<?php

namespace App\Exports;

use App\Models\ProductCategoryModel;
use App\Models\ProductModel;
use App\Models\PurchaseOrderModel;
use App\Models\StoreModel;
use App\Models\StoreOrderItemModel;
use App\Models\SupplierModel;
use App\Services\PurchaseEditService;
use Illuminate\Support\Collection;
use Maatwebsite\Excel\Concerns\FromCollection;
use Maatwebsite\Excel\Concerns\WithHeadings;
use Maatwebsite\Excel\Concerns\WithMapping;
use Maatwebsite\Excel\Concerns\WithStyles;
use PhpOffice\PhpSpreadsheet\Worksheet\Worksheet;

/**
 * 采购单导出（C2 全品类按分类 sort 排序 / C3 仅蔬果分类）
 * 数据源为订货明细按商品聚合（无独立采购明细表），每门店一列显示数量
 */
class PurchaseOrderExport implements FromCollection, WithHeadings, WithMapping, WithStyles
{
    /** @var array<int, string> 商品ID => 顶级分类名 */
    private array $categoryNames = [];

    /** @var array<int, string> 供应商ID => 名称 */
    private array $supplierNames = [];

    /** @var array<int, string> 门店ID => 名称（导出列） */
    private array $storeNames = [];

    private ?Collection $items = null;

    /**
     * @param PurchaseOrderModel $purchase 采购单
     * @param string $type all 全品类 / category 仅蔬果分类
     */
    public function __construct(
        private readonly PurchaseOrderModel $purchase,
        private readonly string $type = 'all',
    ) {
    }

    /**
     * 导出行（商品聚合行，按 分类sort → 商品sort 排序；蔬果分类时按顶级分类名过滤）
     */
    public function collection(): Collection
    {
        if ($this->items !== null) {
            return $this->items;
        }

        $orderItems = StoreOrderItemModel::query()
            ->join('store_order', 'store_order.id', '=', 'store_order_item.order_id')
            ->where('store_order_item.purchase_id', $this->purchase->id)
            ->whereNull('store_order.deleted_at')
            ->select('store_order_item.*')
            ->get()
            ->makeVisible('cost_price');

        $this->storeNames = StoreModel::withTrashed()
            ->whereIn('id', $orderItems->pluck('store_id')->unique())
            ->pluck('name', 'id')
            ->toArray();

        $products = ProductModel::withTrashed()
            ->with('category:id,sort')
            ->whereIn('id', $orderItems->pluck('product_id')->unique())
            ->get()
            ->keyBy('id');

        $rows = [];
        foreach ($orderItems->groupBy('product_id') as $productId => $group) {
            $first = $group->first();
            $product = $products->get((int) $productId);
            $unitCost = PurchaseEditService::unitCost((string) ($first->cost_price ?? '0'), (string) $first->product_spec);

            $quantity = '0';
            $weight = '0';
            $amount = '0';
            $storeQuantities = array_fill_keys(array_keys($this->storeNames), '0');
            foreach ($group as $item) {
                $quantity = bcadd($quantity, (string) $item->quantity, 2);
                $weight = bcadd($weight, (string) $item->weight, 3);
                $amount = bcadd($amount, PurchaseEditService::costAmount(
                    (string) $item->quantity,
                    (string) $item->weight,
                    $unitCost
                ), 2);
                $storeQuantities[(int) $item->store_id] = bcadd(
                    $storeQuantities[(int) $item->store_id] ?? '0',
                    (string) $item->quantity,
                    2
                );
            }

            $rows[] = [
                'product_id' => (int) $productId,
                'supplier_id' => (int) $first->supplier_id,
                'product_name' => $first->product_name,
                'product_spec' => $first->product_spec,
                'unit' => $first->unit,
                'cost_price' => (float) ($first->cost_price ?? 0),
                'unit_cost' => (float) $unitCost,
                'quantity' => (float) $quantity,
                'weight' => (float) $weight,
                'amount' => (float) $amount,
                'store_quantities' => array_map('floatval', $storeQuantities),
                'category_sort' => (int) ($product->category->sort ?? 9999),
                'product_sort' => (int) ($product->sort ?? 9999),
            ];
        }
        usort($rows, static fn (array $a, array $b): int =>
            [$a['category_sort'], $a['product_sort'], $a['product_id']]
            <=> [$b['category_sort'], $b['product_sort'], $b['product_id']]);

        $items = collect($rows);
        $this->loadLookups($items);

        if ($this->type === 'category') {
            $items = $items->filter(function (array $row): bool {
                $rootName = $this->categoryNames[$row['product_id']] ?? '';
                return str_contains($rootName, '蔬菜') || str_contains($rootName, '水果');
            })->values();
        }

        $sort = 1;
        return $this->items = $items->map(static function (array $row) use (&$sort): array {
            $row['sort'] = $sort++;
            return $row;
        })->values();
    }

    public function headings(): array
    {
        $this->collection();

        return array_merge(
            ['序号', '分类', '品名', '供应商', '包规', '单位', '成本', '单价', '数量', '实际称重', '金额'],
            array_map(static fn (string $name): string => $name . '（数量）', array_values($this->storeNames)),
        );
    }

    public function map($row): array
    {
        return array_merge([
            $row['sort'],
            $this->categoryNames[$row['product_id']] ?? '',
            $row['product_name'],
            $this->supplierNames[$row['supplier_id']] ?? '',
            $row['product_spec'],
            $row['unit'],
            $row['cost_price'],
            $row['unit_cost'],
            $row['quantity'],
            $row['weight'],
            $row['amount'],
        ], array_values($row['store_quantities']));
    }

    /**
     * 表头加粗 + 冻结首行
     */
    public function styles(Worksheet $sheet): array
    {
        $sheet->freezePane('A2');

        return [
            1 => ['font' => ['bold' => true]],
        ];
    }

    /**
     * PDF 模板视图数据
     *
     * @return array{purchase: PurchaseOrderModel, items: Collection, storeNames: array<int, string>, categoryNames: array<int, string>, supplierNames: array<int, string>}
     */
    public function viewData(): array
    {
        return [
            'purchase' => $this->purchase,
            'items' => $this->collection(),
            'storeNames' => $this->storeNames,
            'categoryNames' => $this->categoryNames,
            'supplierNames' => $this->supplierNames,
        ];
    }

    /**
     * 预加载供应商名与商品顶级分类名（商品/供应商均含软删除，保证历史单据可导出）
     */
    private function loadLookups(Collection $items): void
    {
        $this->supplierNames = SupplierModel::withTrashed()
            ->whereIn('id', $items->pluck('supplier_id')->unique())
            ->pluck('name', 'id')
            ->toArray();

        $productCategoryIds = ProductModel::withTrashed()
            ->whereIn('id', $items->pluck('product_id')->unique())
            ->pluck('category_id', 'id');

        $categories = ProductCategoryModel::all()->keyBy('id');
        $this->categoryNames = [];
        foreach ($productCategoryIds as $productId => $categoryId) {
            $rootName = '';
            $cursor = (int) $categoryId;
            $guard = 0;
            while ($cursor > 0 && $guard++ < 20) {
                $category = $categories->get($cursor);
                if ($category === null) {
                    break;
                }
                $rootName = $category->name;
                $cursor = (int) $category->parent_id;
            }
            $this->categoryNames[(int) $productId] = $rootName;
        }
    }
}