<?php namespace App\Services;

use App\Models\Warehouse;
use Illuminate\Support\Facades\DB;

/**
 * Servicio para gestión de almacenes
 */
class WarehouseService
{
    /**
     * Obtener almacén principal
     */
    public function getMainWarehouse(): ?Warehouse
    {
        return Warehouse::main()->first();
    }

    /**
     * Actualizar almacén
     */
    public function updateWarehouse(Warehouse $warehouse, array $data): Warehouse
    {
        return DB::transaction(function () use ($warehouse, $data) {
            // Si se marca como principal, desactivar otros principales
            if (isset($data['is_main']) && $data['is_main']) {
                Warehouse::where('id', '!=', $warehouse->id)
                    ->where('is_main', true)
                    ->update(['is_main' => false]);
            }

            // No permitir desactivar el último almacén principal
            if (isset($data['is_main']) && !$data['is_main'] && $warehouse->is_main) {
                if (Warehouse::main()->count() === 1) {
                    throw new \Exception('No se puede desactivar el único almacén principal. Asigna otro almacén como principal primero.');
                }
            }

            $warehouse->update($data);
            return $warehouse->fresh();
        });
    }

    /**
     * Activar/Desactivar almacén
     */
    public function toggleActive(Warehouse $warehouse): Warehouse
    {
        // No permitir desactivar el almacén principal
        if ($warehouse->is_main && $warehouse->is_active) {
            throw new \Exception('No se puede desactivar el almacén principal.');
        }

        $warehouse->update(['is_active' => !$warehouse->is_active]);
        return $warehouse->fresh();
    }

    /**
     * Obtener stock de un almacén
     */
    public function getWarehouseStock(Warehouse $warehouse)
    {
        return $warehouse->inventories()
            ->with(['category', 'price'])
            ->select('inventories.*')
            ->get()
            ->map(function ($inventory) use ($warehouse) {
                $pivot = $inventory->warehouses()
                    ->where('warehouse_id', $warehouse->id)
                    ->first();

                return [
                    'inventory_id' => $inventory->id,
                    'name' => $inventory->name,
                    'sku' => $inventory->sku,
                    'category' => $inventory->category?->name,
                    'stock' => $pivot?->pivot->stock ?? 0,
                    'min_stock' => $pivot?->pivot->min_stock,
                    'max_stock' => $pivot?->pivot->max_stock,
                    'cost' => $inventory->price?->cost,
                    'retail_price' => $inventory->price?->retail_price,
                ];
            });
    }

    /**
     * Validar que existe almacén principal
     */
    public function ensureMainWarehouse(): void
    {
        if (!Warehouse::main()->exists()) {
            throw new \Exception('No existe un almacén principal configurado.');
        }
    }
}