<?php

use Illuminate\Database\Migrations\Migration;
use Illuminate\Database\Schema\Blueprint;
use Illuminate\Support\Facades\Schema;

return new class extends Migration
{
    public function up(): void
    {
        Schema::create('stocks', function (Blueprint $table) {
            $table->id();
            $table->string('sku_code')->index()->comment('商品编码');
            $table->string('sku_name')->comment('商品名称（冗余）');
            $table->foreignId('warehouse_id')->constrained()->onDelete('cascade');
            $table->integer('quantity')->default(0)->comment('实际库存');
            $table->integer('locked_quantity')->default(0)->comment('锁定库存');
            $table->integer('available_quantity')->storedAs('quantity - locked_quantity')->comment('可用库存（计算字段）');
            $table->integer('warning_threshold')->default(0)->comment('预警阈值');
            $table->timestamps();

            $table->unique(['sku_code', 'warehouse_id']);
        });
    }

    public function down(): void
    {
        Schema::dropIfExists('stocks');
    }
};