activity row was actually written before claiming success.
        if (is_wp_error($log) || !is_object($log) || empty($log->id)) {
            return MCPHelper::error(
                'note_not_added',
                __('The note could not be saved to the order activity log.', 'fluent-cart'),
                ['order_id' => $orderId, 'retryable' => true]
            );
        }

        return MCPHelper::envelope(
            sprintf(
                /* translators: %d: order id */
                __('Note added to order #%d.', 'fluent-cart'),
                $orderId
            ),
            ['order_id' => $orderId, 'note_id' => (int) $log->id, 'note' => MCPHelper::htmlToText($note)]
        );
    }

    // -----------------------------------------------------------------
    // refund-order (write, destructive — dry_run + idempotency)
    // -----------------------------------------------------------------

    public static function refundOrder($params = [])
    {
        if (empty($params['order_id'])) {
            return MCPHelper::error('missing_identifier', __('order_id is required.', 'fluent-cart'));
        }
        $order = Order::query()->where('id', (int) $params['order_id'])->first();
        if (!$order) {
            return MCPHelper::error('order_not_found', __('No order found for the given order_id.', 'fluent-cart'));
        }
        if (!$order->canBeRefunded()) {
            return MCPHelper::error('not_refundable', __('This order cannot be refunded in its current state.', 'fluent-cart'), ['current_state' => ['payment_status' => $order->payment_status]]);
        }

        $remaining = (int) $order->total_paid - (int) $order->total_refund;
        if ($remaining <= 0) {
            return MCPHelper::error('nothing_to_refund', __('There is no remaining refundable balance on this order.', 'fluent-cart'));
        }

        if (!empty($params['transaction_id'])) {
            // Same constraints as the auto-select branch: an explicit id must
            // still be a succeeded charge on this order, never a failed/pending/
            // refund transaction.
            $txn = OrderTransaction::query()
                ->where('order_id', $order->id)
                ->where('id', (int) $params['transaction_id'])
                ->where('transaction_type', 'charge')
                ->where('status', 'succeeded')
                ->first();
        } else {
            $txn = OrderTransaction::query()
                ->where('order_id', $order->id)
                ->where('transaction_type', 'charge')
                ->where('status', 'succeeded')
                ->orderBy('id', 'DESC')
                ->first();
        }
        if (!$txn) {
            return MCPHelper::error('transaction_not_found', __('No refundable charge transaction was found on this order.', 'fluent-cart'));
        }

        $amountCents = isset($params['amount']) ? Helper::toCent($params['amount']) : $remaining;
        if ($amountCents <= 0) {
            return MCPHelper::error('invalid_amount', __('Refund amount must be greater than zero.', 'fluent-cart'));
        }
        if ($amountCents > $remaining) {
            return MCPHelper::error(
                'refund_exceeds_remaining',
                sprintf(
                    /* translators: 1: requested amount, 2: remaining refundable */
                    __('Refund %1$s exceeds the remaining refundable balance %2$s.', 'fluent-cart'),
                    MCPHelper::displayAmount($amountCents, $order->currency),
                    MCPHelper::displayAmount($remaining, $order->currency)
                ),
                ['current_state' => ['refundable_cents' => $remaining]]
            );
        }

        $tool        = 'fluent-cart/refund-order';
        $entityKey   = 'order:' . $order->id;
        // Bind the exact previewed mutation (amount + transaction) into the
        // fingerprint so a token minted for one amount can't confirm another.
        $fingerprint = 'paid:' . (int) $order->total_paid
            . '|refund:' . (int) $order->total_refund
            . '|amount:' . (int) $amountCents
            . '|txn:' . (int) $txn->id;

        if (!empty($params['dry_run'])) {
            return MCPHelper::envelope(
                sprintf(
                    /* translators: 1: amount to refund, 2: remaining refundable, 3: order id */
                    __('Preview: refund %1$s of %2$s remaining on order #%3$d.', 'fluent-cart'),
                    MCPHelper::displayAmount($amountCents, $order->currency),
                    MCPHelper::displayAmount($remaining, $order->currency),
                    (int) $order->id
                ),
                WriteGuard::preview($tool, $entityKey, $fingerprint, [
                    'order_id'            => (int) $order->id,
                    'refundable'          => MCPHelper::money($remaining, $order->currency),
                    'amount'              => MCPHelper::money($amountCents, $order->currency),
                    'transaction'         => ['id' => (int) $txn->id, 'payment_method' => $txn->payment_method, 'payment_mode' => $txn->payment_mode],
                    'live_gateway_action' => WriteGuard::isLiveMode($txn->payment_mode),
                ])
            );
        }

        $confirm = WriteGuard::confirm($tool, $entityKey, $fingerprint, isset($params['confirm_token']) ? $params['confirm_token'] : '');
        if (is_wp_error($confirm)) {
            return $confirm;
        }

        // Real-money guard: a live refund needs explicit opt-in (test always OK).
        $liveGate = WriteGuard::liveGatewayAllowed($txn->payment_mode);
        if (is_wp_error($liveGate)) {
            return $liveGate;
        }

        $reason  = isset($params['reason']) ? sanitize_text_field($params['reason']) : '';
        $idemKey = isset($params['idempotency_key']) ? (string) $params['idempotency_key'] : '';

        $result = WriteGuard::idempotent($tool, $entityKey, $idemKey, function () use ($txn, $amountCents, $reason) {
            return (new Refund())->processRefund($txn, $amountCents, ['reason' => $reason]);
        });

        if (is_wp_error($result)) {
            return $result;
        }

        $order = Order::query()->where('id', (int) $params['order_id'])->first();

        return MCPHelper::envelope(
            sprintf(
                /* translators: 1: refunded amount, 2: order id */
                __('Refunded %1$s on order #%2$d.', 'fluent-cart'),
                MCPHelper::displayAmount($amountCents, $order->currency),
                (int) $order->id
            ),
            [
                'order_id'       => (int) $order->id,
                'refunded'       => MCPHelper::money($amountCents, $order->currency),
                'payment_status' => $order->payment_status,
                'total_refund'   => MCPHelper::money($order->total_refund, $order->currency),
                'gateway_result' => is_array($result) ? array_intersect_key($result, array_flip(['vendor_refund_id', 'manual_refund'])) : null,
            ]
        );
    }

    // -----------------------------------------------------------------
    // helpers
    // -----------------------------------------------------------------

    private static function allowed($params, $key, array $allowed, $default)
    {
        $val = isset($params[$key]) ? $params[$key] : $default;
        return in_array($val, $allowed, true) ? $val : $default;
    }

    private static function total($paginator)
    {
        return MCPHelper::paginatorTotal($paginator);
    }

    private static function toDbDate($value)
    {
        try {
            return (new \DateTime((string) $value, new \DateTimeZone('UTC')))->format('Y-m-d H:i:s');
        } catch (\Exception $e) {
            // Return null so callers reject the input. An epoch fallback would
            // silently turn a typo'd date bound into an unbounded "match all".
            return null;
        }
    }

    private static function invalidDateError($field)
    {
        return MCPHelper::error(
            'invalid_date',
            sprintf(
                /* translators: 1: field name */
                __('%1$s is not a valid date. Use YYYY-MM-DD or ISO 8601.', 'fluent-cart'),
                $field
            ),
            ['fields' => [$field]]
        );
    }
}
