<?php
namespace App\Http\Controllers;

use App\Models\Goods;
use App\Models\Brand;
use App\Models\Supplier;
use Illuminate\Http\Request;
use Illuminate\Support\Facades\DB;
use Illuminate\Support\Str;

class GoodsController extends Controller
{
    /**
     * 商品列表
     */
    public function index(Request $request)
    {
        $query = Goods::with(['brand', 'suppliers']);

        // 搜索
        if ($request->filled('keyword')) {
            $keyword = $request->keyword;
            $query->where(function ($q) use ($keyword) {
                $q->where('name', 'like', "%{$keyword}%")
                  ->orWhere('code', 'like', "%{$keyword}%")
                  ->orWhere('barcode', 'like', "%{$keyword}%");
            });
        }

        // 类型筛选
        if ($request->filled('type')) {
            $query->where('type', $request->type);
        }

        // 品牌筛选
        if ($request->filled('brand_id')) {
            $query->where('brand_id', $request->brand_id);
        }

        $perPage = $request->input('limit', 15);
        $goods = $query->orderBy('created_at', 'desc')->paginate($perPage);

        // 格式化数据
        $goods->getCollection()->transform(function ($item) {
            return [
                'id' => $item->id,
                'name' => $item->name,
                'code' => $item->code,
                'barcode' => $item->barcode,
                'type' => $item->type,
                'type_label' => $item->type == 'normal' ? '普通商品' : '组套商品',
                'retail_price' => $item->retail_price,
                'cost_price' => $item->cost_price,
                'unit' => $item->unit,
                'brand' => $item->brand ? ['id' => $item->brand->id, 'name' => $item->brand->name] : null,
                'suppliers' => $item->suppliers->map(function ($s) {
                    return ['id' => $s->id, 'name' => $s->name];
                }),
                'weight' => $item->weight,
                'packaging_cost' => $item->packaging_cost,
                'shipping_packaging_cost' => $item->shipping_packaging_cost,
                'volume' => $item->volume,
                'length' => $item->length,
                'width' => $item->width,
                'height' => $item->height,
                'batch_management' => $item->batch_management,
                'created_at' => $item->created_at,
                'updated_at' => $item->updated_at,
            ];
        });

        return response()->json([
            'code' => 200,
            'data' => [
                'list' => $goods->items(),
                'total' => $goods->total(),
                'current_page' => $goods->currentPage(),
                'last_page' => $goods->lastPage(),
            ],
            'message' => 'success'
        ]);
    }

    /**
     * 获取所有商品（用于下拉选择）
     */
    public function all(Request $request)
    {
        $query = Goods::select('id', 'name', 'code', 'retail_price', 'cost_price', 'type');

        if ($request->filled('type')) {
            $query->where('type', $request->type);
        }

        $goods = $query->get();
        return response()->json([
            'code' => 200,
            'data' => $goods,
            'message' => 'success'
        ]);
    }

    /**
     * 商品详情
     */
    public function show($id)
    {
        $goods = Goods::with(['brand', 'suppliers', 'comboItems.goods'])->findOrFail($id);

        $data = [
            'id' => $goods->id,
            'name' => $goods->name,
            'code' => $goods->code,
            'barcode' => $goods->barcode,
            'category' => $goods->category,
            'unit' => $goods->unit,
            'weight' => $goods->weight,
            'retail_price' => $goods->retail_price,
            'cost_price' => $goods->cost_price,
            'stock_warning' => $goods->stock_warning,
            'type' => $goods->type,
            'custom_id' => $goods->custom_id,
            'packaging_cost' => $goods->packaging_cost,
            'shipping_packaging_cost' => $goods->shipping_packaging_cost,
            'volume' => $goods->volume,
            'length' => $goods->length,
            'width' => $goods->width,
            'height' => $goods->height,
            'brand_id' => $goods->brand_id,
            'brand' => $goods->brand ? ['id' => $goods->brand->id, 'name' => $goods->brand->name] : null,
            'suppliers' => $goods->suppliers->map(function ($s) {
                return ['id' => $s->id, 'name' => $s->name];
            }),
            'batch_management' => $goods->batch_management,
        ];

        if ($goods->type == 'combo') {
            $data['combo_items'] = $goods->comboItems->map(function ($item) {
                return [
                    'goods_id' => $item->goods_id,
                    'goods_name' => $item->goods->name,
                    'goods_code' => $item->goods->code,
                    'quantity' => $item->quantity,
                ];
            });
        }

        return response()->json([
            'code' => 200,
            'data' => $data,
            'message' => 'success'
        ]);
    }

    /**
     * 创建商品
     */
    public function store(Request $request)
    {
        $rules = [
            'name' => 'required|string|max:255',
            'barcode' => 'nullable|string|max:100',
            'type' => 'required|in:normal,combo',
            'unit' => 'required|string|max:20',
            'retail_price' => 'required|numeric|min:0',
            'cost_price' => 'required|numeric|min:0',
            'weight' => 'nullable|numeric|min:0',
            'packaging_cost' => 'nullable|numeric|min:0',
            'shipping_packaging_cost' => 'nullable|numeric|min:0',
            'volume' => 'nullable|numeric|min:0',
            'length' => 'nullable|numeric|min:0',
            'width' => 'nullable|numeric|min:0',
            'height' => 'nullable|numeric|min:0',
            'brand_id' => 'nullable|exists:brands,id',
            'supplier_ids' => 'nullable|array',
            'supplier_ids.*' => 'exists:suppliers,id',
            'batch_management' => 'nullable|boolean',
            'custom_id' => 'nullable|string|max:100',
            'category' => 'nullable|string|max:50',
            'stock_warning' => 'nullable|integer|min:0',
        ];

        // 如果是组套商品，需要验证组合项
        if ($request->type == 'combo') {
            $rules['combo_items'] = 'required|array|min:1';
            $rules['combo_items.*.goods_id'] = 'required|exists:goods,id';
            $rules['combo_items.*.quantity'] = 'required|integer|min:1';
        }

        $request->validate($rules);

        // 自动生成商品编码（如果未提供）
        $code = $request->code;
        if (!$code) {
            $code = $this->generateGoodsCode();
        } else {
            // 检查唯一性
            if (Goods::where('code', $code)->exists()) {
                return response()->json(['code' => 400, 'message' => '商品编码已存在'], 400);
            }
        }

        try {
            DB::beginTransaction();

            $goods = Goods::create([
                'name' => $request->name,
                'code' => $code,
                'barcode' => $request->barcode,
                'category' => $request->category,
                'unit' => $request->unit,
                'weight' => $request->weight ?? 0,
                'retail_price' => $request->retail_price,
                'cost_price' => $request->cost_price,
                'stock_warning' => $request->stock_warning ?? 0,
                'type' => $request->type,
                'custom_id' => $request->custom_id,
                'packaging_cost' => $request->packaging_cost ?? 0,
                'shipping_packaging_cost' => $request->shipping_packaging_cost ?? 0,
                'volume' => $request->volume ?? 0,
                'length' => $request->length ?? 0,
                'width' => $request->width ?? 0,
                'height' => $request->height ?? 0,
                'brand_id' => $request->brand_id,
                'batch_management' => $request->batch_management ?? false,
            ]);

            // 关联供应商
            if ($request->has('supplier_ids')) {
                $goods->suppliers()->sync($request->supplier_ids);
            }

            // 如果是组套商品，添加组合项
            if ($request->type == 'combo' && $request->has('combo_items')) {
                foreach ($request->combo_items as $item) {
                    // 检查子商品不能是组套商品（避免嵌套）
                    $childGoods = Goods::find($item['goods_id']);
                    if ($childGoods->type == 'combo') {
                        throw new \Exception('组合商品不能包含另一个组合商品');
                    }
                    $goods->comboItems()->create([
                        'goods_id' => $item['goods_id'],
                        'quantity' => $item['quantity'],
                    ]);
                }
            }

            DB::commit();

            return response()->json([
                'code' => 200,
                'data' => ['id' => $goods->id],
                'message' => '创建成功'
            ]);
        } catch (\Exception $e) {
            DB::rollBack();
            return response()->json([
                'code' => 500,
                'message' => '创建失败：' . $e->getMessage()
            ], 500);
        }
    }

    /**
     * 更新商品
     */
    public function update(Request $request, $id)
    {
        $goods = Goods::findOrFail($id);

        $rules = [
            'name' => 'sometimes|required|string|max:255',
            'barcode' => 'sometimes|required|string|max:100',
            'type' => 'sometimes|required|in:normal,combo',
            'unit' => 'sometimes|required|string|max:20',
            'retail_price' => 'sometimes|required|numeric|min:0',
            'cost_price' => 'sometimes|required|numeric|min:0',
            'weight' => 'nullable|numeric|min:0',
            'packaging_cost' => 'nullable|numeric|min:0',
            'shipping_packaging_cost' => 'nullable|numeric|min:0',
            'volume' => 'nullable|numeric|min:0',
            'length' => 'nullable|numeric|min:0',
            'width' => 'nullable|numeric|min:0',
            'height' => 'nullable|numeric|min:0',
            'brand_id' => 'nullable|exists:brands,id',
            'supplier_ids' => 'nullable|array',
            'supplier_ids.*' => 'exists:suppliers,id',
            'batch_management' => 'nullable|boolean',
            'custom_id' => 'nullable|string|max:100',
            'category' => 'nullable|string|max:50',
            'stock_warning' => 'nullable|integer|min:0',
        ];

        if ($request->has('code') && $request->code != $goods->code) {
            $rules['code'] = 'required|string|unique:goods,code,' . $id;
        }

        if ($request->type == 'combo') {
            $rules['combo_items'] = 'sometimes|array|min:1';
            $rules['combo_items.*.goods_id'] = 'required|exists:goods,id';
            $rules['combo_items.*.quantity'] = 'required|integer|min:1';
        }

        $request->validate($rules);

        try {
            DB::beginTransaction();

            $updateData = $request->only([
                'name', 'code', 'barcode', 'category', 'unit', 'weight',
                'retail_price', 'cost_price', 'stock_warning', 'type',
                'custom_id', 'packaging_cost', 'shipping_packaging_cost',
                'volume', 'length', 'width', 'height', 'brand_id', 'batch_management'
            ]);
            $goods->update($updateData);

            // 更新供应商关联
            if ($request->has('supplier_ids')) {
                $goods->suppliers()->sync($request->supplier_ids);
            }

            // 更新组合项（如果类型是组套）
            if ($request->type == 'combo') {
                if ($request->has('combo_items')) {
                    // 删除旧的组合项
                    $goods->comboItems()->delete();
                    // 添加新的
                    foreach ($request->combo_items as $item) {
                        $childGoods = Goods::find($item['goods_id']);
                        if ($childGoods->type == 'combo') {
                            throw new \Exception('组合商品不能包含另一个组合商品');
                        }
                        $goods->comboItems()->create([
                            'goods_id' => $item['goods_id'],
                            'quantity' => $item['quantity'],
                        ]);
                    }
                }
            } else {
                // 如果是普通商品，删除所有组合项
                $goods->comboItems()->delete();
            }

            DB::commit();

            return response()->json([
                'code' => 200,
                'message' => '更新成功'
            ]);
        } catch (\Exception $e) {
            DB::rollBack();
            return response()->json([
                'code' => 500,
                'message' => '更新失败：' . $e->getMessage()
            ], 500);
        }
    }

    /**
     * 删除商品
     */
    public function destroy($id)
    {
        $goods = Goods::findOrFail($id);
        // 检查是否被组合商品引用
        if ($goods->parentCombos()->exists()) {
            return response()->json([
                'code' => 400,
                'message' => '该商品已被组合商品引用，无法删除'
            ], 400);
        }
        $goods->delete();
        return response()->json([
            'code' => 200,
            'message' => '删除成功'
        ]);
    }

    /**
     * 生成商品编码
     */
    private function generateGoodsCode()
    {
        $prefix = 'G';
        $date = date('Ymd');
        $last = Goods::where('code', 'like', $prefix . $date . '%')
                     ->orderBy('code', 'desc')
                     ->first();
        if ($last) {
            $num = intval(substr($last->code, -4)) + 1;
        } else {
            $num = 1;
        }
        return $prefix . $date . str_pad($num, 4, '0', STR_PAD_LEFT);
    }
}