<?php

namespace app\common\service;

use app\common\logic\InvItemLogic;
use app\common\validate\InvItemValidate;
use app\common\traits\crud\CrudServiceTrait;
use app\common\model\InvItem;
use support\Request;
use support\exception\BusinessException;

class InvItemService
{

    use CrudServiceTrait;

    /**
     * 指定当前要操作的模型
     */
    protected string $modelClass = InvItem::class;

    /**
     * 验证器
     */
    protected $validator = InvItemValidate::class;

    protected $logic;

    public function __construct()
    {
        $this->logic = (new InvItemLogic());
    }
    /**
     * 获取验证器
     */
    public function getValidator()
    {
        return  new $this->validator;
    }

    /**
     * 构造 CrudUtil 查询配置
     */
    protected function buildQueryConfig(Request $request, string $scene = 'default'): array
    {
        $p = $request->all();

        $config = [];
        $config['model'] = $this->modelClass;
        switch ($scene) {
            case 'default':
                $config['where']['status'] = 1;
                $config['order']['sort'] = 'desc';
                $config['order']['id'] = 'desc';
                break;
            case 'index':
                $config['where']['status'] = 1;

                // 关键字
                if (isset($p['keyword']) && $p['keyword']) {
                    $k = '%' . $p['keyword'] . '%';
                    foreach (['item_name'] as $col) {
                        $config['orWhere'][] = [$col, 'like', $k];
                    }
                }

                $config['order']['sort'] = 'desc';
                $config['order']['id'] = 'desc';
                break;
            case 'show':
                $config['where']['id'] = $p['id'];
                $config['where']['status'] = 1;
                break;
            case 'store':
                break;
            case 'update':
                $config['where']['id'] = $p['id'];
                break;
            case 'destroy':
                $config['where']['id'] = $p['id'];
                break;
        }

        return $config;
    }

    /**
     * 生成 8-12 位的物品编码（默认10位）
     *
     * @param int $length 编码长度，默认为10（范围 8-12）
     * @return string     返回大写的字母数字组合编码
     */
    private function generateItemCode($length = 10)
    {
        // 排除易混淆字符：0, O, o, 1, I, l
        $chars = '23456789ABCDEFGHJKLMNPQRSTUVWXYZ';
        $code = '';
        $maxIndex = strlen($chars) - 1;

        for ($i = 0; $i < $length; $i++) {
            $code .= $chars[mt_rand(0, $maxIndex)];
        }

        return $code;
    }


    public function beforeServiceStore($data, Request $request): array
    {
        $data['item_code'] = $this->generateItemCode();
        $data['category_id'] = 0;
        $data['spec_model'] = '';
        $data['unit'] = '件';
        $data['is_consumable'] = 0;
        $data['stock_qty'] = 1;
        $data['location'] = '';
        return $data;
    }


    /**
     * 变动物品库存数量
     *
     * @param int  $itemId        物品ID
     * @param int  $changeQty     变动数量：>0 入库，<0 出库
     * @param bool $allowNegative 是否允许库存变成负数，默认不允许
     *
     * @return InvItem            最新的物品记录
     * @throws BusinessException
     */
    public function changeStock(int $itemId, int $changeQty, bool $allowNegative = false): InvItem
    {
        if ($changeQty === 0) {
            throw new BusinessException('库存变动数量不能为 0');
        }

        $now = time();

        // 构建查询
        $query = InvItem::query()->where('id', $itemId);

        // 如果不允许负数，并且是出库场景（变动为负）
        if (! $allowNegative && $changeQty < 0) {
            // 要保证：当前 stock_qty >= 出库数量
            $query->where('stock_qty', '>=', -$changeQty);
        }

        // 使用 increment 实现：UPDATE inv_item SET stock_qty = stock_qty + ?, updated_at = ? WHERE ...
        $affected = $query->increment('stock_qty', $changeQty, [
            'updated_at' => $now,
        ]);

        if ($affected === 0) {
            // 更新不到行：
            // 1) 物品不存在
            // 2) 或者库存不足（不允许负数时）
            $exists = InvItem::query()->where('id', $itemId)->exists();
            if (! $exists) {
                throw new BusinessException('物品不存在');
            }
            throw new BusinessException('库存不足，无法完成库存变动');
        }

        // 再查一次最新数据返回（在外层事务中也会保持一致）
        /** @var InvItem $item */
        $item = InvItem::query()->find($itemId);
        return $item;
    }

    /**
     * 出库（减库存，默认不允许负数）
     */
    public function stockOut(int $itemId, int $qty, bool $allowNegative = false): InvItem
    {
        if ($qty <= 0) {
            throw new BusinessException('出库数量必须大于 0');
        }
        return $this->changeStock($itemId, -$qty, $allowNegative);
    }

    /**
     * 入库（加库存）
     */
    public function stockIn(int $itemId, int $qty): InvItem
    {
        if ($qty <= 0) {
            throw new BusinessException('入库数量必须大于 0');
        }
        return $this->changeStock($itemId, $qty, true);
    }

    /**
     * 获取车型list
     */
    public function getList()
    {
        return $this->logic->getList();
    }
}